Use Of Advanced Oxidation Processes Research Articles

Spectroscopic methods for aqueous cyclodextrin inclusion complex binding measurement for 1,4-dioxane, chlorinated co-contaminants, and ozone

Recalcitrant organic contaminants, such as 1,4-dioxane, typically require advanced oxidation process (AOP) oxidants, such as ozone (O3), for their complete mineralization during water treatment. Unfortunately, the use of AOPs can be limited by these oxidants' relatively high reactivities and short half-lives. These drawbacks can be minimized by partial encapsulation of the oxidants within a cyclodextrin cavity to form inclusion complexes. We determined the inclusion complexes of O3 and three common co-contaminants (trichloroethene, 1,1,1-trichloroethane, and 1,4-dioxane) as guest compounds within hydroxypropyl-β-cyclodextrin. Both direct (ultraviolet or UV) and competitive (fluorescence changes with 6-p-toluidine-2-naphthalenesulfonic acid as the probe) methods were used, which gave comparable results for the inclusion constants of these species. Impacts of changing pH and NaCl concentrations were also assessed. Binding constants increased with pH and with ionic strength, which was attributed to variations in guest compound solubility. The results illustrate the versatility of cyclodextrins for inclusion complexation with various types of compounds, binding measurement methods are applicable to a wide range of applications, and have implications for both extraction of contaminants and delivery of reagents for treatment of contaminants in wastewater or contaminated groundwater.

Simultaneous removal of NO and SO2 from flue gas by combined heat and Fe2+ activated aqueous persulfate solutions

The use of advanced oxidation processes (AOPs) to integrate flue gas treatments for SO2, NOx and Hg0 into a single process unit is rapidly gaining research attention. AOPs are processes that rely on the generation of mainly the hydroxyl radical. This work evaluates the effectiveness of the simultaneous removal of NO and SO2 from flue gas utilizing AOP induced by the combined heat and Fe2+ activation of aqueous persulfate, and elucidates the reaction pathways. The results indicated that both SO2 in the flue gas and Fe2+ in solution improved NO removal, while the SO2 is almost completely removed. Increased temperature led to increase in NO removal in the absence and presence of both Fe2+ and SO2, and in the absence of either SO2 or Fe2+, but the enhanced NO removal due to the presence of SO2 alone dominated at all temperatures. The removal of NO increased from 77.5% at 30 °C to 80.5% and 82.3% at 50 °C and 70 °C in the presence of SO2 alone, and from 35.3% to 62.7% and 81.2%, respectively, in the presence of Fe2+ alone. However, in the presence of both SO2 and Fe2+, NO conversion is 46.2% at 30 °C, increased only slightly to 48.2% at 50 °C; but sharply increased to 78.7% at 70 °C compared to 63.9% for persulfate-only activation. Results suggest NO removal in the presence of SO2 is equally effective by heat-only or heat-Fe2+ activation as the temperature increases. The results should be useful for future developments of advanced oxidation processes for flue gas treatments.

Avaliação de custos de sistema de remediação utilizando peroxone para tratamento de etenos clorados

A utilização de Processos Oxidativos Avançados para remediação de áreas contaminadas tornou-se uma alternativa eficaz na destruição de contaminantes, seja na aplicação direta no solo e água subterrânea, ou através de sistemas de tratamento. Este trabalho teve como objetivo avaliar o custo de implantação e operação de um sistema de remediação Pump & Treat utilizando peroxone como forma de tratamento para água subterrânea contaminada por etenos clorados. O sistema de remediação considerou as características hidrogeológicas da área de estudo e dos contaminantes. Foram considerados como custos de investimentos os relativos aos equipamentos e materiais necessários para a implantação do sistema de remediação, enquanto que os custos operacionais consideraram energia elétrica, peróxido de hidrogênio, mão de obra, manutenção, administração e análises laboratoriais da água subterrânea. Os resultados obtidos indicaram que cerca de 20% do custo de investimento está associado com a etapa de tratamento; o custo operacional foi de 551.484,86 (Ano 1), R$ 606.913,32 (Ano 2) e R$ 336.352,53 (Ano 3), demonstrando-se vantajoso em relação ao método tradicional de tratamento com carvão ativado.

Quaternary magnetic BiOCl/g-C3N4/Cu2O/Fe3O4 nano-junction for visible light and solar powered degradation of sulfamethoxazole from aqueous environment

Novel magnetic quaternary BiOCl/g-C3N4/Cu2O/Fe3O4 (BGC-F) nano-heterojunction with excellent photocatalytic activity was prepared by facile co-precipitation method. The visible photodegradation activity of the junction was analyzed for sulfamethoxazole (SME) as target pollutant. BGC-F with a dosage of 0.2 g L−1 exhibits high photocatalytic activity with 99.5% of SME (100 µM) degraded in 60 min under visible (Xe) lamp and 92.1% in 120 min under natural sunlight. The activity of quaternary junction was found to be 7.2, 6.8 and 4.2-fold higher as compared to C3N4/BiOCl/Fe3O4, Cu2O/BiOCl/Fe3O4 and Cu2O/BiOCl/C3N4 junctions respectively. Formation of an effective p-n-p junction (BiOCl-C3N4-Cu2O) leads to shifting of energy bands and rising of an in-built electric field and charge separation. The effect of parameters as pH, catalysts loading amount, NO3− and HCO3− have been studied. The O2− and OH was found to be major reactive species identified by scavenging experiments and the band gap structure analysis The results for mineralization were analyzed in terms of Liquid chromatography-mass spectroscopy (LC-MS), total organic carbon (TOC) removal and chemical oxygen demand (COD). 41.6% of TOC was removed in 3 h experiment under Xe lamp exposure. The drug degradation was also confirmed by testing activity on E. coli and cyto-toxicity on human peripheral blood lymphocytes (PBL). Only 2.1 mm zone of inhibition was observed for E. coli in case of exposure to SME degraded products while for pure SME it was 18.1 mm hinting complete mineralization. In addition 99% cell viability was observed for PBL cells treated with degraded products of SME. Furthermore, BGC-F exhibited good reusability after magnetic separation and regeneration, rendering it a promising multi-functional catalyst with active use of advanced oxidation processes for treating pharmaceutical waste water.

Degradation and Fate of Pharmaceutically Active Contaminants by Advanced Oxidation Processes

The purpose of this review is to investigate the use of advanced oxidation processes (AOPs) including ozonation, UV photolysis, Fenton-type processes, UV/H2O2, and other photocatalytic processes to degrade persistent pharmaceutically active contaminants in water. The review focuses on four common pharmaceuticals carbamazepine (CBZ), diclofenac (DCF), sulfamethoxazole (SMX), and trimethoprim (TMP) which are used as exemplars. Insights into the removal efficiency of each compound by AOPs under various applied conditions are systematically elucidated. This review also investigates the fate of these pharmaceuticals during treatment by advanced oxidation treatment. The effectiveness of AOP processes for the degradation of pharmaceuticals varies significantly, depending on factors such as the nature of the process itself, operating conditions, and the target compound. Ozone can completely remove all four pharmaceuticals. By contrast, direct UV photolysis was effective for the removal of DCF and SMX, whereas the combination with H2O2 was essential to improve CBZ and TMP removal. In addition, a large number of transformation products were frequently detected during the degradation of the selected pharmaceuticals by AOPs. In addition, it has been confirmed that several transformation products were more resistant toward the applied AOPs than their original parent compounds. A major challenge with the use of AOPs for the degradation of the selected pharmaceutically active contaminants is the formation of by-products that are often more persistent than the original contaminants. Therefore, the existence of transformation products must be essentially investigated after the treatment of target pharmaceutical contaminants by AOPs in order to evaluate the effectiveness of the applied technique.

Salicylic acid–methanol modified steel converter slag as heterogeneous Fenton-like catalyst for enhanced degradation of alachlor

Significant effort has recently been directed toward the use of advanced oxidation processes (AOPs) to degrade organic pollutants. In this work, an affordable and effective heterogeneous Fenton-like process was proposed and studied. Preparation and utilization of an iron-rich catalyst, salicylic acid–methanol (SAM) modified steel converter slag (SCS), were investigated for the degradation of alachlor in wastewater. Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to assess the morphology and crystal structure of the prepared catalysts. Results showed that SAM modification can selectively remove calcium silicate minerals from surface of SCS. The modification decreased the alkalinity of SCS and led to a prominent decrease in the specific surface areas and iron content, which dramatically improved the catalytic property of SCS. The removal rate of alachlor at initial pH 3.0 in SAM-modified SCS/H2O2 system was 3.07 times of that in SCS/H2O2 system. Further studies showed that this heterogeneous Fenton-like process was more suitable to be performed at relative higher temperature (30–40°C) and lower initial pH (2.0–3.0). A small decrease (2.1%) was found in the activity of SAM-modified SCS after four runs, indicating a feasible way to utilize SCS and also achieve excellent environmental benefit.

Light-Assisted Advanced Oxidation Processes for the Elimination of Chemical and Microbiological Pollution of Wastewaters in Developed and Developing Countries.

In this work, the issue of hospital and urban wastewater treatment is studied in two different contexts, in Switzerland and in developing countries (Ivory Coast and Colombia). For this purpose, the treatment of municipal wastewater effluents is studied, simulating the developed countries’ context, while cheap and sustainable solutions are proposed for the developing countries, to form a barrier between effluents and receiving water bodies. In order to propose proper methods for each case, the characteristics of the matrices and the targets are described here in detail. In both contexts, the use of Advanced Oxidation Processes (AOPs) is implemented, focusing on UV-based and solar-supported ones, in the respective target areas. A list of emerging contaminants and bacteria are firstly studied to provide operational and engineering details on their removal by AOPs. Fundamental mechanistic insights are also provided on the degradation of the effluent wastewater organic matter. The use of viruses and yeasts as potential model pathogens is also accounted for, treated by the photo-Fenton process. In addition, two pharmaceutically active compound (PhAC) models of hospital and/or industrial origin are studied in wastewater and urine, treated by all accounted AOPs, as a proposed method to effectively control concentrated point-source pollution from hospital wastewaters. Their elimination was modeled and the degradation pathway was elucidated by the use of state-of-the-art analytical techniques. In conclusion, the use of light-supported AOPs was proven to be effective in degrading the respective target and further insights were provided by each application, which could facilitate their divulgation and potential application in the field.

Photochemical oxidation of antibiotic gemifloxacin in aqueous solutions – A comparative study

The amount of organic micro pollutants like antibiotics detected in effluents, lakes, rivers, hospital wastewater, sewage water and ground water. These antibiotics are affecting aquatic organisms. Common wastewater treatment plants are not built to remove these substances. Thus there is a need for new technologies. The present study focuses on the application of a promising technology, that is the use of advanced oxidation processes (AOPs), which works based on the intermediacy of hydroxyl and other radicals to oxidized non-biodegradable compounds. Hence, in the present study treatment of certain gemifloxacin commonly used in day-to-day life has been carried out. The combination of UV, UV/H2O2, Fenton, and UV/Fenton systems has been studied. Gemifloxacin concentration degradation, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) are monitored. Among all the processes studied photo-Fenton process has been found to be the maximum removal of gemifloxacin (97%).

A Critical Evaluation of Advanced Oxidation Processes for Emerging Contaminants Removal

Removing emerging contaminants from waste streams has become a topic of growing interest. The adverse effects of endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs) have been well documented, but much remains to be known about these contaminants and their removal. Their removal with traditional methods has not been entirely successful. However, adequate degradation can be achieved through the use of advanced oxidation processes (AOPs). Multiple factors must be considered when completing an in-depth comparison; therefore, process engineering, environmental, and economic and social parameters were included in a deeper analysis. This study presents a ranking system to numerically score the performance of various AOPs (e.g., Ozonation, UV irradiation, Photocatalysis, Fenton reaction, and integrated processes) in several categories of parameters under engineering, environmental, and socioeconomic components. From this preliminary assessment, it was noted that H2O2/O3 (Perozonation) presented the highest average ranking (3.45), with other processes showing comparable performance. TiO2 photocatalysis received the lowest ranking (2.11).

The effect of operational parameters on decolourisation of textile dyes and comparison efficiencies of the UV/H2O2, fenton and photo-fenton processes: A review

In this review article, we summarize the current knowledge about the applicability of advanced oxidation processes (AOPs) such as UV/H2O2, Fenton and photo-Fenton for removal of textile dyes from wastewater and the effect of operational parameters (initial dye concentration, initial H2O2 concentration, initial Fe2+ concentration and initial pH) on these processes. Numerous studies have reported the use of AOPs for degradation of textile dyes, and the results show that they are very effective. By comparing the results of the previous studies, it seems that the photo- Fenton process is more efficient than the Fenton and UV/H2O2 process.

Solar photo-Fenton and UV/H 2 O 2 processes against the antidepressant Venlafaxine in urban wastewaters and human urine. Intermediates formation and biodegradability assessment

Abstract In this work, the use of Advanced Oxidation Processes (AOPs) against the degradation of an emerging contaminant has been subjected under systematic investigation. The optimization of treatment of the anti-depressant drug Venlafaxine (VFA) was performed, using UV light, the combined UV/H 2 O 2 process, solar light, Fenton and finally the solar photo-Fenton process in laboratory scale. The degradation kinetics, the time necessary to remove 90% of the contaminant and the optimal reactants concentration were proposed. The treatment in pure water, (synthetic) wastewater and urine was assessed, in an effort to identify the opportunities and pitfalls the application of process would encounter in a field application. Treatment by the UV-based methods was found sufficiently efficient and the application of the solar photo-Fenton process showed feasibility in a potential field application with appropriate context. Real urban wastewater effluents after biological and physicochemical treatment were tested, as well as human urine, as a proposal for on-site collection and treatment was also treated. Biological treatment before applying the tested AOPs improved their efficiency, and the strategy of diluting urine prior to treatment greatly enhanced the efficacy of the process. Finally, the identification of the degradation pathway and the biodegradability tests of AOPs treated VFA solutions exhibit promising results concerning the strategy of treatment for similar pollutants of emerging concern.

Biological and photochemical degradation of cytostatic drugs under laboratory conditions

Cytostatic drugs, used in chemotherapy, have emerged as new environmental contaminants due to their recurrent presence in surface waters and genotoxic effects. Yet, their degradability and environmental fate is largely unknown. The aim of this study was to determine the degradation kinetics of 16 cytostatic drugs, prioritized according to their usage and occurrence in hospital and wastewater treatment plants (WWTP) effluents, through the following laboratory scale processes: hydrolysis, aerobic biodegradation, UV-C photolysis, UV-C/H2O2 and simulated solar radiation. Some drugs were unstable in milli-Q water (vincristine, vinblastine, daunorubicin, doxorubicin and irinotecan); others were photodegraded under UV-C light (melphalan and etoposide) but some others were found to be recalcitrant to biodegradation and/or UV-C, making necessary the use of advanced oxidation processes (AOPs) such as UV-C/H2O2 for complete elimination (cytarabine, ifosfamide and cyclophosphamide). Finally, radiation in a solar box was used to simulate the fate of cytostatic drugs in surface waters under natural radiation and complete removal was not observed for any drug. The degradation process was monitored using liquid chromatography coupled to high resolution mass spectrometry and pseudo-first order kinetic degradation constants were calculated. This study provides new data on the degradability of cytostatic compounds in water, thus contributing to the existing knowledge on their fate and risk in the environment.

Adsorption of methanol from methanol–water mixture by activated carbon and its regeneration using photo-oxidation process

Activated carbon (AC) has been used as an adsorbent for centuries as a result of its ability to remove a large variety of compounds from contaminated waters. The objective of this study was to investigate the removal of methanol by adsorption and the use of advanced oxidation process for the regeneration of the exhausted AC as an alternative to thermal, biological, and chemical methods that are currently applied. Several experimental tests were carried out to examine the ability of AC for adsorbing methanol from methanol–water mixture. The results show fast saturation of the AC and short breaking time, especially for solutions consisting of methanol above 3% vol. However, adsorption capacity of exhausted AC with methanol, after washing, showed an improvement in its adsorption capacity over that of fresh AC. This improvement may be due to that methanol may harsh the surface of AC causing an increase in the sizes of pores and cavities. Large cavities were micrograph using scanning electron microscope (SEM). After saturation, AC was regenerated using the photo-catalytic process, the adsorption capacity of AC was fully restored. The results showed that the titanium dioxide with the aid of UV light can easily regenerate the AC by oxidizing the organic compounds adsorbed on the surface of AC. It was observed that the increase of UV light intensity had a positive effect on adsorption capacity. However, the increases of TiO2 concentrations had a limited effect on the adsorption capacity of the AC.

The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review.

The paper industry is adopting zero liquid effluent technologies to reduce freshwater use and meet environmental regulations, which implies closure of water circuits and the progressive accumulation of pollutants that must be removed before water reuse and final wastewater discharge. The traditional water treatment technologies that are used in paper mills (such as dissolved air flotation or biological treatment) are not able to remove recalcitrant contaminants. Therefore, advanced water treatment technologies, such as advanced oxidation processes (AOPs), are being included in industrial wastewater treatment chains aiming to either improve water biodegradability or its final quality. A comprehensive review of the current state of the art regarding the use of AOPs for the treatment of the organic load of effluents from the paper industry is herein addressed considering mature and emerging treatments for a sustainable water use in this sector. Wastewater composition, which is highly dependent on the raw materials being used in the mills, the selected AOP itself, and its combination with other technologies, will determine the viability of the treatment. In general, all AOPs have been reported to achieve good organic removal efficiencies (COD removal >40%, and about an extra 20% if AOPs are combined with biological stages). Particularly, ozonation has been the most extensively reported and successfully implemented AOP at an industrial scale for effluent treatment or reuse within pulp and paper mills, although Fenton processes (photo-Fenton particularly) have actually addressed better oxidative results (COD removal ≈ 65-75%) at a lab scale, but still need further development at a large scale.

Advanced Oxidation Processes for Wastewater Treatment 2013

Environmental remediation, particularly, in the field of wastewater treatment, has gained utmost importance in recent years. There is no alternative except to make use of Advanced Oxidation Processes (AOPs) for the treatment of wastewater with high degree of pollution. Hence, the recent research is mainly focused on the efficient, cost-effective, and ecofriendly AOPs in the degradation of any kind of pollutants. This is reflected by the publication of this second special issue in this journal. This special issue contains 18 original research articles and a review article entitled “Recent developments in homogeneous advanced oxidation processes (AOPs) for water and wastewater treatment.” The review article by M. Muruganandham et al. reports on recent development of AOPs, such as O 3 , UV/O 3 , UV/O 3 /H 2 O 2 , UV/H 2 O 2 , Fe/H 2 O 2 , and UV/Fe/H 2 O 2 , on the degradation of pollutants. The influence of various experimental processes such as solution pH, temperature, concentration of the oxidants, and dosage of the light source on the process efficiency is also discussed.

Inactivation of MS2 coliphage by UV and hydrogen peroxide: Comparison by cultural and molecular methodologies

The use of advanced oxidation processes (AOP) are expected to increase for removal of emerging contaminants and pathogens from drinking water. In this study, the performance of a small community ultraviolet light reactor in combination with hydrogen peroxide (H2O2) for MS2 coliphage inactivation with two different flow rate conditions of 1 gal/min (gpm) and 2 gpm was evaluated. Following UV radiation, MS2 showed a reduction of 5.3–5.8 log10 when quantified with cultural plaque counts, whereas corresponding quantitative polymerase chain reaction (qPCR) data showed only a 1.7–2.8 log10 reduction in viral RNA copy number. When H2O2 was added at either 2.5 or 5 ppm with UV at both flow rate conditions, enhanced MS2 inactivation occurred with a more than 7 log10 reduction observed via plaque counts, indicating that all added MS2 had been inactivated, since no plaques were formed after incubation at 37°C for 24 h. In contrast, qPCR only showed a corresponding 3–4 log10 reduction in viral RNA copy number. This research also sheds light on the inactivation of MS2 with ultraviolet light and in the presence of hydroxyl radicals and provides a practical use of qPCR to detect MS2 concentration following advanced oxidation relative to traditional plaque methodology; however qPCR detection overestimates the true number of infective virus.

Toxicity of the micropollutants Bisphenol A, Ciprofloxacin, Metoprolol and Sulfamethoxazole in water samples before and after the oxidative treatment

The amount of organic micropollutants detected in surface waters increases steadily. Common waste water treatment plants are not built to remove these substances. Thus there is a need for new technologies. A promising technology is the use of advanced oxidation processes through which organic micropollutants can be removed from waste water. However, the formation of oxidation by-products is likely and needs to be investigated since the by-products not only differ from their parent compounds in regard to their chemical and physical properties but they can also differ in toxicity. Therefore this study was designed to combine chemical and toxicological analyses of the advanced oxidation (O3 [5mg/L] or UV/H2O2 [Hg-LP lamp; 15W; 1g/L H2O2]) of waste water treatment plant effluents and pure water. Effluent samples from conventional activated sludge waste water treatment (mechanical treatment, activated sludge basin, and primary as well as secondary treatment steps) and high-purity deionized water (pure water) were spiked with Bisphenol A, Ciprofloxacin, Metoprolol or Sulfamethoxazole and treated with O3 or UV/H2O2. For the toxicological analyses mammalian cells (CHO-9, T47D) were exposed to the water samples for 24h and were tested for cytotoxicity (MTT Test), genotoxicity (Alkaline Comet Assay) and estrogenicity (ER Calux(®)). The results indicate that the oxidative treatment (O3 or UV/H2O2) of Bisphenol A, Metoprolol, Sulfamethoxazole or Ciprofloxacin in waste water did not result in toxic oxidation by-products, whereas the UV/H2O2 treatment of Bisphenol A and Ciprofloxacin in pure water resulted in by-products with cytotoxic but no estrogenic effects after 60min.

Degradation of organic pollutants by a Co3O4-graphite composite electrode in an electro-Fenton-like system

A novel composite electrode was constructed by pressing together Co3O4 and graphite and it was used as the cathode in an electro-Fenton-like (EFL) system. The poor electron transport characteristic of Co3O4 was overcome by incorporating graphite. In situ electro-catalytic generation of hydroxyl radicals (center dot OH) occurred at high current efficiencies from pH 2-10, extending the traditional Fenton reaction pH range. Cyclic voltammetry and AC impedance spectrometry were used to characterize the composite electrode. The ability of the EFL system to degrade organic compounds was investigated using sulforhodamine B (SRB) and 2,4-dichlorophenol (2,4-DCP) as probes. Decoloration of SRB (1.0x10(-5) mol/L) was complete (100%) in 150 min and SRB was effectively degraded from pH 2-10. The decomposition of SRB was studied using Fourier transform infrared spectroscopy (FT-IR) and total organic carbon (TOC) analysis and results indicated that the final degradation products were carbon dioxide, carboxylic acids and amines. The EFL system also decomposed 2,4-DCP and the degradation was 98.6% in 240 min. Electro-catalytic degradation of SRB occurs by a center dot OH mechanism. After 5 times reused, the degradation rate of SRB did not significantly slow down. The electrode shows excellent potential for use in advanced oxidation processes (AOPs) used to treat persistent organic pollutants (POPs) in wastewater.

Ozonation of the food dye Brilliant Blue in aqueous medium: monitoring and characterization of products by direct infusion electrospray ionization coupled to high‐resolution mass spectrometry

Dyes have been widely used to accentuate or to provide different colors to foods. However, the high concentrations of dyes in effluents from the food industries can cause serious and unpredictable damages to aquatic life in general. Furthermore, since conventional biological treatments have been shown to be ineffective, the use of advanced oxidation processes to promote the depletion of such dyes in water bodies has turned out to be mandatory. The degradation of the food dye Brilliant Blue by ozone in aqueous solution is reported herein. The overall process was monitored in real time by using direct infusion electrospray ionization high-resolution mass spectrometry in the negative ion mode, ESI(-)-HRMS. Preliminary results (visual inspection and UV-vis spectra) showed the high efficiency of ozonation in causing the decoloration of an aqueous solution of the dye whereas TOC (total organic carbon) measurements revealed that such an oxidation process was unable to promote its complete mineralization. ESI(-)-HRMS data showed that the substrate consumption occurred concomitantly with the appearance of four by-products, all of them produced by an initial attack of hydroxyl radicals (generated via the decomposition of ozone) on the two imino moieties of the dye molecule. Structures were proposed for all the by-products based mainly on the high-resolution mass measurements and on the characteristic reactivity of typical functional groups towards hydroxyl radicals. An unprecedented degradation route of Brilliant Blue by ozone in aqueous solution could thus be proposed. A greater ecotoxicity against Artemia salina was observed for the by-products than for the original dye. This indicates that the identification of by-products arising from oxidation treatments is of primary importance since such compounds can be more hazardous than the precursor itself.

Degradation of Abamectin Using the Photo-Fenton Process

The cultivation of strawberries generally requires substantial use of pesticides, and abamectin is the active principle of one of those most commonly employed. Conventional water treatment does not remove pesticides efficiently, so there is a need to investigate alternative procedures. The use of advanced oxidation processes (AOPs) can achieve good results in removal of toxic organic compounds present in aqueous solutions. The photo-Fenton process, one example of an AOP, was employed to study the degradation of abamectin. Results showed that when natural water samples contaminated with abamectin were treated using the photo-Fenton process, 70% of the initial amount of the compound was removed within 60 minutes of UV irradiation, and 60% mineralization was observed after 180 minutes of reaction.