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Residual pharmaceutical compounds (PCs) are among the emerging organic contaminants detected in our water cycle. Diclofenac (Dic) is one of the commonly detected pharmaceutical contaminant in aquatic systems. This study was designed to investigate the degradation and mineralization of Dic in aqueous solutions by ionizing radiation emitted from radioactive Co60 under several conditions. Ultra-performance liquid chromatography, ion chromatography and TOC measurements confirmed the radiolytic degradation of Dic. The absorbed doses needed to degrade 99% Dic at 25, 50, 100, 190, 280, and 480 μM were 0.560, 0.950, 1.950, 4.000, 5.400, and 7.400 kGy, respectively. This process follows pseudo-first-order kinetics. The γ-ray/N 2 O system decreased the dose required to degrade 99% to 1.47 kGy. The presence of bromide anions inhibits degradation. Remarkably, adding H 2 O 2 , S 2 O 8 2−, or N 2 O promotes mineralization. Conversely, the absence of dissolved oxygen hinders mineralization. This study provides a viable finding that ionizing radiation are useful tolls to remedy water containing pharmaceutical organic compounds. Unlabelled Image • The kinetics of diclofenac radiolysis by Co60 was studied at several concentrations. • The effect of hydrated electron was discussed. • Bromide anion inhibits radiolysis. • Persulfate and hydrogen peroxide addition and nitrous oxide saturation were probed. • The main organic byproducts proposed in the literature are summarized. [ABSTRACT FROM AUTHOR]

In this study, the strategy of combining radiation with ferrate oxidation was proposed to decrease the adsorbed dosse and enhance the mineralization of carbamazepine in aqueous solution. Compared to single radiation (800 Gy), the combined process of ferrate pretreatment and radiation required lower dose (600 Gy) for totally removing carbamazepine. During the combined process, the removal efficiency of total organic carbon (TOC) reached 22.2%. However, the removal efficiencies of carbamazepine and TOC decreased when ferrate and radiation were used simultaneously, indicating that the addition of ferrate during the radiation process had negative effect on the removal of carbamazepine. In contrast, the radiation followed by ferrate oxidation presented the best performance in decreasing the absorbed dose and enhancing the mineralization of carbamazepine. Carbamazepine could be completely removed under all conditions. TOC removal efficiency reached 18.3%, 31.3%, 52.9% and 60.6%, respectively, at the adsorbed dose of 100, 300, 600 and 800 Gy when 0.4 mM ferrate was adopted. The enhanced TOC removal could be due to the enhanced oxidation capacity of ferrate caused by the pH decrease at the end of radiation and the further oxidation of intermediate products formed during the radiation process by ferrate. Seven degradation products were identified in total, and thus the degradation pathway of carbamazepine was proposed. This study provides a possible way to decrease the adsorbed dose and enhance the mineralization of carbamazepine by radiation. Unlabelled Image • The combined process of radiation and ferrate oxidation was developed. • Radiation followed by ferrate oxidation effectively decreased absorbed dose. • Radiation followed by ferrate oxidation significantly increased mineralization. • Combining radiation with ferrate oxidation is promising for antibiotics removal. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon (NC) materials have been extensively investigated for their great potential applications in adsorption, catalysis, etc. Herein, we report a facile one-step pyrolysis process for NC synthesis using abundant bio-waste of excess sludge as carbon source and cheap precursor of urea as nitrogen source. The developed materials were evaluated for organic pollutants removal through adsorption and catalytic oxidation by peroxymonosulfate (PMS) activation. Experimental results demonstrated that nitrogen doping significantly affected the elemental composition and microstructure of NC, leading to improved adsorption capability as well as PMS activation activity for methylene blue (MB) removal. The adsorption capacity for MB reached 35.831 mg g−1 over NC-700 sample (NC prepared at 700 °C). In MB catalytic oxidation experiments, effects of sample calcination temperature, catalyst dosage, PMS loading, and co-existing ions were investigated. Under optimal reaction conditions, 98.70% of MB could be removed in 20 min. Through radical quenching and electron spin resonance (ESR) tests, it was confirmed that singlet oxygen (1O 2) was the main reactive species for MB degradation. Additionally, NC-700 performed well in recycle studies without significant efficiency loss. Other typical organic pollutants including malachite green (MG), methyl orange (MO), bisphenol A (BPA), phenol (PE), and sulfamethoxazole (SMX) could also be removed using NC-700 as adsorbent and catalyst. These features manifest that excess sludge-derived NC could be a promising material for organic pollutants remediation. Unlabelled Image • Bio-waste of excess sludge was converted to adsorbent and catalyst. • The introduction of urea in precursor tailored the structure and surface chemistry of N-doped carbon. • NC-700 exhibited a strong adsorption ability and high catalytic activity for MB removal. • Mechanisms of PMS activation and MB degradation over NC-700/PMS system were revealed. [ABSTRACT FROM AUTHOR]

Abstract This work presents the treatment of selected emerging concern pharmaceuticals in real hospital wastewater (HWW) from Tumaco-Colombia by combination of a biological system with a sonochemical process. Fifteen compounds, commonly present in HWW, were considered: acetaminophen, diclofenac, carbamazepine, venlafaxine, loratadine, ciprofloxacin, norfloxacin, valsartan, irbesartan, sulfamethoxazole, trimethoprim, clarithromycin, azithromycin, erythromycin and clindamycin. Initially, HWW was characterized in terms of global parameters and the pharmaceuticals content. HWW contained a moderate amount of organic matter (i.e., total organic carbon: 131.56 mg L−1 (C)) mainly associated to biodegradable components. However, the most of pharmaceuticals were found at levels upper than their predicted no effect concentration (PNEC). Then, a conventional biological treatment was applied to the HWW. After 36 h, such process mainly removed biodegradable substances, but had a limited action on the pharmaceuticals. The resultant biotreated water was submitted to the sonochemical process (375 kHz and 88 W L−1, 1.5 h), which due to its chemical (i.e., radical attacks) and physical (i.e., suspended solids disaggregation) effects induced a considerable pharmaceuticals degradation (pondered removal: 58.82%), demonstrating the complementarity of the proposed combination. Afterwards, Fe2+ (5 ppm) and UVC light (4 W) were added to the sonochemical system (generating sono-photo-Fenton process), which significantly increased up to 82.86% the pondered pharmaceuticals removal. Subsequently, to understand fundamental aspects of the pharmaceuticals degradations, a model compound (norfloxacin) in distilled water was treated by sonochemical system, sono-photo-Fenton process and their sub-systems (i.e., sono-Fenton and UVC alone). This allowed proving the hydroxyl radical action in sonochemical treatment, plus the contribution of Fenton reaction and direct photodegradation in the pharmaceuticals removal by sono-photo-Fenton. Finally, it was found that 91.13% of the initial pharmaceuticals load in HWW was removed by the biological/sono-photo-Fenton combination. The high pollutants abatement evidenced that this combination is a powerful alternative for removing pharmaceuticals from complex-matrix waters, such as raw HWW. Graphical abstract Unlabelled Image Highlights • Real hospital wastewater (HWW) was treated by a biological/sonochemical train. • Biological system removed macro-components and sonochemistry degraded pharmaceuticals. • Chemical and physical effects of sonochemistry led to pharmaceuticals degradation in HWW. • Fe2+ and UVC addition to sonochemistry (sono-photo-Fenton) enhanced pharmaceuticals elimination. • Biological/sono-photo-Fenton combination removed ~91% of pharmaceuticals load. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to assess the efficiency of photocatalysis by TiO 2 on the removal of 17-β-estradiol (E2) (at environmentally relevant concentrations) and the toxicity caused by this emerging pollutant. After 60 min of TiO 2 /UV treatment at pilot scale (14 L), E2 was removed from water approximately 85%. The toxicity was established by using Cyprinus carpio as bioindicator organism and oxidative stress biomarkers (OSB): [lipid peroxidation level (LPX), hydroperoxide content (HPC) and protein carbonyl content (PCC)] and enzymes [superoxide dismutase (SOD) and catalase (CAT)]. It was found that the photocatalytic treatment led to significantly reduce OSB in approximately 85–95%. Thus, it can be concluded that heterogeneous photocatalysis by TiO 2 is an efficient process to eliminate the toxicity caused by E2 and thus to remediate water polluted with this molecule. Graphical abstract Unlabelled Image Highlights • Water with E2 induces oxidative stress in C. carpio. • This study confirms the efficiency of the heterogeneous photocatalysis to remove E2 from water. • Treated water significantly reduces the oxidative stress in C. carpio. [ABSTRACT FROM AUTHOR]

Abstract Sulfamethoxazole (SMX) is a widespread and persistent antibiotic pollutant in the aquatic environment. In this paper, SMX was degraded by gamma irradiation, and various influencing factors were explored. The experimental results revealed that after 1.5 kGy irradiation, 20 mg/L SMX could be completely decomposed. Kinetics studies suggested that the radiation-induced degradation process of SMX conformed first-order kinetic. The pH value had influence on the decomposition efficiency through changing the species of reactive radicals and the existing form of SMX molecules and their distribution. Additionally, the effect of inorganic anions (CO 3 2−, HCO 3 −, NO 3 −, SO 4 2−, Cl−, HPO 4 2−) and organic matters (peptone, glucose, humic acid) on SMX degradation was evaluated, which had negative influence on SMX degradation. The degradation efficiency of SMX decreased in the effluent water of WWTP in comparison with that in deionized water, suggesting that the components in the effluent inhibited the radiation-induced decomposition of SMX. The mineralization of SMX by ionizing radiation was also evaluated. These results revealed that ionizing radiation is a promising technology to degrade SMX in aqueous solution as well as in wastewater. Graphical abstract Unlabelled Image Highlights • Ionizing radiation was effective to degrade sulfamethoxazole in aqueous solution. • The radiolytic degradation of sulfamethoxazole followed pseudo first-order kinetics. • Inorganic anions (CO 3 2−, HCO 3 −, NO 3 −, SO 4 2−, Cl−, HPO 4 2−) inhibited SMX degradation. • Ionizing radiation is a promising way to remove SMX from water and wastewater. [ABSTRACT FROM AUTHOR]

Abstract Dodecyltrimethylammonium chloride (DTAC) is a quaternary ammonium compound (QAC) that is a widespread contaminant in environmental media and therefore of increasing concern. The synergistic effect with UV irradiation and persulfate (UV/PS) was used to degrade DTAC. The removal of DTAC was 91% with the PS dosage of 75.6 μM (UV/PS) and UV fluence of 870 mJ·cm−2. The second-order rate constants of DTAC with HO and SO 4 − were determined to be k HO , DTAC (4.2 ± 0.18) × 109 M−1 s−1 and k SO 4 ∙−, DTAC (2.5 ± 0.27) × 109 M−1 s−1, respectively. The contributions of HO and SO 4 − to DTAC degradation in the UV/PS were found to be 30% and 62% at pH 7, respectively. The contributions of SO 4 − and HO were not significantly influenced by acidic medium (pH 3–pH 7), whereas they were significantly affected by basic medium (pH 7–pH 11). The wastewater matrixes of HCO 3 −, Cl− and humic acid inhibited the DTAC elimination, whereas NO 3 − and SO 4 2− had no significant impact on its elimination. Moreover, the k obs,DTAC in the reverse osmosis influent (ROI) and reverse osmosis concentrate (ROC) were examined to be 0.04 to 0.1 min−1 and 0.02 to 0.05 min−1, respectively, as the PS dosage increased from 18.9 to 113.4 μM. The inhibitive effects of matrix in ROI and ROC was 70% and 81%, respectively. The contribution of radical scavenging effect by matrix ROI and ROC was more significant to DTAC degradation than UV scattering effect in ROI and ROC matrices. A UV fluence of 1305 mJ·cm−2 was necessitated for complete detoxification and DTAC solution by UV/PS. Graphical abstract Unlabelled Image Highlights • UV/PS oxidation can significantly degrade dodecyltrimethylammonium chloride (DTAC). • Reaction rate constants of DTAC with HO and SO 4 − were (4.2 ± 0.18) × 109 and (2.5 ± 0.27) × 109 M−1 s−1. • The generated HO and SO 4 − were comprised dominant radical species during UV/PS oxidation under neutral condition. • Acute toxicity of DTAC solution treated by UV/PS is completely detoxified. [ABSTRACT FROM AUTHOR]

Abstract The surface properties of nanocomposites are influenced by the existence of inorganic species that may affect its performance for specific catalytic applications. The impact of different ionic species on particular catalytic activity had not been investigated to date. In this study, the surface charge (zeta potential) of graphene-oxide-supported nano zero valent iron (G-nZVI) was tested in definitive cationic (Na+, K+, Ca2+ and Mg2+) and anionic (Br−, Cl−, NO 3 −, SO 4 2−, and HCO 3 −) environments. The efficiency of G-nZVI catalyst was inspected by measuring the generation of reactive oxygen species (ROS) for the degradation of 1,1,1-trichloroethane (TCA) in sodium percarbonate (SPC) system. Tests conducted using probe compounds confirmed the generation of OH and O 2 − radicals in the system. In addition, the experiments performed using scavenging agents certified that O 2 − were primary radicals responsible for TCA removal, along with prominent contribution from OH radicals. The study confirmed that G-nZVI catalytic capability for TCA degradation is notably affected by various cationic species. The presence of Ni2+ and Cu2+ significantly enhanced (94%), whereas Na+ and K+ had minor effects on TCA removal. Overall, the results indicated that groundwater ionic composition may have low impact on the effectiveness of G-nZVI-catalyzed peroxide TCA treatment. Graphical abstract Unlabelled Image Highlights • Dominant groundwater cations effect the performance efficiency for degradation • Surface charge and organic ions effect investigated for the degradation of TCA a persistent contaminant in hydrosphere. • Generation of reactive oxygen species for remediation of TCA in percarbonate system • The ionic composition of groundwater has a relatively minor effect on TCA removal for the G-nZVI catalyzed system. [ABSTRACT FROM AUTHOR]

Abstract In this study, a favorable CO 3 2−/PMS system for efficient degradation of organic contaminants (acid orange 7 (AO7), acetaminophen, para -aminobenzoic acid, phenol, methylene orange, methylene blue) in water was firstly reported. Under optimal conditions, the decolorization ration of AO7 was 100% within 40 min. Data fitting showed that the AO7 decolorization could be described by the pseudo-first-order kinetics, and the rates constant values ranging from 0.0006 to 0.2297 min−1 depending on the operating parameters (initial PMS, CO 3 2−, AO7 concentrations). Radical scavenging studies revealed that superoxide anion radical (O 2 −) and singlet oxygen (1O 2) rather than sulfate (SO 4 −) nor hydroxyl (HO) were the dominant oxidants might be responsible for AO7 degradation. The presence of NO 3 −, HPO 4 2− and low concentration of Cl−, NO 2 −, HCO 3 −, H 2 PO 4 −, HA had no significantly effect on the decolorization of AO7. Adding a higher Cl− concentration displayed favorable effects on the removal efficiencies of AO7, but adding a higher NO 2 −, HCO 3 −, H 2 PO 4 − and HA concentration apparently inhibited this process. The decolorization of AO7 was lower in wastewater in comparison to other natural waters and ultrapure water, which was probably due to the presence of higher concentration of colloids in wastewater. Nevertheless, up to 94.8%, 97.0% and 85.1% of AO7 were degraded from the filtrate, permeate, and retentate phases of wastewater within 60 min, respectively. Consequently, CO 3 2−/PMS would be promising for removal methodology for AO7 in wastewater containing considerable colloids. Finally, three intermediates were identified and degradation pathways of AO7 were proposed. Graphical abstract Unlabelled Image Highlights • CO 3 2−/PMS system was first applied in the organic pollutants degradation. • O 2 − and 1O 2 were the dominant oxidants in the CO 3 2−/PMS system. • AO7 was efficiently degraded in real wastewater containing lots of colloids. • The activation mechanisms of PMS and reaction pathways of AO7 were proposed. [ABSTRACT FROM AUTHOR]

Non-potable reuse of treated wastewater is becoming widespread as means to address growing water scarcity. Removal of micropollutants (MPs) from such water often requires advanced oxidation processes using OH radicals. OH can be generated in-situ via water photolysis under vacuum-UV (λ < 200 nm) irradiation. The aim of this study was to investigate the potential of unmasking V-UV radiation from low pressure Hg lamps (emitting at 185 and 254 nm), commonly used in decentralized treatment systems, for enhancing MPs removal efficiency. Triclosan, a biocide of limited biodegradability, served as a model compound for MPs that are not very biodegradable. Its degradation kinetics and identification of intermediate products were investigated under 254 nm and under combined 254/185 nm irradiation both in dry thin films and in aqueous solutions. In the latter, degradation was faster under combined 254/185 nm radiation, although the 185 nm radiation accounted for only 4% of the total UV light intensity. In contrast, triclosan photodegradation in dry film did not show significant differences between these irradiation wavelengths, suggesting that the enhanced degradation of dissolved triclosan under combined radiation is mainly due to oxidation by OH formed via water photolysis under V-UV. This conclusion was supported by slower TCS degradation in aqueous solution when methanol was added as OH scavenger. Under both irradiation types (254, 254/185 nm) three transformation products (TPs) were identified: 2,8-dichlorodibenzo-p-dioxin, 5-chloro-2-(4- or 2-chlorophenoxy)phenol, and 2-hydroxy-8-chlorodibenzodioxin. In-silico QSAR toxicity assessment predicted potential toxicity and moderate-to-low biodegradability of these TPs. Removal of these TPs was faster under 254/185 nm irradiation. Considering the low cost, simple operation (i.e. no chemicals addition) and small size of such low-pressure mercury lamps, this is a promising direction. Further investigation of the process in flow-through reactors and real wastewater/greywater effluent is needed for its future implementation in small on-site systems for post-treatment of persistent pollutants. [ABSTRACT FROM AUTHOR]

The potential of photocatalytic membrane reactors (PMR) to degrade cytostatic drugs is presented in this work as an emerging technology for wastewater treatment. Cytostatic drugs are pharmaceutical compounds (PhCs) commonly used in cancer treatment. Such compounds and their metabolites, as well as their degraded by-products have genotoxic and mutagenic effects. A major challenge of cytostatic removal stands in the fact that most drugs are delivered to ambulant patients leading to diluted concentration in the municipal waste. Therefore safe strategies should be developed in order to collect and degrade the micro-pollutants using appropriate treatment technologies. Degradation of cytostatic compounds can be achieved with different conventional processes such as chemical oxidation, photolysis or photocatalysis but the treatment performances obtained are lower than the ones observed with slurry PMRs. Therefore the reasons why slurry PMRs may be considered as the next generation technology will be discussed in this work together with the limitations related to the mechanical abrasion of polymeric and ceramic membranes, catalyst suspension and interferences with the water matrix. Furthermore key recommendations are presented in order to develop a renewable energy powered water treatment based on long lifetime materials. [ABSTRACT FROM AUTHOR]

Water recycling and industrial effluents remediation are a hot topic of research to reduce the environmental impact of the human activity. Persistent organic pollutants are highly recalcitrant compounds with hazardous effects associated to their fate in water bodies. Several novel technologies have been developed during the last decades to deal with this novel contamination. However, the natural sources and idiosyncrasy of each country lead to the potential application of different technologies. In this context, we have focused on the development of phocotalytic treatment of solutions containing dyes using a novel photocatalytic material, the NbO 2 OH. The NbO 2 OH was synthesized and characterized with different techniques. Several assays demonstrated the solar photoactivity of this novel oxyhydroxide catalyst, achieving complete decolorizations after 10 min of treatment under optimal conditions of 1.0 g L − 1 NbO 2 OH photocatalyst loading, 0.1 M of H 2 O 2 as electron scavenger, pH 4.0 and methyl orange concentrations up to 15 mg L − 1 . Also, the catalyst recuperation demonstrated the potential reuse of this photocatalyst without losing catalytic response after five cycles. This work is of significant importance because niobium is a natural resource, mainly extracted in Brazil and the annual global sunlight irradiation in the near-equatorial region of northeast Brazil is over the average solar irradiation of the planet. Thus, the solar photocatalytic treatment using NbO 2 OH in northeast Brazil appears as a highly potential environmental-friendly nanotechnology to mitigate the water pollution. [ABSTRACT FROM AUTHOR]

Oxidation and removal of organic micropollutants (OMPs) on ultrapure (UPW) and natural water (NW) by ozone (O 3 ) and ozone/powdered activated carbon (O 3 /PAC) have been studied. The OMPs atrazine (ATZ, herbicide), carbamazepine (CBZ, anticonvulsant), diclofenac (DCL, anti-inflammatory) and triclosan (TCS, antimicrobial) are incorporated continuously and uncontrolled on water treatment systems (e.g., drinking water treatment plants, wastewater treatment plants). Batch experiments on ultrapure and natural water showed that ATZ treated with O 3 and O 3 /PAC has the slowest transformation rate (> 90% at 30 min reaction) while CBZ, DCL and TCS were oxidized very fast (> 90% at ~ 5 min). The radical scavenger tert-Butyl alcohol (TBA) was used to evaluate the contribution of HO on the OMPs oxidation. TBA, a hydrophilic compound with low adsorbability, was used as a strong HO scavenger to assess the role of the OH radical in the oxidation of the OMPs studied. ATZ oxidation was mainly driven by OH radicals. On the contrary, CBZ, DCL and TCS were removed by direct reaction with ozone. Infrared analysis (FTIR) showed changes in the PAC surface functional groups of the carbon exposed to ozone, decreasing its basic properties. The acute toxicity assays of the OMPs mixture dissolved in UPW performed with D. magna was significantly reduced by ozonation. The addition of PAC to the ozonation process, strongly improved the acute toxicity removal. Short chain mono- and di-carboxylic acids were identified as some of the oxidation intermediates formed during ozone treatment. [ABSTRACT FROM AUTHOR]

4- tert -butylphenol (4- t -BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4- t -BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC–MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4- t -BP by hydroxyl radical (HO ) was also studied and H 2 O 2 was added to produce HO . 4- tert -butylcatechol and 4- tert -butylphenol dimer were produced in 4- t -BP direct photolysis. 4- tert -butylcatechol and hydroquinone were produced by the oxidation of HO . But the formation mechanism of 4- tert -butylcatechol in the two processes was different. The benzene ring was fractured in 4- t -BP oxidation process and 29% of TOC was degraded after 16 h irradiation. [ABSTRACT FROM AUTHOR]

This article reviews different photodegradation technologies used for the removal of four endocrine disrupting chemicals (EDCs): estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2). The degradation efficiency is greater under UV than visible light; and increases with light intensity up to when mass transfer becomes the rate limiting step. Substantial rates are observed in the environmentally relevant range of pH 7–8, though higher rates are obtained for pH above the pK a (~ 10.4) of the EDCs. The effects of dissolved organic matter (DOM) on EDC photodegradation are complex with both positive and negative impacts being reported. TiO 2 remains the best catalyst due to its superior activity, chemical and photo stability, cheap commercial availability, capacity to function at ambient conditions and low toxicity. The optimum TiO 2 loading is 0.05–1 g l − 1 , while higher loadings have negative impact on EDC removal. The suspended catalysts prove to be more efficient in photocatalysis compared to the immobilised catalysts, while the latter are considered more suitable for commercial scale applications. Photodegradation mostly follows 1st or pseudo 1st order kinetics. Photodegradation typically eradicates or moderates estrogenic activity, though some intermediates are found to exhibit higher estrogenicity than the parent EDCs; the persistence of estrogenic activity is mainly attributed to the presence of the phenolic moiety in intermediates. [ABSTRACT FROM AUTHOR]

Synthetic pharmaceutical effluents loaded with the β-lactam antibiotic oxacillin were treated using advanced oxidation processes (the photo-Fenton system and TiO 2 photocatalysis) and chloride mediated electrochemical oxidation (with Ti/IrO 2 anodes). Combinations of the antibiotic with excipients (mannitol or tartaric acid), an active ingredient (calcium carbonate, i.e. bicarbonate ions due to the pH) and a cleaning agent (sodium lauryl ether sulfate) were considered. Additionally, urban wastewater that had undergone biological treatment was doped with oxacillin and treated with the tested systems. The evolution of antimicrobial activity was monitored as a parameter of processes efficiency. Although the two advanced oxidation processes (AOPs) differ only in the way they produce OH, marked differences were observed between them. There were also differences between the AOPs and the electrochemical system. Interestingly, each additive had a different effect on each treatment. For water loaded with mannitol, electrochemical treatment was the most suitable option because the additive did not significantly affect the efficiency of the system. Due to the formation of a complex with Fe 3 + , tartaric acid accelerated the elimination of antibiotic activity during the photo-Fenton process. For TiO 2 photocatalysis, the presence of bicarbonate ions contributed to antibiotic activity elimination through the possible formation of carbonate and bicarbonate radicals. Sodium lauryl ether sulfate negatively affected all of the processes. However, due to the higher selectivity of HOCl compared with OH, electrochemical oxidation showed the least inhibited efficiency. For the urban wastewater doped with oxacillin, TiO 2 photocatalysis was the most efficient process. These results will help select the most suitable technology for the treatment of water polluted with β-lactam antibiotics. [ABSTRACT FROM AUTHOR]

The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H 2 O 2 , UV/Fe 2 + /H 2 O 2 and UV/TiO 2 . Prescreening experiments varying the H 2 O 2 and TiO 2 concentrations were performed in order to set the best catalyst concentrations in the UV/H 2 O 2 and UV/TiO 2 experiments, whereas the UV/Fe 2 + /H 2 O 2 process was optimized varying the pH, Fe 2 + and H 2 O 2 concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe 2 + /H 2 O 2 and UV/TiO 2 processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H 2 O 2 treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H 2 O 2 treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri . In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. [ABSTRACT FROM AUTHOR]

Abstract: Due to their carcinogenic, mutagenic and teratogenic potential, the removal of polycyclic aromatic hydrocarbons (PAHs) from aqueous environment using physical, biological and chemical processes has been studied by several researchers. This paper reviews the current state of knowledge concerning PAHs including their physico-chemical properties, input sources, occurrence, adverse effects and conventional and alternative chemical processes applied for their removal from water. The mechanisms and reactions involved in each treatment method are reported, and the effects of various variables on the PAH degradation rate as well as the extent of degradation are also discussed. Extensive literature analysis has shown that an effective way to perform the conversion and mineralization of this type of substances is the application of advanced oxidation processes (AOPs). Furthermore, combined processes, particularly AOPs coupled with biological treatments, seem to be one of the best solutions for the treatment of effluents containing PAHs. [Copyright &y& Elsevier]

Abstract: The effects of dissolved O2, phosphate buffer and the initial concentration of diclofenac on the vacuum ultraviolet photolysis of this contaminant molecule were studied. Besides kinetic measurements, the irradiated, multicomponent samples were characterized via the proliferation and migratory responses (in sublethal concentrations) of the bioindicator eukaryotic ciliate Tetrahymena pyriformis. The results suggest that hydroxyl radicals, hydrogen atoms and hydroperoxyl radicals may all contribute to the degradation of diclofenac. The aromatic by-products of diclofenac were presumed to include a hydroxylated derivative, 1-(8-chlorocarbazolyl)acetic acid and 1-(8-hydroxycarbazolyl)acetic acid. The biological activity of photoexposed samples reflected the chemical transformation of diclofenac and was also dependent on the level of dissolved O2. The increase in toxicity of samples taken after different irradiation times did not exceed a factor of two. Our results suggest that the combination of vacuum ultraviolet photolysis with toxicity and chemotactic measurements can be a valuable method for the investigation of the elimination of micropollutants. [Copyright &y& Elsevier]