Organic Pollutants In Aquatic Environment Research Articles

A review on hybrid techniques for the degradation of organic pollutants in aqueous environment.

The creation of the modern world requires many industrial sectors, however, sustainability needs to be considered while developing industries. In particular, organic pollutants generated by many of these industries contaminate the environment leading to health and other issues. Advanced oxidation processes (AOPs) have been introduced to remove organic pollutants present in wastewater. Sonolytic degradation of organic pollutants is considered as one of the AOPs, however, this process has its limitations. In order to overcome the limitations, hybrid techniques involving ultrasound and other AOPs have been developed. That is, ultrasound combined with heterogeneous AOPs (ultrasound/metal ions, ultrasound/metal oxides, and ultrasound/photocatalysis) and homogeneous AOPs (ultrasound/ozone, ultrasound/H2O2, and ultrasound/persulfate) for the degradation/mineralization of organic pollutants. This review highlights the advantages of using hybrid techniques involving ultrasound for the degradation of organic pollutants in aqueous solutions.

Photoelectro-Fenton system including electromagnetic induction electrodeless lamp and black carbon poly tetra fluoro ethylene air-diffusion cathode: Degradation kinetics, intermediates and pathway for azo dye

The role of illumination and cathode is important to improve the efficiency of photoelectro-Fenton (PEF) system. In this study, cathodes with black carbon-poly tetra fluoro ethylene (BC-PTFE) for increase the concentration of hydrogen peroxide in PEF. A new PEF system using EIEL and BC-PTFE air-diffusion cathode was established. The electrode performance was tested and the influence factors, degradation kinetics, intermediates, pathway and mechanism of the model compound methyl orange (MO) were studied. The capacities of concentration decays and total organic carbon (TOC) removals were compared between different electrochemical advanced oxidation processes. The experimental conditions were optimized for a current density of 20 mA cm−2 with 0.5 mM Fe2+ and 100 mg L−1 MO at 20 °C and pH 3.0 in an 8 L reservoir. The higher MO concentration was, the smaller pseudo-first-order kinetic constants of concentration decays and TOC removals were. Intermediate products were identified by gas chromatography-mass spectrometry and ion-exclusion high performance liquid chromatograph in EIEL-PEF. Combined with frontier electron density, the degradation pathway was deduced as follows: destruction of azo bond, substitution of •OH, dehydrogenation and oxidation, opening-ring and mineralization. In EIEL-PEF, the concentration of oxalic acid and oxamic acid reached the maximum value 9.2 and 1.5 mg L−1 at 60 and 90 min, respectively. The photolysis of N-intermediates produced NH4+-N was released in more proportion than NO3−-N and oxamic acid-N. The study indicated that PEF system has the potential to remove organic pollutants in aquatic environments.

Quartz crystal microbalance-based method to study adsorption of endocrine disruptor compounds on zeolite

ABSTRACT Endocrine disrupting chemicals (EDCs) can be present as trace-level organic pollutants in aquatic environments and are difficult to measure and remove. In this study, a method was developed using a modified quartz crystal microbalance (QCM) to investigate the adsorption of EDCs by zeolite filter. Bisphenol A (BPA), oestrone (E1), oestradiol (E2), and sulfamethoxazole (SMZ) were selected as four representative endocrine disruptors in a water environment and their adsorption on zeolite was measured by QCM in real-time. The adsorption results were well described by a pseudo-first-order kinetic model and by a Sips isotherms model. The adsorption of the four adsorbents is related to their molecular structure, molecular polarity, and chargeability. The removal rate of EDCs by zeolite for different initial concentrations appeared to plateau, with the removal rates of the four selected EDCs all above 80% except for the maximum initial concentration. Changes of pH and ionic strength had no effect on the adsorption capacity of the four EDCs, with a removal rate of about 90%. However, the response time at pH 5.50 was about 300 s faster than that at pH 8.50 and the addition of electrolyte shortened the mass response time of several organic compounds on QCM.

Biorenewable triblock copolymers consisting of l-lactide and \u03b5-caprolactone for removing organic pollutants from water: a lifecycle neutral solution

BackgroundCurrent methods of removing organic pollutants from water are becoming ineffective as the world population increases. In this study, a series of biorenewable triblock copolymers with hydrophobic poly(ε-caprolactone) block and hydrophilic poly(l-lactide) blocks were synthesized and tested as agents to remove environmental pollutants from an aqueous solution. The percent of pollutant removed and equilibrium inclusion constants were calculated for the polymers. These values were compared to previously known removal agents for their effectiveness.ResultsTriblock copolymer samples removed over 70% of the polycyclic aromatic hydrocarbon (PAH) phenanthrene from an aqueous solution, with selectivity for the adsorption of phenanthrene over other PAHs tested. The inclusion constant was 7.4 × 105 M−1 and adsorption capacity was 5.8 × 10−7 mol phenanthrene/g polymer. Rose Bengal was used to further probe the nature of interactions between the copolymers and a small molecule guest. Solid samples of the block-poly(l-lactide)–block-poly(ε-caprolactone)–block-poly(l-lactide) (PLLA–PCL–PLLA) systems were found to rapidly remove over 90% of Rose Bengal from aqueous solution, resulting in a complete disappearance of the characteristic pink color. Solutions of the copolymers in dichloromethane also removed Rose Bengal from water with a similar level of efficiency. Large inclusion constant values were obtained, ranging from 1.0 × 105 to 7.9 × 105 M−1, and the average adsorption capacity value of 6.2 × 10−7 mol/g polymer was determined. Aged polymer samples exhibited different adsorption characteristics and mechanistic theories for the removal of Rose Bengal were determined.ConclusionThe triblock copolymer consisting of l-lactide and ε-caprolactone was effective in removing various organic pollutants in aqueous environments. It is a biorenewable material which leads to minimal waste production during its lifecycle. These polymers were in general more effective in removing organic pollutants than commercially available pollution removal systems.

Hydrothermal synthesis of type II ZnIn2S4/BiPO4 heterojunction photocatalyst with dandelion-like microflower structure for enhanced photocatalytic degradation of tetracycline under simulated solar light

In this work, the type II ZnIn2S4/BiPO4 heterojunction solar -light driven photocatalysts were synthesized via a facile hydrothermal method, which possessed the unique dandelion-like microflower heterostructure. Among all the ZnIn2S4/BiPO4 with different mass ratios, 70 wt% ZnIn2S4/BiPO4 heterojunction displayed the highest photocatalytic activity, which can degrade 84% tetracycline (TC, 40 mg/L) in 90 min and the rate constant is 0.02017 min−1. It is about 1.89 and 3.14 times that of ZnIn2S4 and BiPO4, respectively. The enhanced photocatalytic activity mainly derives from the formed type II heterojunction between ZnIn2S4 and BiPO4, thereby effectively improving the separation efficiency of electron-hole pairs during the photocatalytic reaction. On the basis of the results of active species capturing and ESR experiments, •OH and •O2− were proven two predominant species in the photocatalytic system. This work is expected to provide a design opportunity to construct highly efficient BiPO4-based type II heterojunction photocatalysts for photocatalytic applications of degradation on organic pollutants in aqueous environment.

Fe(III)-citrate enhanced sunlight-driven photocatalysis of aqueous Carbamazepine

We investigated the effect of Fe(III)-citrate complexes on the photodegradation of Carbamazepine (CBZ) upon 365 nm irradiation in aqueous solution. A preliminary study of a {CBZ/Fe(III)-citrate} mixture in the dark and at room temperature showed no evidence of reaction. CBZ degradation efficiency depends on the pH of the medium, an effect attributed mainly to the speciation of Fe(III)-citrate. The influence of [CBZ] or [Fe(III)-citrate] on the kinetics of the reaction was studied. The reaction is biphasic, the first stage ends after ca. fifteen minutes and accounts for the major percentage of degradation. The presence of Fe(III)-citrate complex largely enhances the formation of Fe2+ and HO radicals; they form at the same rate at the beginning of the reaction. Increasing [O2] improved the degradation rate, and the use of i-PrOH as a scavenger confirmed the participation of HO in CBZ photodegradation. CBZ photodegradation was also studied under natural sunlight showing a degradation only slightly lower than under artificial light. HPLC/MS analysis confirmed 11% yield epoxycarbamazepine as the only reaction product observable with this technique after 180 min irradiation. An appropriate mechanism is proposed for CBZ transformation. CBZ phototransformation reached 65% at pH = 6.24, 87% at pH = 4.30 and ca. 100% at pH = 2.86 after 180 min upon 365 nm irradiation and the mineralization efficiency reaches 70% of TOC removal after 6 h of treatment. Our evidences show the epoxide photoproduct is just an intermediate that further reacts towards mineralization. This work highlights the important role of Fe(III)-carboxylate complexes may have on the fate of persistent organic pollutants in aquatic environments when irradiated with UV-A light.

Biodiversity Drives Micropollutant Biotransformation in Freshwater Phytoplankton Assemblages.

Biotransformation of chemical pollutants is an ecological process requiring multifunctionality (multiple metabolic pathways) and, potentially, high biodiversity. Phytoplankton communities are highly diverse functionally and taxonomically and co-occur with complex mixtures of organic pollutants in aquatic environments. Here, we investigated how phytoplankton species richness (SR) and class richness (CR) determine the biotransformation of a mixture of 37 structurally diverse pollutants using laboratory experiments and analysis of high-resolution mass spectrometry data. Laboratory phytoplankton communities were assembled from pure cultures by creating a gradient from one to five taxonomic groups, and 5 to 11 total species, in defined medium. The biotransformation of pollutants over 6 days and the total number of transformed chemicals increased with CR for 13 considerably transformed compounds. The total number of transformation products (TPs, up to 42) was positively affected by both CR and SR: CR had a positive effect on stable TPs found, and SR led to more transient TPs. Our data indicate that both taxonomic and functional diversity are important for biotransformation of anthropogenic chemicals in phytoplankton and suggest that plankton biodiversity could play a role in the remediation of pollutant loads in aquatic ecosystems.

Solar Decolorization of Methylene Blue by Magnetic MgFe2O4-MWCNT/Ag3VO4 Visible Active Photocatalyst

MgFe2O4-MWCNT/Ag3VO4 photocatalyst was prepared for benefiting the visible region of solar spectrum. Prepared catalyst was characterized by using scanning electron microscope (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). Photocatalytic activity was measured by methylene blue (MB) decolorization under visible light obtained from a 105-W tungsten light bulb. Dye decolorization and its kinetics were followed up by means of a UV-vis spectrophotometer. Kinetic model of decolorization was found to be compatible with first-order kinetics. The effects of pH and concentration of MB solution on the decolorization efficiency were determined. Low and high pH conditions were found to be more effective in increasing the MB decolorization yield and rate. On the other hand, due to the low transparency of concentrated MB solutions, an increase on decolorization time and a lowering in decolorization yield were encountered. Thanks to the magnetic MgFe2O3 nanoparticles, 96% of the catalyst could be recovered by a simple magnetic bar. It was observed that simulated wastewater containing MB was also successfully decolorized showing that visible region-sensitive MgFe2O4-MWCNT/Ag3VO4 photocatalyst can be benefited as a potential, efficient, and reusable material for the removal organic pollutants in aquatic environment.

Interactive effects of polystyrene microplastics and roxithromycin on bioaccumulation and biochemical status in the freshwater fish red tilapia (Oreochromis niloticus)

There are hundreds of thousands metric tons of microplastics (MPs) present in aquatic environments. The MPs coexist with other pollutants in water bodies, such as pharmaceuticals, and may carry and transfer them into aquatic organisms, consequently causing unpredictable ecological risks. The purpose of the present study was to evaluate the effect of the presence of polystyrene microplastics (PS-MPs) on the distribution and bioaccumulation of roxithromycin (ROX) in freshwater fish red tilapia (Oreochromis niloticus) as well as their interactive biochemical effects in red tilapia. PS-MPs were found to enhance the bioaccumulation of ROX in fish tissues compared to ROX-alone exposure. In the treatment of PS-MPs (100 μg L−1) combined with ROX (50 μg L−1), the highest concentrations of ROX reached 39,672.9 ± 6311.4, 1767.9 ± 277.8, 2907.5 ± 225.0, and 4307.1 ± 186.5 μg kg−1 in gut, gills, brain, and liver, respectively. Furthermore, compared to the ROX alone, the neurotoxicity caused by ROX was alleviated due to the presence of MPs after 14 d of exposure. The activities of cytochrome P450 (CYP) enzymes [7-ethoxyresorufin O-deethylase (EROD) and 7-benzyloxy-4-trifluoromethyl-coumarin O-dibenzyloxylase (BFCOD)] in fish livers exposed to all co-exposure treatments exhibited great variability compared to ROX alone after 14 d of exposure, suggesting that the presence of MPs may affect the metabolism of ROX in tilapia. Compared with ROX alone, the superoxide dismutase (SOD) activity increased significantly, and malondialdehyde (MDA) contents decreased in the co-exposure treatments, showing that oxidative damage in situations of co-exposure to MPs and ROX was mitigated in fish livers after 14 d of exposure. Collectively, the presence of MPs could affect the fate and toxicity of other organic pollutants in fish. The results emphasize the importance to study the interactions between MPs and other organic pollutants in aquatic environments.

Removal, biotransformation and toxicity variations of climbazole by freshwater algae Scenedesmus obliquus

Climbazole (CBZ) is an antibacterial and antifungal agent widely used in personal care products. In this study, we investigated the interactions between climbazole (CBZ) and freshwater microalgae Scenedesmus obliquus (S. obliquus). Dose-effect relationships between CBZ concentrations and growth inhibitions or chlorophyll a content were observed. After 12 days of incubation, the algae density and chlorophyll a content in 2 mg/L treatment group was 56.6% and 15.8% of those in the control group, respectively. Biotransformation was the predominant way to remove CBZ in the culture solution, whereas the contribution of bioaccumulation and bioadsorption were negligible. More than 88% of CBZ was removed by S. obliquus across all treatments after 12 days of incubation, and the biotransformation of CBZ followed the first order kinetic model with half-lives of approximately 4.5 days at different treatments. CBZ-alcohol (CBZ-OH) was the only biotransformation product identified in algal solution. Moreover, the toxicity of biotransformation products was much lower than its corresponding precursor compound (CBZ). The results of this study revealed that S. obliquus might have a great impact on the environmental fates of CBZ and could be further applied to remove organic pollutants in aquatic environment.

Cellulose Microfiber-Supported TiO2@Ag Nanocomposites: A Dual-Functional Platform for Photocatalysis and in Situ Reaction Monitoring

Photocatalytic degradation of toxic organic pollutants in aquatic environments provides an efficient, cost-effective, and sustainable approach to environmental remediation. The optimization of photocatalytic detoxification processes essentially relies not only on the capability to fine-tailor the structures and compositions of the photocatalysts but also on detailed understanding of the mechanisms that dictate the photocatalytic interfacial molecular transformations. Here we have designed and constructed a hierarchically organized suprastructure comprising TiO2@Ag nanocomposite particles supported by cellulose microfiber matrices, which serves as both an efficient photocatalyst for the photodegradation of 4-chlorophenol into mineralized small molecules and a robust substrate for plasmon-enhanced molecular spectroscopy. Such dual functionalities provide unique opportunities for us to precisely monitor, in real time, the detailed photocatalytic molecular transformations occurring at the molecule–catalyst interfaces using surface-enhanced Raman scattering as an ultrasensitive, time-resolving, and molecular fingerprinting spectroscopic tool.

Numerical simulation of seasonality in the distribution and fate of pyrene in multimedia aquatic environments with Markov chains

This case study investigated the distribution and fate of organic pollutants in aquatic environments based on laboratory experiments and modeling. Pyrene (Pyr) is a hydrocarbon pollutant with adverse effects on aquatic ecosystems and human health, and was thus selected for this case study. The movement of Pyr was primarily influenced by its sorption from water onto sediment, and its desorption from sediment into water. Its elimination was mainly via biodegradation by microorganisms in sediment and by volatilization from water into air. The transport and elimination rates for Pyr were considerably influenced by temperature and moisture. Results of modeling with Markov chains revealed that the elimination of Pyr from water/sediment systems was the most rapid under wet conditions. Under average conditions, a Pyr concentration of 100 μg/L of in water in such a system declined to a negligible level over 250 h. Under wet conditions, this decrease occurred over 120 h. Finally, under dry conditions, it took 550 h to achieve the same degree of elimination.

Immobilization of Horseradish Peroxidase on ModifiedElectro -spunNanofibrous Membrane for DESRemoval

Polyacrylontrile (PAN)/Poly (m-phenylene isophthalamide) PMIA electrospun nanofibrous membranes were hydrophobic ones that were not suitable for the removal of organic pollutants in aquatic environment. We employed an easy and simple method to convert the hydrophobic membranes into hydrophilic ones. Horseradish peroxidase (HRP) was immobilized on the modified PAN/PMIA/Cu membrane and the maximum enzyme loading was approximately 900 mg/g. Compared with free HRP, the pH, temperature, operational and storage stability were greatly improved after immobilization. Diethylstilbestrol (DES) removal experiment showed that the immobilized HRP and free HRP showed a similar removal efficiency (87% and 93%, respectively). However, the immobilized HRP has an excellent reusability.

Low-cost synthesis of titanium dioxide anatase nanoclusters as advanced materials for hydrogen photoproduction

Sub-nm titanium dioxide (TiO2) clusters are synthesized via the hydrolysis of TiCl4 in order to produce clean and surfactant-free oxide surfaces. By controlling the synthesis, stable TiO2 nanoclusters with well-defined size distributions are obtained. The prepared clusters are characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy in order to gain information about the size and morphology of the material. Photoresponsive methylene blue dye monitoring and hydrogen production under UV irradiation are described in detail and performed. The rate order of photodegradation and hydrogen photoproduction under UV light irradiation of the samples is increased by decreasing the size of TiO2 nanoparticles from 47 nm to 3 nm. The hydrogen evolution rate of TiO2 nanoclusters with size lower than 5 nm is about 3.03 times and 1.96 times faster than that of 47 nm of TiO2 and 12 nm of TiO2, respectively. The enhanced photocatalytic performance suggests that the ternary TiO2 nanoclusters can serve as a highly efficient catalyst for photodegradation of organic pollutants in aquatic environments and hydrogen production from water splitting.

An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide

An ordered array of hierarchically-structured core-nanosphere@space-layer@shell-nanoparticles has been fabricated for surface-enhanced Raman scattering (SERS) detection. To fabricate this hierarchically-structured chip, a long-range ordered array of Au/Ag-nanospheres is first patterned in the nano-bowls on the planar surface of ordered nanoporous anodic titanium oxide template. A ultra-thin alumina middle space-layer is then conformally coated on the Au/Ag-nanospheres, and Ag-nanoparticles are finally deposited on the surface of the alumina space-layer to form an ordered array of Au/Ag-nanosphere@Al2O3-layer@Ag-nanoparticles. Finite-difference time-domain simulation shows that SERS hot spots are created between the neighboring Ag-nanoparticles. The ordered array of hierarchical nanostructures is used as the SERS-substrate for a trial detection of methyl parathion (a pesticide) in water and a limit of detection of 1 nM is reached, indicating its promising potential in rapid monitoring of organic pollutants in aquatic environment.

Environmentally relevant impacts of nano-TiO2 on abiotic degradation of bisphenol A under sunlight irradiation

Understanding the effects of nano-TiO2 particles on the environmental behaviors of organic pollutants in natural aquatic environments is of paramount importance considering that large amount of nano-TiO2 is being released in the environment. In this study, the effect of nano-TiO2 on the degradation of bisphenol A (BPA) in water was investigated under simulated solar light irradiation. The results indicated that nano-TiO2 at environmentally relevant concentration (1 mg/L) could significantly facilitate the abiotic degradation of BPA (also at low concentration) under mild solar light irradiation, with the pseudo first-order rate constant (kobs) for BPA degradation raised by 1–2 orders of magnitude. As reflected by the inhibition experiments, hydroxyl radicals (OHs) and superoxide radical species were the predominant active species responsible for BPA degradation. The reaction was affected by water pH, and the degradation rate was higher at acidic or alkaline conditions than that at neutral condition. Humic acid (HA) also affected the reaction rate, depending on its concentration. At lower concentration (the mass ratio of HA/nano-TiO2 was 0.1:1), HA improved the dispersion and stability of nano-TiO2 in aquatic environment. As a result, the yield of OHs by nano-TiO2 under sunlight irradiation increased and BPA degradation was facilitated. When the HA concentration increased, a coating of HA formed on the surface of nano-TiO2. Although nano-TiO2 became more stable, the light absorption by nano-TiO2 was significantly reduced due to the strong light absorption of the HA coated on the surface. As a consequence, the yield of OH decreased and BPA degradation was depressed. The results imply that nano-TiO2 at low concentration may distinctly mediate BPA degradation, and can contribute to the natural attenuation of some organic pollutants in aquatic environment with low level of HA. However, this process would be significantly reduced in the presence of high level of HA.

The role of methanol addition to water samples in reducing analyte adsorption and matrix effects in liquid chromatography–tandem mass spectrometry

Liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis coupled simply with water filtering before injection has proven to be a simple, economic and time-saving method for analyzing trace-level organic pollutants in aqueous environments. However, the linearity, precision and detection limits of such methods for late-eluting analytes were found to be much poorer than for early-eluting ones due to adsorption of the analytes in the operating system, such as sample vial, flow path and sample loop, creating problems in quantitative analysis. Addition of methanol (MeOH) into water samples as a modifier was shown to be effective in alleviating or even eliminating the negative effect on signal intensity for the late-eluting analytes and at the same time being able to reduce certain matrix effects for real water samples. Based on the maximum detection signal intensity obtained on desorption of the analytes with MeOH addition, the ratio of the detection signal intensity without addition of MeOH to the maximum intensity can be used to evaluate the effectiveness of methanol addition. Accordingly, the values of <50%, 50–80%, 80–120% could be used to indicate strong, medium and no effects, respectively. Based on this concept, an external matrix-matched calibration method with the addition of MeOH has been successfully established for analyzing fifteen pesticides with diverse physico-chemical properties in surface and groundwater with good linearity (r2: 0.9929–0.9996), precision (intra-day relative standard deviation (RSD): 1.4–10.7%, inter-day RSD: 1.5–9.4%), accuracy (76.9–126.7%) and low limits of detection (0.003–0.028μg/L).

Passive Sampling of Polycyclic Aromatic Hydrocarbons in Johor Strait by Sol–gel Polydimethylsiloxane

Passive sampling technique is an alternative technique in the monitoring of organic pollutants in aqueous environment. This technique is able to overcome several drawbacks of the conventional grab sampling technique. In this study, passive sampler consists of glass tubes coated with sol–gel polydimethylsiloxane (PDMS) were fabricated in the laboratory. The passive samplers were used to study the level and distribution of 15 polycyclic aromatic hydrocarbons (PAHs) in Johor Strait. Performance of the passive sampler was tested in the laboratory with an exposure system that has similar flow rate, temperature and water salinity with Johor Strait. Then, the passive sampler was deployed to five sampling stations located in Johor Strait for 7 and 30 days to accumulate PAHs in seawater. High performance liquid chromatography with fluorescence detector was used to analyze PAHs in the samples. All PAHs spiked in the exposure system were found to accumulate in the PDMS coating. Mass of 15 PAHs extracted from the passive sampler after deployment to Johor Strait was in the range of 0.372–1.131 ng/PDMS glass tube. Findings obtained from passive sampling method and seawater analysis were comparable. Passive sampling technique is low cost, simple and less solvent consumption.

The degradation of linear alkylbenzene sulfonate (LAS) in the presence of light and natural biofilms: The important role of photosynthesis

Photosynthesis of algae usually changes the chemical conditions of microenvironment in natural waters. However, few studies have been carried out to examine the effects of diurnal variation and photosynthesis on behavior of organic pollutants in aquatic environments. In this study, linear alkylbenzene sulfonate (LAS) was selected as a representative of non-persistent organic pollutants to investigate the degradation of this type of pollutants in the presence of light and natural biofilms by laboratory batch experiments, with special emphasis on the effect of photosynthesis of the biofilms. The maximum decrease of LAS was observed in the coexistence of both illumination and fully active biofilms, and about 75% of the LAS were removed after a 36-h degradation experiment. The removal of LAS was found to be dominated by photosynthesis of the biofilms, with lesser roles attributed to biodegradation and adsorption by the biofilms, and the role of direct photolysis was negligible. The production of some reactive oxygen species might account for the role of photosynthesis in decomposing the LAS. The study confirms the important roles of algae biofilms and their photosynthesis in determining the fate of organic pollutants in aquatic environments.

Degradation of antibiotics amoxicillin by Co3O4‐catalyzed peroxymonosulfate system

Sulfate radical‐based advanced oxidation processes (SR‐AOPs) are attracting considerable attention due to the high oxidizing ability of sulfate radical to degrade organic pollutants in aqueous environments. In this study, the degradation of antibiotics amoxicillin using SR‐AOPs was investigated. This process is based on the generation of sulfate radicals through Co3O4‐mediated activation of peroxymonosulfate (PMS). Several parameters affecting antibiotics degradation such as Co3O4, PMS, pH, and temperature were investigated. The optimal conditions were found to be as follows: oxone concentration 0.01 mol·L −1, Co3O4 dosage 0.06 g, pH 6.0, reaction temperature 60°C, and reaction time 45 min. Under these optimum conditions, it was found that the chemical oxygen demand (COD) removal efficiency of 91.01% was achieved. The effect of ultrasound in the Co3O4/PMS system for amoxicillin degradation was also studied. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 193‐197, 2013