The Study On The Treatment Of Pesticide Intermediates (Isophthalonitrile) Wastewater By Electrochemical Process

The Isophthalonitrile belong to high concentration of refractory organic wastewater, which was toxic and poor biodegradable. Because of its simple operation, less pollution and wide application, electrochemical technology has became more and more popular. This paper studied the degradation of the Isophthalonitrile by membrane electrochemical reactor using Ti/SnO2+Sb2O3/PbO2 electrode as anode, and stainless steel electrode as the cathode. In this paper, we investigate the effects of Isophthalonitrile initial concentration, reaction time, wastewater initial pH, current density and the electrolyte concentration on the degradation of the Isophthalonitrile, and the reaction kinetics and degradation mechanism were further researched.The results of experiment showed that:the degradation effect of Isophthalonitrile by electrochemical oxidation was not obvious without membrane, the removal rate of Isophthalonitrile was 20%, and the Isophthalonitrile was difficult to oxidize. The degradation effect of Isophthalonitrile by electrochemical reduction became better with the membrane., and the degradation reaction followed first-order kinetics. Current density, electrolyte concentration, S/V value, Isophthalonitrile initial concentration and the initial pH had obvious effect on the degradation reaction.Current density had the greatest effect and the plate spacing had no effect. Considering of the energy consumption and the removal rate of Isophthalonitrile, the optimum conditions as follows:current density was 25mA/cm2 concentration of Na2SO4 was 5g/L, pH=7, plate area was 20cm2, plate spacing was 4cm, S/V value was 1:6. Under these conditions, after 120minutes reaction, the removal rate of Isophthalonitrile(250mg/L) reached 84.1%.According to the degradation mechanism of Isophthalonitrile by UV and HPLC, We concluded that the Isophthalonitrile can be reduced into m-Xylylenediamine in the cathodic.