Table 1.

Solar photo-Fenton performed in the post-treatment of secondary municipal wastewater treatment plant for the removal of pharmaceutical drugs.

CEC	Concentration	Matrix (treatment technology)	Reactor	Reactor features	Iron Source	pH	Experimental Scale	Results	Reference
Acetamiprid (ACTM) group of 77 CECs, mainly drugs, belonging to different therapeutic groups, including some of their metabolites.	ACTM: 200 μg L−1 Total CECs: 30.3 ± 0.3 μg L−1	SW and MSE (CAS)	RPR (fiberglass – SW, and PVC – MWW)	SW: 5 cm liquid depth, 120 L of total volume and a mixing time of 5 min. MWW: 80 L of total volume with 15 cm of liquid depth with a mixing time of 3 min, or 18 L of total volume, with a liquid depth of 5 cm and a mixing time of 2 min.	Fe2+ (5.5 mg L−1)	Acid 3.0	Pilot-scale	No significant difference for different liquid depths tested during continuous operation mode (87 % for 15 cm and 89 % for 5 cm). For the different HRT, removal rates were: 79 % (20 min), 84 % (40 min) and 89 % (80 min).	(Arzate et al., 2017)
77 CECs, mainly drugs, belonging to different therapeutic groups, including some of their metabolites	0.1 ng L−1 to 31 μg L−1	MSE (CAS)	RPR (PVC)	0.98 m of length and 0.36 m width, divided by a central wall. A paddlewheel at 200 rpm, mixing time of ~1.52 min.	Fe2+ (3 × 20 mg L−1)	Natural	Pilot-scale	99 % removal of total CECs load within 90 min of treatment. However, some compounds still showed resistance to oxidation (salicylic acid). 56 % of the DOC was removed during treatment, decreasing from 20.6 to 9.1 mg L−1.Total H2O2 consumption after 90 min.	(Freitas et al., 2017)
Sulfamethoxazole (SMX) as a model CEC and 116 CECs including drugs, belonging to different therapeutic groups.	SMX: 50 μg L−1. Total CECs: 14 to 44 μg L−1.	MSE (CAS)	RPR	Lab. scale: internal diameter = 10 cm; height = 20 cm. Lateral walls covered. Pilot scale: 19 L of total volume, channel width 22 cm and mixing time = 2 min.	Fe2+ (20 mg L−1) Fe3+-EDDS (5.6:58 mg L−1)	Natural	Laboratory and pilot-scale	Lab. scale: For the Fe3+-EDDS, decrease in the liquid depth increased SMX removal, leading to >70 % removal regardless of the liquid depth. Pilot scale: 34–45 CECs were detected in wastewater. 35 ± 11 % CECs removal achieved with FeSO4 and 81 ± 17 % with Fe3+-EDDS after 15 min of reaction.	(Soriano-Molina et al., 2021)
Diclofenac (DCF), Trimethoprim (TMP) and Carbamazepine (CBZ)	200 μg L−1 of each	UP and MSE (CAS)	CTC	Irradiated volume of 10.24 L, 8 acrylic glass tubes (150 cm length, 3.3 cm external diameter and 0.25 cm thickness).	Fe2+ (5.6 mg L−1) Fe3+-EDDS (5.6:58 mg L−1)	Natural	Pilot-scale	Fe2+in MWW: Dark Fenton (0 min) removed 50 % of DCF; photo-Fenton reached 85 % removal of DCF in 30 min, and 40 % CBZ removal in 120 min. Fe3+-EDDS in MWW: 99 % removal of all CECs in 15 min.	(Maniakova et al., 2020)
Naproxen (NAP)	226,36 μg L−1	UP and MSE (UASB + PT)	Solar reactor	Conventional glass recipient depth: 4.9 cm; diameter: 15.5 cm, irradiated surface: 189 cm2, total volume: 500 mL artificial irradiation by two black light lamps (10 W each, 350–400 nm) placed in parallel (3.5 cm) 1.0 cm above the surface	Fe3+-oxalate Fe3+-citrate Fe3+-NTA Fe3+-EDTA Fe3+-EDDS	7.0	Laboratory scale	Best results obtained in the presence of Fe/EDDS (1:1) and Fe/NTA (1:1), Fe/EDTA (1:2), Fe/Cit (1:3) and Fe/Ox (1:12). NAP removal from UP was faster when using H2O2 (20 kJ m−2 required) compared to S2O82− (90 kJ m−2 required). Better performance of S2O82− was observed in MWW. Fe3+-citrate complex with H2O2 was the most cost-effective alternative for both matrices.	(Silva et al., 2021a)
Caffeine (CAF), carbendazim (CBZ), and losartan potassium (LP)	100 μg L−1 each	MSE (CAS)	Solar reactor and RPR	Lab. scale: Conventional glass recipient (400 mL) under simulated solar radiation (SunTest CPS+). RPR pilot-scale: 1.22 m maximum length, 1.02 m central wall length and 0.20 m width; total volume of 12 L; 5 cm liquid depth	Fe2+ (5 × 11 mg L−1)	7.0	Laboratory and pilot scale	Lab. scale: the strategy to perform solar photo-Fenton at neutral pH using intermittent iron additions was effective for modified photo-Fenton using persulfate as oxidant. Pilot scale: final removal of CECs obtained during solar/Fe/H2O2 at near-neutral pH reached 49 % (2.5 kJ L−1). Solar/Fe/S2O82− showed higher efficiency of CECs removal (55 %) (1.9 kJ L−1).	(Starling et al., 2021a)
Nimesulide (NMD), furosemide (FRS), paracetamol (PCT), propranolol (PPN), dipyrone (DIP), fluoxetine (FXT), diazepam (DZP), and progesterone (PRG)	500 μg L−1 of each	UP and SW	Solar reactor	1 L of total volume in a bold bottom reflector.	Fe3+-EDDS (EDDS: 0.05, 0.28 and 0.50 mmol L−1)	Natural	Laboratory-scale	99.9 % and 98.7 % removal of total CECs from UP and SW, respectively.	(Cuervo Lumbaque et al., 2019)
Acetamiprid (ACTM)	100 μg L−1	SW	RPR (Cylindrical PVC)	Lab scale: Stirred tank reactors, 0.85 L total volume, 15 cm diameter, conducted in SunTest CPS. Pilot scale: RPR made of PVC, 19 L, liquid depth of 5 cm, channel width of 22 cm and mixing time of 2 min.	Fe3+-EDDS (0.1:0.1 mM)	Natural	Laboratory and Pilot-scale	Lab scale: In all cases, the model was accurate to reproduce experimental data regarding ACTM removal in the first 5 min of reaction and with good prediction until 10 min. Pilot scale: results are similar to those observed in the solar simulator. Nearly 80 % removal of ACTM in winter and spring.	(Soriano-Molina et al., 2018)
O-desmethyltramadol (O-DSMT), O-desmethylvenlafaxine (O-DSMV) and gabapentin (GBP)	O-DSMT: 0.32–1.98 μg L1 O-DSMV: 0.681.32 μg L1, GBP: 0.94–7.86 μg L−1	MSE (CAS)	RPR (PVC)	Liquid depth of 5 cm, volume of 19 L and length of the straight section of 2.4 m. For the liquid depth of 15 cm, volume of 78 L and length of the straight section of 5.1 m.	Fe3+-EDDS (5.6:29 mg L−1)	Natural	Pilot-Scale	Comparing kinetic constants obtained for CEC oxidation, differences between effluents are not causally related to salinity. In the continuous operation flow, 78 % (HRT 15 min) and 76 % (HRT 10 min) CECs removal were obtained in 5 cm and 15 cm depth in the RPR.	(Soriano-Molina et al., 2019b)
A group of 92 CEC, most of them pharmaceuticals and agrochemicals	Total load ranges from 6.2 to 58 μg L−1	MSE (CAS)	RPR (PVC)	Total volume of 19 L, liquid depth of 5 cm, channel width of 22 cm and mixing time of 2 min.	Fe3+-EDDS (5.6:29 mg L−1)	Natural	Pilot-Scale	No detrimental effect of the initial concentration of the main anions upon CECs removal. Average removal of CECs for the 5 MWW effluents from CAS was 83 % (15 min; 30 W m−2).	(Soriano-Molina et al., 2019a)
A group of 92 CEC, most of them pharmaceuticals and agrochemicals	Total load of 15.8 ± 81 μg L−1	MSE (CAS)	RPR (PVC)	Total volume of 16 L, length of 0.98 m and width of 0.38 m; liquid depth of 5 cm.	Fe3+-EDDS (5.6:29 mg L−1 5.6:58 mg L−1)	Natural	Pilot-Scale	CEC removal for both Fe3+EDDS molar ratios tested in batch were similar: 65 % (1:1) and 69 % (1:2). In continuous treatment, CEC removal was 51 ± 3 % (1:1) and 57 ± 8 % (1:2).	(Arzate et al., 2020)
Acetaminophen, caffeine, carbamazepine, diclofenac, sulfamethoxazole and trimethoprim	Lab scale: 100 μg L−1 Pilot scale: 20 μg L−1	MSE (CAS)	RPR	Lab. scale: internal diameter of 19 cm and height of 19 cm. Liquid depth of 7 cm (1.6 L), 10 cm (2.4 L) and 15 cm (3.9 L). The lateral walls were covered. Pilot scale: volume of 19 L, channel width of 22 cm and. Reflexive aluminum surface at the bottom.	Fe3+-EDDS (Fe3+: 1, 2, 3, and 5.5 mg L−1)	Natural	Laboratory and Pilot-Scale	All experimental conditions achieved maximum efficiency for all the different liquid depths tested within 15 min of reaction. The positive influence of the reflexive surface on the bottom of the reactor was more apparent with lower initial iron concentrations.	(Costa et al., 2020)

Note: SW = simulated wastewater; MSE = municipal secondary effluent; UP = ultrapure water; CAS = conventional activated sludge; UASB + TP = Upflow anaerobic sludge blanket reactor followed by post-treatment; RPR = raceway pond reactor; CTC = compound triangular collector. Only Arzate et al. (2017) did not perform the treatment at circumneutral pH.