Catalytic ozonation of p-chlorobenzoic acid by activated carbon and nickel supported activated carbon prepared from petroleum coke

Ni-based catalysts used in heterogeneous catalytic ozonation for organic pollutant degradation: a minireview

Among various advanced oxidation processes for wastewater treatment, heterogeneous catalytic ozonation (HCO) has a growing interest in pollutant degradation, e.g., pesticides, pharmaceuticals, cresols, detergents, polymers, dyes, and others. Direct oxidation with ozone can occur by this route or indirectly, generating reactive oxygen species through the catalytic activation of the ozone molecule. Then, many catalytic materials were evaluated, such as unsupported and supported oxides, activated carbon, nanocarbons, carbon nitride, and mesoporous materials. This review focuses on the properties and performance of Ni-based catalysts (NiO, supported NiO, Ni ferrites, and M-Ni bimetallic), emphasizing the reaction mechanisms and the importance of the reactive oxygen species in removing toxic organic compounds.

Recent Developments in Activated Carbon Catalysts Based on Pore Size Regulation in the Application of Catalytic Ozonation

Due to its highly developed pore structure and large specific surface area, activated carbon is often used as a catalyst or catalyst carrier in catalytic ozonation. Although the pore structure of activated carbon plays a significant role in the treatment of wastewater and the mass transfer of ozone molecules, the effect is complicated and unclear. Because different application scenarios require catalysts with different pore structures, catalysts with appropriate pore structure characteristics should be developed. In this review, we systematically summarized the current adjustment methods for the pore structure of activated carbon, including raw material, carbonization, activation, modification, and loading. Then, based on the brief introduction of the application of activated carbon in catalytic ozonation, the effects of pore structure on catalytic ozonation and mass transfer are reviewed. Furthermore, we proposed that the effect of pore structure is mainly to provide catalytic active sites, promote free radical generation, and reduce mass transfer resistance. Therefore, large external surface area and reasonable pore size distribution are conducive to catalytic ozonation and mass transfer.

Degradation of tetracycline hydrochloride in aqueous via combined dielectric barrier discharge plasma and Fe-Mn doped AC

Dielectric barrier discharge (DBD) plasma coupled with Fe-Mn doped AC (Fe-Mn/AC) was used to enhance the degradation of tetracycline hydrochloride (TCH) wastewater. Fe-Mn/AC catalysts with different Fe/Mn molar ratios were prepared by hydrothermal method, and the physical and chemical properties of the samples were explored by different characterization techniques, including XRD, SEM, TEM and XPS. The results showed that the combination of DBD with Fe₂-Mn₁/AC system had the highest effect, and the degradation efficiency of TCH could reach 98.8 % after 15 min treatment, which was 25.5 % higher than that of DBD-only. With the increase of discharge voltage and catalyst dosage, the degradation efficiency of TCH promoted. And initial pH had little effect on the degradation of TCH. In the combined system, the Fe₂-Mn₁/AC catalyst could retain an excellent stability and reusability. The addition of dimethyl sulfoxide (DMSO) showed that ·OH participated in the TCH degradation. The generated O₃ might be catalyzed by Fe-Mn/AC catalyst to produce more ·OH. And more H₂O₂ was produced in DBD-only system than that in DBD-catalytic system. Nine main degradation intermediate products in the combined system were detected by HPLC-MS, and three possible degradation pathways were proposed.

Effective mineralization of p-nitrophenol by catalytic ozonation using Ce-substituted La1‒xCexFeO3 catalyst

In this study, cerium-doped lanthanum ferrite perovskite oxides (La_1‒xCe_xFeO₃) with different A-site were synthesized using a sol-gel method and they were used as ozonation catalyst for p-nitrophenol (PNP) mineralization for the first time. Catalytic activity in terms of total organic carbon (TOC) removal followed the order of La_0.8Ce_0.2FeO₃ > La_0.4Ce_0.6FeO₃ > La_0.6Ce_0.4FeO₃ > La_0.2Ce_0.8FeO₃ > LaFeO₃ with 77, 66, 61, 60 and 56% respectively. The synthesized catalysts were characterized by diffraction of X-ray (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET) and scanning electronic microscopy (SEM). Moreover, electron spin resonance (ESR) and radicals quenching experiments showed that the active oxygen species in the ozone decomposition process are mainly hydroxyl radical (·OH), and also include superoxide radical (O₂^-) and singlet oxygen (¹O₂). Furthermore, the superior activity of La_0.8Ce_0.2FeO₃ could be attributed to the higher surface area, the richer lattice oxygen, richer surface -OH groups and the facilitated redox Ce³⁺/Ce⁴⁺ and Fe²⁺/Fe³⁺ cycling. In addition, this study provides an insight to use metal-doped perovskite catalysts for catalytic ozonation.

Activated carbon prepared from catechol distillation residue for efficient adsorption of aromatic organic compounds from aqueous solution

At present, activated carbon (AC) derived from industrial wastes has a great practical significance. In this work, residue activated carbon (RAC) was successfully synthesized from catechol distillation residue by a simple activation process based on two steps. The optimized RAC (RAC-800, activated at 800 °C) had high specific surface area (1800 m²/g) and large total pore volume (0.91 cm³/g). RAC-800 portrayed the evident increase of the graphitic structure and possessed abundant functional groups. Catechol (CC), phthalic acid (PA) and dimethyl phthalate (DMP) were chosen as typical pollutant to investigate the effect of different functional groups on adsorption aromatic compounds, and the equilibrium adsorption capacity of RAC-800 for CC, PA and DMP was 221.5, 365.0 and 449.9 mg/g, respectively. The adsorption behaviors were systematically studied by the combination of kinetic and thermodynamic model. The adsorption process was dominated by the π-π interaction, assisted by hydrogen bonding, hydrophobic and electrostatic interactions. In addition, regeneration study showed that the adsorption capacity can still remain over 88.5% after five cycles. In total, fine chemical distillation residues are promising to turn into the precursor of activated carbon, which has potential to be used as a good adsorbent for removal of aromatic compounds.

Catalytic Ozonation and Membrane Contactors—A Review Concerning Fouling Occurrence and Pollutant Removal

Membrane filtration has been widely used in water and wastewater treatment. However, this process is not very effective for the removal of refractory organic compounds (e.g., of pharmaceutical origin). Coupling membrane filtration with ozonation (or other Advanced Oxidation Methods) can enhance the degradation of these compounds and, subsequently, the incidence of membrane fouling (i.e., the major problem of membrane uses) would be also limited. Ozonation is an efficient oxidative process, although ozone is considered to be a rather selective oxidant agent and sometimes it presents quite low mineralization rates. An improvement of this advanced oxidation process is catalytic ozonation, which can decrease the by-product formation via the acceleration of hydroxyl radicals production. The hydroxyl radicals are unselective oxidative species, presenting high reaction constants with organic compounds. An efficient way to couple membrane filtration with catalytic ozonation is the deposition of an appropriate solid catalyst onto the membrane surface. However, it must be noted that only metal oxides have been used as catalysts in this process, while the membrane material can be of either polymeric or ceramic origin. The relevant studies regarding the application of polymeric membranes are rather scarce, because only a few polymeric materials can be ozone-resistant and the deposition of metal oxides on their surface presents several difficulties (e.g., affinity etc.). The respective literature about catalytic membrane ozonation is quite limited; however, some studies have been performed concerning membrane fouling and the degradation of micropollutants, which will be presented in this review. From the relevant results it seems that this hybrid process can be an efficient technology both for the reduction of fouling occurrence as well as of enhancement of micropollutant removal, when compared to the application of single filtration or ozonation.

Catalytic ozonation of phenylamine in water with a manganese ore

Recalcitrant pollutants, which form surface complexes with surface metal sites of the catalyst, are difficult to remove by catalytic ozonation in water. Phenylamine (PA), one of the refractory pollutants, was degraded by ozone catalysis with manganese ore in this paper. And the effectiveness and the mechanism of catalytic ozonation with manganese ore for the degradation of PA in water were studied. After the BET test, the specific surface area of the raw and calcined manganese ore was 27.65 m2 g-1 and 33.49 m2 g-1, respectively. The effects of solution pH, catalyst dose and reaction time on the degradation of PA were evaluated. Results showed that the catalytic potential of calcined manganese ore was better than that of raw manganese ore and ozonation alone in the degradation of PA. It revealed that the increase of hydroxyl radicals generated on the surface of the catalyst or in the solution improved PA degradation. Oxidation of free radicals was the main mechanism of PA degradation in the catalytic ozonation process, occurring with a pseudo-first-order reaction rate at a constant of 0.0993 min-1 (CMP) under the pH of 7.20 and catalyst dose of 3 g L-1. Also, an activation energy of 20.4 kJ mol-1 for PA oxidation over CMP in the presence of O3 was estimated.

Study of the photodegradation of 2-chlorobenzoic acid by TiO2 and the effects of eutrophicated water on the reaction

The photodegradation of 2-chlorobenzoic acid (2-CBA) in suspensions of TiO₂ was examined under different operational parameters. The optimal condition could be obtained through the experiment, i.e. that the concentration of 2-CBA was 30 mg/L and the dosing quantity of TiO₂ was 0.01 g under UV light in the case of pH 3.5. Above reaction process was in accordance with first order kinetics model. The influence on photocatalytic degradation caused by typical anions in eutrophicated water body such as NO₃ ^- and H₂PO₄ ^- was explored in this work, which revealed that both two anions had inhibitory effect on the degradation process. In addition, alcohol was introduced into the process to identify the degradation mechanism of 2-CBA with TiO₂, and the reaction route of 2-CBA could be predicted through the analysis on the intermediate.

Industrial Textile Wastewater Ozone Treatment: Catalyst Selection

One of the recent trends in textile wastewater treatment has become catalytic ozonation. The necessity of effective color removal in a short treatment time is a standard during industrial implementation. At the same time, efficient chemical oxygen demand (COD), total organic carbon (TOC), and toxic by-product removal are highly expected. This study presents the results of a catalytic ozonation treatment. Three types of catalysts: a metal oxide (TiO2 as P25 by Degussa), activated carbon (nano-powder by Sigma, AC), and metal particles (platinum, 1% wt. supported on AC matrix by Sigma, Pt–AC) have been applied. The investigations were conducted for real industrial wastewater originated in textile dyeing with Reactive Black 5 dye (RB5). The experiments ran for the raw wastewater (without pretreatment), exposed blocking of the catalytic action by all used catalysts. The catalytic effect could be observed when catalytic ozonation was used as a polishing step after electrocoagulation (EC). Although the catalytic effect could be observe for all catalysts then, especially in the removal of colorless by-products, the AC was exposed as the most effective. This contributed to 35% and 40% of TOC and COD removal. While only 18% and 23% of TOC and COD were removed in the same process without AC. The decrease in toxicity was 30%. The results of the study revealed the complexity of the issue and resulted in an extensive discussion devoted to the basis of the catalytic activity of each catalyst.

Preparation and Characterization of Cu-Mn-Ce@γ-Al2O3 to Catalyze Ozonation in Coal Chemical Wastewater-Biotreated Effluent

Cu-Mn-Ce@γ-Al₂O₃ was prepared by incipient wetness impregnation and used to catalyze ozonation in a coal chemical wastewater-biotreated effluent. The preparation factors that considerably affected the catalytic performance of Cu-Mn-Ce@γ-Al₂O₃, specifically metal oxide loading percentage, calcination temperature, and calcination time, were examined. The catalyst was characterized by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and Brunauer-Emmett-Teller analysis. The optimal catalytic ozonation operating parameters, such as ozone dosage, catalyst dosage, pH, and reaction time, were also investigated. Results showed that an optimized catalyst consisted of 17.0% CuO, 3.0% MnO₂, and 2.0% CeO₂ (wt.%). The optimal calcination temperature and calcination time were 600 °C and 5 h. The optimal catalytic ozonation operating parameters, including ozone dosage, catalyst dosage, pH, and reaction time, were 7, 80.0 mg/L, 20.0 mg/L, 7 and 50 min, respectively. The COD removal of biotreated effluent increased to 61% under these optimal operating conditions. Meanwhile, ozonation alone resulted in only 20% removal. This work proposes the use of easily available Cu-Mn-Ce@γ-Al₂O₃ catalyst and might drive the advancement of catalytic ozonation for chemical wastewater purification.

Catalytic ozonation of 4-chloronitrobenzene by goethite and Fe2+-modified goethite with low defects: A comparative study

In this study, Fe²⁺-modified goethite with low defects (α-Fe(Fe²⁺)OOH) was synthesized and characterized. Results revealed that α-Fe(Fe²⁺)OOH is a nano magnetic material with goethite (α-FeOOH) -type structures and has fewer Lewis acid of Fe³⁺ on its surface. Moreover, α-Fe(Fe²⁺)OOH was effective in catalytic ozonation of 4-chloronitrobenzene (4-CNB), which is a probe contaminant that cannot be efficiently removed through sole ozonation. The removal of 4-CNB increased with ozone concentration and α-Fe(Fe²⁺)OOH dosage, but decreased with the presence of carbonate, sulfate and phosphate. The catalytic activity of α-Fe(Fe²⁺)OOH also showed a dependence on solution pH. The presence of humic acid accelerated 4-CNB removal at low concentration but inhibited the removal at high concentration. In comparison with α-FeOOH, α-Fe(Fe²⁺)OOH significantly enhanced hydroxyl radicals generation and reduced Fe ions release in this process. The hydroxyl groups of Fe³⁺ on α-FeOOH and α-Fe(Fe²⁺)OOH surface was active site for ozone decomposition into hydroxyl radicals. Introducing Fe²⁺ significantly increased the density of surface hydroxyl groups relative to α-FeOOH. This enhancement significantly promoted hydroxyl radicals generation and 4-CNB degradation in the solution.

Acid-treated clay catalysts for organic dye ozonation - Thorough mineralization through optimum catalyst basicity and hydrophilic character

Catalytic ozonation of Methylene Blue, Methyl Green, Methyl Orange and Methyl-thymol Blue was investigated in the presence of ion-exchanged montmorillonite (NaMt and Fe(II)Mt), crude bentonite and acid-activated counterparts. An original approach never tackled so far consisted in correlating the basicity and hydrophilic character to the dye-catalyst interactions occurring on the catalyst surface. This was achieved through CO₂ and water thermal programmed desorption. Kinetics study revealed that ozonation starts in the bulk solution, and dye adsorption turns out to be an essential requirement for high catalytic effectiveness. On NaMt, dye molecules appear to adsorb mainly via hydrophobic interaction. On Fe(II)Mt, the contributions of hydrophobic interaction, cation-exchange and Fe²⁺ mobility to the catalytic activity prevail. Acid activated clay catalysts exhibited lowest hydrophilic character favoring adsorption through organophilic interaction and affording thorough and fast dye mineralization. This was explained in terms of increased number of silanols and -Si-O-Si- groups. For all catalysts, short ozonation of all dye molecules resulted in similar end-chain products, which were totally eliminated after prolonged reaction times. This result is of great importance because it provides valuable theoretical findings that allow envisaging total mineralization of organic molecules by recyclable metal-free clay catalysts.

Trichloroethene (TCE) hydrodechlorination by NiFe nanoparticles: Influence of aqueous anions on catalytic pathways

Amending bulk and nanoscale zero-valent iron (ZVI) with catalytic metals significantly accelerates hydrodechlorination of groundwater contaminants such as trichloroethene (TCE). The bimetallic design benefits from a strong synergy between Ni and Fe in facilitating the production of active hydrogen for TCE reduction, and it is of research and practical interest to understand the impacts of common groundwater solutes on catalyst and ZVI functionality. In this study, TCE hydrodechlorination reaction was conducted using fresh NiFe bimetallic nanoparticles (NiFe BNPs) and those aged in chloride, sulfate, phosphate, and humic acid solutions with concurrent analysis of carbon fractionation of TCE and its daughter products. The apparent kinetics suggest that the reactivity of NiFe BNPs is relatively stable in pure water and chloride or humic acid solutions, in contrast to significant deactivation observed of PdFe bimetallic particles in similar media. Exposure to phosphate at greater than 0.1 mM led to a severe decrease in TCE reaction rate. The change in kinetic regimes from first to zeroth order with increasing phosphate concentration is consistent with consumption of reactive sites by phosphate. Despite severe kinetic effect, there is no significant shift in TCE ¹³C bulk enrichment factor between the fresh and the phosphate-aged particles. Instead, pronounced retardation of TCE reaction by NiFe BNPs in deuterated water (D₂O) points to the importance of hydrogen spillover in controlling TCE reduction rate by NiFe BNPs, and such process can be strongly affected by groundwater chemistry.

Mechanism insight of pollutant degradation and bromate inhibition by Fe-Cu-MCM-41 catalyzed ozonation

A flexible catalyst, Fe-Cu-MCM-41, was employed to enhance diclofenac (DCF) mineralization and inhibit bromate formation in catalytic ozonation process. Greater TOC removal was achieved in Fe-Cu-MCM-41/O₃ process (78%) than those in Fe-MCM-41/O₃ (65%), Cu-MCM-41/O₃ (73%) and sole ozonation (42%). But it was interesting that both Cu-MCM-41/O₃ and Fe-MCM-41/O₃ achieved 93% bromate inhibition efficiency, only 71% inhibition efficiency was observed in Fe-Cu-MCM-41/O₃. Influence of pH, TBA/NaHSO₃ and detection of by-products were conducted to explore the mechanism. By Pyridine adsorption-IR and XPS, a relationship was found among activity of catalysts, Lewis acid sites and electron transfer effect between Fe (II/III) and Cu (I/II). Fe-Cu-MCM-41 promoted ozone decomposition to generate OH, which accounted for enhanced DCF mineralization. The consumption of aqueous O₃ also suppressed the oxidative of Br^- and HBrO/Br^-. More HBrO/BrO^- accumulated in catalytic ozonation process and less bromate generated. Bromate formation in Fe-Cu-MCM-41/O₃ process was sensitive with pH value, the acidic condition was not favor for bromate formation. Both DCF mineralization and bromate inhibition were influenced by surface reaction. Moreover, Fe-Cu-MCM-41 showed excellent catalytic performance in suppressing the accumulation of carboxylic acid, especially for oxalic acid. Nearly no oxalic acid was detected during Fe-Cu-MCM-41/O₃ process.

Synthesis of manganese incorporated hierarchical mesoporous silica nanosphere with fibrous morphology by facile one-pot approach for efficient catalytic ozonation

Manganese incorporated fibrous silica nanosphere (MnOx-0.013/KCC-1) was synthesized by one step hydrothermal method for the first time and its catalytic activity for ozonation of oxalic acid was studied. For comparison, manganese loaded MCM-41 (MnOx-0.013/MCM-41) was prepared by impregnation method. Various characterizations showed that the morphological, structural and textural properties of MnOx-0.013/KCC-1 were well preserved. Ozonation and catalytic ozonation by MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41 led to 4, 85 and 60% reduction in TOC respectively. Furthermore, 0.05 and 1.2mgL(-1) leaching of Mn was detected from MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41, which are approximately 2.0 and 42.0% of the total Mn present in MnOx-0.013/KCC-1 and MnOx-0.013/MCM-41 respectively. The high catalytic activity was attributed to the generation of hydroxyl radical. Surface hydroxyl groups investigated by using phosphates and ATR-FTIR were believed to be the active sites. Our proposed method of synthesis can be generalized for the synthesis of other metal oxides incorporated fibrous silica for environmental catalysis and other catalytic reactions.

Insights into the mechanism of phenolic mixture degradation by catalytic ozonation with a mesoporous Fe3O4/MnO2 composite

Mesoporous Fe₃O₄/MnO₂ is more active than Fe₃O₄ and MnO₂ in catalytic ozonation of phenols mixtures, and it is easily magnetically separated and very stable in recycling at pH 9.

Enhanced catalytic ozonation over reduced spinel CoMn2O4 for NOx removal: active site and mechanism analysis

In this paper, CO atmosphere reduced cobalt manganate (CoMn₂O₄/CO), prepared by a hydrothermal method, was successfully utilized in catalytic ozonation for NO_x removal.

Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse

Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

Heterogeneous catalytic ozonation of dibutyl phthalate in aqueous solution in the presence of iron-loaded activated carbon

Iron-loaded activated carbon was prepared and used as catalyst in heterogeneous catalytic ozonation of dibutyl phthalate (DBP). The catalytic activity of iron-loaded activated carbon was investigated under various conditions and the mechanisms of DBP removal were deduced. Characterization of catalyst indicated that the iron loaded on activated carbon was mainly in the form of goethite, which reduced its surface area, pore volume and pore diameter. The presence of metals on activated carbon positively contributed to its catalytic activity in ozonation of DBP. Iron loading content of 15% and initial water pH of 8 achieved highest DBP removal among all the tried conditions. Catalyst dosage of 10 mg L(-1) led to approximately 25% of increase in DBP (initial concentration 2 mg L(-1)) removal in 60 min as compared with ozone alone, and when catalyst dosage increased to 100 mg L(-1), the DBP removal was further improved by 46%. Based on a comparison of reaction rates for direct and indirect transformation of DBP, the increased removal of DBP in this study likely occurred via transformation of ozone into hydroxyl radicals on the catalyst surface.

Catalytic ozonation of 2,4-dichlorophenoxyacetic acid over novel Fe–Ni/AC

Novel Ni–Fe oxides supported on AC can highly improve the degradation and mineralization efficiency of 2,4-D by synergic oxidation.

Activated carbon enhanced ozonation of oxalate attributed to HO oxidation in bulk solution and surface oxidation: effect of activated carbon dosage and pH

Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon (AC) in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals (HO) in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol (tBA) with low dosages of AC, while it was hardly affected by tBA when the AC dosage was greater than 0.3g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05g/L, but it did not work when the AC dosage was no less than 0.1g/L. These observations indicate that HO in bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HO oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HO oxidation in basic bulk solution. A mechanism involving both HO oxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.

Photocatalytic ozonation of dimethyl phthalate with TiO2 prepared by a hydrothermal method

TiO(2) was prepared by a hydrothermal method at a low temperature and used to degrade and mineralize dimethyl phthalate (DMP). TiO(2) was characterized by XRD, TEM, BET and UV-vis techniques. The characteristics of TiO(2) prepared by a hydrothermal method (h-t TiO(2)) included a good crystalline anatase phase, greater surface area, stronger absorption to UV light wavelength and lower agglomeration than TiO(2) prepared by a classic sol-gel method (s-g TiO(2)). The photocatalytic activity of h-t TiO(2) prepared under optimal hydrothermal condition (180°C for 10h) was 2.5 times higher than that of s-g TiO(2) in degrading DMP. The process of photocatalysis combined with UV irradiation and ozonation (TiO(2)/UV/O(3)) considerably improved the mineralization and degradation of DMP compared to photocatalysis combined with UV irradiation (TiO(2)/UV), ozonation combined with UV irradiation (UV/O(3)), and ozonation alone (O(3)). A kinetic study showed the mineralization in TiO(2)/UV/O(3) followed the Langmuir-Hinshelwood model.