响应面法优化Fenton预处理干法腈纶废水

Optimization of Fenton process for pretreatment of dry-spun acrylic fiber wastewater with response surface methodology

采用Fenton法预处理难降解干法腈纶废水,选取H2O2用量、Fe2+用量、初始pH和反应温度4个因素为变量,COD去除率为响应值进行中心组合设计。利用响应面法对实验结果进行分析,建立了以COD去除率为响应值的二次多项式模型并进行了显著性检验,分析了各因素单独及交互作用对COD去除率的影响,确定了最佳反应条件,并考察了最佳条件下处理前后废水可生化性和毒性变化。结果表明,所选取的4个因素影响COD去除率的主次顺序依次为:H2O2用量、Fe2+用量、初始pH和反应温度;在H2O2浓度为90.0 mmol/L、Fe2+浓度为23.9 mmol/L、初始pH值为3.4、温度为38.5℃的最佳条件下,COD去除率为53.8%,与模型预测值51.9%吻合度较高,偏差仅为3.66%;最佳条件下处理后废水可生化性显著提高,生物毒性明显降低,适宜于后续的生化处理。

The Fenton process was employed in the pretreatment of bio-refractory dry-spun acrylic fiber （DAF） wastewater. H：O2 dosage, Fe^2＋ dosage, initial pH and reaction temperature were selected as the varia-bles and COD removal efficiency as the response in the central composite design （CCD）. Response surface methodology （RSM） was used for the analysis of the experimental results based on CCD. A second-order polyno-mial regression equation was developed to describe the COD removal efficiency and was validated by significance test. The single and interactive effects of the operational parameters were investigated using response surface a-nalysis and the optimum reaction conditions were determined. Furthermore, the biodegradability and toxicity of the raw and treated DAF wastewater were also analyzed. The results showed that the effect of factors on COD re-moval was in the order of H2O2 dosage 〉 Fe^2＋ dosage 〉 initial pH value 〉 reaction temperature. Under the op-timum reaction conditions （H202 dosage of 90.0 mmol/L, Fe^2＋ dosage of 23.9 retool/L, initial pH value of 3.4 and reaction temperature of 38.5% ）, the COD removal efficiency was 53.8% , which was highly consistent with value 51.9% predicted by the model equation, with a deviation of 3.66%. After Fenton pretreatment under the optimum reaction conditions, the biodegradability of wastewater was significantly improved and the toxicity largely decreased, which was suitable for biological treatment.