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. 2023 Jul 24;13:11933. doi: 10.1038/s41598-023-38821-3

Table 1.

Adsorption isotherms, kinetics, and thermodynamics.

Isotherms, kinetics, and thermodynamics Equation References Parameters
Langmuir 1qe=1qm+1qm×KL×(Ce)-1 37 qm = maximum adsorption on MPPs (mg/g), KL = Langmuir constant (L/mg)
Freundlich Logqe=1nLogCe+LogKf 38

qe = chemicals absorbed per unit adsorbent at equilibrium (mg/g)

Ce = equilibrium adsorbate concentration (mg/L)

Kf and n = Freundlich adsorption isotherm constants

Pseudo-first-order lnqe-qt=lnqe-K1t 39

qe = chemicals adsorbed at equilibrium (mg/g)

qt = chemicals absorbed at time t (mg/g)

K1 = pseudo-first-order constant rate (min−1)

Pseudo-second-order tqt=1K2qe2+tqe 40 K2 = pseudo-second-order constant rate (g mg−1 min−1)
Thermodynamics

ΔG=-R×T×ln(KL)

KL=qeCe

ln(KL)=-ΔHRT+ΔSR

ΔG=ΔH-T×ΔS

41

ΔG° = Gibbs free energy,

ΔS° = standard entropy

ΔH°= standard enthalpy

T = temperature (K)

R = the universal gas constant (8.314 J/mol K)