靛蓝废水无机盐环境下铝极板溶解与电化学行为分析

Analysis of aluminum electrode dissolution and electrochemical behavior in inorganic salt environment of indigo wastewater

摘要:

为提升靛蓝染色废水电絮凝效率，确定电絮凝过程中最佳水解金属盐形态形成条件，采用Al-Ferron逐时络合比色法探讨电絮凝过程中初始pH、共存阴离子种类、电流密度对铝盐形态分布的影响，同时监测絮体Zeta电位、终止pH、体系电流与电导率的变化。通过显微观察电极溶解腐蚀情况，利用电化学工作站测定电极的极化曲线与电化学阻抗谱，分析其电化学行为。结果表明：靛蓝废水电絮凝过程中，最佳初始pH范围为6 ~7，此时具有优势絮凝形态的Alb含量较高；Cl-的加入可抑制电极钝化，提升电絮凝反应速率；低电流密度有利于电极均匀腐蚀和Alb的存在，电流密度为15 mA/cm2时体系内Alb含量达4.76 mg/L，可产生较好絮凝效果。

Abstract:

In order to improve the efficiency of electrocoagulation of indigo dyeing wastewater, and determine the optimal conditions formation conditions of hydrolyzed metal salts. The Al-Ferron timed spectrophotometry was used to investigate the effect of initial pH value, coexisting anion species, and current density on the distribution of aluminum salts during electrocoagulation. The changes of floc Zeta potential, termination pH, system current and conductivity were also monitored. The dissolution and corrosion of the electrode were observed microscopically, and the electrochemical behavior was analyzed by measuring the electrode polarization curve and electrochemical impedance spectroscopy using an electrochemical workstation. The results showed that the optimal initial pH value range was 6 ~ 7 during the electrocoagulation, when the content of Alb with the dominant flocculation form is higher; the addition of chloride ions inhibited the electrode passivation and enhanced the electrocoagulation reaction rate; the low current density was beneficial to the uniform corrosion of electrodes and the existence of Alb. When the current density was 15mA/cm2, the content of Alb in the system could reach 4.76mg/L, which could produce a good flocculation effect.