Photo Assisted Fenton in a Batch and a Membrane Reactor for Degradation of Drugs in Water

Abstract

Some advanced oxidation processes (AOP's) such as Fenton H₂O₂/Fe²⁺, photo assisted Fenton UV/H₂O₂/Fe²⁺, UV photolysis, and photo assisted Fenton—like UV/O₂/Fe²⁺ have been tested for the degradation of Gemfibrozil in aqueous solution in a batch system and then in a membrane reactor. A nanofiltration/reverse osmosis type cross‐linked polyamide, UTC‐60 (Toray) membrane (19 cm²) was used. In the batch degradation tests, the gemfibrozil, used at 5 mg/L, was degraded by employing the four AOP's but numerous peaks of intermediates were observed at the HPLC. Indeed DOC analyses showed poor mineralization in the case of photolysis (3.1%) and UV/O₂/Fe (10%), while it was 62% using the photo assisted Fenton and 24% using the Fenton. Thus in the membrane reactor only the Fenton and the photo assisted Fenton were tested. Obtained results showed a drug degradation higher than 92%, a mineralization higher than 55%, and a membrane retention of the catalyst in solution higher than 95%.     

Degradation of 2,4-dichlorophenol in aqueous solution by sono-Fenton method

This study presents the results of the Sono-Fenton process for the degradation of 2,4-dichlorophenol (DCP). The influential parameters such as H₂O₂, Fe²⁺ and pH for the Sono-Fenton process were investigated. Sono-Fenton method was found to be the best one for degradation efficiency of DCP when compared with that of the Fenton process. The optimum concentrations for the degradation of DCP using conventional Fenton’s method were found to be 20 mg/L of Fe²⁺ and 580 mg/L of H₂O₂ at pH 2.5. In the case of Sono-Fenton, the optimal concentrations were found to be 10 mg/L of Fe²⁺ and 400 mg/L of H₂O₂ at pH 2.5. Sono-Fenton method resulted in the reduction of required Fe²⁺ concentration (50%) and H₂O₂ concentration (31%). In addition, this method could be applicable even at pH 5.0 and a degradation efficiency of DCP was 77.6%. Kinetic studies for the degradation of DCP proved that the degradation of DCP tends to follow pseudo first order reaction and the rate constant was found to be 7 × 10⁻⁴ min⁻¹.     

Fenton‐ and Fenton‐Like AOPs for Wastewater Treatment: From Laboratory‐To‐Plant‐Scale Application

Abstract

Fenton‐and Fenton‐like AOPs systems have been utilized for the oxidative degradation of some chlorinated pollutants such as chloral hydrate or 1,1,1‐trichloroethane, and for the treatment of real industrial wastewaters. Both ferrous sulfate (FeSO₄ · 7 H₂O) and Mohr's salt (NH₄)₂Fe(SO₄)₂. 6 H₂O have been used as Fe²⁺ ion sources. With Mohr's salt (MS) the Fenton‐and Fenton‐like reaction has been successfully carried out under acidic (pH 3) and neutral (pH 7) reaction conditions. The new Fenton‐like system utilizes zero‐valent iron (Fe^o) instead of ferrous sulfate has been applied for the 1,1,1‐trichloroethane and chloral hydrate degradation. Similarly, the application of catechol‐ and hydroquinone‐driven Fenton reaction for the degradation of chloral hydrate under acidic and neutral pH is a new Fenton‐like AOPs approach. The photo‐Fenton‐like reactions such as Fe³⁺/hν, Fe²⁺/H₂O₂/hν, and ferrioxalate system have been also studied for the degradation of chloral hydrate. As an irradiation source a daily light or sun light have been used. In comparison with photoreactor experiments the best system was observed to be Fe³⁺/hν. In some experiments the influence of standing time prolongation after Fenton reaction on the final degradation efficiency due to hydrolysis of intermediates such as phosgene (CCl₂?O) has also been studied. The Fenton reaction was successfully utilized for the treatment of real industrial wastewaters, in two cases even in plant‐scale applications.     

Ecotoxicological evaluation of a fish farming effluent treated by Fenton oxidation and coagulation process

ABSTRACT

This study has evaluated the efficiency of Fenton process followed by coagulation to treat real effluent from fish farm. Fenton obtained Chemical Oxygen Demand and turbidity removal of 48% at (0.5 mg L^?1 Fe²⁺ and 10 mmol H₂O₂). Fenton followed by coagulation reduced COD and turbidity by almost 100%. The process also decreased the concentrations of suspended solids, phosphate, nitrate, Biological Oxygen Demand, and nitrite. Ecotoxicology test indicated that the effluent treated with 0.5 mmol L^?1 Fe²⁺ in 10 mmol L^?1 H₂O₂ displayed the lowest toxicity. These findings can indicate an environmental friendly alternative to treat fish farm effluent.     

Degradation of C.I. Acid Orange 7 by heterogeneous Fenton oxidation in combination with ultrasonic irradiation

BACKGROUND: A mesoporous alumina supported nanosized Fe₂O₃ was prepared through an original synthesis procedure and used as a heterogeneous catalyst for the Fenton process degradation of the model azo dye C.I. Acid Orange 7 enhanced by ultrasound irradiation (US/Fe₂O₃‐Al₂O₃‐meso/H₂O₂ system). The effect of various operating conditions was investigated, namely hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading. RESULTS: The results indicated that the degradation of C.I. Acid Orange 7 followed a pseudo‐first‐order kinetic model. There exists an optimal hydrogen peroxide concentration, initial pH, ultrasonic power and catalyst loading for decolorization. The aggregate size of the spent catalyst was reduced after dispersion in water by ultrasonic irradiation. A very low level of iron leaching was observed ranging from < 0.1 to 0.23 mg L^?1. The intermediate products of C.I. Acid Orange 7 degradation were identified using gas chromatography–mass spectrometry (GC‐MS). CONCLUSION: The optimal conditions for efficient C.I. Acid Orange 7 degradation were pH close to 3, hydrogen peroxide concentration 4 mmol L^?1, catalyst loading 0.3 g L^?1, and ultrasonic power 80 W. Copyright © 2011 Society of Chemical Industry     

Comparison of a new immobilized Fe3+ catalyst with homogeneous Fe3+–H2O2 system for degradation of 2,4‐dinitrophenol

BACKGROUND: Heterogeneous Fenton catalysts have been used to treat various organic pollutants in an aqueous environment. The present study has investigated the degradation of 2,4‐dinitrophenol (2,4‐DNP), a priority pollutant generated by such industries as pharmaceuticals, pesticides, pigments and dyes. Degradation of 2,4‐DNP (100 mg L^?1) was studied using Fe³⁺ loaded on Al₂O₃ as a heterogeneous catalyst in the presence of H₂O₂, and the efficiency compared with the homogeneous Fe³⁺/H₂O₂ based Fenton‐like process. The effect of different parameters for both processes, such as catalyst loading, H₂O₂ concentration, initial solution pH, initial substrate concentration and temperature were investigated and the optimum operating conditions determined. RESULTS: Under optimal operating conditions of the homogeneous system ([Fe³⁺] 125 mg L^?1; [H₂O₂] 250 mg L^?1; pH 3; room temperature), 92.5% degradation was achieved in 35 min for an initial 2,4‐DNP concentration of 100 mg L^?1. In the case of immobilized Fe (Fe³⁺–Al₂O₃ catalyst), degradation improved to 98.7% under the condition 10 wt% [Fe³⁺–Al₂O₃] 1 g L^?1 catalyst loading; [H₂O₂] 250 mg L^?1; pH 3; at room temperature for the same duration. CONCLUSIONS: This study demonstrated the stability and reusability of the prepared heterogeneous catalyst. This process is a viable technique for treatment of aqueous solutions containing contaminants. Copyright © 2012 Society of Chemical Industry     

Removal of metsulfuron methyl by Fenton reagent

The removal of metsulfuron methyl (MeS)—a sulfonyl urea herbicide from contaminated water was investigated by advanced oxidation process (AOP) using Fenton method. The optimum dose of Fenton reagent (Fe²⁺/H₂O₂) was 10 mg/L Fe²⁺ and 60 mg/L H₂O₂ for an initial MeS concentration ([MeS]₀) range of 0–80 mg/L. The Fenton process was effective under pH 3. The degradation efficiency of MeS decreased by more than 70% at pH > 3 (pH 4.5 and 7). The initial Fe²⁺ concentration ([Fe²⁺]₀) in the Fenton reagent affected the degradation efficiency, rate and kinetics. The degradation of MeS at optimum dose of Fenton reagent was more than 95% for [MeS] ₀ of 0–40 mg/L and the degradation time was less than 30 min. The determination of residual MeS concentration after Fenton oxidation by UV spectrophotometry was affected by the interferences from Fenton reagent. The estimation of residual MeS concentration after Fenton oxidation by high pressure/performance liquid chromatograph (HPLC) was interference free and represented the actual concentration of MeS and does not include the by-products of Fenton oxidation. The degradation kinetics of MeS was modelled by second order reactions involving 8 rate constants. The two reaction constants directly involving MeS were fitted using the experimental data and the remaining constants were selected from previously reported values. The model fit for MeS and the subsequent prediction of H₂O₂ were found to be within experimental error tolerances.     

The sonochemical decolorisation of textile azo dye CI Reactive Orange 127

In the present study, Fenton and sono‐Fenton processes were applied to the oxidative decolorisation of synthetic textile wastewater including CI Reactive Orange 127 and polyvinyl alcohol. Process optimisation [pH, ferrous ion (Fe²⁺) and hydrogen peroxide (H₂O₂)], kinetic studies and their comparison were carried out for both of the processes. The sono‐Fenton process was performed by indirect sonication in an ultrasonic water bath, which was operated at a fixed 35‐kHz frequency and 80 W power. The optimum conditions were determined as [Fe²⁺] = 20 mg l^?1, [H₂O₂] = 15 mg l^?1 and pH = 3 for the Fenton process and [Fe²⁺] = 25 mg l^?1, [H₂O₂] = 5 mg l^?1 and pH = 3 for the sono‐Fenton process. The colour removals were 89.9% and 91.8% by the Fenton and sono‐Fenton processes, respectively. The highest decolorisation was achieved by the sono‐Fenton process because of the production of some oxidising agents as a result of sonication. Consequently, ultrasonic irradiation in the sono‐Fenton process slightly increased the colour removal to 91.8%, while decreasing the hydrogen peroxide dosage to one‐third of that of the Fenton process.     

Ozone/H2O2 Performance on the Degradation of Sulfamethoxazole

This work aims to analyze the contribution of H₂O₂ on ozonation of Sulfamethoxazole (SMX). A single ozonation was able to totally remove SMX. TOC and COD depletion rates after a transferred ozone dose of 60 mg/L was related to the formation and decomposition of H₂O₂. An increase on O₃ gas inlet concentration from 10 g/m³ to 20 g/m³ improved COD abatement from 11% to 36%. When the presence of H₂O₂ at the beginning of ozonation was tested, it was verified that COD and TOC degradation were enhanced, attaining maximum values of 76% and 32%, respectively, when compared with 35% and 15% reached in a single ozonation.     

Distinct synergetic effects in the ozone enhanced photocatalytic degradation of phenol and oxalic acid with Fe3+/TiO2 catalyst

In this work, phenol and oxalic acid(OA) degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe~(3+)/TiO_2 catalyst. The ferrioxalate complex formed between Fe~(3+) and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of ·OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe~(3+)/TiO_2catalyzed processes, because Fe~(3+) was greatly reduced but not regenerated in many cases.The synergetic effect was found to be highly related with the property of the target pollutants. Fe~(3+)/TiO_2 catalyzed system showed the highest ability to destroy organics, but the TiO_2 catalyzed system showed little higher synergy.     

Chelate-modified fenton treatment of sulfidic spent caustic

Spent caustic can be treated by several treatment methods. Among the advanced techniques, Fenton reagent has many advantages. But since spent caustic contains excessive amounts of sulfide compounds, utilizing this technique in treatment of such wastewaters is not economical. The acid neutralization step, which was applied as the pretreatment process, showed an 84% COD abatement at temperature equal to 80 °C and a pH equal to 4.0. The acid neutralized wastewater was then introduced to the chelate-modified Fenton system and oxidized. Using a ratio of tartrate/Fe²⁺=1.1, reaction time=50min, temperature=95 °C, Fe²⁺=110mg/l and a ratio of H₂O₂/COD=1.2 in the chelate-modified Fenton system at an optimum pH value equal to 1.9, total COD abatement of the wastewater reached over 99.4%. Having tartrate added to the Fenton system, a series of photochemical reactions enhanced Fe²⁺ and hydroxyl radicals’ generation. This method has proved to be the recommended technique for the contamination abatement of spent caustic.     

The Fenton Chemistry and Its Combination with Coagulation for Treatment of Dye Solutions

Abstract

Aqueous solutions of Acid Blue 74, Acid Orange 10, and Acid Violet 19 were subjected to Fenton/Fenton‐like oxidation and its combination with lime coagulation. The analysis indicated no dependence of chemical oxidation efficacy on dye concentration in the range of 0.1–1 g L^?1. Complete or nearly complete (higher than 95%) color removal of all treated samples was observed. Dye:H₂O₂ weight ratio of 1∶2 proved optimal for treatment of all dye solutions by means of Fenton/Fenton‐like oxidation. Moderate doses of hydrogen peroxide led to the improvement of biodegradability of dye solutions. No formation of any toxic intermediates during the oxidation of Acid Orange 10 and Acid Violet 19 was detected. Only a slight toxicity increase was observed after Acid Blue 74 degradation by Fenton chemistry. H₂O₂/Fe³⁺ system with pH adjusted to 3 proved the most effective oxidation process. The combination of Fenton chemistry and subsequent lime coagulation was the most feasible treatment method of removing COD and UV₂₅₄ and UV_max absorbance of dye solutions. Combined oxidation and coagulation was more effective for Acid Blue 74 and Acid Orange 10 elimination than for Acid Violet 19.     

Comparison between Fenton oxidation process and electrochemical oxidation for PAH removal from an amphoteric surfactant solution

The decomposition of polycyclic aromatic hydrocarbons in a creosote oily solution and in synthetic solutions containing naphthalene and pyrene was investigated in the presence of an amphoteric surfactant using electrooxidation by comparison to Fenton oxidation process. Electrolysis was carried out using a parallelepipedic electrolytic 1.5-L cell containing five anodes (expanded titanium covered with ruthenium) and five cathodes (stainless steel) alternated in the electrode pack, whereas Fenton oxidation process was carried out in 500 mL Erlenmeyer glass-flasks in which H₂O₂ and Fe²⁺ were added. Using electrochemical oxidation, the sum concentration of 16 polycyclic aromatic hydrocarbons investigated could be optimally diminished by up to 80–82% by applying a current density of 9.23 mA cm⁻² and a pH of 4.0 or 7.0 for 90-min reaction period. By comparison, the best yield (46%) of Fenton oxidation process for polycyclic aromatic hydrocarbons degradation was recorded by using H₂O₂/Fe²⁺ molar ratio of 11.0 and a pH of 4.0.     

Post-Treatment of Pulp and Paper Industry Wastewater by Advanced Oxidation Processes

The aim of this study was to investigate the effectiveness of chemical oxidation by applying ozonation, combination of ozone and hydrogen peroxide and Fenton's processes for decolorization and residual chemical oxygen demand (COD) removal of biologically pretreated pulp and paper industry effluents. The batch tests were performed to determine the optimum operating conditions including pH, O₃, H₂O_2, and Fe²⁺ dosages. H₂O₂ addition reduced the reaction times for the same ozone dosages; however combinations of ozone/hydrogen peroxide were only faintly more effective than ozone alone for COD and color removals. In the Fenton‘s oxidation studies, the removal efficiencies of COD, color and ultraviolet absorbance at 254 nm (UV₂₅₄) for biologically treated pulp and paper industry effluents were found to be about 83, 95, and 89%, respectively. Experimental studies indicated that Fenton oxidation was a more effective process for the reduction of COD, color, and UV₂₅₄when compared to ozonation and ozone/hydrogen peroxide combination. Fenton oxidation was found to have less operating cost for color removal from wastewater per cubic meter than the cost for ozone and ozone/hydrogen peroxide applications.     

PREPARATION AND THERMAL EXPANSION OF FE2-xYxW3O12 POWDER BY CITRATE SOL-GEL PROCESS

Fe_2-xY_xW₃O₁₂ powder has been synthesized by the citrate sol-gel process. A model was proposed to calculate the concentration of species in a citric solution. The calculated results could provide valuable information for determining the optimal molar ratio of cation to citric acid and pH value of solution for Fe_2-xY_xW₃O₁₂ preparation. The predicted parameters derived from this model are in good agreement with the experimental results. The prepared gel and the Fe_2-xY_xW₃O₁₂ powder were characterized by X-ray diffraction (XRD) and differential thermal analysis-thermogravimetry (DTA-TG). The results show that it is very difficult to obtain pure Fe₂W₃O₁₂ powder by the citrate sol-gel process in the temperature range 500°–1000°C, however, Y₂W₃O₁₂ can easily be prepared even at 500°C. Y₂W₃O₁₂ annealed at 1000°C for 10 h is favorable for absorbing moisture in air to form Y₂W₃O₁₂·3.3H₂O. The thermal expansion coefficients of Y₂W₃O₁₂·3.3H₂O are: α_a = ? 8.01 × 10^?6°C^?1, α_b = ? 2.51 × 10^?7°C^?1, and α_c = ? 5.55 × 10^?6°C^?1 in 473–1173 K.     

亚甲基蓝光度法研究基于CaO2的Fenton反应条件

CaO₂作为原位Fenton 氧化修复中H₂O₂持续供源的作用逐渐受到关注。利用亚甲基蓝分光光度法评价了基于CaO₂的Fenton反应中催化剂种类、初始pH值、CaO₂用量、催化剂和CaO₂比例、磷酸缓冲溶液浓度对羟基自由基（HO·）产率的影响。结果表明,采用Fe²⁺作为催化剂,在pH值为4、CaO₂相似文献   

Removal of organic contaminants in paper pulp effluents by AOPs: an economic study

The degradation of the organic content of a bleaching Kraft mill effluent was carried out using Advanced Oxidation Processes (AOPs). The study was focused on the identification of the AOP, or combination of AOPs, that showed the highest efficiency together with the lowest cost. Direct UV photolysis (UV), TiO₂ assisted‐photocatalysis (TiO₂/UV), Fenton, Fenton‐like, and photo‐Fenton reactions (Fe(II)/H₂O/UV), UV‐assisted ozonation (O₃/UV) and addition of Fe²⁺ and/or H₂O₂ to the TiO₂/UV and the O₃/UV systems, were used for the degradation of a conventional cellulose bleaching effluent. The effluent was characterized by the general parameters TOC, COD and color, and analyzed for chlorinated low molecular weight compounds using GC–MS. The costs of the systems per unit of TOC reduction were compared. Fenton, Fenton‐like and photo‐Fenton reactions achieved better levels of TOC degradation than photocatalysis and with lower cost's than photocatalytic treatments. Ozonation is an effective but rather expensive process. The use of UVA light, however, increased the effectiveness of ozonation with a significant decrease (>25%) in the operational cost. © 2002 Society of Chemical Industry     

The feasibility of using combined Fenton-SBR for antibiotic wastewater treatment

The first part of this study examined the effect of operating conditions on Fenton pretreatment of an antibiotic wastewater containing amoxicillin and cloxacillin. The optimum H₂O₂/COD and H₂O₂/Fe²⁺ molar ratios were 2.5 and 20, respectively. Under the optimum operating conditions, complete degradation of the antibiotics occurred in 1 min. In the second part of this study, a bench-scale SBR was operated for 239 days and fed with Fenton-treated wastewater under different operating conditions. BOD₅/COD ratio below 0.40 of the Fenton-treated wastewater had negative effect on the SBR performance. Hydraulic retention time (HRT) of 12 h was found suitable for the SBR and increasing HRT to 24 and 48 h did not significantly improve the SBR efficiency. Statistical analysis (two-way ANOVA) was made on the results to optimize the H₂O₂/Fe²⁺ molar ratio and Fenton reaction time and it was found possible to reduce the Fe²⁺ dose and increase the Fenton reaction time. Under the best operating conditions (H₂O₂/COD molar ratio 2.5, H₂O₂/Fe²⁺ molar ratio 150, Fenton reaction time 120 min and HRT 12 h), the combined Fenton-SBR process efficiency was 89% for sCOD removal and the SBR effluent met the discharge standards. Combined Fenton-SBR is a feasible process for antibiotic wastewater treatment.     

Active Species of Nonheme Iron and Manganese-Catalyzed Oxidations

The intense catalytic and spectroscopic studies of the last decade provided important insights into the mechanisms of some nonheme iron-catalyzed oxidations with hydrogen peroxide. For manganese-based analogs, direct spectroscopic data on the structure of the reactive intermediates are scarce; mechanistic proposals are mainly based on catalytic studies and on analogy with iron systems. Herein, these data are summarized and contemporary mechanistic landscape is presented. We have mainly focused on iron and manganese complexes with N ₄-donor aminopyridine ligands, which are one of the most successful catalysts for chemo-, regio- and enantioselective transformations of organic substrates with H₂O₂ and H₂O₂/CH₃COOH as oxidants. The low-spin Fe^III–OOH, Fe^IV = O and Fe^V = O species can be spectroscopically trapped in the catalyst systems studied, low-spin Fe^V = O intermediate being the most likely key oxidizing agent.     

Degradation of Carbamazepine by Photo-assisted Ozonation: Influence of Wavelength and Intensity of Radiation

This article presents the results of an investigation into the function of UV in a photo-assisted ozonation process for treatment of carbamazepine (CBZ) in treated domestic wastewaters. Experiments were conducted on synthetic spiked water and secondary treated municipal wastewater. Degradation of CBZ was studied for various combination of O₃ dosage ranging from 4.8 to 14.4 mg/h and UV intensities with varying intensity and wavelength (UVC: λ = 254 nm and UVA: 352 nm). In synthetic spiked water, CBZ was degraded to below detectable limits within 0.5 min for ozone dose of 14.4 mg/h. The rate of degradation of CBZ increased exponentially with increase in ozone dose following a zero-order rate at each dose level. The degradation rate of CBZ in wastewater was slower compared to deionized water (DI) water by 40–75% for various doses of ozone, presumably due to the presence of organic matter remaining in treated wastewater. Optimal UV intensities for UVA and UVC were obtained as 0.62 and 0.82 mW/cm² for all doses of ozone in synthetic spiked water samples and UV intensities beyond this resulted in lower rates of degradation of CBZ. For photo-assisted ozonation with ozone doses of 9.6 and 14.4 mg/L, rate constants were two times higher for UVA irradiations as compared to UVC irradiation. Contrary to observations in DI water, experiments in wastewater showed increase in rate of degradation with higher UV intensities. Overall, photo-assisted ozonation was found to be appropriate for both water and wastewater treatment by exploiting the benefit of direct attack of ozone and of produced ^?OH radicals to yield a greater extent of mineralization of CBZ.