采用以Ti/SnO2+金属铁为组合阳极的铁促双电极电化学氧化法和Fenton氧化法对丙烯腈生产废水进行了处理.对比了2种方法的处理效果,考察了诸多因子对处理效果的影响及反应过程的规律.结果表明,在外加相同量H2O2条件下,铁促双电极氧化法的COD去除率比Fenton氧化法可提高约30%-35%,且可获得超过90%的色度去除率;但当H20:初始剂量小于1700mg·L^-1时Fenton试剂氧化法处理后的废水色度反而增加.外加H202剂量的增加强化了Fenton氧化过程,使2种方法COD去除率均随之增加.当外加H2O2初始浓度为2200mg·L^-1、电压为4.0V、反应时间为180min时,双电极电化学氧化法的COD去除率达75%.2种氧化反应过程中,H2O2浓度下降速率很快,反应60min(电化学)和30min(Fenton)时几乎均被耗尽.铁阳极通电时间对铁促双电极电化学氧化法的COD去除率和电流效率影响显著.铁促双电极氧化法(外加H2O2)对丙烯腈生产废水处理效果明显优于Fenton+铁促双电极氧化法(无外加H2O2),表明前者在有机废水处理领域有较好的应用潜力.
Wastewater from acrylonitrile production was treated by chemical Fenton oxidation or dual electrode iron-promoted electrochemical oxidation using Ti/SnO2 and Fe as the combined anodes. The results from the two processes were compared, and the effects of several factors and reaction behaviors were investigated. The COD removal efficiencies from the electrochemical oxidation with H2O2 added were about 30% - 35% higher than those from Fenton oxidation, and more than 90% color removal was achieved by the electrochemical process, but increases of color were observed when the initial H2O2 concentration was less than 1700 mg·L^-1 in the Fenton process. COD removal efficiency increased with increasing H2 02 dosage owing to the enhancement of Fenton reactions in both processes. At 2200 mg·L^ -1 H2O2 , t = 180 min and 4.0 V, a COD removal efficiency of 75% was obtained. During the course of the two oxidations, H2O2 concentration decreased quickly, and at 60 min (electrochemical) and 30 min (chemical) H2O2 was almost completely consumed. For the electrochemical process, COD removal efficiency and current efficiency were affected by the time length of current passing through the iron anode. The treatment effect of the wastewater by electrochemistry in the presence of H2O2 was also better than the united process: ( I ) Fenton oxidation and ( II ) the electrochemical oxidation with no H2O2 added, which indicates that the former is a promising alternative for the treatment of organic wastewater.