【作者】 王斌；

【导师】 杨卫身；

【作者基本信息】 大连理工大学 ， 环境工程， 2005， 硕士

【摘要】 染料废水具有组成复杂,色度高,COD、TOC含量高,悬浮物多,水质、水量变化大,难降解物质多等特点,是难处理工业废水之一。电化学水处理方法作为一种环境友好技术,具有无需或少量投加化学药剂,不产生二次污染,后处理简单,占地面积小,管理方便等优点又被称作环境友好技术,在染料废水处理领域,已成为一类具有竞争力的废水处理方法。 目前,电化学方法处理染料废水的研究多数是在给定槽压或恒流供电方式下,以考察电极材料、槽压、电流密度、电解质浓度、pH或传质速率等控制条件对脱色率、有机物去除率、电流效率以及能耗的影响为主要内容,而在恒电位或恒电流模式下,电极电位或电流密度对染料脱色行为影响的研究鲜有报道。对于异相界面电极反应,电极电位决定了反应的难易程度,而电流密度在一定程度上决定了反应速率。同时,大部分研究采用了无隔膜电解槽,由于阴、阳极反应的相互干扰,因而不能准确确定电氧化或电还原在染料降解脱色过程中所起的作用。 本论文以考察电极电位和电流密度如何影响蒽醌染料在ACF上电化学脱色行为为目的。采用由阳离子交换膜分隔的双室电解槽,以ACF为工作电极（阳极或阴极）,在恒电位和恒电流模式下,考察了电极电位和电流密度对活性艳蓝KN-R电化学脱色行为,即脱色机理、脱色动力学和色度、COD、TOG的去除的影响,并确定了其在ACF电极上的起始氧化电位和起始还原电位;对两种模式下单位质量染料的脱色电耗进行了计算,并给出了相应结果;另外,通过测试线性极化曲线和恒电位整体电解确定了活性艳蓝KN-R在ACF电极上的氧化峰电位。 研究结果表明本实验模式可成功地完成电极电位和电流密度对活性艳蓝KN-R在ACF上电化学脱色行为影响的研究。实验条件下（pH=6.6）,活性艳蓝KN-R在ACF电极上的起始氧化电位和起始还原电位分别为0.5V和-0.7V,氧化峰电位为1.1V。恒电位模式下,当电位为-0.7V～-1.5V时,电还原是脱色的主要原因;当电位为-0.6V～0.4V时,脱色是由于染料在ACF上的吸附,且吸附不受ACF极化的影响;当电位为0.5V～1.6V时,脱色以染料的电氧化为主。恒电流模式下,当阴极电流密度为-0.938～-1.12mA·cm^-2时,脱色的主要原因是染料的电还原;当电流密度为为-0.875～0.0625mA·cm^-2时,脱色源于染料在ACF上的吸附,吸附同样不受ACF极化的影响;当阳极电流密度为0.125～0.5mA·cm^-2时,主要是染料电氧化导致脱色。对实验结果进行动力学拟合,表明活性艳蓝KN-R在ACF上的电氧化和电还原脱色过程均遵循准活性艳蓝KN--R在ACF上的电化学脱色一级反应动力学。 对恒电位和恒电流模式下脱色过程中的电耗进行计算,表明单位质量染料的电氧化及电还原脱色电耗明显低于充电过程吸附脱色电耗,且电还原脱色电耗要高于电氧化脱色电耗。关键词:活性炭纤维（ACF）;活性艳蓝KN一R;脱色;电氧化;电还原更多还原

【Abstract】 Dye wastewater is characterized by complicated components, strong color, highly fluctuating pH, high COD, TOC concentration and suspend solids, low biodegradability, and widely varied quality and quantity, so it has been rather difficult to be treated. As an eco-friendly technology, electrochemical method added little or no additional chemicals without secondary pollutants for wastewater treatment. In recent years, there has been increasing interest in the use of electrochemical methods for the treatment of dye wastewater.Most study on dye wastewater treatment with electrochemical method was conducted with cell voltage or current constantly controlled and the parameters of voltage, current density, wastewater conductivity, pH, current efficiency and energy consumption were evaluated. However, there are few reports on the relationship between the decolorization and the potential and current density. It is known that potential and current density are the fundamental factors for the electrochemical process. So it is necessary and important to evaluate the effect of potential and current density on the decolorization of dye wastewater. Besides, a great number of experiments were performed in a single compartment electrolytic cell. As a result, it is difficult to make sure the pure contribution of electrooxidation and electroreduction for the decolorization of dye wastewater because of the cross- interference of the anode and cathode.The objective of this study is to investigate the effect of the potential and current density on the decolorization of Reactive Blue 19, one of anthraquinone dyes. Activated carbon fiber (ACF) was used as anode or cathode under potentiostatic and galvanostatic model, respectively. The electrolytic cell was designed as a two-compartment cell separated by cation selective membrane. The linear sweep voltammograms of ACF in dye solution were measured; the effects of potential and current density on the decolorization kinetics, color, total organic carbon (TOC) and chemical oxygen demand (COD) removal ratio were investigated, and the energy consumptions of experimental processes were calculated, too.The results obtained were shown as: (1) the onset reduction potential and the onset oxidation potential of Reactive Blue 19 are about -0.7V and 0.5V respectively, and the optimal oxidation potential is 1.1V.(2) In the range of -0.6V ~ 0.4V and -0.875 ~0.0625mA · cm-2, the decolorization results from the adsorption of Reactive Blue 19 on ACF and the adsorption behavior is insignificantly affected by polarization; (3) In the range of -0.7V~--1.5V and -0.938~-1.12mA · cm-2, the electroreduction plays an important role in the decolorization. Furthermore, the decoloring process follows pseudo-first order kinetics; (4) In the range of 0.5V~ 1.6V and 0.125~0.5mA · cm-2, the electrooxidation results in the decolorization and the decoloring process also follows pseudo-first order kinetics; (5) Energy consumptions of electrooxidation and electroreduction of the dye on ACF are lower than that of adsorption, and energy consumptions of the electrooxidation are higher than that of the electroreduction.更多还原