自养硝化颗粒污泥吸附铅离子的性能

Performance of Autotrophic Nitrification Granular Sludge for Adsorption of Lead Ions

稀土冶炼产生了大量重金属废水,污泥因其来源广而成为常用的生物吸附剂,用于重金属废水治理。研究探索了自养硝化颗粒污泥(ANGS)吸附铅离子效果。通过单因素试验探究了铅离子浓度、吸附时间、污泥浓度及pH对吸附效果的影响,确定了实现ANGS对铅离子高效吸附适应的反应条件,即:吸附时间为2.0~2.5 h;污泥质量浓度为5000~9000 mg/L;pH值为3~5;铅离子质量浓度≤300 mg/L。利用响应曲面法分析各影响因素与铅离子去除率之间的交互作用并确定最佳吸附条件,影响力排序为:污泥量>pH>吸附时间;最佳吸附条件为:吸附时间=2.03 h,污泥质量浓度=6061.98 mg/L,pH值=3.01,此时,ANGS吸附铅离子的预测值可达100%,实际值>95%。利用Freundlich方程描述吸附过程,拟合度R^(2)为0.9453,表明该吸附是一个非均相表面吸附过程;最大吸附量(Q_(max))为40.09 mg/g,证实了ANGS可以作为一种高效的铅离子生物吸附剂,旨在为稀土冶炼废水治理提供技术支持。

A large amount of heavy metal wastewater is discharged by rare earth smelting.Because of its wide sources,sludge has become a common biosorbent for heavy metal wastewater treatment.Adsorption of lead ion by autotrophic nitrifying granular sludge(ANGS)was investigated.Effects of lead ion concentration,adsorption time,sludge concentration and pH value on adsorption performance were investigated by single factor experiments.The reaction conditions for achieving high lead ions adsorption efficiency of ANGS were determined,which were as follows:adsorption time of 2.0~2.5 h,sludge concentration of 5000~9000 mg/L,pH value of 3~5 and concentration of lead ions no more than 300 mg/L.Interaction between the influencing factors and lead ion removal efficiency was analyzed and the optimal adsorption conditions were determined by response surface methodology(RSM).Significant order was as follows:sludge volume>pH value>adsorption time,and the optimal adsorption conditions were:adsorption time of 2.03 h,sludge concentration of 6061.98 mg/L and pH value of 3.01.The predicted value of lead ions adsorption efficiency by ANGS could reach 100%,and the actual removal efficiency was greater than 95%.The adsorption process of lead ion by ANGS was described by Freundlich equation.The degree of fitting R^(2)was 0.9453,indicating that the adsorption process was an heterogeneous surface adsorption process.The maximum adsorption capacity was 40.09 mg/g,which indicated that ANGS can be used as an effective lead ions biological adsorbent.