Arsenite removal from groundwater in a batch electrocoagulation process: Optimization through response surface methodology

In this study, influences of seven process variables such as initial pH (pH_i), applied current (i), operating time (t_EC), initial As(III) concentration (C_o), diameter of Fe ball anode (d_p), column height in the electrocoagulation (EC) reactor (h) and airflow rate (Q_air) for removal of As(III) from groundwater by a new air-fed fixed-bed EC reactor were evaluated with a response surface methodology (RSM). The proposed quadratic model fitted very well with the experimental data for the responses. The removal efficiencies and operating costs were determined to be 99% and 0.01 $/m³ at the optimum operating conditions (a pH_i of 8.5, 0.05 A, 4.94 min, d_p of 9.24 mm, h of 7.49 cm, Q_air of 9.98 L/min for 50 µg/L). This study clearly showed that the RSM in the EC process was a very suitable method to optimize the operating conditions at the target value of effluent As(III) concentration (10 µg/L) while keeping the operating cost to minimal and maximize the removal efficiency.     

A^2O/高压脉冲电絮凝/O3-BAC/膜法处理焦化废水

吕梁三泉焦化工业园区污水处理厂率先采用A^2O/高压脉冲电絮凝/高密度澄清池/臭氧-活性炭滤池/超滤/反渗透组合工艺处理焦化废水。该组合工艺设计紧凑,技术先进,处理效果好。在废水处理量为9550 m^3/d,进水COD、氨氮、SS、电导率、浊度、总硬度、Cl-平均浓度分别为574 mg/L、44.2 mg/L、275 mg/L、5600μS/cm、146 NTU、210 mg/L和740 mg/L时,系统出水所有指标均远优于《工业循环冷却水处理设计规范》(GB/T 50050—2007)规定的再生水水质标准,并全部实现达标回用。本工程直接运行费用合计为4.47元/m^3。     

高压脉冲电絮凝处理综合电镀废水的试验研究

采用高压脉冲电絮凝技术处理某电镀厂的电镀废水,考察了高压脉冲电絮凝设备对Cu2＋、Ni2＋、CN-和CODCr的去除效果.结果表明,高压脉冲电絮凝技术对电镀综合废水的处理效果显著,Cu2＋、Ni2＋、CN-和CODCr的去除率分别可以达到99.80％、99.70％、99.68％和67.45％,达到GB 8978-1996《污水综合排放标准》的要求.该高压脉冲电絮凝技术处理电镀废水具有处理效率高、速度快、占地面积小、操作方便的特点,有良好的工程应用前景.     

电絮凝-活性炭纤维吸附法处理电镀废水的研究

提出了以铝板作为电极板,采用电絮凝法处理含铬、镍及铜电镀废水。研究了电流密度、处理时间、电极板间距和p H等因素对铬、镍及铜离子去除效率的影响。实验结果表明,电流密度控制在5 A/dm2,极板间距为2.0~2.5 cm,电解时间控制在30 min,p H在6~9范围内,能达到较理想的去除效果。当采用电絮凝-活性炭纤维吸附法处理混合电镀废水,对废水中重金属离子的去除率达到99.97%以上。     

脉冲电絮凝在废水处理中的应用

脉冲电絮凝是一种崭新的废水处理方法,它不仅具有电凝聚的优势,而且克服了传统电化学法处理废水能耗大、成本高等缺陷。本文综述了脉冲电解的原理发展方向、传统电絮凝的原理、脉冲电絮凝的优缺点以及其在废水处理中的具体应用。     

Degradation of Disperse Red 167 Azo Dye by Bipolar Electrocoagulation

This study investigates the influence of variables on the removal efficiency of solution containing azo dye Disperse Red 167 by bipolar electrocoagulation (BEC). Current density, time of electrolysis, interelectrode distance, supporting electrolyte concentration, and total surface area were the variables that mostly influenced the azo dye removal. The efficiency of different electrode materials (Fe, Al) for azo dye removal is compared. The obtained results showed the effectiveness of the aluminum and iron electrodes for azo dye removal. The present study allows achieving a high level of decolorization (100%) with a short reaction time for both electrodes. The method was found to be highly efficient and relatively fast compared to conventional existing techniques.     

电凝聚处理生活污水的试验研究

研究电凝聚处理生活污水的有效性和可行性。采用铝铁电极组、铝不锈钢电极组和双铁电极组的电极构造方式,进行pH值、电解时间、电流密度、投加电解质、温度和电极连接方式等影响因素的静态试验。试验结果表明：在原水pH值6．8、电解时间30min、电流密度0．25A／dm^2的条件下,COD、SS及色度去除率分别在68％、69％和88．1％以上。     

电混凝-反渗透工艺处理垃圾渗滤液的试验研究

采用电混凝-反渗透组合工艺处理渗滤液经膜生物反应器的出水,考察组合工艺的处理效果及电混凝作为RO进水预处理的可行性。结果表明,组合工艺出水COD和NH3-N、TP的质量浓度分别为100 mg/L和20、0.2 mg/L,去除率分别达到95%、90%、98%,可以满足GB 16889-2008的排放要求;出水电导率为355μS/cm,膜出水电导率与进水电导率的比大于0.94。电混凝工艺能够有效降低RO进水的COD、TP含量,明显地减缓膜结垢污染,改善膜的产水率,可以作为膜前预处理。     

Comparative Study of Electrocoagulation and Electrooxidation Processes for the Degradation of Ellagic Acid From Aqueous Solution

A comparative study of electrocoagulation and electrooxidation processes for the degradation of ellagic acid from aqueous solution was carried out. For the electrocoagulation process, metallic iron was used as electrodes whereas graphite and RuO₂/IrO₂/TaO₂ coated titanium electrodes were used for the electrooxidation processes. The effect of the process variables such as initial pH, concentration of the supporting electrolyte, applied current density, electrolysis time, and anode materials on COD removal were systematically examined and discussed. Maximum COD removal of 93% was obtained at optimum conditions by electrocoagultion using an iron electrode. The ellagic acid was degraded completely by electrooxidation using graphite electrodes under the optimum conditions. During electrooxidation, the chloride ion concentration was estimated and the effect of the Cl^? ion was discussed. The finding of this study shows that an increase in the applied current density, NaCl concentration, and electrolysis time enhanced the COD removal efficiency. The UV–Vis spectra analysis confirms the degradation of ellagic acid from aqueous solution.     

Advanced treatment of copper smelting wastewater by the combination of internal micro-electrolysis and electrocoagulation

ABSTRACT

In this study, a combined process of internal micro-electrolysis (IME)–electrocoagulation was developed at lab scale for treating a real copper smelting wastewater. By IME, 92.4% of Cu, 88.6% of Pb, and 72.2% of Zn were removed after 30 min at an initial solution pH of 3, a Fe/C dosage of 40 g/L, and a Fe/C mass ratio of 1:1. Removal of residual metals by electrocoagulation was affected by wastewater pH and current density. Electrocoagulation with iron/aluminum electrodes at a current density of 5 mA/cm², electrocoagulation time of 30 min, and pH 8 resulted in 99.3% Cu, 99.5% Pb, and 98.6% Zn removal. The final effluent quality could satisfy the National Discharge Standard of China. This work demonstrates that the hybrid system has the potential to be applied for the advanced treatment of high-strength copper smelting wastewater.