Photodegradation of the novel fungicide fluopyram in aqueous solution: kinetics,transformation products,and toxicity evolvement

The aqueous photodegradation of fluopyram was investigated under UV light (λ?≥?200 nm) and simulated sunlight irradiation (λ?≥?290 nm). The effect of solution pH, fulvic acids (FA), nitrate (NO₃ ^?), Fe (III) ions, and titanium dioxide (TiO₂) on direct photolysis of fluopyram was explored. The results showed that fluopyram photodegradation was faster in neutral solution than that in acidic and alkaline solutions. The presence of FA, NO₃ ^?, Fe (III), and TiO₂ slightly affected the photodegradation of fluopyram under UV irradiation, whereas the photodegradation rates of fluopyram with 5 mg L^?1 Fe (III) and 500 mg L^?1 TiO₂ were about 7-fold and 13-fold faster than that without Fe (III) and TiO₂ under simulated sunlight irradiation, respectively. Three typical products for direct photolysis of fluopyram have been isolated and characterized by liquid chromatography tandem mass spectrometry. These products resulted from the intramolecular elimination of HCl, hydroxyl-substitution, and hydrogen extraction. Based on the identified transformation products and evolution profile, a plausible degradation pathway for the direct photolysis of fluopyram in aqueous solution was proposed. In addition, acute toxicity assays using the Vibrio fischeri bacteria test indicated that the transformation products were more toxic than the parent compound.     

Photooxidation of arsenite by natural goethite in suspended solution

Iron and arsenic have been found to coexist in a water environment and the fate of arsenite in the aquatic system is influenced by iron. Goethite is a form of iron hydroxide, which is commonly found in sediments. In previous studies, we have used iron complexes to degrade organic pollutants. Results have shown that some organic pollutants could be totally degraded by iron complexes and our work indicated that iron might cause conversion of arsenic when irradiated. This work attempts to investigate the conversion of arsenite [As(III)] using natural goethite, as the iron source, to quantify the effect of various factors on photooxidation. We also consider the possible mechanism for photooxidation of As(III) using a suspension of natural goethite. The As(III) concentration variation under illumination was compared with the one in the dark to quantify the contribution of light to As(III) oxidation to As(V) in goethite suspended solution. The experiments under N₂ and air atmosphere confirmed the participation of dissolved oxygen. The photooxidation efficiency of As(III) under different conditions was compared to determine the effect of different environmental factors such as pH value, goethite concentration, and humic acid concentration on the photooxidation reaction. In the solution containing 100 μg L^?1 arsenite and 0.1 g?L^?1 suspended goethite at pH 3.0, nearly 80 % of As(III) was photooxidized after irradiation by a 250-W metal halogen lamp (λ?≥?313 nm) after 6 h. The effects of initial pH and goethite concentration and humic acid concentration were all examined. The results show that the greatest efficiency of photooxidation of As(III) was at pH 3.0. The extent of photooxidation decreased with increasing goethite concentration and fell sharply in the presence of humic acid under the conditions in this work. Although about 80 % of As(III) was photooxidized after irradiation by a 250-W halogen lamp at pH 3.0 in the presence of goethite suspension, photooxidation was also affected by factors such as pH, concentration of goethite, and presence of humic acid. The scavenger experiments showed that the HO? radical and photogenerated hole are the predominant oxidants in this system responsible for 87.1 % oxidation of As(III), while HO ₂ ^? /O ₂ ^?? is responsible for 12.9 % oxidation of As(III).     

Quantitation of Hydroxyl Radicals from Photolysis of Fe(III)-Citrate Complexes in Aerobic Water (5 pp)

Background For their high photoreactivity, Fe(III)-carboxylate complexes are important sources of H2O2 for some atmospheric and surface waters. Citrate is one kind of carboxylate, which can form complexes with Fe(III). In our previous study, we have applied Fe(III)-citrate complexes to degrade and decolorize dyes in aqueous solutions both under UV light and sunlight. Results have shown that carboxylic acids can promote the photodegradation efficiency. It is indicated that the photolysis of Fe(III)-citrate complexes may cause the formation of some reactive species (e. g. H2O2 and ·OH). This work is attempted to quantify hydroxyl radicals generated in the aqueous solution containing Fe(III)-citrate complexes and to interpret the photoreactivity of Fe(III)-citrate complexes for degrading organic compounds. Methods By using benzene as the scavenger to produce phenol, the photogeneration of ·OH in the aqueous solution containing Fe (III)-citrate complexes was determined by HPLC. Results and Discussion In the aqueous solution containing 60.0/30.0 mM Fe(III)/citrate and 7.0 mM benzene at pH 3.0, 96.66 mM ·OH was produced after irradiation by a 250W metal halide light (l ≥ 313 nm) for 160 minutes. Effects of initial pH value and concentrations of Fe(III) and citrate on ·OH radical generation were all examined. The results show that the greatest photoproduction of ·OH in the aqueous solution (pH ranged from 3.0 to 7.0) was at pH 3.0. The photoproduction of ·OH increased with increasing Fe(III) or citrate concentrations. Conclusion In the aqueous solutions containing Fe(III)-citrate complexes, ·OH radicals were produced after irradiation by a 250W metal halide light. It can be concluded that Fe(III)-citrate complexes are important sources of ·OH radicals for some atmospheric and surface waters. Recommendations and Outlook It is believed that the photolysis of Fe(III)-citrate complexes in the presence of oxygen play an important role in producing ·OH both in atmospheric waters and surface water where high concentrations of ferric ions and citrate ions exist. The photoproduction of ·OH has a high oxidizing potential for the degradation of a wide variety of natural and anthropogenic organic and inorganic substances. We can use this method for toxic organic pollutants such as organic dyes and pesticides.     

Ferric citrate-induced photodegradation of dyes in aqueous solutions

The photooxidation of dye solutions containing Fe(III)-citrate complexes was studied. The photodegradation under near-UV light of the five dyes, C. I. reactive red 2, C. I. reactive blue 4, C. I. reactive black 8, C. I. basic red 13 and C. I. basic yellow 2, in aqueous solutions at pH2.0 containing Fe(III)-citrate complexes was found to follow pseudo-first order kinetics. The photodegradation rates of the dye, C. I. reactive red 2, decreased with increasing the initial dye concentration in range of 20 – 60 mg/L . A comparatively higher photodegradation efficiency of the dye was gained under the condition of pH2.0 and the Fe(III) to citrate ratio 1:2.     

Remediation of DDT-Contaminated Water and Soil by Using Pretreated Iron Byproducts from the Automotive Industry

The objective of this study was to quantify the effectiveness of different pretreated iron byproducts from the automotive industry to degrade DDT [(1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane] in aqueous solutions and soil slurry. Iron byproducts from automotive manufacturing were pretreated by three different methods (heating, solvent and 0.5N HCl acid washing) prior to experimentation. All pretreated irons were used at 5% (wt v^{? 1}) to treat 0.014 mM (5 mgL^{? 1}) of DDT in aqueous solution. Among the pretreated irons, acid pretreated iron results in the fastest destruction rates, with a pseudo first-order degradation rate of 0.364 d^{? 1}. By lowering the pH of the DDT aqueous solution from 9 to 3, destruction kinetic rates increase more than 20%. In addition, when DDT-contaminated soil slurry (3.54 mg kg^{? 1}) was incubated with 5% (wt v^{? 1}) acid-pretreated iron, more than 90% destruction of DDT was observed within 8 weeks. Moreover, DDT destruction kinetics were enhanced when Fe(II), Fe(III) or Al(III) sulfate salts were added to the soil slurry, with the following order of destruction kinetics: Al(III) sulfate > Fe(III) sulfate > Fe(II) sulfate. These results provide proof-of concept that inexpensive iron byproducts of the automotive industry can be used to remediate DDT-contaminated water and soil.     

Effect of Fe (III) on acid degradation of methylparathion

A study was undertaken to determine the transformation kinetic of methylparathion (O, O, -dimethyl O-4 nitrophenylphosphorotioate) in the presence of Fe(III) between pH 2 and 7. The Fe(III) was not electroactive under the conditions used in this study, and polarographic signals were exhibited by methylparathion and main degradation product only. Data suggest that hydrolysis of methylparathion in an acid medium is catalyzed by Fe(III) and the pesticide did not degrade in this medium without this cation. Methylparathion degradation was observed at all the pHs studied and was independent of the predominant chemical form of Fe(III) in the aqueous medium. The reaction was first-order with pH-dependent rate constant (k) values ranging from 3.3 × 10^{? 3} h^{? 1} to 7.0 × 10^{? 3} h^{? 1}. The k values increased as pH decreased, suggesting that Fe(III) acted as an electrophile in the reaction mechanism.     

Decomposition of phenylarsonic acid by AOP processes: degradation rate constants and by-products

The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm^?3 phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H₂O₂, UV/O₃, H₂O₂, and O₃ systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45?×?10^?3 and 20.12?×?10^?3) and degradation efficiencies at pH 2 and 7 were obtained at UV/O₃ processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified.     

Photocatalytic Degradation of an Organophosphorus Pesticide Phosalone in Aqueous Suspensions of Titanium Dioxide

Abstract

The present work deals with photocatalytic degradation of an organophosphorus pesticide, phosalone, in water in the presence of TiO₂ particles under UV light illumination (1000 W). The influence of the basic photocatalytic parameters such as pH of the solution, amount of TiO₂, irradiation time, stirring rate, and distance from UV source, on the photodegradation efficiency of phosalone was investigated. The degradation rate of phosalone was not high when the photolysis was carried out in the absence of TiO₂ and it was negligible in the absence of UV light. The half-life (DT₅₀) of a 20 ppm aqueous solution of phosalone was 15 min in optimized conditions. The plot of lnC (phosalone) vs. time was linear, suggesting first order reaction (K = 0.0532 min^?1). The half-life time of photomineralization in the concentration range of 7.5–20 ppm was 13.02 min. The efficiency of the method was also determined by measuring the reduction of Chemical Oxygen Demand (COD). During the mineralization under optimized conditions, COD decreased by more than 45% at irradiation time of 15 min. The photodegradation of phosalone was enhanced by addition of proper amount of hydrogen peroxide (150 ppm).     

Sonochemical degradation of a pharmaceutical waste,atenolol, in aqueous medium

Atenolol is a β-blocker drug and an identified emerging pollutant. Advanced oxidation processes (AOPs) utilise the reaction of a highly oxidising species (hydroxyl radicals, ^?OH) for the mineralisation of emerging pollutants since conventional treatment methodologies generally fail to degrade these compounds. In the present work, degradation of atenolol was carried out using ultrasound with frequencies ranging from 200 kHz to 1 MHz as a source of hydroxyl radical. The degradation was monitored by HPLC, total organic carbon (TOC) and chemical oxygen demand (COD) reduction and ion chromatography (IC). Nearly 90 % of degradation of atenolol was observed with ultrasound having 350 kHz. Both frequency and power of ultrasound affect the efficiency of degradation. Nearly 100 % degradation was obtained at a pH of 4. Presence of various additives such as sodium dodecyl sulphate, chloride, sulphate, nitrate, phosphate and bicarbonate was found to reduce the efficiency of degradation. Although nearly 100 % degradation of atenolol was observed under various experimental conditions, only about 62 % mineralisation (from TOC and COD measurements) was obtained. Nearly eight intermediate products were identified using high-resolution mass spectrometry (LC-Q-TOF). These products were understood as the results of hydroxyl radical addition to atenolol. The degradation studies were also carried out in river water which also showed a similar degradation profile. A mechanism of degradation and mineralisation is presented.     

Immobilized Fe (III)-doped titanium dioxide for photodegradation of dissolved organic compounds in water

Photocatalytic degradation of dissolved organic carbon (DOC) by utilizing Fe(III)-doped TiO₂ at the visible radiation range is hereby reported. The photocatalyst was immobilized on sintered glass frits with the coating done by wet method, calcinated at 500 °C and then applied in a photodegradation reactor. The addition of a transition metal dopant, Fe(III), initiated the red shift which was confirmed by UV–Vis spectroscopy, and the photocatalyst was activated by visible radiation. X-ray diffraction patterns showed that Fe(III) doping had an effect on the crystallinity of the photocatalysts. Mixtures of DOC and associated coloured solutions were degraded in first-order kinetics, showing that the degradation process was not dependent on intermediates or other species in solution. A reactor with a catalyst coating area of 12.57 cm² was able to degrade 0.623 mg of the dissolved material per minute. Exposure of the reactor to hostile acidic conditions and repeated use did not compromise its efficiency. It was observed that the reactor regenerates itself in the presence of visible light, and therefore, it can be re-used for more than 100 runs before the performance dropped to <95 %. The results obtained indicate that the photocatalyst reactor has a great potential of application for use in tandem with biosorbent cartridges to complement water purification methods for domestic consumption.     

Solar CPC pilot plant photocatalytic degradation of bisphenol A in waters and wastewaters using suspended and supported-TiO2. Influence of photogenerated species

Photocatalytic degradation of bisphenol A (BPA) in waters and wastewaters in the presence of titanium dioxide (TiO₂) was performed under different conditions. Suspensions of the TiO₂ were used to compare the degradation efficiency of BPA (20 mg L^?1) in batch and compound parabolic collector (CPC) reactors. A TiO₂ catalyst supported on glass spheres was prepared (sol–gel method) and used in a CPC solar pilot plant for the photodegradation of BPA (100 μg L^?1). The influence of OH·, O₂ ^·?, and h ⁺ on the BPA degradation were evaluated. The radicals OH· and O₂ ^·? were proved to be the main species involved on BPA photodegradation. Total organic carbon (TOC) and carboxylic acids were determined to evaluate the BPA mineralization during the photodegradation process. Some toxicological effects of BPA and its photoproducts on Eisenia andrei earthworms were evaluated. The results show that the optimal concentration of suspended TiO₂ to degrade BPA in batch or CPC reactors was 0.1 g L^?1. According to biological tests, the BPA LC₅₀ in 24 h for E. andrei was of 1.7?×?10^?2 mg cm^?2. The photocatalytic degradation of BPA mediated by TiO₂ supported on glass spheres suffered strong influence of the water matrix. On real municipal wastewater treatment plant (MWWTP) secondary effluent, 30 % of BPA remains in solution; nevertheless, the method has the enormous advantage since it eliminates the need of catalyst removal step, reducing the cost of treatment.     

Behavior and mechanism of arsenate adsorption on activated natural siderite: evidences from FTIR and XANES analysis

Activated natural siderite (ANS) was used to investigate its characteristics and mechanisms of As(V) adsorption from aqueous solution. Batch tests were carried out to determine effects of contact time, initial As(V) concentration, temperature, pH, background electrolyte, and coexisting anions on As(V) adsorption. Arsenic(V) adsorption on ANS well-fitted pseudo-second-order kinetics. ANS showed a high-adsorption capacity of 2.19 mg/g estimated from Langmuir isotherm at 25 °C. Thermodynamic studies indicated that As(V) adsorption on ANS was spontaneous, favorable, and endothermic. ANS adsorbed As(V) efficiently in a relatively wide pH range between 2.0 and 10.0, although the removal efficiency was slightly higher in acidic conditions than that in basic conditions. Effects of background electrolyte and coexisting anions were not significant within the concentration ranges observed in high As groundwater. Results of XRD and Fe K-edge XANES analysis suggested ANS acted as an Fe(II)/(III) hybrid system, which was quite effective in adsorbing As from aqueous solution. There was no As redox transformation during adsorption, although Fe(II) oxidation occurred in the system. Two infrared bands at 787 and 872 cm^?1 after As(V) adsorption suggested that As(V) should be predominantly adsorbed on ANS via inner-sphere bidendate binuclear surface complexes.     

Remediation of acid mine drainage (AMD)-contaminated soil by Phragmites australis and rhizosphere bacteria

Experiments were conducted to assess the impact of citric acid (CA) and rhizosphere bacteria on metal uptake in Phragmites australis cultured in a spiked acid mine drainage (AMD) soil. Rhizosphere iron-oxidizing bacteria (Fe(II)OB) enhanced the formation of Fe plaque on roots, which decreased the uptake of Fe and Mn. CA inhibited the growth of Fe(II)OB, decreased the formation of metal plaque, raised the metal mobility in soil, and increased the accumulation of metals in all tissues of the reeds. The higher the CA dosage, the more metals accumulated into reeds. The total amount of metals in reeds increased from 7.8?±?0.5?×?10^?6 mol plant^?1 (Mn), 1.4?±?0.1?×?10^?3 mol plant^?1 (Fe), and 1.0?±?0.1?×?10^?4 mol plant^?1 (Al) in spiked soil without CA to 22.2?±?0.5?×?10^?6 mol plant^?1 (Mn), 3.5?±?0.06?×?10^?3 mol plant^?1 (Fe), and 5.0?±?0.2?×?10^?4 mol plant^?1 (Al) in soil added with 33.616 g C₆H₈O₇·H₂O for per kilogram soil. CA could be effective at enhancing the phytoremediation of metals from AMD-contaminated soil.     

Photodegradation of hexabromocyclododecane (HBCD) by Fe(III) complexes/H2O2 under simulated sunlight

Hexabromocyclododecane (HBCD) is a globally produced brominated flame retardant used primarily as an additive flame retardant in polystyrene and textile products. Photodegradation of HBCD in the presence of Fe(III)-carboxylate complexes/H₂O₂ was investigated under simulated sunlight. The degradation of HBCD decreased with increasing pH in the Fe(III)-oxalate solutions. In contrast, the optimum pH was 5.0 for the Fe(III)-citrate-catalyzed photodegradation within the range of 3.0 to 7.0. For both Fe(III)-oxalate and Fe(III)-citrate complexes, the increase of carboxylate concentrations facilitated the photodegradation. The photochemical removal of HBCD was related to the photoreactivity and speciation distribution of Fe(III) complexes. The addition of H₂O₂ markedly accelerated the degradation of HBCD in the presence of Fe(III)-citrate complexes. The quenching experiments showed that ·OH was responsible for the photodegradation of HBCD in the Fe(III)-carboxylate complexes/H₂O₂ solutions. The results suggest that Fe(III) complexes/H₂O₂ catalysis is a potential method for the removal of HBCD in the aqueous solutions.     

Photodegradation of bisphenol Z by UV irradiation in the presence of beta-cyclodextrin

In this work, the formation of the inclusion complex of bisphenol Z (1,1-bis(4-hydroxyphenyl)cyclohexane, abbreviated as BPCH) with beta-cyclodextrin (beta-CD) has been studied, 1:1 inclusion complex can be obtained, the formation constant of the beta-CD/BPCH complex is 5.94x10(3)M(-1). The photodegradation behavior of BPCH was investigated under monochromatic UV irradiation (lambda=254 nm). The photodegradation rate constant of BPCH in aqueous solutions with beta-CD showed a 9.0-fold increase, and simultaneously the mineralization of BPCH can be enhanced by beta-CD. The influence factors on photodegradation of BPCH were also studied and described in details, such as concentration of beta-CD, initial concentration of BPCH, organic solvent and pH. The photodegradation of BPCH in the presence of beta-CD includes the direct photolysis and the photooxidation of BPCH during the photochemical process. Some predominant photodegradation products are 4-(2,4,5-trihydroxy-phenyl)-4-(4-hydroxyphenyl) butanoic acid, 5,5-bis(4-hydroxyphenyl)pentanoic acid, meta-hydroxylated BPCH, ortho-hydroxylated BPCH and 4-(1-(4-hydroxyphenyl)pentyl)phenol respectively. The enhancement of photodegradation of BPCH mainly results from moderate inclusion depth of BPCH molecule in the beta-CD cavity. This kind of inclusion structure allows BPCH molecule sufficient proximity to secondary hydroxyl groups of the beta-CD cavity, and these hydroxyl groups could be activated and converted to hydroxyl radicals under UV irradiation, which can enhance the photooxidation of BPCH.     

Anodic oxidation of benzoquinone using diamond anode

The anodic degradation of 1,4-benzoquinone (BQ), one of the most toxic xenobiotic, was investigated by electrochemical oxidation at boron-doped diamond anode. The electrolyses have been performed in a single-compartment flow cell in galvanostatic conditions. The influence of applied current (0.5–2 A), BQ concentration (1–2 g dm^?3), temperature (20–45 °C) and flow rate (100–300 dm³ h^?1) has been studied. BQ decay kinetic, the evolution of its oxidation intermediates and the mineralization of the aqueous solutions were monitored during the electrolysis by high-performance liquid chromatograph (HPLC) and chemical oxygen demand (COD) measurements. The results obtained show that the use of diamond anode leads to total mineralization of BQ in any experimental conditions due to the production of oxidant hydroxyl radicals electrogenerated from water discharge. The decay kinetics of BQ removal follows a pseudo-first-order reaction, and the rate constant increases with rising current density. The COD removal rate was favoured by increasing of applied current, recirculating flow rate and it is almost unaffected by solution temperature.     

Accelerated photo-transformation of 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153) in water by dissolved organic matter

The ubiquitous dissolved organic matter (DOM) has an important influence on transformation of organic contaminants through the production of reactive substances, such as ^?OH, ¹O₂, and ³DOM*. The photolysis of a higher chlorinated polychlorinated biphenyl (PCB) congener (2,2′,4,4′,5,5′-hexachlorobiphenyl, PCB 153) under simulated sunlight in presence of humic acid (HA) was investigated. Degradation of PCB 153 was accelerated significantly by the addition of HA, with a rate constant of 0.0214, 0.0413, and 0.0358 h^?1 in the initial 18 h of irradiation in presence of 1, 5, and 20 mg/L HA, respectively. The main photodegradation products analyzed by gas chromatography mass spectrometry were 4-hydroxy-2,2′,4′,5,5′-pentaCB and 2,4,5-trichlorobenzoic acid. Main reactive species involved were determined by the electron spin-resonance spectroscopy, including ¹O₂ and ^?OH. Special scavengers were added to elucidate the photolysis mechanisms. By using the specific scavengers, it turned out that ^?OH accounted for 29.3 % of the degradation, and the intra-DOM reactive species (¹O₂, ^?OH, and ³DOM*) accounted for 59.6 % of the degradation. Photo-transformation sensitized by DOM, which involves both aqueous and intra-DOM reactions of PCBs with reactive species, may be one of the most important mechanisms for natural attenuation of PCBs.     

Electrochemical Monitoring of Methylparathion Degradation in an Acid Aqueous Medium in Presence of Cu(II)

Abstract

A study was undertaken to determine the effect of Cu(II) in degradation of methylparathion (o,o-dimethyl o, 4-nitrophenyl phosphoriotioate) in acid medium. Initial electrochemical characterization of Cu(II) and methylparathion was done in an aqueous medium at a pH range of 2–7. Cu(II) was studied in the presence of different anions and it was observed that its electroactivity depends on pH and is independent of the anion used. Methylparathion had two reduction signals at pH ≤ 6 and only one at pH > 6. The pesticide's transformation kinetic was then studied in the presence of Cu(II) in acid buffered aqueous medium at pH values of 2, 4, and 7. Paranitrophenol appeared as the only electroactive product at all three pH values. The reaction was first order and had k values of 5.2 × 10^?3 s^?1 at pH 2, 5.5 × 10^?3 s^?1 at pH 4 and 9.0 × 10^?3 s^?1 at pH 7. It is concluded that the principal degradation pathway of methylparathion in acid medium is a Cu(II) catalyzed hydrolysis reaction.     

Assessment of solar driven TiO2-assisted photocatalysis efficiency on amoxicillin degradation

The objective of this work was to evaluate the efficiency of a solar TiO₂-assisted photocatalytic process on amoxicillin (AMX) degradation, an antibiotic widely used in human and veterinary medicine. Firstly, solar photolysis of AMX was compared with solar photocatalysis in a compound parabolic collectors pilot scale photoreactor to assess the amount of accumulated UV energy in the system (Q _UV) necessary to remove 20 mg L^?1 AMX from aqueous solution and mineralize the intermediary by-products. Another experiment was also carried out to accurately follow the antibacterial activity against Escherichia coli DSM 1103 and Staphylococcus aureus DSM 1104 and mineralization of AMX by tracing the contents of dissolved organic carbon (DOC), low molecular weight carboxylate anions, and inorganic anions. Finally, the influence of individual inorganic ions on AMX photocatalytic degradation efficiency and the involvement of some reactive oxygen species were also assessed. Photolysis was shown to be completely ineffective, while only 3.1 kJ_UV?L^?1 was sufficient to fully degrade 20 mg L^?1 AMX and remove 61 % of initial DOC content in the presence of the photocatalyst and sunlight. In the experiment with an initial AMX concentration of 40 mg L^?1, antibacterial activity of the solution was considerably reduced after elimination of AMX to levels below the respective detection limit. After 11.7 kJ_UV?L^?1, DOC decreased by 71 %; 30 % of the AMX nitrogen was converted into ammonium and all sulfur compounds were converted into sulfate. A large percentage of the remaining DOC was in the form of low molecular weight carboxylic acids. Presence of phosphate ions promoted the removal of AMX from solution, while no sizeable effects on the kinetics were found for other inorganic ions. Although the AMX degradation was mainly attributed to hydroxyl radicals, singlet oxygen also plays an important role in AMX self-photosensitization under UV/visible solar light.