均相Fenton法深度处理丙烯腈生化尾水

采用均相Fenton法深度处理丙烯腈生化处理工艺尾水,通过单因素法分析了H_2O_2投加量、Fe~(2+)投加量、初始p H值和反应时间对尾水COD去除率的影响;并采用中心响应曲面法优化Fenton处理的工艺参数,得到最佳反应条件为:Fe~(2+)投加量为1.02 mmol·L-1,H_2O_2投加量为11.13 mmol·L~(-1),初始pH值为3.66,反应时间为105 min,COD去除率达到61.1%.处理后尾水COD值低于50 mg·L~(-1),可满足石化行业一级排放标准.Fenton工艺对尾水中特征污染物均有较好的去除效果,最佳反应条件下丙烯腈、间苯二甲腈、3-氰基吡啶的去除率分别为99.5%、97.6%、73.7%;Fenton法对3种特征污染物的降解能力从大到小依次为:丙烯腈间苯二甲腈3-氰基吡啶.三维荧光光谱分析表明,尾水中存在大量类富里酸荧光物质,其中,紫外区类富里酸含量最高,Fenton工艺在较短反应时间和较少的试剂投加量条件下,便可有效地去除这类难降解物质.

Advanced treatment of bio-treated effluent of acrylonitrile wastewater with homogeneous Fenton process

Homogeneous Fenton process was applied in advanced treatment of bio-treated effluent of acrylonitrile wastewater. The effects of Fe²⁺ and H₂O₂ dosage, initial pH and reaction time on COD removals were evaluated according to the single-factor test, and response surface methodology based on central composite design was developed to optimize the parameters of the Fenton process. The optimum reaction conditions were Fe²⁺ dosage of 1.02 mmol·L^-1, H₂O₂ dosage of 11.13 mmol·L^-1, initial pH at 3.66, and reaction time of 105 min. Under the optimum reaction conditions, the COD removal efficiency was 61.1% and the COD concentration of treated effluent was lower than 50 mg·L^-1, which could meet the top emission standard in petrochemical industry. The Fenton process showed high removal efficiencies on the typical pollutants, under the optimum reaction conditions; the removal efficiencies of acrylonitrile, m-phthalonitrile, and 3-cyanopyridine were 99.5%, 97.6% and 73.7%, respectively. The degradability of these three pollutants followed the order: acrylonitrile>m-phthalonitrile>3-cyanopyridine. Excitation-emission matrix spectra revealed that large amount of fulvic-like fluorescent substances existed in the bio-treated effluent of acrylonitrile wastewater, and the ultra-violet fulvic-like substance accounted for the largest proportion. The Fenton process could effectively remove the refractory substances in short reaction time and with a small amount of reagent dosage.