Table 2.

Research articles published so far on solar or UVA-Visible light photocatalytic ozonation of water contaminants ^a.

Compounds Treated and Processes Applied	Data on Catalysts, Ozone, and Others	Radiation Source	Photoreactor Type	Observations	Ref.
Effluent from an urban wastewater lagoon. Total coliforms followed solar photolysis photocatalytic oxidation (SPO).	P25 TiO2 alone: 2 g L−1. Activated carbon (AC) alone: 0.3 g/L. Mixture TiO2-AC: 2.3 g L−1. Ozone dose or concentration: not given.	Solar light: 10 to 14 h radiation.	Agitated or bubble vessels of 250 mL.	COD removal: 40% with SPO (best result) and AC-TiO2. Total coliforms removal: >99.99%. Inorganic ions determined: NO2−, PO43−. Fourier Transform FTR study.	[41]
2,4 dichlorophenol (DCP) at 100 mg L−1. H2O2 concentration: 250 and 75 mg/L in UV/H2O2 and UV/Fe/H2O2, respectively. O3 + Fe(II) + UV, photo-Fenton, UV + Fe(III), UV + H2O2, photocatalysis and photolysis.	Two catalysts: 1. Fe(III): 10–30 mg L−1 as FeCl3. 2. TiO2: 0.5 g L−1. Ozone: 5.5 g h−1.	1. Blue UVA lamp (350 nm); 2.5 μE s−1. 2. Solar simulator: 6 μE s−1. 3. The Sun: 236 μE s−1. 4. Eight 15 W UVA blue fluorescent lamps (300–420 nm): 120 μE s−1 (μE s−1: μEinstein s−1).	1. UV, UV + H2O2, UV + Fe(II), Photo-Fenton runs in 12 × 13 cm photoreactor. 2. Solar simulator with parabolic mirrors and quartz tube reactor. 3. Three compound parabolic collectors CPC, each with eight tubes in series. 4. One 2 L gas-liquid contactor + tube photoreactor.	Scaling up factors for scaling up to pilot-plant size. Estimation of amount of waste water that could be treated. Analysis: DCP concentration and TOC. DCP degradation is plotted as a function of accumulated photons per liter entering the reactor. Apparent pseudo first order kinetics. Pseudo quantum yield as a function of incident energy.	[42]
2,4-dichlorophenoxyacetic acid, bisphenol A, Sodium butylnaphthalenesulfonate and benzyldodecyldimethyl-ammonium bromide surfactants. 2 mM concentration: 100, 175 and 250 mg L−1. Processes: O3, O3/UV, O2/UV/TiO2 and O3/UV/TiO2.	P25 TiO2 at 2 g L−1.	One 75 W High Pressure Hg lamp (3 mW cm−2 at 360 nm) and the Sun.	Twenty Pyrex glass tubular reactors.	TOC measurement.	[40]
Phenol: 0.169 mg L−1. Processes: O3, O3/Vis, O2/Vis/cat, O3/cat and O3/Vis/cat. Ozone process: 0.45 g h−1.	Commercial WO3 powder and n-TiO2: 0.2 g L−1.	300 W Xe lamp with a cut-off filter (k > 420 nm).	Pyrex inner-irradiation vessel placed in a water bath set at room temperature.	Catalyst characterization: SEM, XRD, SBET. AOP comparison results for compound concentration and TOC. Repetitive experiments for catalyst reuse.	[43]
Orange II dye: 10−4 M. Processes: O3 100 mL/min and 2 mg L−1 of ozone in influent gas. Processes: O3, O3 cat, O2/UV/cat, O3/UV/cat.	Bi2O3 and Au/Bi2O3 nanorods: 1 g L−1.	55 W Xe lamp with 20,200 Lux and a 320 nm cut-off filter. Wavelength > 320 nm.	A 500-mL capacity borosilicate glass photoreactor with walls covered with aluminum foil to avoid the release of radiation.	Microwave and hydrothermal methods of catalyst synthesis. Catalyst characterization: DRX, SEM, TEM, XPS, EDX, DRUV-visible. Dye absorbance and concentration. Role of photosensitization. Reusability studies. Byproduct identification.	[44]
2-Chlorophenol, 2,4-dichlorophenoxyacetic acid, bisphenol A, sodium dodecylbenzenesulfonate, sodium butylnaphthalenesulfonate, and benzyldodecyldimethyl- ammonium bromide surfactants at 0.5 and 0.1 mM in simulated wastewater. Processes: UV/O3, O2/TiO2/sunlight, and O3/TiO2/sunlight. 3 mg L−1 dissolved ozone.	Dispersed TiO2 P25 (0–2 g L−1) and TiO2-coated glass.	Solar light.	Pilot plant: three modules of 40 Pyrex glass tubes (inner diameter, 1.76 cm; length: 145 cm), each connected in series. Photoreactor volume: 42.3 L and total solar light harvest area of the three modules: 3.06 m2. Bubble ozone column connected in series with photoreactor modules. Solar cell for electric power to the photoreactor and ozonator.	Contaminants, chloride ion concentrations, and TOC followed vs. accumulated sunlight energy incident on the photoreactor per liter of the solution.	[45]
Dyes: Rhodamine B for UVA radiation and Methylene Blue for Visible radiation. At 10 mg L−1.	TiO2 and M-TiO2 catalysts. M = Ag+, Cu2+, Mn2+, Ce3+, Fe3+ and Zr4+ ions. Main catalyst used: Mn-TiO2 0.25 g L−1 (0–7% Mn).	Lamp not given; full solar radiation wavelength (300 and above) and only visible light (λ > 400 nm).	Cylindrical Pyrex vessel surrounded by a cooling water jacket in a solar simulating box.	Catalyst characterization: DRX, SBET, DRUV-Vis. Absorbance of dyes solutions followed. Correlation between SBET and dye removal percentage.	[46]
Metoprolol (MTP) at 10 to 50 mg L−1 Processes: O3/Light, O3/Cat/Light, and all combinations.	1. Fe3O4/TiO2/AC 331 m2 g−1, 68% Anatase (0.38 g L−1) 2. P25 TiO2 (0.25 g L−1). Ozone gas inlet: 20 L h−1 and 6 mg L−1.	1500 W Xe lamp with limited radiation above 300 nm with filters. 550 W/m2.	Glass-made agitated tank provided with gas inlet, gas outlet, and liquid sampling ports.	Catalyst characterization: nitrogen adsorption, XRD, FTIR, SEM, EDX, SQUID magnetometer. Reusability and activity in five cycles. MTP Concentration. TOC followed.	[47]
Dichloroacetonitrile at 1 ppm. Ozone: 1–1.4 g L−1 h−1. Processes: UVsolar/TiO2, O3, O3/TiO2, UVsolar/O3, and UVsolar/TiO2/O3.	P25 TiO2 ozono dosage: 1–1.38 g L−1 h−1.	Three halide lamps (100, 250, and 400 W) and the Sun with similar light spectra from 300 to 800 nm.	1. Bench system: three halide lamps (100, 250, and 400 W), 60 cm at the top of three quartz tubes (40 cm × 2.7 cm). 2. CPC reactor (38° tilted) and cylindrical ozone reactor (1.1 m high, 10 cm internal diameter) in series. Turbulent regime.	Influence of different AOPs, pH (3, 6.5, and 10), W (4.6 to 33.8 W m−2), catalyst dosage 0.2–2.5 g L−1. Temperature: 10 to 40 °C.	[48]
Bisphenol A (BPA) and oxalic acid, 10 mg L−1. Ozone: 1 mL min−1 and 500 mgh−1. Processes: O3, UV-Vis/cat/O2, O3/UV-Vis/cat.	Graphitic carbon nitride (g-C3N4): Composed of numerous interconnected nanosheets, 0.5 g L−1.	High-pressure Xee long-arc lamp jacketed by a quartz thimble (GXZ500 W). Filter with Na2NO2 to cut λ < 400 nm.	One 1 L glass tubular photoreactor (8.5 × 40 cm).	Synthesis (from urea) and characterization TEM, FTIR, BET (67 m2 g−1), XRD, UV-Vis (2.7 eV, 450 nm max.). Rates for oxalic acid and BPA higher than sum of rates of single processes. Tert-butanol (TBA), triethanolamine (TEOA), and benzoquinone (BQ) act as the hydroxyl radical, hole and O2—scavenger.	[49]
Metoprolol, 50 ppm. Processes: O3/Light, O3/Cat/Light, and all combinations.	1. Fe3O4/TiO2/AC 331 m2 g−1, 68%. Anatase (0.38 g L−1) 2. P25 TiO2 (0.25 g L−1). Ozone gas inlet: 20 L h−1 and 6 mg L−1.	1500 W Xe lamp with limited radiation above 300 nm with filters. 550 Wm−2. 300–800 nm, 320–800 nm, and 390–800 nm.	Glass-made agitated tank provided with gas inlet, gas outlet, and liquid sampling ports.	Catalyst preparation and characterization (nitrogen adsorption, XRD, SEM, EDX, XPS and SQUID magnetometer). MTP concentration and TOC, dissolved O3, H2O2, acid intermediates.	[50]
Atenolol, Hydrochlorothiazide, Ofloxacin, and Trimethoprim in ultrapure water (10 mg L−1 doping) and WWSE (0.5 mg L−1 doping). Processes: O3, UVA-Vis, O3/cat, O3/UVA-Vis, O2/cat/UVA-Vis, O3/Cat/UVA-Vis.	P25 TiO2 45 L h−1 and 20 mg L−1 for ozone in the inlet gas.	Solar light (visible + UVA) with: 35 ± 5 W m−2.	CPC: four tubes in series, 300–400 L h−1. Water flow rate for recirculation T = 18–30 °C.	ECs concentration, TOC, ecotoxicity (Daphnia magna), Phenolic compounds formed, BOD/COD. Ozone consumption.	[51]
Caffeine, metoprolol, and ibuprofen: 2 mg L−1 each in Municipal Wastewater MWW Processes: O3, UVA-Vis, O3/cat, O3/UVA-Vis, O2/cat/UVA-Vis, O3/Cat/UVA-Vis. 20 mg/L O3 and 20 L h−1.	WO3/TiO2 (from P25 and titanate nanotubes) 3.8%. WO3 and 0.5 g L−1.	1500 W Xe lamp with limited radiation restricted to wavelengths over 320 nm because of the presence of quartz, glass, and polyester cut-off filters with 550 W m−2.	0.5L semi-batch glass-made spherical reactor, provided with a gas inlet, a gas outlet, and a liquid sampling port in a commercial solar simulator chamber.	Catalyst characterization: ICP, N2 adsorption–desorption isotherms (SBET), XRD, TEM, Raman, XPS, and DRUV-Vis spectroscopy. Contaminant concentration and TOC followed.	[52]
Oxalic acid: 0.01 M (TOC = 240 ppm).	TiO2P25, Nb2O5, SnO2, WO3, Fe2O3, In2O3, and BiVO4: 2 g/L. O3: 14 mg L−1 and 0.45 g h−1.	300 W Xe lamp with an IR cut-off filter. Incident light was ca. 200 mW in the range of 360 to 470 nm. For only visible irradiation, another filter was used: λ > 410 nm.	Pyrex inner irradiation vessel placed in a thermostatic water bath.	SBET: 1.7 to 54.1 m2 g−1 TOC. Visible active properties of semiconductors (only WO3, Fe2O3, In2O3, and BiVO4). WO3: Best material for photocatalytic ozonation under visible light irradiation.	[53]
Ibuprofen: 10 mg L−1, and a mixture of acetaminophen, metoprolol, caffeine, hydrochlorothiazide, antipyrine, sulfamethoxazole, carbamazepine, ketorolac, diclofenac, and ibuprofen in an MWWT: 0.5 mg L−1 each Processes: adsorption, photolysis, O3, UVA-Vis, O3/cat, O3/UVA-Vis, O2/cat/UVA-Vis, O3/cat/UVA-Vis. Ozone processes: 10 mg L−1 and 20 L h−1 gas.	WO3: 0.25 g L−1.	1500 W air-cooled Xe arc lamp with emission restricted to visible light (λ > 390 nm) because of quartz, glass, and polyester cut-off filters. 550 Wm−2.	0.5-L glass-made spherical reactor in the chamber of a box simulator.	Preparation conditions: Calcination temperature and time. Characterization: TGA-DTA, XRD, N2 adsorption-desorption isotherms, pHPZC, XPS, and DRUV-Vis spectra. Contaminant concentrations and TOC followed. Mechanism, kinetic regime of ozonation.	[54]
N,N-diethyl-meta-toluamide DEET: 5 mg L−1 Processes: adsorption, photolysis, O3, UVA-Vis, O3/cat, O3/UVA-Vis, O2/cat/UVA-Vis, O3/Cat/UVA-Vis. Ozone processes: 10 mg L−1 and 15 L h−1 gas.	Commercial and homemade WO3 catalysts: 0.25 g L−1. Calcination temperature: 500 to 700 °C.	1500 W air-cooled Xe arc lamp with emission restricted to visible light (λ > 390 nm) because of quartz, glass, and polyester cut-off filters. 550 Wm−2.	0.5 L glass-made spherical Reactor in the chamber of a box simulator	Synthesis method. Catalyst characterization: XRD, Raman, N2 adsorption-desorption isotherms (SBET), SEM, XPS. Contaminant concentration and TOC followed. Oxalic, acetic, and formic acids were followed.	[55]
Acetaminophen, antipyrine, bisphenol A, caffeine, metoprolol, testosterone. Concentratoin: 1.5 and 2.9 mg L−1 (10−5 M each). Processes: Sun, O3, Fe(III), or P25 TiO2 combinations. Also, H2O2 for photo-Fenton.	Fe(III) (homog.: 2.79 mg L−1, pH 3), TiO2 (heterog.: 200 mg L−1, pH 7). In some cases: Fe(III)/H2O2 = 6.09 mass ratio. 13 mg L−1 ozone in gas.	The Sun. Average solar radiation: 40 W m−2.	Four borosilicate glass tube CPCs (29.4 × 75 cm). Collector surface 0.25 m2. Illumination volume: 1.8 L. Tilted 45° to the south. Parabolic anodized aluminum reflectors. Turbulent regime. Semi-batch mode.	Concentrations and TOC removal. Energy and ozone demands. Kinetic regimes. Kinetics.	[56]
Acetaminophen, antipyrine, bisphenol A, caffeine, metoprolol, testosterone in secondary WWSE effluent (BOD = 10, COD = 58.6; TOC = 20 mg L−1). Presence of anionic ions. Concentrations between 1.5 and 0.2 mg L−1. Processes: Sun, O3, Fe(III), or P25 TiO2 and their combinations. Also, H2O2 in some cases.	Fe(III) (homog.: 2.8 mg L−1, pH 3), TiO2 (heterog.: 200 mg L−1, pH 7). 13 mg L−1 ozone in gas.	The Sun. Average solar radiation: 40 Wm−2.	Four borosilicate glass tube CPCs (29.4 × 75 cm). Collector surface 0.25 m2. Illumination volume: 1.8 L. Tilted 45° to the south. Parabolic anodized aluminum reflectors. Turbulent regime. Semi-batch mode. Reaction time: 5 h (+30 min, previous for adsorption).	Concentrations and TOC removal. Also, ions and total phenol concentration. Daphnia magna ecotoxicity measurements. Measurements of HO· radicals concentration with p-chlorobenzoic acid as a probe compound. Biodegradability as BOD/COD. Economic considerations.	[57]
Diuron, o-phenylphenol, 2-methyl-4-chlorophenoxyaceticacid (MCPA), and tert-buthylazine (5 mg L−1 each). Processes: O3, UVA-Vis, O3/cat, O3/UVA-Vis, O2/cat/UVA-Vis, O3/cat/UVA-Vis.	TiO2 and 0.5–0.8 wt. % B-TiO2 0.33 g L−1. Ozone in the inlet gas: 5 mg L−1 and 10 L h−1.	1000 W Xe lamp. Incident radiation flux: 8.96 × 10−4 Einstein min−1. Radiation intensity: 500 W m−2.	Glass-made agitated tank provided with gas inlet, gas outlet, and liquid sampling ports in a solar simulator box.	Synthesis and characterization: ICP-OES, N2 adsorption–desorption, XRD, XPS, and DRUV-Vis spectroscopy (3.01 and 3.03 eV band gap) Compound concentration. TOC, dissolved ozone, and H2O2 concentrations. B leached.	[58]
Acetaminophen (ACM), antipyrine (ANT), caffeine (CAF), ketorolac (KET), metoprolol, sulfamethoxazole (SFX), carbamazepine (CARB), hydrochlorothiazide (HCT), and diclofenac (DIC). In WWPE doped: 200 μg L−1 each. Processes: solar photocatalysis with O3/TiO2, solar photo-Fenton, or ozonation.	Three catalysts: 1. pH 3 with 2.8 mg L−1 Fe(III). 2. 150 mg L−1Fe3O4. 3. Natural pH with 250 mg L−1 P25 TiO2. Ozone in the inlet gas: 33.6 L h−1 and 13 mg L−1.	Radiation source: Sun.	Aerobic tank: HRT of 7 h, biomass sludge aged 5–6 days. MLVSS.MLSS−1: 0.8. Oxygen: 2–4 mg L−1. Reactor Volume: 5 L (1.8 L of irradiated volume) compound. Parabolic collector. Four borosilicate glass tube CPCs (29.4 × 75 cm).	Aerobic degradation followed by AOP, solar photocatalysis. ECs concentration, TOC, COD, ecotoxicty. Accumulated UV-vis energy calculated.	[59]
Bisphenol A and oxalic acid (OA), 10 mg L−1 at 1 mL min−1 and 500 mgh−1.	Graphitic carbon nitride: g-C3N4 composed of numerous interconnected nanosheets. Concentration: 0.5 g L−1	High-pressure Xe long-arc lamp, jacketed by a quartz thimble (GXZ500 W). Filter with Na2NO2 to cut λ < 400 nm.	1 L glass tubular photoreactor (8.5 × 40 cm).	Synthesis (from urea) and characterization (TEM, FTIR, BET (67 m2/g), XRD, UV-Vis (2.7 eV, 450 nm max.). Rates for oxalic acid and BPA higher than sum of single processes: O3 and UV-Vis/cat/O2. Tert-butanol, (TBA), triethanolamine (TEOA), and benzoquinone (BQ) as HO·, hole and O2—scavengers.	[60]
Oxalic acid, 0.11 mM.	gC3N4-reduced graphene oxide (rGOxide) 0.2 g/L. Ozone: 75 mgh−1.	As in Reference [56].	As in Reference [56].	Catalyst characterization. 2% rGO leads to best results for OA removal. Catalyst activity and stability. Basic mechanism.	[61]
Phenol in water and urban wastewater: 50 mg/L (DOC: 20 mg L−1, COD: 40 mg L−1, pH 7.4) Processes: Ozonation, photocatalysis, and photocatalytic ozonation	Ag, Cu, Fe on TiO2: 0.5 g L−1 Ozone: 20.83 mg L−1 min−1	Heraeus TQ 150 W immersion medium-pressure Hg lamp 70 mW cm2. The lamp emission spectrum has main peaks at 253.7, 313, and 366 nm in the UV range and 436, 546, and 578 nm in the visible range. For solar runs: 37.6 mW cm−2.	For UV runs: cylindrical quartz photochemical reactor (0.7 L) wrapped in aluminum foil. For solar runs: glass tubular reactor (1 m in length and 0.04 m in diameter) and a parabolic solar collector.	Best catalyst: Fe-TiO2 which presents the highest BET area and higher λ visible absorption (530 nm). Phenol concentration. COD, Langmuir kinetics applied simplified to pseudo first order kinetics. Synergic index, pseudo first rate constants calculated.	[62]
t-Butilazina: 5 mg L−1. Processes: Adsorption onto AC and multi-walled carbon nanotube (MWCNT), UV photolysis, UV/H2O2, single ozonation, O3/H2O2, catalytic ozonation (AC, MWCNT and TiO2 as catalysts) and some solar driven processes such as photo ozonation, TiO2-photocatalytic oxidation, and TiO2-photocatalytic ozonation.	AC (DARCO®, 12–20 mesh) and MWCNTs (purity > 95%) carbon, P25 TiO2, and other TiO2 prepared and TiO2-MWCNT. Ozone: 10 mg L−1, 20 L h−1.	Low-pressure Hg lamp with emission at 254 nm (Heraeus, model TNN15/32). Average fluence rate: 0.6 W–1 (2.9 mW cm−2). For UVA-visible: 1000 W Xe lamp (300–800 nm). 581 W m−2 (62 Wm−2 UV-A irradiance.	For UVC photolysis and UV/H2O2: photoreactor provided with a central quartz well. For O3 and O3/cat runs: 400 mL semi-batch spherical Pyrex-made reactor provided with magnetic agitation. For photoprocesses: The same reactor as in ozone processes inside a Suntest solar simulator equipment	Characterization: XRD, SBET, TEM, FTIR. Isotherm and different AOPs and adsorption kinetics TBA concentrations and intermediates by HPLC-qTOF.	[63]
N,N-diethyl-meta-toluamide (DEET): 5 mg L−1. Processes: Different AOPs and adsorption.	Two CeO2 catalysts: nanorod and nanocubes. Hydrothermal method. Concentration: 0.25 g L−1. Ozone: 10 mg L−1. 15 L h−1.	1500 W Xe lamp: 550 W m−2 and 300 to 800 nm or 400 to 800 nm with filter.	Semi-batch borosilicate glass-made round flask in a Suntest CPS solar simulator.	Catalyst preparation and characterization: XRD, XPS, SBET, DR UV-Vis. DEET concentration, TOC, O3 dis. H2O2, short chain carboxylic acids. Pseudo first order kinetics.	[64]
N,N-diethyl-meta-toluamide (DEET): 15 mg L−1. Ozone processes: 10 mg L−1, 15 L h−1 gas flow rate.	Monoclinic WO3 calcined at 600 °C (see Mena et al., 2015): 0.25 g L−1.	1500 W air-cooled Xe arc lamp with emission restricted to visible light (λ > 390 nm) because of quartz, glass, and polyester cut-off filters. 550 W m−2.	0.5 L glass-made spherical reactor in the chamber of a box simulator.	HPLC-qTOF identification of intermediates. Mechanism and kinetics based on TOC removal. Scavengers used: t-butanol and oxalate. Arrhenius equation determined for DEET-O3 reaction.	[65]

^a COD: Chemical Oxygen Demand. AC: Activated Carbon. FTIR: Fourier Transform Infrared. SEM: Scanning electron microscopy. XRD: X-ray diffraction. SBET: Surface area from Brunauer-Emmer-Teller isotherm. TEM: Transmission electron microscopy, XPS: X-ray photoelectron spectroscopy. DRUV-Vis: Diffuse reflectance UV-Visible spectroscopy, EDX: Energy dispersive X-ray spectroscopy, SQUID: Superconducting quantum interference device, WWSE: Wastewater secondary effluent. BOD: Biological Oxygen Demand. ECs: Emerging contaminants. WWPM: Wastewater primary effluent. ICP-OES: Inductively coupled plasma-optical emission spectroscopy. HRT: Hydraulic residence time. HPLC-qTOF: High performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. TGA-DTA: Thermogravimetric and differential thermal analysis.