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1.
This article reports the first use of coupled electrocoagulation and electro-Fenton (EF-EC) to clean domestic wastewater. Domestic wastewater contains high amounts of organic, inorganic and microbial pollutants that cannot be usually treated in a single step. Here, to produce an effluent suitable for discharge in a single process step, a hybrid process combining electrocoagulation and electro-Fenton was simultaneously used to decrease chemical oxygen demand (COD), turbidity and total suspended solids (TSS) from domestic wastewater. The electrocoagulation–electro-Fenton process was firstly tested for the production of H2O2 using Ti–IrO2 and vitreous carbon- or graphite electrodes arranged at the anode and the cathode, respectively. The concentration of H2O2 recorded at 1.5 A of current intensity during 60 min of electrolysis using vitreous carbon- and graphite electrodes at the cathode was 4.18 and 1.62 mg L?1, respectively. By comparison, when the iron electrode was used at the anode, 2.05 and 1.06 mg L?1 of H2O2 were recorded using vitreous carbon and graphite, respectively. The H2O2 concentration decrease was attributed to hydroxyl radical formation generated by the Fenton reaction. Electro-Fenton using iron electrode at the anode and vitreous carbon at the cathode with a current density imposed of 0.34 A dm?2 ensures the removal efficiency of 50.1 % CODT, 70.8 % TSS and 90.4 % turbidity. The electrocoagulation–electro-Fenton technique is therefore a promising secondary treatment to simultaneously remove organic, inorganic and microbial pollutants from domestic, municipal and industrial wastewaters. 相似文献
2.
Zakaria Al-Qodah Mohammad Al-Shannag Khalid Bani-Melhem Eman Assirey Mohd Adib Yahya Ali Al-Shawabkeh 《Environmental Chemistry Letters》2018,16(3):695-714
The combination of electrocoagulation with another process is a promising approach to enhance the removal efficiency of water pollutants. For instance, free radical-assisted electrocoagulation is a new combination showing higher performance. There are different combinations depending on the free radical source. This article reviews free radical-assisted electrocoagulation processes. We discuss electrocoagulation mechanisms; ozone-assisted electrocoagulation processes; advanced oxidation-assisted electrocoagulation processes; and ultrasound-assisted electrocoagulation. We present kinetic models used in free radical-assisted electrocoagulation, scale-up of free radical-assisted electrocoagulation and cost estimation. The major points are: most of the available studies have been done at laboratory scale with synthetic wastewater, and lack holistic and systematic approaches to consider the process complexity. The performance of the combined process is improved, and the removal efficiency is increased especially with ozone-assisted electrocoagulation, which gives a removal efficiency of more than 95%. The use of ultrasound energy with electrocoagulation is advantageous in reducing the problem of electrode passivation. 相似文献
3.
Unprecedented total mineralization of atrazine and cyanuric acid by anodic oxidation and electro-Fenton with a boron-doped diamond anode 总被引:1,自引:0,他引:1
This article reports the complete mineralization of atrazine. Atrazine has been the most widely used s-triazine herbicide.
Atrazine occurs in natural waters and presents a potential danger for public health because atrazine is considered as an endocrine
disruptor. The use of chemical, photochemical and photocatalytic advanced oxidation processes (AOPs) to decontaminate waters
containing atrazine only allowed its conversion into the cyanuric acid as ultimate end products, since it cannot be completely
degraded by hydroxyl radicals (•OH) produced by these techniques. The same behavior was previously reported for anodic oxidation and electro-Fenton with Pt
anode, although better performances were found using boron-doped diamond (BDD) anode but without explaining the role of generated
•OH. Here, the oxidative action of these radicals in such electrochemical AOPs has been clarified by studying the mineralization
process and decay kinetics of atrazine and cyanuric acid in separated solutions by anodic oxidation with BDD and electro-Fenton
with Pt or BDD anode using an undivided cell with a carbon-felt cathode under galvanostatic conditions. Results showed that
electro-Fenton with BDD anode was the more powerful treatment to degrade both compounds. Almost total mineralization, 97%
total organic carbon (COT) removal, of atrazine was only feasible by this method with a faster removal of its oxidation intermediates
by •OH formed at the BDD surface than that formed in the bulk from Fenton reaction, although the latter process caused a more
rapid decay of the herbicide. Cyanuric acid was much slowly mineralized mainly with •OH produced at the BDD surface, and it was not degraded by electro-Fenton with Pt anode. These results highlight that electrochemical
advanced oxidation processes (EAOPs) using a BDD anode are more powerful than the classical electro-Fenton process with Pt
or PbO2 anodes. 相似文献
4.
Bhawana Jain Ajaya Kumar Singh Hyunook Kim Eric Lichtfouse Virender K. Sharma 《Environmental Chemistry Letters》2018,16(3):947-967
Nowadays, the water ecosystem is being polluted due to the rapid industrialization and massive use of antibiotics, fertilizers, cosmetics, paints, and other chemicals. Chemical oxidation is one of the most applied processes to degrade contaminants in water. However, chemicals are often unable to completely mineralize the pollutants. Enhanced pollutant degradation can be achieved by Fenton reaction and related processes. As a consequence, Fenton reactions have received great attention in the treatment of domestic and industrial wastewater effluents. Currently, homogeneous and heterogeneous Fenton processes are being investigated intensively and optimized for applications, either alone or in a combination of other processes. This review presents fundamental chemistry involved in various kinds of homogeneous Fenton reactions, which include classical Fenton, electro-Fenton, photo-Fenton, electro-Fenton, sono-electro-Fenton, and solar photoelectron-Fenton. In the homogeneous Fenton reaction process, the molar ratio of iron(II) and hydrogen peroxide, and the pH usually determine the effectiveness of removing target pollutants and subsequently their mineralization, monitored by a decrease in levels of total organic carbon or chemical oxygen demand. We present catalysts used in heterogeneous Fenton or Fenton-like reactions, such as H2O2–Fe3+(solid)/nano-zero-valent iron/immobilized iron and electro-Fenton-pyrite. Surface properties of heterogeneous catalysts generally control the efficiency to degrade pollutants. Examples of Fenton reactions are demonstrated to degrade and mineralize a wide range of water pollutants in real industrial wastewaters, such as dyes and phenols. Removal of various antibiotics by homogeneous and heterogeneous Fenton reactions is exemplified. 相似文献
5.
Removal of boron by electrocoagulation 总被引:2,自引:0,他引:2
Boron compounds are used in many manufacturing products and may be introduced into the environment in the form of hazardous materials. Here the feasibility of removal of boron from aqueous solutions by electrocoagulation was investigated. The process was examined under various factors in order to assess optimal operating conditions. The results showed that electrocoagulation for boron removal depends on current density, initial concentration and time. Under a current density of 30 mA/cm2 the percentage of boron removal from aqueous solutions is in the range of 92–96%. 相似文献
6.
Fatih Ilhan Kubra Ulucan-Altuntas Yasar Avsar Ugur Kurt Arslan Saral 《Frontiers of Environmental Science & Engineering》2019,13(5):73
7.
This article reviews both the pollution by the electrochemical industry and the use of electrochemistry to clean water. Main pollutants include Pd, Cd, Ni, Hg and other metals and cyanide as well as organic pollutants. The cause for water pollution by electrochemistry is due to the effluents from different electrochemical industries such as mercury from chlor-alkali industry; lead, cadmium and mercury from battery industry; heavy metals and organic contaminants from electroplating wastes; contaminants from corrosion processes; and persistent organic pollutants from the synthesis and use of pesticides, dyes and pharmaceuticals. Most pollutants can be successfully eliminated or converted to non-toxic materials by methods based on the electrochemical principles. Electrochemical depolluting methods are mainly electrodialysis, electrocoagulation, electroflotation, anodic processes, cathodic processes and electrochemical advanced oxidation processes. 相似文献
8.
Oleksandra Ganzenko Nihal Oturan Ignasi Sirés David Huguenot Eric D. van Hullebusch Giovanni Esposito Mehmet A. Oturan 《Environmental Chemistry Letters》2018,16(1):281-286
Cytostatic drugs are a troublesome class of emerging pollutants in water owing to their potential effects on DNA. Here we studied the removal of 5-fluorouracil from water using the electro-Fenton process. Galvanostatic electrolyses were performed with an undivided laboratory-scale cell equipped with a boron-doped diamond anode and a carbon felt cathode. Results show that the fastest degradation and almost complete mineralization was obtained at a Fe2+ catalyst concentration of 0.2 mM. The absolute rate constant for oxidation of 5-fluorouracil by hydroxyl radicals was 1.52 × 109 M?1 s?1. Oxalic and acetic acids were initially formed as main short-chain aliphatic by-products, then were completely degraded. After 6 h the final solution mainly contained inorganic ions (NH4 +, NO3 ? and F?) and less than 10% of residual organic carbon. Hence, electro-Fenton constitutes an interesting alternative to degrade biorefractory drugs. 相似文献
9.
Removal of textile dyes from water by the electro-Fenton process 总被引:5,自引:0,他引:5
Amal Lahkimi Mehmet A. Oturan Nihal Oturan Mehdi Chaouch 《Environmental Chemistry Letters》2007,5(1):35-39
An environmentally friendly electrochemical treatment, electro-Fenton process, was applied to the depollution of a synthetic
dismissal composed of three dyes, yellow drimaren, congo red and methylene blue, frequently used in textile and dyehouses.
Here, we show that those dyes and their mixture are quickly degraded under current controlled electrolysis conditions, leading
to an almost complete mineralization. The results show the efficiency of electro-Fenton process to quickly degrade aqueous
effluents polluted by synthetic organic dyes. 相似文献
10.
Zhenlian Qi Shijie You Ranbin Liu C. Joon Chuah 《Frontiers of Environmental Science & Engineering》2020,14(3):40
11.
自然环境中,大多数氯代有机污染物厌氧还原脱氯反应是与土壤环境中一些生源要素的生物化学还原过程相伴生。有机污染物的种类、生物有效性以及毒性能够显著影响这些生源要素的转化,反过来,土壤中活跃的氧化还原反应也可以显著影响有机污染物的动力学转化过程。本文从氧化还原顺序上综述了反硝化过程、铁还原过程、硫酸盐还原过程和产甲烷过程对氯代有机污染物厌氧还原脱氯过程的影响与作用机制,旨在为氯代有机污染物在厌氧环境中还原脱氯的过程与机理的进一步研究、以及还原脱氯与微生物介导的生源要素氧化还原过程的耦合作用机制的揭示提供参考。 相似文献
12.
R. Krishna Prasad 《Environmental Chemistry Letters》2010,8(2):149-155
The electrocoagulation studies of distillery spentwash using copper anodes were utilized to demonstrate the usefulness of
Box–Behnken experimental design of response surface analysis to derive a statistical model and the optimum parameters for
color removal. The current intensity (1.5 A), dilution (10%) and time of electrolysis (5 h) had been found to be the optimum
conditions for maximum 77.11% color removal. The actual color removal at optimized conditions was found to be 78.26%, which
is to the predicted response using response surface methodology. The energy consumption and current efficiency were determined
from reduction in chemical oxygen demand. 相似文献
13.
酵母菌处理高浓度色拉油加工废水研究 总被引:11,自引:0,他引:11
从含油土壤中筛选出适用于色拉油加工废水的酵母菌菌群,并用摇瓶试验研究了该菌群对未经预处理的高浓度含油色拉油加工废水的降解效果.采用酵母菌菌群处理总有机碳( T O C) 含量为ρ T O C= 2 500 mg L- 1 的色拉油加工废水,24 h 内可以去掉85 .2 % 的 T O C.酵母菌菌群在酸性条件下(p H3 左右) 表现出更好的处理效率,反应温度升高时 T O C 去除率有降低的趋势.结果表明,高浓度含油色拉油废水可以直接用酵母菌法进行处理 相似文献
14.
15.
Mababa Diagne Virender K. Sharma Nihal Oturan Mehmet A. Oturan 《Environmental Chemistry Letters》2014,12(1):219-224
Hazardous wastes are generated in the synthesis of dyes and pigments applied in industries. Efficient methods are thus needed to clean wastewaters. Here, we use anodic oxidation and electro-Fenton with B-doped diamond anode to degrade the synthetic dye indigo in aqueous sodium dithionite. Results show the near-complete mineralization of the dye within 80 min at 500 mA. Mineralization was faster by electro-Fenton than anodic oxidation. The second-order rate constant (k) for the reaction of indigo with ·OH was measured as 4.03 × 109 M?1 s?1 at pH 3.0 and was compared with the rate constants of reactions between dyes and ·OH. The results clearly demonstrate that both electro-Fenton and anodic oxidation can be used to depollute dyes in textile effluent with high efficiency and low cost. The main oxidant, ·OH, being a non-selective reagent, the method could be applied to degrade other organic pollutants. 相似文献
16.
Degradation of the herbicide imazapyr by Fenton reactions 总被引:4,自引:0,他引:4
The degradation of the herbicide imazapyr has been carried out by three advanced oxidation processes involving iron ions as catalysts: Fentons reagent, photo-Fenton and electro-Fenton. We show that all processes are rapid and efficient. The kinetic rate constant was found to be
k=5.4×109 M–1
s–1. The mineralization of imazapyr is almost complete using the photo-Fenton and electro-Fenton processes. 相似文献
17.
Rongbing FU Na MU Xiaopin GUO Zhen XU Dongsu BI 《Frontiers of Environmental Science & Engineering》2015,9(5):867
Nanoscale zerovalent iron (nZVI) synthesized using sepiolite as a supporter was used to investigate the removal kinetics and mechanisms of decabromodiphenyl ether (BDE-209). BDE-209 was rapidly removed by the prepared sepiolite-supported nZVI with a reaction rate that was 5 times greater than that of the conventionally prepared nZVI because of its high surface area and reactivity. The degradation of BDE-209 occurred in a stepwise debromination manner, which followed pseudo-first-order kinetics. The removal efficiency of BDE-209 increased with increasing dosage of sepiolite-supported nZVI particles and decreasing pH, and the efficiency decreased with increasing initial BDE-209 concentrations. The presence of tetrahydrofuran (THF) as a cosolvent at certain volume fractions in water influenced the degradation rate of sepiolite-supported nZVI. Debromination pathways of BDE-209 with sepiolite-supported nZVI were proposed based on the identified reaction intermediates, which ranged from nona- to mono-brominated diphenylethers (BDEs) under acidic conditions and nona- to penta-BDEs under alkaline conditions. Adsorption on sepiolite-supported nZVI particles also played a role in the removal of BDE-209. Our findings indicate that the particles have potential applications in removing environmental pollutants, such as halogenated organic contaminants. 相似文献
18.
Yaobin Lu Songli He Dantong Wang Siyuan Luo Aiping Liu Haiping Luo Guangli Liu Renduo Zhang 《Frontiers of Environmental Science & Engineering》2018,12(5):9
19.
海洋环境中多环芳烃的微生物降解研究进展 总被引:15,自引:0,他引:15
多环芳烃 (PAHs)是一类广泛分布于海洋环境中的含有两个苯环以上的有毒有害污染物 ,主要来源于人类活动和能源利用过程 ,如石油、煤、木材等的燃烧过程 ,石油及石油化工产品的生产过程 ,海上通过地面径流、污水排放及机动车辆等燃料不完全燃烧后的废气随大气颗粒的沉降进入海洋环境中 .由于多环芳烃的潜在毒性、致癌性及致畸诱变作用[1,2 ] ,通过生物累积及食物链的传递作用 ,给海洋生物、生态环境和人体健康带来极大危害 ,已引起各国环境科学家的极大重视 .美国环保局在上世纪 80年代把 16种未带分支的多环芳烃确定为环境中的优先污染物[… 相似文献
20.
A soil washing process was applied to remediate arsenic (As)-contaminated stream sediments around an abandoned mine in Goro,
Korea. Laboratory scale soil washing experiments for As-contaminated stream sediments were performed under various washing
conditions in order to maximize As removal efficiency. Stream sediments were taken from two sites (S1 and S5) along the main
stream connected to an abandoned mine. Stream sediments at the two sites were divided into two groups (≥0.35 and <0.35 mm
in diameter), giving four types of sediments, which were thereupon used for soil washing experiments. The results of soil
washing experiments involving various pH conditions suggested that As removal efficiency is very high in both strongly acidic
and basic solutions (pH 1 and 13), regardless of sediment type. Removal efficiencies for fine sediments from S1 and S5 were
>95% after 1 h of washing with 0.2 M citric acid (C6H8O7). When using 0.2 M citric acid mixed with 0.1 M potassium phosphate (KH2PO4), the As removal efficiency increased to 100%. When recycled washing solution was applied, As removal efficiency was maintained
at a level greater than 70%, even after eight recycling events. This suggests that the recycling of washing solution could
be successfully applied as a means of decreasing the cost of the washing process. Results from the experiments suggest that
soil washing is a potentially useful process for the remediation of As-contaminated stream sediments around abandoned mines. 相似文献