电絮凝净化海水过程中电流效率和总磷去除率的研究

采用铁电极对电絮凝工艺处理受污染海水过程中电流效率和总磷去除率的变化进行了研究。研究结果表明,在电絮凝工艺处理海水的过程中存在较高的电流效率,电流密度对电流效率的影响高于极板间距的影响;电絮凝工艺对海水中的总磷具有很好的去除效果,总磷去除率能达到80.58%,且总磷去除率随着电流密度的增大和通电时间的延长而增加;总磷的剩余浓度与通电电流呈一级反应关系,并由此拟合出电絮凝处理海水中总磷的动力学方程。     

壳聚糖絮凝剂处理水源水中有机物的试验研究

研究了壳聚糖絮凝剂的絮凝特性,进行了壳聚糖絮凝剂跟无机絮凝剂复合絮凝对水源水中浊度和有机物去除的试验。实验结果表明,复合絮凝能够相互促进各自的絮凝性能,显著提高有机物的去除效果,并使除浊和去除有机物得到了统一。在壳聚糖絮凝剂分别与三种常用无机絮凝剂(硫酸铝、氯化铁和聚合铝铁)的复合絮凝的效果的实验表明,其中聚合铝铁跟壳聚糖的复合絮凝剂的效果最好,在最佳条件下,其浊度、CODMn和UV254的去除率分别达到了97％、44％和55％。     

电絮凝法去除兰炭废水中的COD

考察了铝及不锈钢作阳极的电絮凝法去除兰炭废水COD的可行性,以及处理时间、pH、电流密度、电解质浓度、极板间距等操作条件对兰炭废水COD去除效果的影响。实验结果表明:铝阳极电絮凝去除兰炭废水COD的效果好于不锈钢阳极。用铝阳极在电流密度为0.05 A/cm2、pH=7的条件下电絮凝4 h,兰炭废水COD去除率最高可达75%。实验结果表明,铝阳极电絮凝法可实现对兰炭废水的预处理。     

絮凝技术用于高有机物海水预处理的研究

为了将盐田海水用作海水淡化水源,针对高有机物海水的预处理进行了烧杯絮凝实验,考察了絮凝条件、絮凝剂和助凝剂等参数对絮凝效果的影响。结果表明,最佳絮凝条件为:快速搅拌350 r/min、3 min,慢速搅拌80 r/min、8 min,沉淀时间30 min。聚合氯化铝铁去除浊度效果最好,在添加量为100 mg/L时,去除率达到85.37%;聚合硫酸铁去除COD效果最好,在同样添加量下,去除率为43.63%;而三氯化铁去除二者的效果均处于中间水平。骨胶和聚丙烯酰胺(PAM)均可以提高絮凝效果,其中PAM效果略好,在三氯化铁40 mg/L时,添加1 mg/L的PAM可使浊度和COD的去除率分别提高8.23%和8.10%。     

直接过滤法处理隔油池出水中试研究

针对中石油兰州化工厂隔油池出水尚未达标，该文采用微絮凝一接触过滤直接过滤工艺对其进行深度处理。研究了油、浊度和COD的去除效果及规律，同时对比考察了添加两种絮凝剂聚硅氯化铝铁和聚乙烯亚胺的去除效果。实验表明，直接过滤工艺对含油废水中的油、浊度和COD的去除率分别达到78％、93％和40％以上，在相同试验条件下，聚乙烯亚胺较聚硅氯化铝铁具有更好的除油除浊性能。     

电凝聚－气浮工艺处理景观水的试验研究

选择电凝聚-气浮工艺,对处理景观水进行了试验研究.采用铝电极,研究了不同电流密度、电导率和pH条件下,电凝聚-气浮工艺对浊度、叶绿素a、UV254的去除效率,并与常规混凝处理效果进行了当量比较.结果表明,电凝聚-气浮工艺在处理景观水中表现出一定的优势.电凝聚-气浮工艺对叶绿素a和UV254去除率分别达到81%和56%,出水浊度低于2.6 NTU,效果优于硫酸铝和聚合氯化铝.在一定的铝离子浓度范围内,电凝聚气浮工艺产泥量低于常规混凝.     

电絮凝-超滤集成技术处理洗浴废水

采用电絮凝-超滤集成技术处理洗浴废水,实验研究了电极材料、电流密度、电解时间和电导率等因素对电解洗浴废水COD、浊度去除率的影响,并确定了超滤膜的清洗周期和清洗方法.结果表明,电解工艺中Al电极较Fe电极具有更好的处理效果,电絮凝-超滤集成技术对洗浴废水的COD和浊度的去除率分别为85%和95%以上,超滤透过液达到了生活杂用水标准.超滤膜清洗周期为12天,采用化学清洗和水力冲洗相结合的清洗方法可使超滤膜的通量恢复.     

铝铁电极电絮凝法处理镀镉废水的研究

为了探讨电絮凝法对钢铁厂镀镉废水的处理效果,先对铝铁电极活化预处理后,采用电絮凝法原理对镀镉废水中的镉离子去除净化。系统地分析了铝电极的极化效应,对影响絮凝体的平均粒径、含量、镉离子去除率的因素进行探讨。结果表明：最佳电解时间为70 min,此时絮凝体平均粒径为54 μm,含量为3.80 g/L。铝铁电极的阳极极化效应强于阴极极化效应。当起始pH=4.0、极板间距为20 mm、极板电压为5 V、电流密度为30 mA/cm²时,Cd²⁺初级去除率达到96.8%,三级去除率超过99.9%,废水中Cd²⁺含量达到国家现行电镀污染物排放标准。采用电絮凝法通过铝铁电极处理镀镉废水的实验效果优良。     

电絮凝工艺处理垃圾填埋场渗滤液

介绍了电絮凝法去除垃圾填埋场渗滤液中有机污染物的试验。结果表明，电絮凝法处理本试验垃圾渗滤液的最佳条件为：极板材料采用铁电极，极板间距为20mm，pH为6～8，电流强度为3A。最佳条件下对垃圾渗滤液COD的去除率可以达到65．4％。     

几种无机混凝剂除磷优化及污水深度净化研究

以城市生活污水为处理对象,对比了5种常用药剂的化学除磷效果,并对COD、TN和浊度的去除情况进行了研究。结果表明,在试验投药量范围内,聚合硫酸铁对TP的去除效果最好,去除率达到了78.99%,其次是液态聚合铝铁、聚合氯化铝、聚合硅酸铝铁和聚合氯化铝铁。当选择液态聚合铝铁作为同步除磷药剂时,在β≤4.33的条件下,β与出水TP浓度呈现较好的相关性。     

Separation of Pollutants from Restaurant Wastewater by Electrocoagulation

Abstract

Of late, electrocoagulation has been widely used to treat a wide variety of wastewaters, including textile, dye, electroplating, chemical mechanical polishing wastewaters, etc. Excessive coagulant material may be avoided by electrocoagulation. The contaminants present in wastewaters are maintained in solution by electrical charges. When metal ions of opposite electric charge, provided by an electrocoagulation system, may become unstable and precipitate in a form that is usually very stable. The present work involves the treatment of nearby restaurant effluent in Surat, Gujarat, India. Two different electrodes, aluminum and iron, are used for electrocoagulation. The effect of applied voltage and time of electrolysis on various parameters—such as conductivity, COD, TDS, and turbidity are studied. The removal efficiency of COD is found to be between 50–72% and the optimum time is between 15–30 minutes. Electrocoagulation proved to be a process which could neutralize pH significantly. The major impact of change in electrode is considered and aluminum is found to be better than iron in many respects. The operating cost is estimated from the power cost and cost of electrode material.     

Treatment of wastewater from synthetic textile industry by electrocoagulation–electrooxidation

Treatment of wastewater from a textile industry that produces synthetic polyester cloths was studied employing electrochemical techniques. The sample was initially subjected to electrocoagulation to remove suspended solids. Mild steel and aluminum electrodes were tried as anodes; and aluminum was found to be effective for the removal of suspended solids. Using aluminum as anode, the chemical oxygen demand (COD) concentration of the effluent which was initially at the level of 1316 mg L⁻¹ could be reduced to 429 mg L⁻¹ by electrocoagulation. After electrocoagulation, the effluent was further subjected to electrooxidation using graphite and RuO₂/IrO₂/TaO₂ coated titanium as anodes. During the electrooxidation tests, both COD and chloride ion were simultaneously estimated; and the effect of Cl⁻ ion is discussed. The measurements have revealed the depletion of Cl⁻ ion concentration implying the generation of free chlorine during electrooxidation. The depletion of Cl⁻ ion concentration and the COD removal were observed to be comparatively high in the presence of graphite electrode. The effects of electrode materials and current density on COD removal are discussed. The instantaneous current efficiency (ICE), mass transfer coefficient and energy consumption were estimated.     

Treatment of Endocrine Disrupting Chemical From Aqueous Solution by Electrocoagulation

The removal of endocrine disrupting chemical (BPA; Bisphenol–A) from aqueous solution was experimentally investigated by electrocoagulation process. The effects of different combinations of aluminum (Al) and iron (Fe) electrode pair, supporting electrolyte type, supporting electrolyte concentration, initial pH and applied current density and initial BPA concentration on the Chemical Oxygen Demand (COD), and energy consumption performances were critically evaluated. The experiment results indicate that Al–Al electrode pair is the most efficient choice of the four electrode pairs. The COD removal efficiency was increased when NaCl was used as the supporting electrolyte instead of Na₂SO₄ and NaNO_3. The optimum supporting electrolyte type and its concentration, initial pH, applied current density and treatment time were found to be NaCl, 0.05 M, pH 7.0, 12 mA cm^?2 and 40 min, respectively. Energy consumption was found to decrease with increase of NaCl concentration while it increases with increasing applied current density. The initial and treated sample was characterized by UV–vis spectroscopy to confirm the treatment efficiency. The sludge formed during electrocoagulation was characterized by XRD and SEM/EDAX analysis.     

电絮凝法去除新农村微污染水体中磷的研究

文章采用光伏电池为电源,采用电絮凝工艺来治理新农村微污染水体中的磷,并从电解时间、电极材料、电极板间距和起始pH等影响因素进行了研究。研究结果表明:电解时间越长,总磷的去除率越高,45 min时,达95%以上;电导率在5 min内,有一个快速升高过程,此后逐渐下降;铝板电极和铁板电极总磷的去除速率和去除效率均比不锈钢板电极高,铝极板为最佳的电极材料;最佳间距为25 mm,此时总磷的去除效率和去除速度较高;最适宜的pH范围为4～5.5该工艺可行。     

Electrocoagulation/electroflotation of real printing wastewater using copper electrodes: A comparative study with aluminum electrodes

Most studies investigated electrocoagulation/electroflotation process (EC/EF) using either aluminum or iron electrodes. The main aim of this study is to investigate the performance of EC/EF to treat printing wastewater under various experimental conditions using copper electrodes. The effects of several variables, including different electrode materials (copper and aluminum), different current densities, electrolysis time, and spacing between electrodes on the removal efficiency of various parameters were investigated. The results showed that the maximum removal efficiencies for COD,TDS, and oil and grease were obtained when using a copper electrode. The maximum removal efficiencies were obtained at a gap distance of 4 cm.     

Treatment of dairy wastewater by electrocoagulation process: Advantages of combined iron/aluminum electrodes

ABSTRACT

The objective was to assess the efficiency of electrode material in an electrocoagulation (EC) process for wastewater treatment by comparing the efficiency of aluminum (Al–Al), iron (Fe–Fe) and combined Fe–Al electrodes. The treatment of synthetic dairy wastewater, characterized by high levels of 5-day biological oxygen demand (BOD₅) and chemical oxygen demand (COD), was used to compare electrode materials. Experimental results showed that all electrodes materials achieved the same final removal yield in the range of current studied (55% COD, 60% total organic carbon, 90% total nitrogen, and nearly 100% turbidity) when equilibrium was achieved. But at fixed current density and initial concentration of dairy waste, the Al–Al assembly exhibited the fastest elimination, whereas the slowest removal rate was observed with the Fe–Fe electrodes, even though adsorption was always the main removal mechanism. Finally, an Fe–Al system using an Fe anode with an Al cathode emerged as a techno-economic trade-off because of the low price of iron: both metals contributed to the removal of dairy waste, and the treatment time to achieve equilibrium values was closer to the Al–Al assembly at fixed current density. Moreover, experimental results proved the additivity of the mechanisms reported for Al–Al and Fe–Fe systems with Fe–Al.     

Pre-Treatment of Pistachio Processing Industry Wastewaters (PPIW) by Electrocoagulation using Al Plate Electrode

The objective of the present study is to assess the efficiency of electro-coagulation treatment of pistachio processing industry wastewaters (PPIW) using an aluminum plate electrode. The effect of some of the parameters was examined on the removal of chemical oxygen demand (COD), total organic carbon (TOC), and total phenols (TP) removal efficiency. The treatment was carried out in a batch system. The influences of current density (from 1 to 6 mA cm^?2), initial pH of wastewater (from 2 to 8), constant pH of wastewater (from 3 to 7), stirring speed (from 100 to 500 rpm), and supporting electrolyte concentration (from 10 to 50 mg L^?1 NaCl) on removal efficiency were investigated to determine the best experimental conditions. The evaluation of the physico-chemical parameters during the treatment by electrocoagulation showed that the best removal efficiency was obtained under the conditions of 180 min electrolysis time, wastewater with constant pH of 6, and 6 – mA cm^?2 current density. Under such experimental conditions, COD, TOC, and TP removal efficiency were found to be 60.1%, 50.2%, and 77.3%, respectively, while energy consumption was 39.6 kW-h m^?3. The results of the study show that the electrocoagulation can be applied to PPIW pre-treatment.     

Investigation of shipyard wastewater treatment using electrocoagulation process with Al electrodes

In this study, shipyard oily wastewater treatment was investigated by electrocoagulation (EC) using aluminum electrodes in a batch reactor by evaluating different operation conditions. The maximum chemical oxygen demand (COD) removal efficiency of 88.83% was obtained at current density of 3 mA/cm². The removal efficiency was gradually improved with increasing current density and decreased with increasing COD concentration. However, initial pH value was not determinant factor for this process. Total energy and electrode cost were calculated as $0.88 per m³ treated wastewater. The result of this research shows that EC process seems to be an efficient method for the oily wastewater treatment.     

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.