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. 2025 Jun 20;15:20175. doi: 10.1038/s41598-025-05836-x

Multidimensional insights of electrochemical and quantum investigations of morpholinium cationic surfactants as corrosion inhibitors for carbon steel in acidic solution

A Elaraby 1,, Doaa F Seyam 2,, Sherine A Abdelkader 3
PMCID: PMC12181321  PMID: 40542061

Abstract

Three novel morpholinium-cationic surfactants (coded: DCSM-8, DCSM-10, and DCSM-12) with chemical structure confirmed via FT-IR, HNMR, and mass analysis were applied for carbon steel (CS) corrosion control in acidic 4 M HCl solution. The investigated compounds decreased water surface tension (72 mN.m-1) to 19.85 mN.m-1 after the addition of DCSM-12. The surfactants mitigation performance was assessed via weight loss (WL), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The synthesized surfactants protected CS efficiently with higher inhibition efficiencies up to 97.029% at 1 × 10–3 M for DCSM-12 using PDP which also indicated that, the prepared surfactants inhibited both CS anodic and cathodic sites with cathodic dominant. EIS data showed higher CS resistance from 35.24 Ω.cm2 to 1245.54 Ω.cm2 after addition of 1 × 10–3 M for DCSM-12 with mitigation potency 97.17% which can be attributed to their adsorption process over CS surface forming a protective film layer that followed Langmuir adsorption isotherm reflecting the chemical adsorption affinity of the prepared mitigators with higher adsorption energy (ΔG*ads) values (> -40 kJ.mol-1). Also, the protection effect of the prepared inhibitor (DCSM-12) was confirmed using SEM (scanning electron microscopy) and EDX (energy-dispersive X-ray) showing improvement in CS surface morphology. The reactivity of the prepared surfactants and their mitigation role in CS deterioration were confirmed theoretically using DFT (density functional theory) and MCs (Monte Carlo simulations).

Keywords: Cationic surfactant, Surface tension, EIS, Quantum investigations

Subject terms: Corrosion, Quantum chemistry

Introduction

Sudden failure of materials in several industries is usually caused by acids which are severe to metals1. UNS G10300 steel is a medium carbon steel that contains carbon from 0.30% to 2.0% and is characterized by its higher strength, extreme hardness, and wear resistance which make it suitable for manufacturing machinery parts24. This kind of steel suffers from severe corrosion in acidic solutions or marine environment due to its higher content of pearlite than that in low carbon steel. Pearlite is made up of ferrite and cementite which considered a galvanic microcell inside the structure itself, in the existence of corrosive environment ferrite acts as anode and cementite acts as cathode5. Surfactants were used for CS protection against corrosion process in acidic medium due to the existence of heteroatoms like Nitrogen, Oxygen, Phosphorous, Sulphur, and/or functionalities with pi electrons which act as adsorption sites onto metal surface film68. Cationic surfactants are widely used in many applications such as corrosion inhibitors, emulsifiers, wetting agents, and lubricants due to their lower critical micelle concentration, lower surface energy, better physicochemical characteristics and higher solubilization capacity911. Their higher surface activity form very strong electrostatic bonds with metal surfaces. The main structure of cationic surfactants consists of two positive hydrophilic head linked with hydrophobic chain1214. Most modifications on cationic surfactants have been focused on varying the hydrophobic tail, hydrophilic headgroup, and spacer group in cased of Gemini surfactant by introducing groups such as phenyl or hydrazide, etc. that increase its surface activity and its application as corrosion inhibitors1517. Today, the use of strong acids is an important source of promoting petroleum well productivity. Hydrochloric acid (HCl) is injected into the pipelines to remove the scale layers from their surface. During acid washing, the strong acid causes severe corrosion in the steel pipe wall, reducing the pipe’s strength and resulting in material destruction1820. In economic terms, the huge damage resulted from the corrosion process in petroleum field is more than 3% of the Press Information Bureau (PIB) in the USA. The annual direct cost of metallic corrosion ranges from 2 to 4% of the gross domestic product (GDP) in industrialized countries, and the trend is becoming higher and higher in the future2123.

Guangqiang Xia et al.24 evaluated the mitigation power of N-alkyl-3-(2-methoxycarbonyl-vinyl)pyridinium-bromide (MPA-n, n = 8–14) inhibitors using various multi measurements as WL, PDP, EIS, SEM, and EDX showing that, the prepared MPA-n inhibited X70 steel from corrosion in 5 M HCl with inhibition efficiency 96.8% and the inhibition capacity was in the order of MPA-14 > MPA-12 > MPA-10 > MPA-8. Dingli et al.25studied the application of two cationic surfactants coded DBBD and QBBD as corrosion mitigators for mild steel in 15% HCl using various measurements including weight loss, electrochemical measurements, scanning kelvin probe (SKP), scanning electron microscope (SEM) and theoretical calculations showing the mitigation power of the prepared mitigators for mild steel corrosion with inhibition potency 95.03 and 97.98 for DBBD and QBBD respectively. M. A. Deyab et al.26 investigated the anti-corrosion properties of cationic Gemini surfactant (DMAEB) for N80 C-steel pipe in acid washing solution (15.0% HCl) via gravimetric measurement and potentiodynamic polarization techniques which both confirmed the inhibition performance of the studied mitigators through their adsorption process with mitigation competence efficiency reached 96.8%. A unique kind of conventional surfactant known as a “Cationic Surfactant” has two polar and two non-polar groups that are separated by a spacer21,22. This type’s advantages over traditional types include high solubilizing capacity, greatest reduction of surface tension, significant inhibitory efficacy, and low toxicity. Lately various cationic surfactants showed their excellent inhibition against corrosion due to their positive end which is always a quaternary ammonium27,28. Cationic surfactants, to the greatest extent of our understanding, have recently been widely used as metal corrosion inhibitors in environment with variable concentrations of HCl, although it has been claimed that these kinds of substances have only sometimes been used in oil field wells29.

The novelty in this study is exploring economical, cost-effective, low-toxic, and readily three newly di-cationic surfactants (DCSM-8, DCSM-10, and DCSM-12) based on morpholine containing two polar morpholine heads with ester, hydroxyl and ether groups which facilitate the interaction between the adsorption center of the prepared inhibitors and the empty d-orbital of iron forming a protective barrier layer consequently, mitigate CS (UNS G10300) corrosion even at very low concentrations in highly aggressive medium (4 M HCl). In practical applications, it is ideal to provide high protection with a low inhibitor dosage for economical applications. a wide range of concentrations of the inhibitor was used for more comprehensive study starting with lower concentration (1×10–6 M) to higher concentration (1×10–3 M) showing inhibition efficiency increased till reach 97.029% in the presence of DCSM-12. The studied DCSM-8, DCSM-10, and DCSM-12 with good surface-active parameters were prepared through simple chemical reactions and confirmed using FT-IR,1HNMR and Mass spectrum. It is worthwhile to notice that, the prepared cationic surfactants appear to have a good solubility in polar solvents such as water, methanol, ethanol and acetone. The mitigation power of the prepared DCSM-8, DCSM-10, and DCSM-12 was investigated using various techniques as WL, PDP, and EIS besides CS surface examination via SEM and EDX were applied. Also, the surface-active parameters of the prepared surfactants showed that, both linked di-functionalized morpholine heads with the accompanying hydrophobic chains have an excellent impact on surface activity and protective properties of the surfactants. Finally, the theoretical quantum chemical investigations reflected the relation between chemical structure of the studied DCSM-8, DCSM-10, and DCSM-12 with their inhibition performance based on DFT and MCS.

Experimental and techniques

Materials

Dichloromethane (99%, 1.324 g.cm-3), nitromethane (98%, 1.130 g.cm-3), Morpholine (98.5%, 0.999 g.cm-3) and Epichlorohydrin (98.5%, 1.176 g.cm-3) were purchased from Loba Chemie, India. Chloroacetic acid (99%, 1.58 g.cm-3) was purchased from Piochem, Egypt. octanol, triethylamine, Diethyl ether (99.5%, 0.714 g.cm-3), dodecanol (98%, 0.833 g.cm-3), hydrochloric acid (35%, 1.18 g.cm-3), petroleum ether40-60 (99%, 0.653 g.cm-3), ethanol (95%, 0.78 g.cm-3), decanol, NaOH (97%, 2.13 g.cm-3) and acetone (99.8%, 0.792 g.cm-3) were obtained from AL-Nasr Chemicals Co., Egypt. p-Toluene sulfonic acid (98.5%, 1.24 g.cm-3), 1,2-dibromoethane (99%, 2.18 g.cm-3) and triethylamine (99%, 0.727 g.cm-3) were purchased from Sigma-Aldrich, Saint Louis, USA. Also, CS (UNS G10300) with a composition of C% 0.28–0.34, Mn% 0.60–0.90, Si% 0.10–0.20, P% 0.04, S% 0.05, Cr% 0.1, Ni% 0.1, Cu% 0.15, N% 0.012, Fe% > 98 (wt. %) was obtained from Suez Steel Company, Suez, Egypt.

Synthesis of gemini-based morpholinium cationic surfactants

The synthetic route was represented in Fig. 1Si (Supplementary file) as follow:

  • Esterification reaction step

Using toluene as a solvent, an esterification reaction was established between. 2-chloroacetic acid and different primary alcohols (octanol, decanol, and dodecanol) in presence of dehydrating agent (p-Toluene sulfonic acid) to obtain three varied ester compounds that were washed with petroleum ether after solvent removal30.

  • Ether formation step

A mixture of 1 mmol of epichlrohydrin, 1 mmol of primary alcohol (octanol, decanol, or dodecanol) and 1 mmol of sodium hydroxide was refluxed at 313 K for 5 h. Then, the reaction mixture was purified using distilled water and petroleum ether31.

  • Tertiary amine formation step

The prepared ether compounds (2-((alkoxy) methyl) oxirane) and Morpholine was stirred in molar ratio 1:1 in presence of nitromethane (31 mmol) was at 298 K for 8 h. The mixture was allowed to cool and quenched with water, then extracted with dichloromethane. On the other hand, 1 mmol of Morpholine was refluxed with 1mmol of the obtained ester compounds (alkyl chloroacetate and triethylamine (10 ml) in presence of benzene as a solvent at 80 ⁰C for 6 h. The obtained morpholin-N-ethylalkylate (brown yield) was cooled at room temperature and recrystallized from ethanol32.

  • Quaternization step

The cationic surfactants (DCSM-8, DCSM-10, and DCSM-12) were prepared by reaction of 1,2-dibromoethane with the obtained two tertiary amines in molar ratio 1:1:1 in dry acetone for 24 h. the reaction mixture was cooled to obtain DCSM-8, DCSM-10, and DCSM-12 as yellow solid precipitate that was washed with acetone and recrystallized with absolute ethanol33.

Surface activity measurements

Surface activity measurements were accomplished with different concentrations of the prepared DCSM-8, DCSM-10, and DCSM-12 at room temperature (298 K) using Tensiometer-K6, KRÜSS, Hamburg, Germany, with a platinum ring in distilled water. The platinum ring was washed distilled water and ethanol to remove any attached particles. Each reading was repeated three times before taking the average final value. Also, all solutions were prepared using double-distilled H2O with 72 mN/cm surface tension.

Weight loss technique (WL)

Using varied emery paper, samples of CS were pretreated then washed by a mixture of acetone/ethanol before immersion in corrosive media containing 4 M HCl free and mixed with DCSM-8, DCSM-10, and DCSM-12 at different concentrations (1 × 10–6, 1 × 10–5, 4 × 10–5, 1 × 10–4, 4 × 10–4, 1 × 10–3 M) at room temperature 25 ± 1°C. The corresponding corrosion rate (r, mg cm-2 h-1) and the inhibition efficiency (Inline graphic) were estimated via the following Eqs.34:

graphic file with name d33e500.gif 1
graphic file with name d33e506.gif 2

where; t is immersion time (h), A is CS exposed area (cm2), and Wi and WHCl represent the mass change with and without inhibitors respectively.

Electrochemical measurements

Metrohm potentiostat was used for evaluation the mitigation performance of the prepared DCSM-8, DCSM-10, and DCSM-12 via PDP and EIS measurements. Working electrode with surface area 1.0 cm2 was connected with platinum electrode as a counter electrode and saturated calomel electrode (SCE) as a reference electrode in 4 M HCl free with and without various concentrations of DCSM-8, DCSM-10, and DCSM-12. Because all kinetics and electrochemical behavior of CS is observed fully, PDP curves were presented at large potential window ± 1.0 V around OCP (open circuit potential) using a low scan rate (1 mV.s-1)35,36. Also, EIS was achieved at frequency range of 100 kHz—0.1 Hz and 10 mV amplitude. The inhibition efficiency was calculated from PDP and EIS based on corrosion current density (icorr) and polarization resistance (RP) respectively as follow:

graphic file with name d33e557.gif 3
graphic file with name d33e563.gif 4

where, iblank and iinh. are corrosion current densities for blank solution (4 M HCl) and inhibitors (DCSM-8, DCSM-10, and DCSM-12) respectively. RP.blank and RP.inh. are the polarization resistance for CS in 4 M HCl free and containing surfactants inhibitors respectively21. The standard deviation (Sd) values for RP and those of icorr have been calculated and reported in Table 1Si.

Quantum studies

For more information about the suppression mechanism of the studied inhibitors, theoretical computer–based quantum chemical methods were carried out for determination of the chemical behavior and electron density of DCSM-8, DCSM-10, and DCSM-12 inhibitors based on density fictional theory (DFT). Using Gaussian 09 software, Version Number Rev. C.01, https://gaussian.com/g09_c01/,37 supported with GaussView 6, Version Number: 6.0.16, https://gaussian.com/gaussview6/, Semi-mpirical PM6 method was applied for determination DCSM-8, DCSM-10, and DCSM-12 optimized geometry structures then applying B3LYP/6–311 +  + G(d,p) method. The reactivity of the studied inhibitors was discussed by the help of determining the region or sites of HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) in the inhibitor’s structure. Also, some quantum chemical parameters as electronegativity (χ), the calculated affinity of electron (A), fraction of transferred electrons (∆N), hardness (γ) and the potential of ionization (I) were calculated and discussed. Using, BIOVIA Materials Studio 6.0 (17.1.0.48) software, https://www.3ds.com/products-services/biovia/products/molecular-modeling-simulation/biovia-materials-studio, the adsorption of DCSM-8, DCSM-10, and DCSM-12 inhibitors on Fe (110) plane was simulated using MCs for more evidences about its ability to shield CS surface from the corrosive particles and the interaction between the studied inhibitors and Fe (110) in aqueous phase (40 H2O). MCs was performed using adsorption locator module involved in BIOVIA Materials Studio 17.1.0.48 software under control COMPASS (Condensed phase Optimized Molecular Potentials for Atomistic Simulation Studies) force field using the optimized structures of the investigated mitigators. The MC annealing process was run in a simulation box of 31.55 × 31.33 × 16.31 Å dimension, and Fe was expanded to a cleavage plan (5 × 5) supercell. Subsequently, a 15-Å vacuum slab was assembled to eliminate the periodic boundary effect over the Fe (110) plane.

Surface analysis

SEM analysis for CS specimens was studied in blank corrosive solution (4 M HCl) with and without 1 × 10–3 M of the prepared DCSM-12 after 6 h for more indication about the dissolution behavior of CS and DCSM-12 mitigation process using JSM-IT700HR/LA SEM, MA, USA. Besides, EDX unit was used for more data about the outer layer components covered CS surface.

Results and discussion

Characterization of inhibitors structure

The chemical structure of DCSM-8, DCSM-10, and DCSM-12 was confirmed using FT-IR (Thermos Nicolet IS10 FT-IR Spectrophotometer, Thermo Fisher Scientific Inc.), 1HNMR (AVANCE III 400 MHz spectrometer, Bruker, Billerica, MA, USA), and Mass (Thermo Scientific, USA, Trace GC Ultra/ISQ Single Quadrupole MS, TG-5MS ) spectrum. Fig. 2Si showed the FT-IR bands of the prepared DCSM-8 at 3439 cm-1 (νOH), 3030 cm-1 (νCH), 2981, 2935 cm-1 (νCH Alkane), 1685 cm-1 (νC = O), 1612 cm-1 (νCOO), 1397 cm-1 (νCH3), 1305 cm-1 (νCH2), 1147 cm-1 (νC-O). In case of DCSM-10, the FT-IR (Fig. 2Si) confirmed its chemical structure showing bands at 3414 cm-1 (νOH), 3031 cm-1 (νCH), 2983, 2938 cm-1 (νCH Alkane), 1699 cm-1 (νC = O), 1612 cm-1 (νCOO), 1424 cm-1 (νCH3), 1274 cm-1 (νCH2), 1181 cm-1 (νC-O). While, in case of DCSM-12, the FT-IR (Fig. 1) showed bands at 3424 cm-1OH), 3027 cm-1 (νCH), 2978, 2934 cm-1 (νCH Alkane), 1698 cm-1 (νC = O), 1604cm-1 (νCOO), 1384 cm-1 (νCH3), 1280 cm-1 (νCH2), 1160 cm-1 (νC-O).

Fig. 1.

Fig. 1

FT-IR of the prepared DCSM-12.

Fig. 3Si showed the 1HNMR of DCSM-8 at 6.12 (m, 1H, 18), 4.72 (s, 1H, 17), 4.16 (m, 2H, 16), 3.88 (m, 2H, 39), 3.85 (m, 8H, 2, 4, 10, 12), 3.82 (m, 4H, 7, 8), 3.80 (m, 2H, 21), 3.78 (m, 2H, 15), 3.48 (m, 8H, 1, 5, 9, 13), 1.35 (m, 6H, 29, 30, 39), 1.26 (m, 22H, 24, 25, 26, 27, 28, 33, 34, 35, 36, 37, 38), 0.86 (m, 6H, 23, 32). In case of DCSM-10, the 1HNMR (Fig. 3Si) at 6.11 (m, 1H, 18), 4.87 (s, 1H, 17), 4.14 (m, 2H, 16), 4.00 (m, 2H, 43), 3.89 (m, 8H, 2, 4, 10, 12), 3.86 (m, 4H, 7, 8), 3.83 (m, 2H, 21), 3.80 (m, 2H, 15), 3.77 (m, 8H, 1, 5, 9, 13), 1.61 (m, 6H, 31, 32, 43), 1.26 (m, 30H, 24, 25, 26, 27, 28, 29, 30, 35, 36, 37, 38, 39, 40, 41, 42), 0.88 (m, 6H, 23, 34). While, in case of DCSM-12, the 1HNMR (Fig. 2) at 6.21 – 6.08 (d, J = 7.5 Hz, 1H, 18), 4.79 – 4.65 (s, 1H, 17), 4.18 – 4.15 (t, J = 2.9 Hz, 2H, 16), 4.14 – 4.09 (t, J = 6.2 Hz, 2H, 47), 4.01 – 3.97 (ddd, J = 7.0, 3.6, 1.9 Hz, 8H, 2, 4, 10, 12), 3.96 – 3.87 (m, 4H, 7, 8), 3.87 – 3.82 (m, 2H, 21), 3.82 – 3.73 (m, 2H, 15), 3.59 – 3.41 (m, 8H, 1, 5, 9, 13), 1.39 – 1.31 (m, 6H, 33, 34, 46), 1.30 – 1.20 (m, 36H, 24, 25, 26, 27, 28, 29, 30, 31, 32, 37, 38, 39, 40, 41, 42, 43, 44, 45), 0.91 – 0.83 (m, 6H, 23, 36).

Fig. 2.

Fig. 2

1HNMR of the prepared DCSM-12.

Fig. 4Si showed the Mass Spectrum (C31H62N2O62+) m/z of DCSM-8 with a molecular ion peak at (280.14) m/z: (28.24%), and the Mass Spectrum (C35H70N2O62+) m/z of DCSM-10 (Fig. 4Si) with a molecular ion peak at (308.48) m/z: (22.81%). While the Mass Spectrum (C39H78N2O62+) m/z of the of DCSM-12 (Fig. 3) with a molecular ion peak at (337.41) m/z: (20.52%).

Fig. 3.

Fig. 3

Mass spectra of the prepared DCSM-12.

Surface-active behavior

The surface activity of the prepared DCSM-8, DCSM-10, and DCSM-12 can be analyzed by measuring surface tension (γ) versus surfactant concentration (-ln) at room temperature (25 °C). Figure 4 showed that, with surfactant concentration rising, a decrease in γ values was observed which can be attributed to the adsorption of surfactant molecules at the air/solution interface. Also, a notable break at (critical micelle concentration) CMC with constant γ values as shown in Fig. 4 can be explained by the saturation occurred at the interface with formation of larger spherical molecules38,39. As noticed, DCSM-12 with longer hydrophobic alkyl chain length exhibited the lowest CMC. Some surface-active parameters such as πCMC (effectiveness), Maximum surface excess (Γmax), minimum surface area (Amin), the free Gibbs energy of micellization (Inline graphic), and free energy of adsorption (Inline graphic) were calculated and listed in Table.1 as the following equations:

graphic file with name d33e860.gif 5
graphic file with name d33e866.gif 6
graphic file with name d33e872.gif 7
graphic file with name d33e879.gif 8
graphic file with name d33e885.gif 9

where n, R, T and NA are, number of ions dissociation (n = 3), absolute temperature (K) and Avogadro’s number29. As noticed in Table 1, DCSM-12 with highest πCMC value indicating its ability to decrease surface tension compared with the other surfactants consequently its high inhibition efficacy40,41. Also, the drops in Inline graphic accompanied with Inline graphic enhancement as shown in Table 1, indicating the role hydrophobic chain in large surface area occupation42. The values of Inline graphic and Inline graphic with -ve sign reflecting the spontaneous process of micellization and adsorption. The calculated value of Inline graphic relative to that of Inline graphic exhibited that the prepared surfactants favored adsorption than micellization which confirmed that their higher mitigation power43,44.

Fig. 4.

Fig. 4

Surface tension variation with surfactants concentration at room temperature.

Table 1.

Surface active parameters of the prepared surfactants at room temperature.

Surfactant CMC,
M × 10–4
γCMC, mN/m πCMC, mN/m Γmax × 1010, mol.cm-2 Amin, nm2 ∆Gomic, kJ/mol ∆Goads, kJ/mol
DCSM-8 5.325 27.92 44.08 3.94 0.422 -28.62 -39.82
DCSM-10 5.247 22.74 49.26 3.73 0.446 -28.66 -41.88
DCSM-12 4.921 19.85 52.15 3.64 0.456 -28.82 -43.15

Electrochemical methods

Potentiodynamic polarization (PDP)

Tafel curves of CS reaction in 4 M HCl free in absence and presence of several doses of DCSM-8, DCSM-10, and DCSM-12 inhibitors were represented as shown in Fig. 5 The similarity of PDP curves of CS with and without several doses of the studied surfactants confirmed that, the corrosion reaction mechanism of CS did not change. Also, the introducing of DCSM-8, DCSM-10, and DCSM-12 inhibitors to the corrosive solution shifted PDP curves to less active areas confirming their mitigation role45. The gap between the PDP curves of the untreated solution.

Fig. 5.

Fig. 5

PDP curves for CS in the absence and presence of DCSM-8, DCSM-10, and DCSM-12 inhibitors at room temperature.

and those of DCSM-8, DCSM-10, and DCSM-12 inhibitors enhanced with increasing their.

concentration owing to the adsorption route pointing that the investigated surfactants inhibit the CS corrosion process46,47. The parallel shape of cathodic lines and their shift to lower current value as in Fig. 5 exhibited that, CS corrosion mechanism and H2 evolution reaction not affected by inhibitors addition4850. This shift increases with rising of inhibitors doses due to number rising of DCSM-8, DCSM-10, and DCSM-12 adsorbed molecules that cover extra CS surface area and consequently limits its dissolution rate and retards H2 evolution mechanism (Volmer-Heyrovsky) via blocking the corrosion reactive sites at CS surface by DCSM-8, DCSM-10, and DCSM-12 adsorbed molecules which decrease the available surface area for H+ ions adsorption and reduction. So, the corrosion reaction mechanism remains unaffected22,51. As in Fig. 5, the addition of the prepared DCSM-8 shifted PDP to both anodic and cathodic regions which confirming its mixed-type of inhibition while a notable shift in PDP curves to -ve direction after the addition of DCSM-10, and DCSM-12 can be explained by more number of DCSM-10, and DCSM-12 molecules adsorbed on CS surface and block CS cathodic regions more than its anodic regions52,53. In addition, anodic Tafel lines give an indication about role of the studied inhibitors in CS corrosion control which can be detected as modification in anodic line slope with inhibitors concentrations via their adsorption process forming an insulation barrier layer over CS surface54,55. Also, some corrosion parameters as anodic and cathodic Tafel slopes (βa and βc) and corrosion potential (Ecorr) were extracted and tabulated as in Table 2. From Table 2, the values of Ecorr, βa and βc reflected that of DCSM-8, and DCSM-10 acted as mixed-type inhibitor while DCSM-12 acted as cathodic type inhibitor56,57. The drops in icorr value after DCSM-8, DCSM-10, and DCSM-12 addition can be explained by their blocking effect for both cathodic and anodic sites of CS surface58,59. The calculated value of Inline graphic confirmed that, the prepared mitigators protect CS effectively in corrosive 4 M HCl through their adsorption process by shielding its surface via construction of defensive layer against the destructive species60. As in Table 2, the value of Inline graphic enhanced till touch 93.966%, 94.453%, and 97.029% at 1 × 10–3 M of DCSM-8, DCSM-10, and DCSM-12 respectively. All these annotations powered the adsorption behavior of the prepared inhibitors and their role in CS protection. The value of Inline graphic increases in the order DCSM-12 > DCSM-10 > DCSM-8 which can be explained by the presence of longer hydrophobic chain in DCSM-12 structure which enhanced its mitigation efficacy for CS in 4 M HCl electrolyte.

Table 2.

PDP data for CS in 4 M HCl free and containing various concentrations of the prepared inhibitors at room temperature.

Inh Conc. M βa (mV/dec) c (mV/dec) -Ecorr (mV) icorr (mA) r
(mm/year)
θ Inline graphic
Blank 141.90 224.80 440.55 23.60 274.18
DCSM-8 1 × 10–6 179.30 255.20 432.92 2.812 32.82 0.88084 88.084
1 × 10–5 180.40 254.20 432.61 2.394 27.73 0.89855 89.855
5 × 10–5 181.90 252.50 476.21 2.057 23.66 0.91283 91.28
1 × 10–4 182.10 250.90 448.66 1.891 21.95 0.91987 91.987
5 × 10–4 183.50 249.30 429.72 1.684 19.85 0.92864 92.864
1 × 10–3 176.10 235.50 451.07 1.424 16.88 0.93966 93.966
DCSM-10 1 × 10–6 138.80 240.20 442.04 2.727 31.42 0.88444 88.444
1 × 10–5 138.70 239.00 498.82 2.254 26.25 0.90449 90.449
5 × 10–5 140.60 236.40 459.02 2.002 22.68 0.91516 91.516
1 × 10–4 144.50 234.90 440.22 1.791 20.49 0.9241 92.411
5 × 10–4 144.90 232.10 507.36 1.558 18.08 0.93398 93.398
1 × 10–3 145.40 238.90 496.52 1.309 15.27 0.94453 94.453
DCSM-12 1 × 10–6 199.80 270.80 543.64 2.286 26.74 0.90313 90.313
1 × 10–5 149.20 267.00 536.99 2.041 23.53 0.91351 91.351
5 × 10–5 170.40 250.30 558.99 1.595 18.26 0.93241 93.241
1 × 10–4 120.20 279.40 553.87 1.112 12.78 0.95288 95.288
5 × 10–4 121.00 256.90 560.76 0.902 10.46 0.96178 96.177
1 × 10–3 155.40 273.00 570.52 0.701 8.13 0.97029 97.029

Electrochemical impedance spectroscopy

It is imperative to achieve a steady state process before starting electrochemical measurements in order to establish CS behavior. Eocp variation of CS with time in the inhibited and uninhibited solutions until the steady-state potential was depicted as seen in Fig. 5Si. It was noticed that, OCP tends to be stable with time and less fluctuates were observed. Also, the rapidly and negligible variations in the OCP may be attributed to the modification of the interface surface at the studied inhibitors doses with a steady-state had been achieved after 5 min. This result suggested that, the studied DCSM-8, DCSM-10, and DCSM-12 have more thermodynamically stable state and effective adsorption over CS surface21,61. Also, the addition of investigated inhibitors shifted Eocp value to negative (cathodic) direction which can be explained by the adsorption process of the prepared inhibitors over CS surface and dominate the cathodic reaction more than anodic reaction62,63. EIS response of CS was presented as in Fig. 6 and Fig. 7 showing CS Nyquist plots and Bode-Phase curves respectively in acidic solutions (4 M HCl) with and without various concentration of the studied surfactants (DCSM-8, DCSM-10, and DCSM-12). As noticed, the diameter of Nyquist semicircle increases with surfactants doses rising which powered the adsorption capacity of the prepared inhibitors over CS surface and their inhibition performance via construction of an insulation layer over CS surface which blocks the ionization of CS that can be confirmed as in Nyquist diameter rising to higher values64,65.Also, the similarity of Nyquist curves in the inhibited and uninhibited solutions as in Fig. 6 indicated that, the corrosion process was governed by charge transfer process, while their imperfect semicircles shapes can be clarified with roughness and inhomogeneity of CS surface66,67. The addition of DCSM-8, DCSM-10, and DCSM-12 inhibitors shifted Phase-curves towards -90 and Bode-curves to higher value which exhibited their adsorption power over CS surface and formation of a shielding layer against the destructive attack of the acidic liquid68. The proposed equivalent circuit (EC) of CS in Fig. 7 for 4 M HCl free consisted of Rs (solution resistance), CPE (constant phase element) which can be defined by Yo and coefficient n and Rp (polarization resistance) which involved Rct (charge transfer resistance), Rd (diffuse layer resistance) and Ra (accumulation resistance)69, while after the addition of the prepared surfactants, EC with two time constant comprised of Rs, CPE and Rp (= Rct + Rd, Ra and Rf “film resistance”) was detected indicating that, the corrosion mechanism of CS changed due to stable film formation7072. n value as tabulated in Table 3 declined with the addition of DCSM-8, DCSM-10, and DCSM-12 indicating that, CS surface become more homogeneous after the addition of surfactants owing to their adsorption over CS73,74. The lowering in n value can be explained by irregular current distribution arises from CS roughness and defects of its surface besides the diameter’s variance between electrons and inhibitors molecules, as electrons dominance charges on CS side of CS/HCl interface, while inhibitors adsorbed molecules dominance charges on HCl solution side. The overall charges of electrons (-ve) and inhibitors adsorbed molecules (+ ve) on CS surface are equal. Also, the n value < 1 is due to CS/solution interface not behaving as an ideal capacitor60,75,76. Also, Yo values decreased with DCSM-8, DCSM-10, and DCSM-12 addition which can be attributed to corrosive particles replacement process from CS surface with the adsorbed inhibitors molecules consequently, the film thickness (T) over CS surface increased1,4. The adsorbed inhibitors layer can change metal interfacial structure. According to Helmholtz equation, the double layer capacitance (Cdl) value decreased with DCSM-8, DCSM-10, and DCSM-12 addition as the following Eq.77:

graphic file with name d33e1985.gif 10
graphic file with name d33e1991.gif 11
graphic file with name d33e1997.gif 12

here, ε◦ and ε are air permittivity and local dielectric constant. A means angular frequency and Fimg → Max denotes maximum frequency at Zi (imaginary resistance)7880. From Table 3, it was observed that, the drop in Cdl value with rising of DCSM-8, DCSM-10, and DCSM-12 doses can be explained by the replacement of the destructive particles on CS surface by mitigators adsorbed molecules consequently the film thickness over CS surface increased with concentration which was also confirmed from the obtained Yo81,82. All these observations exhibited the mitigation power of the studied inhibitors for CS against the corrosive surrounding83,84. Also, the time related to charge distribution equilibrium after an electric disturbance is called Inline graphic (relaxation time). The existence of DCSM-8, DCSM-10, and DCSM-12 shifted Inline graphic value to higher value which reflected the adsorption time process becomes much higher which denotes.

Fig. 6.

Fig. 6

Nyquist plots for CS in 4 M HCl with and without various concentrations of the prepared surfactants. at room temperature.

Fig. 7.

Fig. 7

Bode-Phase diagrams of CS in absence and presence of different concentrations of the prepared DCSM-8, DCSM-10, and DCSM-12 inhibitors at room temperature and the proposed equivalent circuit of CS with and without1 × 10–3 M of the prepared surfactants.

Table 3.

Impedance parameters for CS in 4 M HCl free and containing various concentrations of the prepared inhibitors at room temperature.

Inh Conc. M RS (Ω.cm2) CPE Rct (Ω.cm2) Rf (Ω.cm2) RP (Ω.cm2) Cdl, (F/cm2) × 10–9 τ, (s) χ2 × 10–3 Inline graphic
n Y° (μF)
Blank 2.386 ± 1.02 0.8532 ± 0.07 418.18 ± 1.45 35.24 ± 3.13 35.24 ± 1.15 65.81 0.0134 4.013
DCSM-8 1 × 10–6 2.707 ± 0.91 0.8525 ± 0.08 62.29 ± 1.27 545.53 ± 2.05 8.24 ± 0.15 553.77 ± 1.06 9.75 0.030 3.241 93.64
1 × 10–5 4.488 ± 0.80 0.8488 ± 0.07 22.57 ± 1.35 628.64 ± 3.14 9.31 ± 0.09 637.95 ± 1.33 8.46 0.038 2.847 94.48
5 × 10–5 5.419 ± 0.72 0.8379 ± 0.03 17.33 ± 2.02 704.24 ± 3.42 12.52 ± 0.08 716.76 ± 2.20 6.28 0.050 2.771 95.08
1 × 10–4 6.230 ± 1.13 0.8303 ± 0.09 13.53 ± 1.93 832.3 ± 4.06 16.33 ± 0.08 848.63 ± 1.13 3.62 0.058 1.984 95.85
5 × 10–4 6.809 ± 0.92 0.8232 ± 0.08 11.39 ± 2.28 891.47 ± 2.65 19.84 ± 0.14 911.31 ± 3.05 3.04 0.064 0.859 96.13
1 × 10–3 7.687 ± 0.85 0.8095 ± 0.06 8.25 ± 3.30 982.88 ± 4.12 21.27 ± 0.17 1004.15 ± 2.17 1.63 0.072 1.221 96.49
DCSM-10 1 × 10–6 4.702 ± 1.14 0.8265 ± 0.12 49.48 ± 2.15 593.32 ± 1.55 9.11 ± 0.07 602.43 ± 2.21 7.57 0.071 2.230 94.15
1 × 10–5 4.915 ± 0.76 0.8367 ± 0.08 18.24 ± 2.34 684.48 ± 1.96 11.34 ± 0.14 695.82 ± 2.50 7.02 0.083 2.182 94.94
5 × 10–5 5.296 ± 0.90 0.8452 ± 0.16 16.08 ± 1.86 768.54 ± 2.77 17.02 ± 0.09 785.56 ± 1.37 6.11 0.088 1.873 95.51
1 × 10–4 4.805 ± 1.04 0.8388 ± 0.09 10.43 ± 3.10 872.42 ± 1.69 20.16 ± 0.19 892.58 ± 2.26 3.06 0.091 1.624 96.05
5 × 10–4 4.937 ± 0.82 0.8456 ± 0.09 8.86 ± 1.79 963.72 ± 2.60 24.41 ± 0.16 988.13 ± 3.09 2.24 0.094 0.937 96.43
1 × 10–3 5.602 ± 0.68 0.8456 ± 0.08 7.10 ± 2.46 1087.59 ± 3.15 28.97 ± 0.08 1116.56 ± 1.14 1.41 0.103 0.881 96.84
DCSM-12 1 × 10–6 4.209 ± 0.87 0.8234 ± 0.06 21.17 ± 3.06 676.75 ± 2.51 10.28 ± 0.07 687.03 ± 3.05 4.42 0.166 2.024 94.87
1 × 10–5 5.413 ± 0.96 0.8345 ± 0.03 13.69 ± 3.44 788.73 ± 3.20 13.32 ± 0.13 802.05 ± 3.36 3.65 0.193 1.883 95.61
5 × 10–5 4.722 ± 1.08 0.8133 ± 0.08 11.11 ± 2.71 894.53 ± 2.07 19.21 ± 0.08 913.74 ± 2.32 3.21 0.215 1.540 96.14
1 × 10–4 4.226 ± 0.95 0.8345 ± 0.07 9.58 ± 2.32 1018.73 ± 4.11 23.25 ± 0.08 1041.98 ± 2.27 2.81 0.266 0.802 96.62
5 × 10–4 7.287 ± 1.21 0.8187 ± 0.11 8.04 ± 1.52 1108.53 ± 3.21 27.08 ± 0.12 1135.61 ± 1.56 1.46 0.293 0.626 96.90
1 × 10–3 7.578 ± 0.86 0.8096 ± 0.09 6.78 ± 1.77 1214.17 ± 2.33 31.37 ± 0.11 1245.54 ± 1.72 0.35 0.303 0.792 97.17

The slow adsorption process of DCSM-8, DCSM-10, and DCSM-12 molecules over CS surface42,85. From Table 3, at 1 × 10–3 M of DCSM-8, DCSM-10, and DCSM-12 inhibitors, RP value increased till reach 1004.15 Ω.cm2, 1116.56 Ω.cm2 and 1245.54 Ω.cm2 respectively relative to free 4 M HCl solution 6.55 Ω.cm2. this observation indicated the high adsorption power of the prepared inhibitors and their protection role for CS in acidic solution68,86,87. The calculated value of Inline graphic in Table 3 confirmed the mitigation effect of the prepared surfactants via protective insulation film formation covered CS surface from the aggressive specie88. Inline graphic value increased till reach 96.49%, 96.84% and 97.17% at 1 × 10–3 M of DCSM-8, DCSM-10, and DCSM-12 inhibitors respectively. This bolstered DCSM-12 with high inhibition efficacy which can be explained by extra CS surface coverage and blocking of film pores which enhanced the mitigation potency for CS8991. Finally, the goodness of the EIS data is χ2 (chi–squared) was measured in the absence and presence of the investigated inhibitors to identify the accurate degrees of EIS data and listed in Table 3. The observed data showed that, χ2 of EIS with lower values in both the treated and untreated solutions reflecting that, EIS results were more accurately calculated by utilizing the equivalent circuit model92,93. Also, the obtained data of WL, PDP and EIS measurements were in good agreement with each other.

Weight loss and film stability studies

The inhibition performance of the studied DCSM-8, DCSM-10, and DCSM-12 for CS in corrosive surrounding containing 4 M HCl was evaluated using WL measurements. According to the calculated data in Table 4, after 6 h, the inhibition efficacy of the prepared inhibitors increased with mitigators doses which reflected more CS surface covered with surfactants molecules94. Also, a decrease in r values exhibited CS was protected effectively by the introducing surfactants which can be clarified by their high adsorption over CS surface via their active sites in their molecular structures95. As noticed in Table 4. The mitigation efficacy of the studied surfactants increased till reach 93.537%, 94.003%, and 96.463% for DCSM-8, DCSM-10, and DCSM-12 respectively at 1 × 10–3 M. This obtained data confirmed the high defensive role of the prepared surfactants for CS in 4 M HCl solution which can be explained by their adsorption over CS surface via their active sites as hetero atoms (N and O), π electrons in double bond, + ve nitrogen besides the role of hydrophobic chain96,97.

Table 4.

Weight loss parameters for CS in 4.0 M HCl free and containing various concentration of the prepared inhibitors at room temperature.

Inh Conc. (M) r, g/cm2.h θ Inline graphic
Blank 2.98
DCSM-8

1 × 10–6 M

1 × 10–5 M

5 × 10–5 M

1 × 10–4 M

5 × 10–4 M

1 × 10–3 M

0.4102

0.3382

0.2886

0.2413

0.2077

0.1926

0.86234

0.88651

0.90315

0.91903

0.93031

0.93537

86.234

88.651

90.315

91.903

93.031

93.537

DCSM-10

1 × 10–6 M

1 × 10–5 M

5 × 10–5 M

1 × 10–4 M

5 × 10–4 M

1 × 10–3 M

0.3385

0.3026

0.2653

0.2141

0.1856

0.1787

0.88640

0.89846

0.91097

0.92815

0.93772

0.94003

88.64

89.846

91.097

92.815

93.772

94.003

DCSM-12

1 × 10–6 M

1 × 10–5 M

5 × 10–5 M

1 × 10–4 M

5 × 10–4 M

1 × 10–3 M

0.2817

0.2534

0.2095

0.1719

0.1307

0.1054

0.90546

0.91497

0.92971

0.94232

0.95614

0.96463

90.546

91.497

92.971

94.232

95.614

96.463

The protective film stability of the prepared surfactant was studied at harsh conditions such as different immersion time (6h—24 h) and temperature (25 °C—70°C) using 1 × 10–3 M of DCSM-8, DCSM-10, and DCSM-12. The mitigation efficacy in Table 5 of the studied inhibitors increased with exposure time till touch 95.016%, 95.518%, and 97.408% for DCSM-8, DCSM-10, and DCSM-12 respectively after 24 h which can be attributed to their strong adsorption capacity on CS surface and formation of insulation defensive layer against the corrosive species7,29. While at various temperature, no notable change in the calculated inhibition efficiency in Table 6 for the prepared inhibitors which can be clarified by their strong adsorption over CS surface and linking via chemical bond formation98,99. All these annotations bolstered formation of stable film layer of the prepared inhibitors molecules against the corrosive particles at harsh conditions100,101. Data obtained from WL measurements showed that, the studied DCSM-12 mitigated CS corrosion more than the others mitigators which can be attributed to presence of longer hydrophobic chain in its structure.

Table 5.

Weight loss parameters for CS with time in absence and presence of 1 × 10–3 M of prepared inhibitors at room temperature.

Inh 6 h 9 h 12 h 24 h
r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic
Blank 2.98 4.27 5.97 8.19
DCSM-8 0.1926 0.93537 93.537 0.2374 0.9444 94.440 0.3082 0.94838 94.838 0.4082 0.95016 95.016
DCSM-10 0.1787 0.94003 94.003 0.2261 0.94705 94.705 0.2836 0.95249 95.249 0.3671 0.95518 95.518
DCSM-12 0.1054 0.96463 96.463 0.1361 0.96813 96.813 0.1706 0.97142 97.142 0.2123 0.97408 97.408

Table 6.

Weight loss parameters for CS in absence and presence of 1 × 10–3 M of prepared inhibitors at different temperature.

Inh 25 ºC 35 ºC 45 ºC 55 ºC
r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic r, g/cm2.h θ Inline graphic
Blank 2.98 4.86 6.31 9.47
DCSM-8 0.1926 0.93537 93.537 0.2986 0.93856 93.856 0.4216 0.93318 93.318 0.6862 0.92753 92.753
DCSM-10 0.1787 0.94003 94.003 0.2773 0.94294 94.294 0.3821 0.93944 93.944 0.6073 0.93587 93.587
DCSM-12 0.1054 0.96463 96.463 0.1684 0.96535 96.535 0.2453 0.96112 96.112 0.4164 0.95603 95.603

Also, the activation thermodynamic parameters of CS in Table 7 such as Ea (activation energy), ΔH* (activation enthalpy) and ΔS* (activation entropy) were determined at temperature range (25 ºC – 55 ºC) based on data obtained from WL measurements in absences and presence of 1 × 10–3 M of the studied DCSM-8, DCSM-10, and DCSM-12 inhibitors according to Arrhenius and Transition state equations:

graphic file with name d33e3555.gif 13
graphic file with name d33e3561.gif 14

where, A, R, T, NA and h are Arrhenius constant, gas constant, absolute temperature, Avogadro’s number and Plank constant respectively102. Ea value in Table 7 was calculated based on the slope obtained from ln r vs. 1/T relationship as in Fig. 8 The value of Ea after the addition of the studied mitigators (32.397 kJ.mol-1—36.498 kJ.mol-1) was very closed to that in 4 M HCl free (30.335 kJ.mol-1). The higher activation energy values can be associated with physical adsorption. On the other hand, the adsorption phenomenon of an organic molecule is not considered only as a physical or as a chemical adsorption phenomenon. The slight increase in activation energy after addition the inhibitor can be correlated with the increased thickness of the double layer which enhanced the activation energy of the corrosion process, besides, the competitive adsorption of inhibitors molecules with water molecules whose desorption from the surface needs also some activation energy and formation of inhibitor-Fe complexes which also required additional energy103105. Also, the tabulated ΔH* in Table 7 with positive value for all investigated inhibitors demonstrating that, the activated complex formation during corrosion process is an endothermic reaction. However, the elevation in ΔH* value is markedly accompanied with the existence of the prepared inhibitors which exhibited that, CS dissolution process was more difficult after inhibitors addition35,106. The obtained ΔS* value with -ve sign bolstered activated complex formation rather than dissociation which reflecting more order occurrence (from reactant to activated complex) accompanied with enhancement in the inhibitor’s efficiency42,107.

Table 7.

Activation thermodynamic parameters of CS in 4 M HCl free and containing DCSM-8, DCSM-10, and DCSM-12 at several temperatures.

Inh Arrhenius Transition state
Ea, (kJ.mol-1) R2 ΔH*, (kJ.mol-1) ΔS*, (J.mol-1)
Blank 30.335 0.9898 27.738 -142.498
DCSM-8 36.498 0.9939 29.802 -149.962
DCSM-10 33.733 0.9941 31.136 -154.199
DCSM-12 32.397 0.9937 33.901 -159.241

Fig. 8.

Fig. 8

Arrhenius and Transition state plots for CS in the absence and presence of prepared DCSM-8, DCSM-10, and DCSM-12 inhibitors at different temperatures.

Adsorption isotherm

Based on θ (surface coverage) value obtained from WL measurements, the adsorption behavior of the prepared DCSM-8, DCSM-10, and DCSM-12 in the aqueous acidic solutions (4 M HCl) was studied using Langmuir adsorption isotherms showing linear relationship of C/θ vs. C (concentration) with slope and correlation coefficient (R2) equals to 1.0 as shown in Fig. 9 according to the following equation:

graphic file with name d33e3744.gif 15

where, Kads is the equilibrium adsorption constant. The calculated value of Kads in Table 8 exhibited a strong contact between the prepared surfactants and CS surface via their active sites as π electrons in double bond, + ve nitrogen and hetero atoms (N and O) with unfilled 3d-orbital of Fe forming a defensive film layer protecting CS surface from the corrosive surrounding108. DCSM-12 has higher Kads value indicating its superior adsorption capacity in 4 M HCl solution81,82. The standard free energy of adsorption (Inline graphic) was estimated as follow:

graphic file with name d33e3785.gif 16

where, (55.5) is the molarity of water. The values of Inline graphic in Table 8 were ranged from—43.459 kJ.mol-1 to – 47.177 kJ.mol-1 which demonstrated that the prepared DCSM-8, DCSM-10, and DCSM-12 inhibitors were adsorbed on metal surface through chemical adsorption via formation of coordination bonds between lone pairs of electrons on hetero atoms (N and O) and vacant orbitals of iron43. Also, Inline graphic value in Table 8 with -ve sign reveals a spontaneous process that is often characterized by strong contact and a highly effective adsorption109, 110.

Fig. 9.

Fig. 9

Langmuir adsorption isotherm of the prepared DCSM-8, DCSM-10, and DCSM-12 inhibitors at room temperature.

Table 8.

Langmuir adsorption isotherm for DCSM-8, DCSM-10, and DCSM-12 at room temperature.

Inh Slope R2 Kads, (L.mol-1) Inline graphic
(kJmol-1)
DCSM-8 1.068721 1 747,841.8 -43.459
DCSM-10 1.063195 1 1,012,967 -44.211
DCSM-12 1.060513 1 3,353,075 -47.177

Quantum chemical study

Density functional theory (DFT)

After studying the optimized molecular structures of the neutral and protonated structures for prepared inhibitors in Fig. 10 and 11, HOMO region with the highest molecular occupation was localized essentially over the adjacent hydroxyl-ether, quaternary amine group (N+) and carbonyl-ether groups, which are responsible for adsorption on the Fe surface through electron donation to the empty d-orbitals. While, LUMO with the least empty molecular orbital represents sites related to electron acceptance from Fe surface through a back-bonding mechanism orbitals3,28. The electrostatic potential (ESP) distributed on DCSM-8, DCSM-10, and DCSM-12 active sites attacks, as less-negative yellow areas belong to electrophilic region (poor-electron areas) and the positive red portions belongs to nucleophilic region (electron-rich areas)87,111. The HOMO–LUMO gap (∆E) between electron density surfaces, EHOMO and ELUMO are the lowest energy excitation of electrons from HOMO to LUMO which predict the molecules reactivity. ∆E values for the examined inhibitors in Table 9 follows the series: DCSM-12 < DCSM-10 < DCSM-8 which goes along with the experimental measurements, as lower ∆E value correspond to easier electron excitation, giving more electrons to, and adsorb onto CS surface85. Also, some quantum indices such as χ, η, and ΔN are electronegativity, hardness, and fraction of electron transfer respectively were calculated based on the energies of EHOMO and ELUMO values as the following equations:

graphic file with name d33e3968.gif 17
graphic file with name d33e3974.gif 18
graphic file with name d33e3980.gif 19
graphic file with name d33e3987.gif 20
graphic file with name d33e3993.gif 21

where, I, A, and Inline graphic are ionization potential, electron affinity, and work function of Fe (1 1 0) plan (= 4.82 eV) respectively85. Data in Table 9 clarified that, ∆N value followed the rule of: DCSM-12 > DCSM-10 > DCSM-8, suggesting the electron-sharing between the investigate inhibitors and Fe vacant orbitals that powered the inhibitors molecules adsorption over CS surface, besides the positive value of ΔN reveals the electron-donation capacity of the studied inhibitors towards.

Fig. 10.

Fig. 10

HOMO, LUMO, and ESP of the neutral structures of the studied DCSM-8,

Fig. 11.

Fig. 11

HOMO, LUMO, and ESP of the protonated structures of the studied DCSM-8, DCSM-10, and DCSM-12 using Gaussian 09, Rev. C.01.

Table 9.

Quantum chemical parameters of the prepared DCSM-8, DCSM-10, and DCSM-12 inhibitors.

Parameters Neutral Protonated
DCSM-8 DCSM-10 DCSM-12 DCSM-8 DCSM-10 DCSM-12
EHOMO (eV) -9.17 -8.31 -6.41 -9.66 -8.78 -6.67
ELUMO (eV) -3.82 -3.71 -3.51 -3.28 -3.29 -3.57
∆E (eV) 5.35 4.59 2.90 6.38 5.49 3.10
I (eV) 9.17 8.31 6.41 9.66 8.78 6.67
A (eV) 3.82 3.71 3.51 3.28 3.29 3.57
χ (eV) 6.50 6.01 4.96 6.47 6.04 5.12
η (eV) 2.68 2.30 1.45 3.19 2.74 1.55
∆N 0.09 0.22 0.70 0.08 0.17 0.61

the vacant 3d-orbitals of Fe which powered the adsorption process of inhibitors molecules over CS surface and their anticorrosion property112. Also, the previously quantum parameters were also computed for the protonated structures of the studied inhibitors in Table 9 suggested their higher adsorption capacity and their inhibition. ΔN values are less than those of the neutral structures which indicated the electron transfer from CS surface to the protonated inhibitors molecules. Thus, it can be rationally inferred that the neutral inhibitor molecules generate mainly donating electrons to the empty 3d orbital of the iron atoms while the protonated ones have stronger capability of electron-acceptance from the iron atoms, hence strengthening77. In general, the quantum calculations showed the ability of DCSM-8, DCSM-10, and DCSM-12 molecules to shield CS surface through their adsorption via electrons transfer from the HOMO centered on the oxygen and nitrogen atoms in the middle of the inhibitors structure to CS empty d-orbitals besides the back donation of electrons from metal surface to LUMO regions in DCSM-8, DCSM-10, and DCSM-12 structures85,113.

Monte carlo simulations (MCs)

The adsorption behavior of the prepared DCSM-8, DCSM-10, and DCSM-12 on Fe (110) surface was studied using MCs simulations as shown in Fig. 12 providing their equilibrium configuration. Inspection of Fig. 12 reveals that the prepared inhibitors adsorbed on Fe (110) surface horizontally with a flat orientation reflecting high CS surface coverage against the corrosive surrounding. The adsorption energy (Eads) values in Table 10 for the studied surfactants based on MCs showed that, their Eads value was very low compared with that of corrosive species confirming the stronger adsorption ability of prepared inhibitors via replacement process of water molecules with inhibitors molecules and formation of an adsorption layer over CS surface114118. Also, DCSM-12 with the lowest Eads value exhibited its superior mitigation potency for CS than DCSM-8 and DCSM-10. As noticed, -ve value of Eads for the investigated inhibitors in Table 10 bolstered their spontaneous nature and strong adsorption on CS surface112. The mitigation role of the prepared inhibitors increases with alkyl chain increases via forcing inhibitors molecules to cover and protect extra CS surface area against the corrosive particles9,10. Finally, the theoretical studies of DCSM-8, DCSM-10, and DCSM-12 confirmed their mitigation performance and supported the experimental results.

Fig. 12.

Fig. 12

Equilibrium adsorption configuration of the studied DCSM-8, DCSM-10, and DCSM-12 on Fe (110) obtained by MCs simulations using BIOVIA Materials Studio 6.0 (17.1.0.48).

Table 10.

The outputs energies calculated by MCs for DCSM-8, DCSM-10, and DCSM-12 on Fe (110).

System Total energy (kcal/mol) Adsorption energy (kcal/mol) Rigid adsorption energy (kcal/mol) Deformation energy (kcal/mol) dEads/dNi (kcal/mol) dEads/dNi of H2O (kcal/mol)
Fe + H2O + DCSM-8 66.58 -118.16 -9.77 -108.39 -114.79 -3.08
Fe + H2O + DCSM-10 67.50 -120.75 -11.78 -108.98 -117.28 -3.36
Fe + H2O + DCSM-12 67.84 -123.93 -14.56 -109.36 -120.56 -3.42

Surface analysis (SEM and EDX)

CS surface morphology investigations were studied using SEM as seen in Fig. 13 showing CS 2D images in 4 M HCl solution in absence and presence 1 × 10–3 M of the studied DCSM-12. CS image in 4 M HCl free exhibited roughly and damaged CS surface which can be explained by the destructive effect of the acidic solution82,119. While after treated with DCSM-12 inhibitor, CS surface became more smooth and homogenous owing to insulation defensive layer formation over CS surface that decreased the HCl/CS contact110. EDX spectra in Fig. 13 give a quantitative data about CS outer layer in 4 M HCl free with and without 1 × 10–3 M of the investigated DCSM-12. The weight percentage value of Fe, C, O, Cl- and N atoms confirms SEM annotations. Fe and C peaks intensities increase while O and Cl- peaks intensity decreases after the addition of DCSM-12 inhibitor. Also, the appearance of N-peak confirmed the existence of the DCSM-12 molecules over CS surface forming a protective film layer120. These annotations confirmed the blocking power of the prepared DCSM-12 and its role in CS protection via construction of an insulation defensive layer of DCSM-12 molecule over CS surface against the destructive particles96.

Fig. 13.

Fig. 13

SEM and EDX for CS in 4 M HCl free and after addition of 1 × 10–3 M of DCSM-12 inhibitor.

Conclusion

Three novel Di-cationic surfactants based on morpholinium have been conducted successfully and characterized by FT-IR, HNMR, and mass analysis and evaluated as corrosion mitigators for CS in 4 M HCl solution via chemical (WL) and electrochemical techniques (PDP and EIS). Surface activity measurements showed their high ability towards surface tension reduction with low CMC. The application of the prepared surfactants showed an excellent inhibition effect against CS corrosion in 4 M HCl with inhibition efficacy 97.029% for DCSM-12. The adsorption of the synthesized surfactants over CS surface followed Langmuir adsorption isotherm via chemical adsorption. The quantum computations and the MC simulations were found in a good agreement with the obtained experimental data. Finally, SEM and EDX analysis showed a significant improvement in CS surface morphology with the existence of DCSM-12 which confirmed DCSM-12 adsorption capacity.

Supplementary Information

Supplementary Information. (956.1KB, docx)

Acknowledgements

The authors are grateful to Faculty of Science (Benha University, Egypt), Faculty of Engineering (Benha University, Egypt) and Egyptian Petroleum Research Institute (EPRI) for their support.

Author contributions

A. Elaraby: Supervision, Investigation, Methodology, Data curation, Writing—original draft, review & editing. •Doaa F. Seyam: Writing—review & editing, Investigation, Methodology. •Sherine A. Abdelkader: Supervision, Validation, Writing—review & editing.

Funding

Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB).

Data availability

All data generated or analyzed during this study are included in this manuscript.

Declarations

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

A. Elaraby, Email: a_elaraby19@yahoo.com

Doaa F. Seyam, Email: doaa.fouad17@fsc.bu.edu.eg

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-025-05836-x.

References

  • 1.Elaraby, A., Abd, S., Eman, A. & Zaki, E. G. Theoretical and electrochemical evaluation of tetra - cationic surfactant as corrosion inhibitor for carbon steel in 1 M HCl. Sci. Rep.10.1038/s41598-023-27513-7 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.El-Askalany, A. H., Mostafa, S. I., Shalabi, K., Eid, A. M. & Shaaban, S. Novel tetrazole-based symmetrical diselenides as corrosion inhibitors for N80 carbon steel in 1 M HCl solutions: Experimental and theoretical studies. J. Mol. Liq.223, 497–508 (2016). [Google Scholar]
  • 3.Song, Z. et al. Adsorption and corrosion inhibition performance of rice bran extract on carbon steel in aqueous chloride solution: Experimental, computational and theoretical studies. Constr. Build. Mater.363, 129801 (2023). [Google Scholar]
  • 4.Elaraby, A. et al. Synthesis of Gemini cationic surfactants based on natural nicotinic acid and evaluation of their inhibition performance at C-steel/1 M HCl interface: Electrochemical and computational investigations. Colloid. Surf. A. Physicochem. Eng. Asp.659, 130687 (2023). [Google Scholar]
  • 5.El-Tabei, A. S., Hegazy, M. A., Bedair, A. H. & Sadeq, M. A. Synthesis and inhibition effect of a novel Tri-cationic surfactant on carbon steel corrosion in 0.5 M H2SO4 solution. J. Surfactant. Deterg.17(341), 352 (2014). [Google Scholar]
  • 6.Zaki, E. G. & Zidan, T. A. Methyl acrylate derivatives as corrosion inhibitors for X-65 type carbon steel in 1 M HCl. Int. J. Electrochem. Sci.16, 210374 (2021). [Google Scholar]
  • 7.Eldougdoug, W. I., Ali, A. I., Elaraby, A. & Mabrouk, E. M. Corrosion inhibition of Tri-cationic surfactant on carbon steel in hydrochloric acid solution. J. Basic Environ. Sci.5, 289–300 (2018). [Google Scholar]
  • 8.El-Dougdoug, W. I. et al. Synthesis and assessment of Gemini cationic surfactants as inhibitors for corrosion of carbon steel in hydrochloric acid. Green Chem. Lett. Rev.15, 796–812 (2022). [Google Scholar]
  • 9.El Faydy, M. et al. Appraisal of corrosion inhibiting ability of new 5-N-((alkylamino)methyl)quinolin-8-ol analogs for C40E steel in sulfuric acid. Int. J. Hydrogen Energy46, 30246–30266 (2021). [Google Scholar]
  • 10.Olasunkanmi, L. O., Obot, I. B., Kabanda, M. M. & Ebenso, E. E. Some quinoxalin-6-yl derivatives as corrosion inhibitors for mild steel in hydrochloric acid: Experimental and theoretical studies. J. Phys. Chem. C119, 16004–16019 (2015). [Google Scholar]
  • 11.Nadi, I. et al. Insights into the inhibition mechanism of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole for carbon steel corrosion in hydrochloric acid pickling via experimental and computational approaches. J. Mol. Liq.342, 116958 (2021). [Google Scholar]
  • 12.Cao, S. et al. Task-specific ionic liquids as corrosion inhibitors on carbon steel in 0.5 M HCl solution: An experimental and theoretical study. Corros. Sci.153, 301–313 (2019). [Google Scholar]
  • 13.Kannan, P., Karthikeyan, J., Murugan, P., Rao, T. S. & Rajendran, N. Corrosion inhibition effect of novel methyl benzimidazolium ionic liquid for carbon steel in HCl medium. J. Mol. Liq.221, 368–380 (2016). [Google Scholar]
  • 14.Douadi, T., Hamani, H., Daoud, D., Al-Noaimi, M. & Chafaa, S. Effect of temperature and hydrodynamic conditions on corrosion inhibition of an azomethine compounds for mild steel in 1 M HCl solution. J. Taiwan Inst. Chem. Eng.71, 388–404 (2017). [Google Scholar]
  • 15.Ríos, F., Lechuga, M., Fernández-Serrano, M. & Fernández-Arteaga, A. Aerobic biodegradation of amphoteric amine-oxide-based surfactants: Effect of molecular structure, initial surfactant concentration and pH. Chemosphere171, 324–331 (2017). [DOI] [PubMed] [Google Scholar]
  • 16.Prichard, T. D., Thomas, R. R., Kausch, C. M. & Vogt, B. D. Solubility of non-ionic poly(fluorooxetane)-block-(ethylene oxide)-block-(fluorooxetane) surfactants in carbon dioxide. J. Supercrit. Fluids57, 95–100 (2011). [Google Scholar]
  • 17.Wang, G., Wang, S., Sun, Z., Zheng, S. & Xi, Y. Structures of nonionic surfactant modified montmorillonites and their enhanced adsorption capacities towards a cationic organic dye. Appl. Clay Sci.148, 1–10 (2017). [Google Scholar]
  • 18.Bedair, M. A. et al. Benzidine-based Schiff base compounds for employing as corrosion inhibitors for carbon steel in 1.0 M HCl aqueous media media by chemical, electrochemical and computational methods. J. Mol. Liq.317, 114015 (2020). [Google Scholar]
  • 19.Qasim, K. F. & Mousa, M. A. Effect of oxidizer on PANI for producing ­ BaTiO 3 @ PANI perovskite composites and their electrical and electrochemical properties. J. Inorg. Organomet. Polym. Mater.10.1007/s10904-022-02335-8 (2022). [Google Scholar]
  • 20.Kamar, E. A., Qasim, K. F. & Mousa, M. A. Electrochimica Acta Supercapacitor and oxygen evolution reaction performances based on rGO and Mn 2 V 2 O 7 nanomaterials. 430, 141106 (2022).
  • 21.El-Tabey, A. E., Elaraby, A., El-Tabei, A. S. & Elsharaky, E. A. Inhibition performance of gemini cationic surfactants for carbon steel in formation water: Electrochemical and computational investigations. J. Mol. Liq.409, 125452 (2024). [Google Scholar]
  • 22.El-naggar, M. A., Ahmed, M., Reda, S. M. & Mohamed, M. Thermal decomposition behavior and kinetics for pyrolysis and catalytic pyrolysis of sugarcane bagasse. 44, 101976 (2025).
  • 23.Etman, A. E., Mohammed, A., Mostafa, F. A. & Faisal, K. Journal of industrial and engineering chemistry A 10 years-developmental study on conducting polymers composites for supercapacitors electrodes : A review for extensive data interpretation. 122, 2023 (2023).
  • 24.Xia, G. et al. Journal of Industrial and Engineering Chemistry Enhanced anticorrosion of methyl acrylate by covalent bonded N-alkylpyridinium bromide for X70 steel in 5 M HCl. J. Ind. Eng. Chem.10.1016/j.jiec.2014.12.027 (2015). [Google Scholar]
  • 25.Wang, D., Li, Y., Chen, B. & Zhang, L. Novel surfactants as green corrosion inhibitors for mild steel in 15% HCl: Experimental and theoretical studies. Chem. Eng. J.402, 126219 (2020). [Google Scholar]
  • 26.Deyab, M. A. & Mohsen, Q. Inhibitory influence of cationic Gemini surfactant on the dissolution rate of N80 carbon steel in 15 % HCl solution. Sci. Rep.10.1038/s41598-021-90031-x (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Shaban, S. M., Abd, S., Taw, S. M., Abdel-rahman, A. A. & Aiad, I. Studying surface and thermodynamic behavior of a new multi-hydroxyl Gemini cationic surfactant and investigating their performance as corrosion inhibitor and biocide. J. Mol. Liq.316, 113881 (2020). [Google Scholar]
  • 28.Abdallah, M., Hegazy, M. A., Alfakeer, M. & Ahmed, H. Adsorption and inhibition performance of the novel cationic gemini surfactant as a safe corrosion inhibitor for carbon steel in hydrochloric acid. Green Chem. Lett. Rev.11, 457–468 (2018). [Google Scholar]
  • 29.El Basiony, N. M. et al. ρ -Substituted imine cationic surfactants as carbon steel corrosion inhibitors : Experimental and theoretical ( DFT and MCs ) approaches. J. Mol. Liq.400, 124475 (2024). [Google Scholar]
  • 30.Seyam, D. F., Eid, S., El-Etre, A. Y. & Tantawy, A. H. Study the inhibition effect of three newly synthesized schiff base based cationic surfactants on aluminum corrosion in 0.5 M HCl solution. Egypt J. Chem.66(87), 99 (2023). [Google Scholar]
  • 31.J Surfact Detergents Seyam - Study of the inhibition effect of two novel synthesized amido‐amine‐based cationic.pdf (2021).
  • 32.Migahed, M. A., El-rabiei, M. M., Nady, H. & Zaki, E. G. Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oil fi eld produced water under sweet conditions: Combined experimental and computational investigations. J. Mol. Struct.1159, 10–22 (2018). [Google Scholar]
  • 33.Nasser, A., EL Basiony, N. M., Migahed, M. A., Abd-El-Bary, H. M. & Mohamed, T. A. Experimental and theoretical insights into synthesized Gemini corrosion inhibitor for X65-steel in 1M HCl. Egypt J. Chem.65, 845–867 (2022). [Google Scholar]
  • 34.Nasser, A. J. A. & Sathiq, M. A. ORIGINAL ARTICLE N - [Morpholin-4-yl ( phenyl ) methyl ] acetamide as corrosion inhibitor for mild steel in hydrochloric acid medium. Arab. J. Chem.10.1016/j.arabjc.2011.07.024 (2011). [Google Scholar]
  • 35.Berdimurodov, E. et al. A gossypol derivative as an efficient corrosion inhibitor for St2 steel in 1 M HCl + 1 M KCl: An experimental and theoretical investigation. J. Mol. Liq.10.1016/j.molliq.2021.115475 (2021). [Google Scholar]
  • 36.Bedir, A. G., El-raouf, M. A., Abdel-mawgoud, S., Negm, N. A. & El Basiony, N. M. Corrosion inhibition of carbon steel in hydrochloric acid solution using ethoxylated nonionic surfactants based on schi ff base : Electrochemical and computational investigations. ACS Omega10.1021/acsomega.0c05476 (2021). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.M. Frisch, F. Clemente, Gaussian 09, revision a., 01, mj frisch, gw trucks, hb schlegel, ge scuseria, M., robb, jr cheeseman, g, Scalmani, V. Barone, B., Mennucci, GA Petersson, H. Nakatsuji, M. C. & X. Li, HP Hratchian, AF Izmaylov, J. Bloino, G. Z. No Title. 20–44 (2009).
  • 38.El-Tabei, A. S., Elsharaky, E. A. & El-Tabey, A. E. A comparative the inhibition performance of a newly synthesized cationic surfmer and it’s oligomer surfactant for carbon steel corrosion in 1M acid chloride solution. Int. J. Electrochem. Sci.11, 10978–11001 (2016). [Google Scholar]
  • 39.El-Tabei, A. S., El-Tabey, A. E. & El Basiony, N. M. Newly imine-azo dicationic amphiphilic for corrosion and sulfate-reducing bacteria inhibition in petroleum processes: Laboratory and theoretical studies. Appl. Surf. Sci.573, 151531 (2022). [Google Scholar]
  • 40.Farag, A. A. et al. The inhibition performance of morpholinium derivatives on corrosion behavior of carbon steel in the acidized formation water : Theoretical, experimental and biocidal evaluations. J. Mol. Liq.341, 117348 (2021). [Google Scholar]
  • 41.Petkova, B. et al. Foamability of aqueous solutions : Role of surfactant type and concentration. Adv. Colloid Interf. Sci.276, 102084 (2020). [DOI] [PubMed] [Google Scholar]
  • 42.Elaraby, A. et al. Synthesis of Gemini cationic surfactants based on natural nicotinic acid and evaluation of their inhibition performance at C-steel/1M HCl interface_ Electrochemical and computational investigations. Colloid. Surf. A Physicochem. Eng. Asp10.1016/j.colsurfa.2022.130687 (2022). [Google Scholar]
  • 43.Abd-elhamid, A. et al. Synthesis of gemini cationic surfactants-based pyridine Schiff base for steel corrosion and sulfate reducing bacteria mitigation. J. Mol. Liq.369, 120890 (2023). [Google Scholar]
  • 44.Taha, A. A. et al. Synthesis and evaluation of nonionic surfactants based on dimethylaminoethylamine: Electrochemical investigation and theoretical modeling as inhibitors during electropolishing in-ortho-phosphoric acid. J. Mol. Liq.328, 115421 (2021). [Google Scholar]
  • 45.Uhlig, H. H. & King, C. V. Corrosion and corrosion control. J. Electrochem. Soc.119, 327C (1972). [Google Scholar]
  • 46.RSC Advances Optimizing the performance of Au y / Ni x / TiO 2 NTs photoanodes for photoelectrochemical water. 14032 (2023) 10.1039/d3ra02011h. [DOI] [PMC free article] [PubMed]
  • 47.Mohamed, S. K., Elsalam, A. & Shahat, A. Efficient sucrose-derived mesoporous carbon sphere electrodes with enhanced hydrophilicity for water capacitive deionization at low cell voltages. New J. Chem.10.1039/d0nj05412g (2021). [Google Scholar]
  • 48.Lesar, A. & Milošev, I. Density functional study of the corrosion inhibition properties of 1,2,4-triazole and its amino derivatives. Chem. Phys. Lett.483, 198–203 (2009). [Google Scholar]
  • 49.El-Tabei, A. S., El-Azabawy, O. E., El Basiony, N. M. & Hegazy, M. A. Newly synthesized quaternary ammonium bis-cationic surfactant utilized for mitigation of carbon steel acidic corrosion; theoretical and experimental investigations. J. Mol. Struct.1262, 133063 (2022). [Google Scholar]
  • 50.Hegazy, M. A. Novel cationic surfactant based on triazole as a corrosion inhibitor for carbon steel in phosphoric acid produced by dihydrate wet process. J. Mol. Liq.208, 227–236 (2015). [Google Scholar]
  • 51.Mohamed, S. K., Shahat, A., Atito, M. & Kamel, R. M. Efficient and low-cost mesoporous magnetic carbon composites derived from date palm stones for environmental remediation of hexavalent chromium. J. Porous Mater.10.1007/s10934-024-01611-x (2024). [Google Scholar]
  • 52.Jero, D. et al. Electrochimica acta adsorption kinetics and inhibition mechanisms of a film-forming amine on carbon steel surfaces. Electrochim. Acta498, 144625 (2024). [Google Scholar]
  • 53.Zakaria, K., Abbas, M. A. & Bedair, M. A. Herbal expired drug bearing glycosides and polysaccharides moieties as green and cost-effective oilfield corrosion inhibitor: Electrochemical and computational studies. J. Mol. Liq.352, 118689 (2022). [Google Scholar]
  • 54.Deef Allah, M. et al. Optical and electrochemical investigations of CdSe (NPs) based on nonionic surfactant for carbon steel corrosion control in 1 M HCl solution. Egypt. J. Chem.10.21608/ejchem.2025.354271.11195 (2025). [Google Scholar]
  • 55.Mahmoud, S. B., Elaraby, A., Abd-El-Raouf, M. & Zaki, E. G. Hydrogen production and electrochemical investigations of an environmentally salicornia extract as a green corrosion inhibitor in a 1 M HCl solution. Egypt. J. Chem.10.21608/ejchem.2024.316943.10308 (2024). [Google Scholar]
  • 56.Jin, X. et al. The study of surface activity and anti-corrosion of novel surfactants for carbon steel in 1 M HCl. J. Mol. Liq.353, 118747 (2022). [Google Scholar]
  • 57.Sargolzaei, B. & Arab, A. Synergism of CTAB and NLS surfactants on the corrosion inhibition of mild steel in sodium chloride solution. Mater. Today Commun.29, 102809 (2021). [Google Scholar]
  • 58.Haldhar, R. et al. Development of different chain lengths ionic liquids as green corrosion inhibitors for oil and gas industries: Experimental and theoretical investigations. J. Mol. Liq.372, 121168 (2023). [Google Scholar]
  • 59.Tripathi, V., Prasad, D., Maithani, R. & Ibrahimii, B. E. Corrosion inhibition assessment of a sustainable inhibitor from the weed plant (Pouzolzia zeylanica L.) on SS-410 surface in 0.5 M HCl acidic medium. J. Taiwan Inst. Chem. Eng.165, 105693 (2024). [Google Scholar]
  • 60.Zhang, Q. H. et al. Comparison of the synergistic inhibition mechanism of two eco-friendly amino acids combined corrosion inhibitors for carbon steel pipelines in oil and gas production. Appl. Surf. Sci.10.1016/j.apsusc.2022.152559 (2022). [Google Scholar]
  • 61.Elaraby, A., Faisal, K., Mohamed, S. K. & El-sharkawy, E. A. Multi-scale quantum ( DFT, MCs and MDs ) insights and electrochemical validation of di-imine Schiff base inhibitor for carbon steel corrosion control in 1 M HCl solution. Appl. Mater. Today42, 102615 (2025). [Google Scholar]
  • 62.Elaraby, A., Faisal, K., Mohamed, S. K. & El-sharkawy, E. A. Journal of Environmental Chemical Engineering Di-imine Schiff base inhibitor for carbon steel corrosion in 1 M HCl : Electrochemical, surface and theoretical investigations. 12, 111861 (2024).
  • 63.Mustafa, M., Ahmed, M. & Faisal, K. Preparation, structural, electrical, and ferroelectric properties of solid and lead zirconium titanate ink. 1006, 176390 (2024).
  • 64.Wang, D. Y., Wang, J. H., Li, H. J. & Wu, Y. C. Pectin-amino acid derivatives as highly efficient green inhibitors for the corrosion of N80 steel in CO2-saturated formation water. Ind. Crops Prod.189, 115866 (2022). [Google Scholar]
  • 65.Mobin, M., Aslam, R., Salim, R. & Kaya, S. An investigation on the synthesis, characterization and anti-corrosion properties of choline based ionic liquids as novel and environmentally friendly inhibitors for mild steel corrosion in 5% HCl. J. Colloid Interface Sci.620, 293–312 (2022). [DOI] [PubMed] [Google Scholar]
  • 66.Ragheb, D. M., Abdel-Gaber, A. M., Mahgoub, F. M. & Mohamed, M. E. Eco-friendly method for construction of superhydrophobic graphene-based coating on copper substrate and its corrosion resistance performance. Sci. Rep.12, 1–14 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 67.Shaaban, S. et al. Promising organoselenium corrosion inhibitors for C1018-steel in hydrochloric acid environments. J. Taiwan Inst. Chem. Eng.165, 105766 (2024). [Google Scholar]
  • 68.Elaraby, A., Qasim, K. F., Mohamed, S. K., El-Sharkawy, E. A. & Abdelhamed, S. Di-imine Schiff base inhibitor for carbon steel corrosion in 1 M HCl: Electrochemical, surface and theoretical investigations. J. Environ. Chem. Eng.12, 111861 (2024). [Google Scholar]
  • 69.Solmaz, R. Investigation of the inhibition effect of 5- (( E ) -4-phenylbuta-1, 3-dienylideneamino ) - 1, 3, 4-thiadiazole-2-thiol Schiff base on mild steel corrosion in hydrochloric acid. Corros. Sci.52, 3321–3330 (2010). [Google Scholar]
  • 70.Hassan, H. M. A. et al. Nanocomposite for Highly Efficient Water Treatment. 28073072 (2023). [DOI] [PMC free article] [PubMed]
  • 71.Faisal, K., Abdelhamed, S., Elaraby, A. & Ahmed, M. Journal of Industrial and Engineering Chemistry Polyaniline impact on graphitic C 3 N 4 ’ s structural and physicochemical properties for high stability energy storage systems : Practical and theoretical studies. 139, 2024 (2024).
  • 72.Mobin, M. & Aslam, R. Experimental and theoretical study on corrosion inhibition performance of environmentally benign non-ionic surfactants for mild steel in 3.5% NaCl solution. Process Saf. Environ. Prot.114(279), 295 (2018). [Google Scholar]
  • 73.El-tabey, A. E., Elaraby, A. & Elsharaky, E. A. Inhibition performance of gemini cationic surfactants for carbon steel in formation water: Electrochemical and computational investigations. J. Mol. Liq.10.1016/j.molliq.2024.125452 (2024). [Google Scholar]
  • 74.Faisal, K., Mahmoud, Q. & Mousa, A. Physicochemical Properties of Oriented Crystalline Assembled Polyaniline / Metal Doped L ­ i 4 Ti 5 O 12 Composites for Li ‑ ion Storage. 10904 (2023).
  • 75.Hassan, H. M. A. et al. Colloids and Surfaces A : Physicochemical and Engineering Aspects One-pot phyto-mediated combustion technicality for synthesizing Pd adorned Cu 2 O @ CuO heterojunction with great efficiency in CO oxidation and epoxidation applications. 654, 130056 (2022).
  • 76.Li, X. et al. Two semi flexible nonplanar double Schiff bases as corrosion inhibitors for mild steel in HCl solution: Experimental and theoretical investigations. J. Environ. Chem. Eng.11, 110077 (2023). [Google Scholar]
  • 77.Abdallah, M., Eltass, H. M., Hegazy, M. A. & Ahmed, H. Adsorption and inhibition effect of novel cationic surfactant for pipelines carbon steel in acidic solution. Prot. Met. Phys. Chem. Surfaces52, 721–730 (2016). [Google Scholar]
  • 78.Galal, A., Atta, N. F. & Al-Hassan, M. H. S. Effect of some thiophene derivatives on the electrochemical behavior of AISI 316 austenitic stainless steel in acidic solutions containing chloride ions: I. Molecular structure and inhibition efficiency relationship. Mater. Chem. Phys.89(38), 48 (2005). [Google Scholar]
  • 79.Nasser, A., Migahed, M. A., EL Basiony, N. M., Abd-El-Bary, H. M. & Mohamed, T. A. Electrochemical, surface analysis, computational and anticorrosive studies of novel di-imine Schiff base on X65 steel surface. Sci. Rep.13(1), 17 (2023). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 80.Migahed, M. A., Nasser, A., Elfeky, H. & El-Rabiei, M. M. The synthesis and characterization of benzotriazole-based cationic surfactants and the evaluation of their corrosion inhibition efficiency on copper in seawater. RSC Adv.9, 27069–27082 (2019). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 81.Emara, M. M. Magnetization and optical bandgap of Cu ‑ Mn vanadate ‑ oxide mixed phase nanostructures. 11051 (2022).
  • 82.RSC Advances The interplay between di ff erent potassium performance of potassium – sulfur batteries. 37910 (2024) 10.1039/d4ra06101b.
  • 83.El Basiony, N. M., Badr, E. E., Baker, S. A. & El-Tabei, A. S. Experimental and theoretical (DFT&MC) studies for the adsorption of the synthesized Gemini cationic surfactant based on hydrazide moiety as X-65 steel acid corrosion inhibitor. Appl. Surf. Sci.539, 148246 (2021). [Google Scholar]
  • 84.El-Nagar, R. A., Elaraby, A., Nessim, M. I. & Ghanem, A. Designed imidazolium-based ionic liquids to capture carbon dioxide from natural gas. J. Mol. Liq.401, 124708 (2024). [Google Scholar]
  • 85.Qasim, K. F., Abdelhamed, S., Elaraby, A. & Mousa, M. A. Polyaniline impact on graphitic C3N4’s structural and physicochemical properties for high stability energy storage systems: Practical and theoretical studies. J. Ind. Eng. Chem.10.1016/j.jiec.2024.05.011 (2024). [Google Scholar]
  • 86.Sarkar, T. K., Yadav, M. & Obot, I. B. Mechanistic evaluation of adsorption and corrosion inhibition capabilities of novel indoline compounds for oil well/tubing steel in 15% HCl. Chem. Eng. J.431, 133481 (2022). [Google Scholar]
  • 87.Gouda, M., Khalaf, M. M., Shalabi, K., Al-Omair, M. A. & El-Lateef, H. M. A. Synthesis and characterization of Zn – Organic frameworks containing chitosan as a low-cost inhibitor for. Polymers (Basel).14, 228 (2022). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 88.Abd El-Lateef, H. M., Tantawy, A. H. & Abdelhamid, A. A. Novel quaternary ammonium-based cationic surfactants: Synthesis, surface activity and evaluation as corrosion inhibitors for c1018 carbon steel in acidic chloride solution. J. Surfactants Deterg.20(735), 753 (2017). [Google Scholar]
  • 89.Abd El-Lateef, H. M. et al. Novel natural surfactant-based fatty acids and their corrosion-inhibitive characteristics for carbon steel-induced sweet corrosion: Detailed practical and computational explorations. Front. Mater.9(1), 18 (2022). [Google Scholar]
  • 90.Mustafa, M., Mohamed, D., Sabry, N., Abdallah, W. & Mousa, B. M. A. Large ‑ Scale Synthesis of Silver Nanowire Ink Suitable for Flexible and Wearable Printed Electronics. 11664 (2024).
  • 91.El-naggar, M. A., Mousa, M. A. & Reda, S. M. The electrical conductivity mechanisms and dielectric properties of multiphase co-synthesized CuV 2 O 6 – MnV 2 O 6. 56, 11663 (2025).
  • 92.Zheng, T. et al. Synergistic corrosion inhibition effects of quaternary ammonium salt cationic surfactants and thiourea on Q235 steel in sulfuric acid: Experimental and theoretical research. Corros. Sci.199, 110199 (2022). [Google Scholar]
  • 93.Elbasiony, N. M. Journal of molecular structure controlling C-steel dissolution in 1M HCl solution using newly synthesized ρ- substituted imine derivatives: Theoretical ( DFT and MCs ) and experimental investigations. J. Mol. Struct.10.1016/j.molstruc.2022.134357 (2022). [Google Scholar]
  • 94.El-Tabey, A. E. et al. Synthesis and evaluation of new poly cationic surfactants as corrosion inhibitors for carbon steel in formation water. Egypt. J. Chem.63, 833–850 (2020). [Google Scholar]
  • 95.Li, X., Deng, S. & Fu, H. Inhibition of the corrosion of steel in HCl, H 2SO 4 solutions by bamboo leaf extract. Corros. Sci.62, 163–175 (2012). [Google Scholar]
  • 96.Wu, Q., Jia, X. & Wong, M. Effects of number, type and length of the alkyl-chain on the structure and property of indazole derivatives used as corrosion inhibitors. Mater. Today Chem.23, 100636 (2022). [Google Scholar]
  • 97.Hu, P., Cheng, P., Wu, Y., Guo, L. & AlObaid, A. A. Insight into the corrosion inhibition performance of Capsicum annuum L. leaf extract as corrosion inhibitor for copper in sulfuric acid medium. J. Taiwan Inst. Chem. Eng.161, 105558 (2024). [Google Scholar]
  • 98.El Basiony, N. M. et al. Retard the corrosion reaction of carbon steel in acid solutions using Gemini-nonionic surfactant : Theoretical and experimental studies. Mater. Today Commun.37, 107378 (2023). [Google Scholar]
  • 99.Salim, M., Azab, M. M., Abo-Riya, M. A., Abd-El-Raouf, M. & EL Basiony, N. M. Controlling C-steel dissolution in 1 M HCl solution using newly synthesized ρ-substituted imine derivatives: Theoretical (DFT and MCs) and experimental investigations. J. Mol. Struct.1274, 134357 (2023). [Google Scholar]
  • 100.Moretti, G., Guidi, F. & Fabris, F. Corrosion inhibition of the mild steel in 0. 5 M HCl by 2-butyl-hexahydropyrrolo [ 1 , 2-b ][ 1 , 2 ] oxazole. Corros. Sci.10.1016/j.corsci.2013.06.044 (2013). [Google Scholar]
  • 101.Shaban, S. M., Aiad, I., El-sukkary, M. M. & Soliman, E. A. Journal of industrial and engineering chemistry evaluation of some cationic surfactants based on dimethylaminopropylamine as corrosion inhibitors. J. Ind. Eng. Chem.10.1016/j.jiec.2014.05.012 (2014). [Google Scholar]
  • 102.Sameeh, M., Khairy, M. & Faisal, K. Effect of γ -rays irradiation on the structural , magnetic , and electrochemical properties of ZnMn 2 O 4 nanoparticles. 226, 112343 (2025).
  • 103.Faisal, K., Samar, Q., Hamied, A. & Desoky, M. M. El. Contribution of Ti insertion on nano ‑ crystalline rich oxygen vacancy ­ V 2 O 5 ’ s performance for supercapacitor electrodes. 10008 (2025).
  • 104.Berdimurodov, E. et al. Novel glycoluril pharmaceutically active compound as a green corrosion inhibitor for the oil and gas industry. J. Electroanal. Chem.10.1016/j.jelechem.2022.116055 (2022). [Google Scholar]
  • 105.Negm, N. A. et al. High performance corrosion inhibition of novel tricationic surfactants on carbon steel in formation water: Electrochemical and computational evaluations. J. Mol. Liq.262, 363–375 (2018). [Google Scholar]
  • 106.Tantawy, A. H., Soliman, K. A. & Abd El-Lateef, H. M. Novel synthesized cationic surfactants based on natural piper nigrum as sustainable-green inhibitors for steel pipeline corrosion in CO2-3.5%NaCl: DFT, Monte Carlo simulations and experimental approaches. J. Clean. Prod.250, 119510 (2020). [Google Scholar]
  • 107.Wang, C., Zou, C. & Cao, Y. Electrochemical and isothermal adsorption studies on corrosion inhibition performance of β-cyclodextrin grafted polyacrylamide for X80 steel in oil and gas production. J. Mol. Struct.1228, 129737 (2021). [Google Scholar]
  • 108.Li, X., Deng, S. & Du, G. Journal of the Taiwan Institute of Chemical Engineers Nonionic surfactant of coconut diethanolamide as a novel corrosion inhibitor for cold rolled steel in both HCl and H 2 SO 4 solutions. J. Taiwan Inst. Chem. Eng.131, 104171 (2022). [Google Scholar]
  • 109.Yang, L. et al. N-substituted methyl ethylenediamine derivatives as corrosion inhibitors for carbon steel in 1 M hydrochloride acid. J. Mol. Struct.1270, 133975 (2022). [Google Scholar]
  • 110.Shahmoradi, A. R. et al. Theoretical and surface/electrochemical investigations of walnut fruit green husk extract as effective inhibitor for mild-steel corrosion in 1M HCl electrolyte. J. Mol. Liq.338, 116550 (2021). [Google Scholar]
  • 111.Verma, C., Quraishi, M. A. & Yop, K. Electronic effect vs . Molecular size effect : Experimental and computational based designing of potential corrosion inhibitors. Chem. Eng. J.430, 132645 (2022). [Google Scholar]
  • 112.Khaled, K. F. & Amin, M. A. Electrochemical and molecular dynamics simulation studies on the corrosion inhibition of aluminum in molar hydrochloric acid using some imidazole derivatives. J. Appl. Electrochem.39, 2553–2568 (2009). [Google Scholar]
  • 113.Khaled, K. F. Electrochemical investigation and modeling of corrosion inhibition of aluminum in molar nitric acid using some sulphur-containing amines. Corros. Sci.52, 2905–2916 (2010). [Google Scholar]
  • 114.Li, X., Deng, S. & Xie, X. Experimental and theoretical study on corrosion inhibition of oxime compounds for aluminium in HCl solution. Corros. Sci.81, 162–175 (2014). [Google Scholar]
  • 115.Liu, J., Wang, D., Gao, L. & Zhang, D. Synergism between cerium nitrate and sodium dodecylbenzenesulfonate on corrosion of AA5052 aluminium alloy in 3 wt.% NaCl solution. Appl. Surf. Sci.389(369), 377 (2016). [Google Scholar]
  • 116.Awad, M. K., Metwally, M. S., Soliman, S. A., El-Zomrawy, A. A. & bedair, M. A.,. Experimental and quantum chemical studies of the effect of poly ethylene glycol as corrosion inhibitors of aluminum surface. J. Ind. Eng. Chem.20(796), 808 (2014). [Google Scholar]
  • 117.Sliem, M. H. et al. AEO7 surfactant as an eco-friendly corrosion inhibitor for carbon steel in HCl solution. Sci. Rep.10.1038/s41598-018-37254-7 (2019). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 118.Umoren, S. A., Suleiman, R. K., Obot, I. B., Solomon, M. M. & Adesina, A. Y. Elucidation of corrosion inhibition property of compounds isolated from butanolic date palm leaves extract for low carbon steel in 15% HCl solution: Experimental and theoretical approaches. J. Mol. Liq.356, 119002 (2022). [Google Scholar]
  • 119.Zehra, B. F. et al. Crataegus oxyacantha leaves extract for carbon steel protection against corrosion in 1M HCl: Characterization, electrochemical, theoretical research, and surface analysis. J. Mol. Struct.1259, 132737 (2022). [Google Scholar]
  • 120.Abd El Haleem, S. M., Abd El Wanees, S. & Bahgat, A. Environmental factors affecting the corrosion behaviour of reinforcing steel. VI. Benzotriazole and its derivatives as corrosion inhibitors of steel. Corros. Sci.87, 321–333 (2014). [Google Scholar]

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