The Study On Treatment Of Halogenated Aromatic Wastewater By Reductive Dual-Electrode With Iron-Carbon Particles

In order to solve the problem that traditional iron-carbon electrolysis technology would causes consolidation during waste water treatment after operation for a time, which reduces efficiency, this study presents dual-electrode reductive method by iron-carbon and design a new dual-electrode devise of electrode reductive method. One of the typical halogenated aromatic, 1,4-DCB is choosed as the research target pollutants in this study.This paper studies the main conditions of the dual-electrode reduction, including hydraulic retention time (HRT), load handling, mixing, as well as the pH value of 1,4-dichlorobenzene treatment effect.Results showed that the best retention time of 30 min, treatment load is 50ppm, the best pH is 3; electrode reaction is mainly concentrated in the 10 min prior to treatment; contrast anode and the cathode effect found that the effect of cathode obvious superior to the anode, for example, under the conditions of the processing time of 10 min, pH7, the anode and cathode removal of 1,4 -dichlorobenzene were 53% and 78%; at the same time found that the pH value is greater than the impact of the anode on the Cathode; in the anode influent pH value from 3-9 in the changes, 1,4-dichlorobenzene treatment efficiency decreased from 70.3% to 35.3%, while the cathode influent pH 3-9 from the changes, its 1,4 - dichlorobenzene removal rate decreased from 85.7% to 74.4%.The research on the parameters of iron-carbon electrode effect of the impact, inspected the iron-carbon ratio, the specific iron surface area of 1,4-dichlorobenzene effect of the impact study found that in iron-carbon ratio of 4: 1, the anode and cathode is the optimal treatment effect for the 88% of the surface area of the iron degradation of 1,4-dichlorobenzene no apparent impact, but its impact on iron particle Obviously. If the particle is too small,it will block mass transfer. Under the same conditions, large-size particles should be adopted. The type and concentration of electrolyte are also the important factors for the method.Compared with treated by traditional iron-carbon electrolysis method, dual-electrode reductive method can prevent consolidation, providing long runtime as well as ensure the efficiency. If the two methods run for a week respectively under the same condition, the new method can keep a removal rate of 80% by cathode while the removal rate of traditional method decrease from 91.6% at the very beginning to 43.8% in the end.More experiment were done on the mechanism of dual-electrode reduction for further study. First on the analysis of the treated water by ion chromatography found that 1,4-dichlorobenzene degradation product is the ultimate form of ion. After reacted 30 min, measured chloride concentration of 6.2 ppm, the reaction of chlorine removal rate of 64%. Based on the total carbon and water for GC-MS analysis showed that the total carbon removal rate is 61.8% and 82.9%. The results showed that degradation of 1,4-dichlorobenzene are three kinds of ways, some 1,4 - dichlorobenzene become fully degradable to chloride ion and carbon dioxide, and some degradation of the small molecule organic chlorine, there are some 1,4 - dichlorobenzene through flocculation and electricity aggregation methods to remove. Were derived anode and cathode electrode reaction, the reaction mechanism has also been deduced; and 1,4 - dichlorobenzene Kinetic Model done a preliminary assumptions, the degradation process with a kinetic equation; the iron-carbon double a reduction to a simple calculation of the cost of operation, cost per tonne of waste water about 0.6 yuan, less than other commonly used methods.