化学沉淀结合Fenton法预处理脱硫废液的原理与效果分析

Coupling method of precipitation and Fenton oxidation for pretreating desulfurization wastewater: mechanism and effect analysis

脱硫废液因含有高浓度氰化物、硫氰化物、硫化物等有毒组分而影响焦化废水处理的生物工艺.以焦化企业产生的实际脱硫废液为研究对象,选用化学沉淀-Fenton氧化的串联方法尝试预处理及分析方法的可行性,通过单因素实验,考察了硫酸亚铁投加剂量、反应前后溶液pH值、反应时间3种条件对脱硫废液中总氰及易释放氰去除效果的影响,在优化条件下对经硫酸亚铁沉淀后的脱硫废液残液进行Fenton氧化实验.结果表明,当硫酸亚铁投加量为理论值的1.2倍,H2O2投加量为COD当量的0.3倍时,可使脱硫废液的COD去除率达到76.65%,使初始浓度分别为327.7、704.6和2087.3 mg.L-1的氰化物、硫氰化物及硫化物基本得到去除,为后续生物处理创造了有利条件.化学沉淀结合Fenton法是脱硫废液预处理效率高且实用的方法.

The desulfurization wastewater is difficult to be biodegraded due to the high-concentration of toxic compounds such as cyanide compounds,thiocyanide and sulfide.The chemical precipitation and Fenton oxidation combined technology was developed to pretreat desulfurization wastewater in this study.For the chemical precipitation,the effects of FeSO4 dosages,pH and reaction time on the removal of total cyanide and volatile cyanogen were investigated.Then,Fenton oxidation was conducted for the precipitated wastewater.The experimental results indicated that with the FeSO4 dosage 1.2 times of the theoretical value and the H2O2 dosage 0.3 times of equivalent COD,cyanide（327.71 mg · L-1）,thiocyanide（704.66 mg · L-1） and sulfide（2087.29 mg · L-1） can be removed completely.Therefore,the coupling method could be a potential pre-treatment method for the bio-treatment of desulfurization wastewater.