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A comparison between the performance of electrolysis of three different soil-washing wastes with platinum and boron doped diamond (BDD) anodes is carried out in this work. Results demonstrate that the treatment is more efficient with BDD for perchloroethylene and clopyralid but not for the case of lindane, because in this case there is a competitive oxidation between lindane and Sodium Dodecyl Sulfate used to extract this pollutant from soil. First order kinetics are observed in each compound with higher removal at the early stages and generally better results are obtained when using BDD as anode. The evolution of pH and a voltammetry study indicate a higher direct oxidation rate in the case of platinum and more importance of hydroxyl radical mediated processes with diamond anodes. Similar speciation is obtained during the electro-oxidation using BDD and platinum electrodes although the concentration of intermediates vary significantly., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This work focuses on the treatment of synthetic wastewater polluted with dye Procion Red MX-5B by different Electrochemical Advanced Oxidation Processes (EAOP) based on diamond anodes. The influence of the current density and the supporting electrolyte has been studied on dye removal and total mineralization of the organic matter. Results show that electrolysis with diamond electrodes is a suitable technology for an efficient degradation of dye. Nonetheless, the process efficiency increases when using chloride as supporting electrolyte because of the electrochemical generation of hypochlorite in wastewater which significantly contribute to dye removal. On the contrary, the total mineralization of the organic matter is more efficient in sulfate media. In this case, large amounts of peroxodisulfate are electrogenerated, favoring the complete removal of total organic carbon (TOC). On the other hand, lower current densities (10 mA cm -2 ) lead to a more efficient removal of both dye and TOC due to the mass transfer limitations of the technology. Finally, the coupling of UV light irradiation or ultrasound to electrolysis significantly improves the process performance, being photoelectrolysis the most efficient technology for the treatment of wastewater polluted with Procion Red MX-5B. This fact is due to the potential production of free chlorine or sulfate radicals that takes place by the activation of the electrogenerated oxidants. These species are more reactive than oxidants and, therefore, they quickly attack the organic matter present in wastewater., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In this work, synthetic wastewater polluted with ionic liquid 1-butyl-3-methylimidazolium (Bmim) bis(trifluoromethanesulfonyl)imide (NTf 2 ) undergoes four electrolytic treatments with diamond anodes (bare electrolysis, electrolysis enhanced with peroxosulfate promoters, irradiated with UV light and with US) and results obtained were compared with those obtained with the application of Catalytic Wet Peroxide Oxidation (CWPO). Despite its complex heterocyclic structure, Bmim + cation is successfully depleted with the five technologies tested, being transformed into intermediates that eventually can be mineralized. Photoelectrolysis attained the lowest concentration of intermediates, while CWPO is the technology less efficient in their degradation. However, the most surprising result is that concentration of NTf 2 anion does not change during the five advanced oxidation processes tested, pointing out its strong refractory character, being the first species that exhibits this character in wastewater undergoing electrolysis with diamond. This means that the hydroxyl and sulfate radicals mediated oxidation and the direct electrolysis are inefficient for breaking the C-S, C-F and S-N bounds of the NTf - anion, which is a very interesting mechanistic information to understand the complex processes undergone in electrolysis with diamond.2 - anion, which is a very interesting mechanistic information to understand the complex processes undergone in electrolysis with diamond., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Hospital effluents are a major source for the occurrence of pharmaceuticals in the environment. In this work, the treatment of synthetic urine polluted with chloramphenicol is studied by using three different conductive-diamond electrochemical oxidation technologies: electrolysis (single electrolysis), photoelectrolysis and high-frequency ultrasound sonoelectrolysis. These technologies were evaluated at 10 and 100 mA cm -2 . Results shows that not only chloramphenicol but also other organics contained in urine are completely mineralized by electrolysis. Ammonium is the main inorganic nitrogen species formed and it can react with the electrogenerated hypochlorite, favouring the formation of chloramines. These species prevent the potential formation of perchlorate from chlorides contained in urine at low current densities (10 mA cm -2 ) and delay its occurrence at high current densities (100 mA cm -2 ). On the other hand, irradiation of ultraviolet (UV) light or high-frequency ultrasound (US) produce changes in the performance of the electrolytic treatment, but these changes are not as important as in other cases of study shown in the literature. Nonetheless, the effect of electroirradiated technologies seems to be higher and depends on the type of pollutant when working at low current densities (10 mA cm -2 ). It is positive in the case of the degradation of the antibiotic and the uric acid and negative in the case of urea where there is a clear antagonistic effect. Production of oxidants increases with the current density although in lower ratio than expected. These results are of great importance because clearly point out that electrolytic technologies can be applied to minimize the diffuse pollution associated to pharmaceuticals before discharge into municipal sewers., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The photo-assisted electrochemical degradation of a real effluent of the atrazine manufacturing process containing atrazine, simazine, hydroxy-triazine and propazine was carried out galvanostatically using a pilot-scale tubular flow reactor prototype containing DSA ® and Ti as cathode. The effluent was mainly characterized by a high amount of NaCl, required in the synthesis route used, and it was used as taken in the factory. The variables for process optimization were the current density (3.0, 6.0, and 9.0 mA cm -2 ) and flow rate (300 and 3,000 L h -1 ). These later values produces laminar and turbulent flow regimes, with Reynolds numbers of 1,100 and 11,000, respectively. None of the four organics contained in the waste is refractory to the photo-electrochemical treatment and they are depleted with the photo-electrolytic technology using large current densities and appropriate electric charge passed. Both direct electrochemical process and mediated anodic oxidation occur during the treatment. First process occurs at turbulent flow condition and low current densities, while the chemical oxidation process happens at laminar flow condition and high current densities. Atrazine and propazine are efficiently removed at laminar flow conditions, with an almost total depletion for the largest current densities. On the contrary, simazine is efficiently removed in turbulent flow conditions and intermediate current density, with removals higher than 90% for 20 kWh m -3 . These results have great significance because they demonstrate the applicability of the electrochemical technology in the treatment of real industrial wastes with a cell specially designed to attain high efficiency in the removal of pollutants., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this work, the effect of the cathode material (conductive diamond, stainless steel, silicon carbide, graphite or lead) and the current density (150-1400 A m(-2)) on the removal of nitrates from aqueous solutions is studied by electrolysis in non-divided electrochemical cells equipped with conductive diamond anodes, using sodium sulphate as the electrolyte. The results show that the cathode material very strongly influences both the process performance and the product distribution. The main products obtained are gaseous nitrogen (NO, N(2)O and NO(2)) and ammonium ions. Nitrate removal follows first order kinetics, which indicates that the electrolysis process is controlled by mass transfer. Furthermore, the stainless steel and graphite cathodes show a great selectivity towards the production of ammonium ions, whereas the silicon carbide cathode leads to the highest formation of gaseous nitrogen, which production is promoted at low current densities., (Copyright © 2012 Elsevier B.V. All rights reserved.)

BACKGROUND: This work focuses on the electrochemical production of chlorate solutions for direct use and integration in the manufacture of chlorine dioxide (ClO2), from the perspective of manufacturing portable ClO2 electrochemical generators. RESULTS: Chlorate production was evaluated from the oxidation of sodium chloride (NaCl) contained in brackish solutions (20 g L−1) and brines (200 g L−1) in single chamber flow electrochemical cells. Efficiency in chlorate ion (ClO3−) production increased with temperature and NaCl concentration, but the use of brackish solutions led to a higher quality product, as compared to the brines, with lower concentration of chlorine and hypochlorous acid. To evaluate the production of ClO2, samples corresponding to two different qualities of the electrogenerated solutions underwent stripping to exhaust chlorine, before being mixed with hydrogen peroxide (H2O2) and sulfuric acid. Results showed that using a chlorate solution obtained from the electrolysis of 20 g L−1 NaCl solution at 50 mA cm−2 and passing 57.35 Ah L−1, a maximum concentration of 33.3 mmol L−1 ClO2 could be attained, which corresponds to a maximum conversion of 48.75%. CONCLUSIONS: Efficiency of the synthesis depends on both the purity of chlorate and the H2O2/ClO3− ratio. This confirms that in‐situ electrogenerated chlorate can be used to manufacture ClO2, but there are still many gaps to be overcome and further work must be carried out to optimize the production of the desired oxidant in a portable ClO2 device. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

With the final purpose of manufacturing electrochemically-based devices that produce chloride dioxide efficiently, this paper focuses on the production of chlorates and hydrogen peroxide in two different electrochemical cells, in which operation conditions are selected to obtain high efficiencies, and in the subsequent combination of both electrochemically manufactured solutions to produce chlorine dioxide. Results demonstrate that suitable reagents can be produced by electrolyzing 20 g L−1 sodium chloride solutions at 50 mA cm−2 and 50 °C, and 3000 mg L−1 NaClO4 solutions at 5.0 mA cm−2 and 15 °C with current efficiencies of 30.9% and 48.0%, respectively. Different tests performed with these electrolyzed solutions, and also with commercial hydrogen peroxide and chlorate solutions, demonstrate that the ratio between both reagents plays a very important role in the efficiency in the production of chlorine dioxide. Results clearly showed that, surplus chlorate should be contained in the reagent media to prevent further reduction of chlorine dioxide by hydrogen peroxide and consequently, loses of efficiency in the process. During the reaction, a gas with a high oxidation capacity and consisting mainly in chloride dioxide is produced. The results contributed to the maximum conversion reached being 89.65% using electrolyzed solutions as precursors of ClO2, confirming that this technology can be promising to manufacture portable ClO2 devices. [ABSTRACT FROM AUTHOR]

This work focuses on the use of NaOH produced cathodically by reduction of water to retain gaseous CO2 in a combined electrolyzer‐absorber device. The process deals with two relevant environmental concerns: desalination and carbon sequestering, using only electricity and heat, which can be provided using green sources. Results demonstrate that technology is feasible, and the composition of the final product depends on the operation conditions applied. Removal rates of 130 mmol CO2/h were obtained at 7.5 A with coulombic efficiency in the removal of CO2 of 47.63 %. Efficiency in the production of chlorine, hydrogen and NaOH decreases at large current densities because of the promotion in the oxidation of water and the promoted transport of protons from the anodic to the cathodic compartment of the cell. Low current densities should be used to promote the formation of NaHCO3 and avoid scaling problems (formation of deposits of Na2CO3) in the spray column. The use of heated air to evaporate the product of the absorption column produces evaporated water with higher quality (in terms of lower conductivity) from the product of the absorption column. [ABSTRACT FROM AUTHOR]

Renewable energy storage and conversion is nowadays a major target for the scientific community. Their conversion into hydrogen is a clear and clean alternative for their storage. This work shows, for the first time, the results of the SO 2 depolarized electrolysis for hydrogen production at high temperature (120–170 °C) using phosphoric acid doped polybenzimidazole (PBI) membranes. A standard and a thermally cure PBI membrane doped with phosphoric acid were used for manufacturing the MEA of two electrolyzers. The benefit of the temperature was demonstrated but an unexpected behavior occurs at voltages higher than 0.8 V when temperature increases. Moreover, the thermally cured membrane shows a superior performance as compared with the standard one. Production of sulfur by reduction of SO 2 becomes an important drawback and advices not operating above 130 °C. Results show that PBI membranes doped with phosphoric acid are suitable for high temperature operation for the sulfur dioxide depolarized electrolysis. Increasing temperature is beneficial up to a certain value of potential, showing a considerable influence in the charge transfer resistance of the system. • Westinghouse electrolyzer operated successfully with PBI membranes. • Higher conductivities when membranes are doped with phosphoric acid. • First results above 120 °C with H3PO4 doped PBI membranes for SO2 electrolysis. • Operation under 140 °C allows minimizing the formation of sulfur. • Advanced PBI membranes outperform the standard PBI for SO2 electrolysis. [ABSTRACT FROM AUTHOR]

A new electrochemical cell is conceptualized, designed, manufactured using 3D printing technology, tested, and evaluated for the treatment of VOCs (for which benzene was used as model pollutant). This cell combines into a single device, a packed absorption column, where the pollutant is absorbed into an absorbent liquid, and an electrochemical cell equipped with a membrane-electrode assembly (MEA), for the continuous regeneration of the absorbent. The use of MEA technology allows to use of absorbents with low salt concentration. During operation, oxidants are produced on the electrodes of the electrochemical cell and distributed both in the liquid and gas phase, effectively degrading benzene. Computational Fluid Dynamics (CFD) modeling and experimental characterization of residence time distribution and mass transfer coefficient were also conducted. The results demonstrated that the use of electrochemically assisted absorbers in a single unit maximizes the utilization of the produced oxidants. The maximum removal efficiency of nearly 60% is reached working at 50 mA·cm−2. High current densities lead to pollutant desorption due to the significant increase in the gas phase outflow, resulting in reduced gas phase residence time and the pollutant leaving the system without undergoing reaction. [Display omitted] • 3D-printing to tailor electrochemical devices. • Oxidation of VOCs simultaneously both in liquid and gas phase. • Wasting of oxidants is avoided. • Mass coefficient transfer improves with the application of higher current densities. [ABSTRACT FROM AUTHOR]

In this work, the removal of antibiotic penicillin G by electrolysis with boron doped diamond (BDD) and mixed metal oxide (MMO) anodes in urine media is evaluated. First, electrolysis in different water matrices (sulfate, chloride and urine) were carried out with diamond anodes to shed light on the contribution of mediated mechanisms. Results showed that penicillin G was completely removed by electrolysis for electric charges below 5 Ah dm−3, regardless of the water matrix and the current density applied (10‐100 mA cm−2). Then, the influence of the anode material was evaluated for the degradation of penicillin G in urine media. A complete removal of the antibiotic was attained, regardless of the tested anode material, although the BDD anode was found to be more efficient than MMO. Results also showed that, at the current charges in which the antibiotic is depleted, the removal of other organics was much lower and the formation of chlorates was negligible, especially operating at low current densities. Because of this selective oxidation of the pharmaceutical compound, electrolysis can be proposed to be used as a pre‐treatment technology for later and cheaper biological treatment. Selective electrooxidation of pharmaceuticals in urine? The in‐situ electrochemical generation of powerful oxidants during electrolysis of urine seems to contribute to a selective degradation of antibiotics present in the effluent (mediated oxidation mechanism). This can be due to the higher molecular size of these pollutants in comparison with other organics naturally contained in urine such as urea, creatinine or uric acid. [ABSTRACT FROM AUTHOR]

In this paper, electrooxidation of methyl paraben (MeP) is studied by electrolysis only and electrolysis coupled with sonolysis, using a diamond electrode. Complete mineralization of MeP was achieved for both processes, in chloride and sulfate media. Results showed that, although the oxidation of pollutant is faster in the presence of chloride, the mineralization is favored in sulfate medium. Ultrasound irradiation enhanced the removal of organic matter due to the activation of oxidant species in both supporting electrolytes. Moreover, the formation of chlorine gas in the chloride containing medium improves the ultrasound cavitation effect, promoting faster depletion of the total organic carbon in the first hour of treatment. Regarding the formation of more toxic products, all possible organochlorinated intermediates were removed, since complete mineralization was attained in less than 5 hours. Ultrasonic coupling to the electrolysis process accelerates the destruction of the intermediates and delays the formation of perchlorate, which only begins after the complete removal of the total organic carbon. Low and high ultrasound frequencies were evaluated and were found to produce different effects of cavitation, which affect the electrolysis in different ways. The final result will be a balance between these effects and thus, an optimum frequency can be established for different systems. How ultrasound affects electrolysis? Enhancement of electrolysis by the coupling to sonolytic process for wastewater treatment results in the complete mineralization of a pollutant (methyl paraben) in sulfate and chloride media. Low frequency ultrasound promotes the activation of persulfate, which favors the TOC removal in the presence of sulfate. Cavitation effects of low and high intensities of ultrasound are balanced in an optimal frequency. [ABSTRACT FROM AUTHOR]

This work focuses on the competitive oxidation of two very different molecules, when they underwent electrochemical oxidation with diamond electrodes. To shed light on the mechanisms of this competitive oxidation, solutions containing methyl paraben and propylene glycol at different ratios are electrolyzed (using sulfate or chloride supporting electrolytes). Results obtained pointed out that removal of both species can be easily attained by the electrochemical process, being promoted the mineralization by the action of the sulfate derivative products and the formation of chlorinated hydrocarbons by the action of chlorine oxidants, although the mechanisms of the oxidation do not depend on the primary anion contained in the waste. The higher the concentration of species to be oxidized, the higher is the amount of intermediates and the slower is the mineralization the ratio influences. An important outcome is that there is a limit concentration in each one organic compound interferes on the degradation of a pollutant. Thus, the interference effect of PG on MeP oxidation was only observed for low MeP/PG ratios. What is the effect of the competitive oxidation of pollutants? There is a limit concentration in which an organic compound interferes on the degradation of a contaminant. Interference effect of PG (propylene glycol) on MeP (methyl paraben) oxidation is only observed for low ratios of MeP/PG. Higher concentrations of organic matter promotes faster abatement of initial pollutants but completely hinders the mineralization process. [ABSTRACT FROM AUTHOR]

BACKGROUND This work focuses on the removal of perchloroethylene (PCE) from soils spiked with this hazardous chlorinated hydrocarbon and oil by a combination of two technologies: soil washing and anodic oxidation with diamond electrodes. The first attains the transfer of the pollutant from the soil to a soil washing fluid (SWF), from which the organics are then efficiently removed. RESULTS: Results show that high concentrations of sodium dodecyl sulphate (SDS) are required in the SWF for an efficient extraction of the chlorinated hydrocarbon and electrolysis has to be applied not only to the clarified liquid, but also to the interphase. The surfactant used interacts strongly with soil not only during the washing, but also during the electrolysis step. This interaction seems to play a protective role against the oxidation of SDS. The initial phase of the electrolysis is rather complex and there are several processes which modify the results importantly. CONCLUSIONS: Removal of PCE by electrolysis from soil is less efficient than its removal from synthetic solutions of this chlorinated pollutant. There are two first‐order kinetic zones, which indicate an important competition for the oxidation of the different organics contained in the SWF during the electrolysis. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this work is to evaluate the effectiveness of complete treatment of soil spiked with 2,4-D, consisting of soil washing, followed by bioadsorption with activated sludge and electrochemical and photoelectrochemical oxidation of resulting wastewater using BDD anodes combined with UV light irradiation. RESULTS Results show that 2,4-D is very efficiently removed from synthetic soil by soil-washing without the use of surfactants. The effluent can be treated by bioadsorption with fresh activated sludge coming from a municipal wastewater treatment plant and the maximum adsorption capacity is 0.012 mg 2,4-D mg−1 biomass. Despite the low contact time between the biomass and the soil-washing effluent, results fit well to a Langmuir isotherm. CONCLUSIONS Photoelectrolysis with diamond anodes is more efficient than single electrolysis and the influence of potential radicalary oxidants produced on the anode surface from sulfate and chloride and activated by UV light can explain the better results. Both electrolysis and photoelectrolysis can lead to the complete mineralization of 2,4-D, regardless of the biomass/herbicide ratio applied in the previous bioadsorption process. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This work focuses on the scale-up of electrochemical and photoelectrochemical oxidation processes with diamond anodes for the removal of organic pollutants and disinfection of treated urban wastewater, two of the most important parameters for the reclaiming of wastewater. The removal of organics was studied with actual biologically treated urban wastewater intensified with 100 mg dm of caffeine, added as a trace organic pollutant. The disinfection was also studied with biologically treated urban wastewater, and Escherichia coli was used to monitor the efficiency of the process. Results obtained with a single DiaCell® 101 were compared with those obtained with a single-stack DiaCell® 1001 and with a pilot plant made up of five of these stacks. Results obtained demonstrate that scale-up is not a simple but a very complex process, in which not only the electrode and the irradiation dose are important but also mass transfer conditions. Enhanced mass transport conditions have a determining and very positive effect on the removal of organics and a negative effect on the disinfection. Likewise, ultraviolet (UV) irradiation affects in a different way in the different setups used, having a great influence on the removal of complex organics and on the speciation of oxidants produced during disinfection. This works helps to understand the key differences observed in the scale-up, and it is a first approach for future works focused on the real application of conductive diamond electrochemical oxidation. [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, the application of electrochemical wastewater treatment processes has proven to be very efficient in the removal of recalcitrant organic compounds. However, the scale-up of the boron-doped diamond (BDD) anode system for industrial applications has not been sufficiently evaluated. This study assesses the effect of increasing the number of compartments in the same electrochemicalmodule (DiaCell® 1001) on the treatment of synthetic wastewater with pesticide 2,4-D and chlorides. This commercial module can be considered to be a stack of cells, in which the number of single cells varies from 2-10 and the anode areas range from 140-700 cmâ'2. RESULTS: The results of the study demonstrate that an increase in the number of cells and a decrease in the resulting current density at the same current intensity caused an increase in the removal and mineralisation rates. Complete mineralisation was attained in all configurations tested. The production of hazardous species, such as chlorates and perchlorates, are also affected by the number of stacked cells, which causes them to be positioned lower in the stack due to the large number of cells. CONCLUSIONS: No distinct differences in electrochemical efficiency are observed among the different configurations tested. However, a distinct improvement in the energy efficiency (g kWhâ'1) with an increase in the number of stacked cells is observed due to the reduced stack potential caused by applying the same current intensity to the stack with the higher number of cells. [ABSTRACT FROM AUTHOR]

BACKGROUND In this work, the electrolysis and photo-electrolysis of dimethyl phthalate ( DMP, a widely-use plasticizer) using conductive-diamond anodes are studied. RESULTS Electrolysis and photo-electrolysis are suitable technologies for the removal of DMP from aqueous wastes. Within the range of current densities studied (20-120 mA cm-2), complete mineralization is achieved. UV light irradiation appears to improve mineralization and chemical oxygen demand removal rates, but not DMP removal rates, which worsened with light. The supporting electrolyte (sulfate or chloride salt) plays an important role in the electrochemical oxidation mechanisms but not in single photolysis treatment. Electrochemical mineralization is more efficient in sulfate media due to the formation of chlorates and perchlorates with diamond electrodes in chloride media. Oxidation by photolysis, electrolysis and coupled photo-electrolysis begins with attacks on the methyl ester groups, continues with the breakage of the aromatic ring, and forms carboxylic acids. The process conditions are very harsh, and only small concentrations of intermediates were found. CONCLUSIONS Electrolysis and photo-electrolysis with conductive-diamond anodes led to the complete mineralization of DMP with an almost negligible formation of intermediates. Light irradiation significantly improved mineralization and COD removal, but not DMP degradation. Chloride anions led to less efficient electrolysis than sulfate anions. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND In this work, the electrolysis of dimethyl phthalate ( DMP, a widely-use plasticizer) with conductive-diamond anodes is studied. RESULTS Results show that this technology is capable of depleting this pollutant in a wide range of initial concentrations. Although mass transfer limits the kinetics of the process, there is a significant contribution of mediated oxidation and the rate of the processes improve with increasing current density, while the efficiency decreases. A first stage in the oxidation of DMP consists of the attack on the methyl ester groups, and monomethyl phthalate and phthalate are the main aromatic intermediates. Further oxidation of these species results in the formation of maleic and oxalic acid, which behave as intermediates and are completely mineralized during the electrolysis. The presence of chloride in water leads to the formation of many more aromatic chlorinated intermediates from the action of hypochlorite on aromatics intermediates. Intermediates found and oxidation mechanisms proposed are consistent with those reported in the literature for other advanced oxidation processes. CONCLUSIONS DMP, TOC (total organic carbon) and COD (chemical oxygen demand) can be successfully removed using electrolysis with conductive-diamond anodes. DMP removal is faster than that of COD and TOC indicating the formation of reaction intermediates. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This work evaluates the integration of dehalogenation with Zero Valent Iron (ZVI) and electrochemical oxidation (EO) for the treatment of urines polluted with iodinated X-ray contrast media (ICM). To do this, different strategies were evaluated: pretreatment with ZVI followed by EO (ZVI-EO) or electrolysis enhanced with ZVI-dehalogenation (EO/ZVI). For comparison purposes, single electrolysis was also performed to check the best treatment strategy. Results showed that EO was less efficient than EO/ZVI and ZVI-EO processes. Removal percentages of 74.9%, 87.6% and 99.5% were reached after passing 13.8 Ah dm−3 at 10 mA cm−2 during EO, EO/ZVI and ZVI-EO, respectively. EO/ZVI process favored the production of large amounts of hydroxyl radicals in the effluent through Fenton´s reaction, enhancing the degradation rate of iopamidol (IPM). The pretreatment with ZVI allowed to transform up to 95% of IPM to C 17 H 25 N 3 O 8. Then, electrolysis attained the almost complete removal of the raw pollutant (ZVI-EO). The different iodine species formed at the end of the treatment were also monitored, finding similar proportions of organic iodine species for EO and EO/ZVI processes, although single EO promoted the formation of the stable inorganic iodine (IO 3 -) and EO/ZVI favored the release of I-. Total organic carbon removal percentages lower than 20% were achieved, suggesting that the technologies employed were selective for the removal of the target pollutant under the operating conditions studied. Finally, the organic IPM by-products were also identified by LC-MS and the chromatographic area profiles showed higher values for EO/ZVI followed by ZVI-EO and EO. [Display omitted] • The removal and kinetics of iopamidol by electrolysis can be improved with ZVI. • ZVI-pretreatment followed by electrolysis attains > 99.5% of iopamidol removal. • IO 3 - formation is promoted in the ZVI-pretreatment followed by electrolysis. • A possible degradation pathway of iopamidol is proposed. [ABSTRACT FROM AUTHOR]

Abstract: In this work, electrolyses of solutions containing one anthraquinonic (Acid Blue 62) and three azoic (Reactive Red 141, Direct Black 22, and Disperse Orange 29) synthetic dyes were carried out using conductive-diamond anodes. From the obtained results, clearly the oxidation was largely influenced by the supporting electrolyte used: (i) in the presence of chloride ions, the primary mechanism is mediated electrooxidation in solution with formation of a significant amount of intermediates; (ii) in the presence of sulfate ions, the dyes are directly mineralized by hydroxyl radicals. In every condition, the synthetic dyes were completely removed from the solutions. The kinetics of the electrooxidation process was mass-transport controlled, although the proper treatment of such dye solutions was assured with energy consumptions below 60kWhm−3. [Copyright &y& Elsevier]

Endocrine disrupting compounds (EDCs) are one of the many classes of harmful pollutants frequently found in water resources. Even at low concentrations, EDCs might accumulate in the organisms and interfere on numerous processes controlled by hormones. Parabens, for example, are preservatives widely used in pharmaceutical and cosmetic industries, but several studies related them to human breast cancer. It is well-known that electrochemical technologies are an efficient alternative for wastewater treatment, promoting the appropriate destruction of EDCs. However, most studies are applied to single target contaminant solutions, which may neglect the impact from co-exited inorganic/organic pollutants. Based on that, this study aimed to elucidate the interfering effects of two target organic contaminants of very different nature during electrochemical mediated process. For that, methyl paraben (MeP) and propylene glycol (PG) were selected as models of aromatic/phenolic and carboxylate compounds versus low-molecular aliphatic alcohols. These two compounds are often together used in preservative blends and cosmetic/pharmaceutical formulations. PG is not a harmful chemical, but it is present in several types of effluents in relatively high concentrations. Thus, it may interfere on the degradation of numerous pollutants of low concentrations. The electrochemical treatment of a mixture containing 100 mg L−1 MeP +1000 mg L−1 PG showed that both contaminants suffered interfering effects. The presence of MeP negatively interfered on PG degradation; the carboxylate compound is more easily oxidized even at lower molecular concentration. On the other hand, the presence of PG showed an unexpected positive effect on MeP degradation, that was not reflected on its mineralization. The results indicate that in addition to the expected effect of anodic competition, polymerization and copolymerization reactions may also occur in the studied system. The use of an acidic buffer medium increased the removal of both contaminants and favored the oxidation pathway over the polymerization. In this case, the increase in the removal was reflected in the mineralization process, which increased up to 6 times when the mixture was treated in the buffered medium. [Display omitted] • Electrolysis with DSA®-Cl 2 anode promotes the oxidation and polymerization of PG. • Competitive oxidation is observed for the Mix, decreasing mineralization efficiency. • MeP removal might increase in Mix due to its copolymerization with PG oligomers. • Buffered acid medium resulted in a higher mineralization of MeP, PG and the Mix. [ABSTRACT FROM AUTHOR]

This work focuses on the evaluation of goethite as a catalyst for the transformation of sulfuric acid into sulfur dioxide, a reaction with great interest for the hybrid electrochemical-thermoelectrochemical Westinghouse cycle for hydrogen production. A comparison of the performance of goethite with that of CuO, Fe2O3, and SiC has been carried out. Moreover, a mixture of those catalysts was evaluated. The results demonstrate that goethite can be used as a catalyst for the thermal decomposition of sulfuric acid in the Westinghouse cycle, with an activity higher than that of SiC but lower than that of Fe2O3 and CuO. However, it does not undergo sintering during its use, but just produces small particles in its surface, which remain after the treatment. Mixtures of Fe2O3 with SiC or goethite do not produce synergism, thus operating each catalyst in an independent way. [ABSTRACT FROM AUTHOR]

This work focuses on the evaluation of the degradation of 17β-estradiol in a mixture of synthetic urine and methanol, trying to determine in which conditions the hormone can be more easily degraded than the urine compounds. This is in the frame of an overall study in which the pre-concentration stage with adsorption/desorption technology is evaluated to improve electrolysis efficiency. Results show that this pollutant can be efficiently removed from mixtures of urine/methanol by electrolysis with diamond electrodes. This removal is simultaneous with the removal of uric acid (used as a model of natural pollutants of urine) and leads to the formation of other organic species that behave as intermediates. This opens the possibility of using a concentration strategy based on the adsorption of pollutants using granular activated carbon and their later desorption in methanol. Despite methanol being a hydroxyl radical scavenger, the electrolysis is found to be very efficient and, in the best case, current charges lower than 7 kAh·m−3 were enough to completely deplete the hormone from urine. Increases in the operation current density lead to faster but less efficient removal of the 17β-estradiol, while increases in the operation flowrate do not markedly affect the efficiency in the removal. Degradation of 17β-estradiol is favored with respect to that of uric acid at low current densities and at high flowrates. In those conditions, direct oxidation processes on the surface of the anode are encouraged. This means that these direct processes can have a higher influence on the degradability of the hazardous species and opens the possibility for the development of selective oxidation processes, with a great economic impact on the degradation of the hazardousness of hospitalary wastewater. [ABSTRACT FROM AUTHOR]

In the near future, primary energy from fossil fuels should be gradually replaced with renewable and clean energy sources. To succeed in this goal, hydrogen has proven to be a very suitable energy carrier, because it can be easily produced by water electrolysis using renewable energy sources. After storage, it can be fed to a fuel cell, again producing electricity. There are many ways to improve the efficiency of this process, some of them based on the combination of the electrolytic process with other non-electrochemical processes. One of the most promising is the thermochemical hybrid sulphur cycle (also known as Westinghouse cycle). This cycle combines a thermochemical step (H2SO4 decomposition) with an electrochemical one, where the hydrogen is produced from the oxidation of SO2 and H2O (SO2 depolarization electrolysis, carried out at a considerably lower cell voltage compared to conventional electrolysis). This review summarizes the different catalysts that have been tested for the oxidation of SO2 in the anode of the electrolysis cell. Their advantages and disadvantages, the effect of platinum (Pt) loading, and new tendencies in their use are presented. This is expected to shed light on future development of new catalysts for this interesting process. [ABSTRACT FROM AUTHOR]

In this work, hydrogen peroxide (H 2 O 2) is produced using an optimized electrochemical cell equipped with a gas diffusion electrode (GDE) as cathode, reaching efficiencies as high as 20.1%, when operating in a single compartment configuration, which increases up to the range 50–60, when a proton exchange membrane is used to separate the anodic and cathodic compartments, pointing out the great significance of the anodic oxidation of H 2 O 2 and the scavenging effects of the oxidants produced on the anode surface. As compared to previous materials tested, the GDE implemented in this cell underwent a more sustainable manufacturing procedure and exhibited an outstanding performance. The H 2 O 2 produced electrochemically is dosed to the real leachate of an industrial dump, strongly polluted with derivatives of lindane. This waste is associated to the operation of a large facility in the seventies and contains different isomers of hexachlorocyclohexane and other chlorinated hydrocarbons, produced during the ageing of the dump. Effects of the addition of iron (II) sulfate salts and irradiation of UVC were also evaluated. All electrochemically-assisted technologies evaluated (named as chemical (EACO), Fenton (EAFO), photolysis (EAPO) and photo-Fenton (EAPFO) oxidations) were able to successfully remove the pollutants, although with important differences in the efficiencies reached. Results demonstrate that EACO, that is, oxidation by molecular H 2 O 2 is the most effective treatment for the treatment of this type of wastes, pointing out that activation of H 2 O 2 to hydroxyl radicals, either by electrochemically assisted Fenton or photolysis is not positive for this waste. As well, among the different pollutants contained in the raw waste, removal of hexachlorocyclohexane (HCHs) and non-chlorinated volatile organic compounds (VOCs) stands out (both groups being the primary species contained in the wastes). These results are very important not only because of the outstanding productions of H 2 O 2 reached with the novel approach of electrochemical cell used, but also because of the implications of the mechanistic understanding of the attack of H 2 O 2 species in the design of a full-scale application to remediate this real important problem. [Display omitted] • Improved production of H 2 O 2 with a novel GDE and cell. • H 2 O 2 is produced with efficiencies over 20% in non-divided configurations. • Improved efficiency when using divided cells, with values as high as 50–60%. • Several electrochemical H 2 O 2 based technologies suitable for degradation wastes. • Unexpectedly H 2 O 2 more efficient that hydroxyl radicals in destroying CHCs. [ABSTRACT FROM AUTHOR]

This work focuses on the application of electrolysis with carbon felt cathodes for the reclamation of actual effluents from municipal wastewater treatment facilities (WWTFs) in combination with different anode materials (dimensionally stable anodes-DSA, conductive diamond anodes-CDA and iron–Fe). First of all, the efficiency of electrodisinfection with CDA and DSA was assessed, finding that total elimination of Escherichia coli ( E. coli ) can be attained at applied electric charges below 0.03 Ah dm −3 , and that the disinfection process is more efficient when using CDA. Furthermore, it was observed that the formation of hydrogen peroxide on carbon felt cathodes limits the concurrence of disinfection by-products (chlorates, perchlorates and organic chlorinated by-products), an interesting result that broadens the potential of CDA for the regeneration of urban wastewater. Results with Fe anodes show that it is possible to attain the complete removal of microorganisms with comparable efficiency to that of CDA (due to the contribution of Fenton's reaction) and that it was possible to totally remove the turbidity of the effluent when working at current densities from 12.50 A m −2 . Finally, it was found that Fe is the most efficient anode material (lowest power consumption) at low current densities and CDA is the most appropriate one at current densities higher than 5 A m −2 . According to these results, the pairs anode-cathode CDA-carbon felt and Fe–carbon felt behave as the most promising electrode materials to be applied in wastewater reclamation processes. [ABSTRACT FROM AUTHOR]

• Electrolysis of real leachates polluted with complex mixture of chlorinated organics. • Important differences associated with the type of electrodes. • Diamond coatings more effective leading to non-selective oxidation. • Better performance of electrolysis at low current densities with MMO anodes. • UV irradiation impacts negatively on the removal of pollutants. In this work, the electrolytic treatment of the real leachate of an industrial dump that contains a complex mixture of different isomers of hexachlorocyclohexane and other chlorinated hydrocarbons, produced during the ageing of the dump, is studied using different types of electrodes (boron doped diamond, BBD, or mixed metal oxide, MMO). Results demonstrate the effectivity of this technological approach as well as the important effect of the anode material and the irradiation of UVC light. Regarding the first, the choice of BDD coatings lead to a non-selective and extremely efficient degradation of the chlorinated organic compounds (COCs) with a low dependency on the exerted current density. In contrast, MMO coatings exhibit slower and less efficient degradation, with improved degradation results at lower current densities. Regarding the second, as demonstrated in a previous study for the dosing of electrochemically produced hydrogen peroxide, UVC light irradiation not only does not improve but worsen the degradation of the chlorinated hydrocarbons and this is explained by the better predisposition of the target pollutants for being oxidized with molecular oxidant rather than with radicals. This work provides important lessons learned for future applications of the electrochemical technology in the treatment of comparable environmental problems. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: In this work, arsenic oxidation by an electrochemical process was studied in a batch bench-scale electrolysis plant equipped with mono- and bi-compartment cells, dimensionally-stable anodes (DSAs) and conductive-diamond anodes (CDAs). The results demonstrate that the electrolysis is an adequate technology to transform As(III) into As(V) species, which is an important pre-treatment stage for removing of arsenic from water using technologies such as coagulation or electro-coagulation. The process requires large current densities in non-divided cells to obtain a good As(V)/As(III) ratio, but it can be more efficiently performed at low current densities in cells divided by cationic membranes. The presence of chlorides or sulphates can significantly affect the results due to the formation of powerful oxidants that contribute to the net oxidation process. [Copyright &y& Elsevier]

[Display omitted] • High efficiencies in the oxidation of H 2 SO 4 with different diamond coatings. • Important influence of the diamond coating on the oxidation mechanisms. • Simple model is able to reproduce experimental results very accurately. • UND promotes direct oxidation on the electrode surface. • UND obtained the best efficiency in the production of Caro's acid. In this work new diamonds coating, named as nanocrystalline diamond (ND) and ultrananocrystalline diamond (UND) are evaluated for the production of peroxospecies derived from the electrolysis of sulphuric acid and their performance is compared to that of a commercial diamond coating widely used in the literature and well-known by its outstanding performance. The oxidant production was tested at two different current densities and significant differences were found in oxidant production between the electrodes applied in the different conditions studied. Results demonstrate that when the lowest current is applied (25 mA cm−2), the ND and UND electrodes are more efficient in the persulfate formation. For ND electrode, this behavior can be explained in terms of the promoted hydroxyl radical formation at these conditions. However, the UND electrode presented different behavior: the lesser hydroxyl formation and highest peroxospecies formation. This behavior may be attributed to the sum of two factors: the high sp2 content in the diamond film and its porosity, that can increase the sulphate adsorption at the surface that, in turn, facilitates the persulfate generation. This behavior can be proved by the Tafel plots and are explained by the electrode's features discussed by Raman spectra. When the operation current is increased to harsher conditions (300 mA cm−2), the commercial electrode increases importantly the production of the studied oxidant. One more time it can be attributed to the hydroxyl radical generation at this condition. Considering the energy consumption and the process efficiency, it can be concluded that the UND electrode is more attractive for this application in the studied conditions. [ABSTRACT FROM AUTHOR]

• 1-Butyl-3-methylimidazolium can be easily transformed into intermediates and can be mineralized. • Chloride and acetate anions are removed more efficiently than the Bmim+ cation. • During the oxidation of Bmim+, nitrites, nitrates and ammonium are formed in bulk. • Sonoelectrolysis is the most efficient technology for mineralizing BmimAc. • Photoelectrolysis results in faster mineralization of BmimCl. In this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc) and chloride (BmimCl) were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by UV light or with the application of high-frequency ultrasound (US). Despite its complex heterocyclic structure, the Bmim+ cation was successfully depleted with the three technologies that were tested and was mainly transformed into four different organic intermediates, an inorganic nitrogen species and carbon dioxide. Regardless of the technology that was evaluated, removal of the heterocyclic ring is much less efficient (and much slower) than oxidation of the counter ion. In turn, the counter ion influences the rate of removal of the ionic liquid cation. Thus, the electrolysis and photoelectrolysis of BmimAc are much less efficient than sonoelectrolysis, but their differences become much less important in the case of BmimCl. In this later case, the most efficient technology is photoelectrolysis. This result is directly related to the generation of free radicals in the solution by irradiation of the electrochemical system with UV light, which contributes significantly to the removal of Bmim+. [ABSTRACT FROM AUTHOR]

Abstract In this work, the valorization of brines, with concentrations similar to those produced by reverse osmosis or electrodialysis processes, by electrolysis with diamond anodes is evaluated. To do this, synthetic brines made from solutions of NaCl (with target concentrations ranging from 1.0 to 2.0 M and an additional test at 5.0 M) were used as the raw material for the electrochemical production of perchlorate using commercial electrochemical cells equipped with boron-doped diamond (BDD) anodes. The effect of key parameters on the rate and efficiency of perchlorate production was evaluated. The results show that it is possible to transform more than 80% of the initial chloride concentration into perchlorate, with current efficiencies higher than 70% regardless of the initial concentration of sodium chloride contained in the brine. Moreover, it was observed that both hypochlorite and chlorate were produced almost simultaneously at the beginning of electrolysis, while perchlorate was only produced when a certain value of applied electric charge was passed through the system. The results obtained were essentially independent of the concentration of NaCl, as the high concentrations used in this study avoided mass transfer limitations. Moreover, the specific energy cost of perchlorate production was estimated to range from 26.14 kWh kg−1 (for 2.0 M and 1000 A m−2) to 56.10 kWh kg−1 (for 1.0 M and 2000 A m−2). According to the results obtained, the electrochemical production of perchlorate by BDD electrochemical oxidation stands out as a promising novel technology for the valorization of the brine produced in reverse osmosis or electrodialysis processes. Graphical abstract Image 1 Highlights • Perchlorate is efficiently produced from highly concentrated NaCl by electrolysis. • High current efficiency and conversion to perchlorate were obtained. • A threshold of applied charge is required to produce perchlorate. • The energy consumption of perchlorate production ranges from 26.14–56.10 kWh kg−1. [ABSTRACT FROM AUTHOR]

In this work, the disinfection of highly faecal-polluted surface water was studied using a new electrochemical cell (CabECO ® cell, manufactured by CONDIAS) specifically designed to produce ozone in water with very low conductivity. The disinfection tests were carried out in a discontinuous mode to evaluate the influence of the electrode current charge passed. The effect of the current density was also studied in order to optimize the disinfection conditions and to simultaneously prevent the formation of undesirable by-products (chlorates and perchlorates) during the electrolysis. The results demonstrate that this technology is robust and efficient, and it can suitably disinfect water. During electrolysis, the chloride contained in the water was oxidized to hypochlorite, and this compound was combined with ammonia to form chloramines. Both hypochlorite and chloramines (formed by the well-known break point reaction) promoted persistent disinfection and seemed to be mainly responsible for the disinfection attained during the electrochemical process. Chlorate and perchlorate could also be produced, although the low concentrations of chloride in the tested water made them irrelevant. The removal of the total organic carbon under the applied operating conditions was not very efficient (although it reached 50% in 2 h) and the production of trihalomethanes was very low, below 100 ppb for all tests. [ABSTRACT FROM AUTHOR]

Boron doped diamond (BDD) anode has been used to oxidatively remove Rhodamine B (RhB), as persistent organic pollutant, from synthetic wastewater by electrolysis, photoelectrolysis and chemical oxidation containing sulfate and phosphate as supporting electrolytes. RhB is effectively oxidized by electrolysis and by chemical oxidation with the oxidants separately produced by electrolyzing sulfate or phosphate solutions (peroxodisulfate and peroxodiphosphate, respectively). The results showed that light irradiation improved the electrolysis of RhB due to the activation of oxidants under irradiation at high current densities. Meanwhile, the efficiency of the chemical oxidation approach by ex situ electrochemical production of oxidants was not efficient to degrade RhB. [ABSTRACT FROM AUTHOR]

In this work, it is studied the electrolysis with diamond anodes of three different ionic liquids (ILs): 1-butyl-3-methylimidazolium chloride (BmimCl), 1-hexyl-3-methylimidazolium chloride (HmimCl) and 1-decyl-3-methylimidazolium chloride (DmimCl), which differ only in the length of the aliphatic carbon chain attached to the imidazolium group. In addition, the effect of the presence of sulfate in the electrolyte is also evaluated. Results confirmed that this type of ILs can be completely transformed into carbon dioxide, nitrates, ammonium (the imidazolium cation) and perchlorate and chloramines (the chloride anion) during the electrolysis of the synthetic waste containing sulfate. The electrolysis of wastes without sulfate anions leads to a much less efficient process, with the same final products in the case of the BminCl and HminCl ILs and with the formation of a polymer as the main final product in the case of the DmimCl. These results are of a paramount significance from a mechanistic point of view since, because of the high conductivity of the ILs, there is not a necessity of salt addition and they inform about the pure removal of these compounds by electrolysis with BDD, pointing out the important influence of peroxodisulfate on the electrolyses with diamond of organic wastes. [ABSTRACT FROM AUTHOR]

This work focuses on the application of electrolysis with diamond anodes for the disinfection of urine. To do this, a synthetic human urine was polluted with Escherichia coli and Pseudomonas aeruginosa and then, it was electrolyzed at current densities within the range 0–100 A m −2 . Results show that it is possible to disinfect completely the effluent even at applied electric charges lower than 2 kAh m −3 , regardless the current density applied. This good performance is related to the production of powerful oxidants from the oxidation of the ions present in synthetic urine. Likewise, these species also react with the organics contained in urine (urea, creatinine and uric acid), favoring their degradation. The process efficiency for both microorganisms and organics is higher when working at low current densities. The removal of organics leads to the release of significant amounts of nitrogen in the form of nitrate which are later electroreduced to ammonium, that, in turn, reacts with the electrogenerated hypochlorite, favoring the production of chloramines (which can also contribute to the disinfection process). Regarding the mineralization, TOC removal higher than 90% can be achieved but higher applied electric charges than those required for disinfection have to be applied (around 30 kAh m −3 ). [ABSTRACT FROM AUTHOR]

In this work, it is presented an innovative soil remediation technology consisting of the combination of soil washing, GAC adsorption and electrolysis. This technology is applied for the remediation of soil polluted with herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The new combined process involves three steps into a single chamber: first step is related to the washing of soils using groundwater as soil washing fluid, the second step is related to the herbicide removal from the produced soil washing effluent by adsorption onto granulated active carbon and the third step is the use of electrolysis to oxidize the 2,4-D and provide bubbles that enhance the mixing and separation by dissolved gas flotation. All processes are studied alone and in combination. The obtained results pointed out the possibility for total removing of the herbicide content in the contaminated soil, simultaneously to the herbicide removal contained in soil washing effluent, which become ready to be recycled as a fresh soil washing fluid. The proposed combined treatment for complete decontamination of soils polluted with 2,4-D herbicide was successfully tested for 0.1 kg soil, contained 20 mg herbicide per kg of soil, using 1 dm 3 of synthetic groundwater as washing effluent and 10 g GAC, and passing through this mixture an electrical current of 0.5 A, during 2 h. [ABSTRACT FROM AUTHOR]

In this work, the removal of Procion Red MX-5B dye by electrochemical oxidation with boron doped diamond (BDD) anodes was investigated. The impact of current density, flow rate, initial pH, and supporting electrolyte was evaluated on dye and organic matter removal. Furthermore, the use of dimensionally stable anodes (DSA) was tested to evaluate process performance. Results show that after 240 min, it is possible to achieve full dye and COD (Chemical Oxygen Demand) removal, regardless of applied current density. This is due to the generation of powerful oxidants – i.e. hydroxyl radicals and peroxodisulfate–, which attack the organic matter in the wastewater, promoting its complete degradation. However, process efficiency increases when using lower current densities (10 mA cm −2 ): electric charges of about 5 Ah dm −3 are sufficient to fully remove both dye and COD, while charges higher than 15 Ah dm −3 are required when working at higher current densities (>30 mA cm −2 ). This fact is related to the production of large amounts of hydroxyl radicals, which are wasted in other reactions at higher current densities. On the other hand, higher flow rates (300 dm 3  h −1 ) promote Procion Red MX-5B and organic matter degradation, due to improved mass transfer within the system. Regarding the impact of initial pH on dye removal, no significant differences were observed. Conversely, COD is clearly affected by this parameter: it is only possible to fully remove the organic matter when working at natural pH. Finally, with DSA anodes, higher dye removal efficiencies are attained than with BDD electrodes, when 100 mg dm −3 chlorides are added to the supporting electrolyte. Likewise, higher chloride concentration (100–1000 mg dm −3 ) was observed to enhance process efficiency when using DSA as anode material. However, during electrolysis with both BDD and DSA, chloride ions in the supporting electrolyte promote the production of intermediate organochlorinated compounds. Therefore, under these conditions, no full organic matter removal can be achieved, regardless of the anode material employed. [ABSTRACT FROM AUTHOR]

The electrolysis with diamond anodes of synthetic urines containing different concentrations of ibuprofen and cloxacillin is evaluated in this work, with the aim of determining if this technology is effective in the mineralization of both species in urine matrix and the main characteristics of the competitive oxidation among these two products and the natural organic compounds contained in urine (uric acid, creatinine and urea). Results point out that electrolytic technology can mineralize all organic contained in the urine very efficiently and that oxidation of the two pharmaceuticals is faster than that of the natural products contained in urine, opening the possibility of a selective treatment of the urine up to the point in which it can be merged safely with domestic wastewater without generating a negative impact on environment. Occurrence of perchlorate is the main drawback of this technology, although its impact is not believed to be as serious as the impact of the pharmaceuticals on environment. [ABSTRACT FROM AUTHOR]

In this work, it is studied the photolysis, electrolysis, and photo-electrolysis of a mixture of pharmaceutics (sulfadiazine, naproxen, diclofenac, ketoprofen and ibuprofen) contained in two very different types of real water matrices (obtained from surface and porewater reservoirs), trying to clarify the role of the matrix on the degradation of the pollutants. To do this, a new metrological approach was also developed for screening of pharmaceuticals in waters by capillary liquid chromatography mass spectrometry (CLC-MS). This allows the detection at concentrations lower than 10 ng mL−1. Results obtained in the degradation tests demonstrate that inorganic composition of the water matrix directly influences on the efficiency of the drugs removal by the different EAOPs and better degradation results were obtained for experiments carried out with surface water. The most recalcitrant drug studied was ibuprofen for all processes evaluated, while diclofenac and ketoprofen were found to be the easiest drugs for being degraded. Photo-electrolysis was found to be more efficient than photolysis and electrolysis, and the increase in the current density was found to attain a slight improvement in the removal although with an associated huge increase in the energy consumption. The main reaction pathways for each drug and technology were also proposed. [Display omitted] • CLC-MS screening of pharmaceuticals in waters and detection at concentrations lower than 10 ng mL−1. • Removal of a mixture of five drugs was evaluated using several EAOP. • Ibuprofen more recalcitrant than sulfadiazine, naproxen, diclofenac and ketoprofen. • Photo-electrolysis more efficient than photolysis and electrolysis. • Important differences in reactions pathways proposed for each technology studied. [ABSTRACT FROM AUTHOR]