白鹭　吴春英　谷风

摘要：利用NaOH浸泡预处理、NaClO溶液氧化改性板蓝根药渣对含铅废水的处理进行了研究。考察了吸附剂投加量、初始Pb2+浓度、pH、吸附时间及温度对改性板蓝根药渣吸附Pb2+的影响。结果表明，对50 mL 50 mg/L的含铅废水，在投入0.15 g改性板蓝根时，吸附率达到最大（92.1%），吸附容量达到最高（15.25 mg/g）。随着Pb2+初始浓度的增大，吸附容量逐渐增大，初始浓度增加到50 mg/L时达到平衡。pH对Pb2+的去除有重要影响，最佳pH是6，去除率达到92.7%。当吸附时间为3 h时，吸附过程达到平衡。改性板蓝根药渣对铅的吸附率在30 ℃时最高，为92.3%。Langmuir模型对改性板蓝根药渣吸附铅离子有更好的拟合效果，表明板蓝根药渣对Pb2+的吸附属于单层吸附，最大吸附量可达15.8 mg/g。吸附过程可以用准二级动力学模型描述。

关键词：板蓝根药渣；Pb2+；吸附；等温线；动力学

中图分类号：X703.1 文献标识码：A 文章编号：0439-8114（2015）24-6219-04

DOI：10.14088/j.cnki.issn0439-8114.2015.24.030

Abstract：Isatis indigotica Fort. draff modified by NaOH and NaClO was researched as an effective biosorbent for removing Pb2+ from wastewater. The effects of the biosorbent dosage， the initial Pb2+ concentration， pH， time and temperature on the adsorption of Pb2+ by the biosorbent were studied. The experimental results indicated that， for 50 mL wastewater containing Pb2+ with a concentration of 50 mg/L，when 0.15 g biosorbent was added into it， the adsorption rate and adsorption capacity reached the maximum（92.1% and 15.25 mg/g）. With the increase of the initial concentration of Pb2+， the adsorption capacity increased gradually，and the equilibrium was reached when the initial concentration was 50 mg/L.The pH had a noticeable effect on the removal of Pb2+，the optimal pH was 6.0， and the adsorption rate was 92.7%. When the adsorption time was 3 h，the adsorption process reached equilibrium. When the adsorption temperature was 30 ℃，the adsorption rate reached the maximum（92.3%）. The data fitted well with the Langmuir isotherms. The experimental data could be better explained by the pseudo-second-order model.

Key words：Isatis indigotica Fort. Draff；Pb2+； biosorption；isotherm；kinetics

随着工业化进程的发展，含铅废水的排放量越来越大，而铅是污染严重的重金属离子，富集在人和动物体内会损害人体的各个系统和器官，对人体健康及环境带来极大的危害，引起人们的高度重视。铅主要存在于冶金、金属加工、机械制造、化学药剂、石油加工、纺织、印染、化纤、电镀、火柴、照相材料等工业生产的废水中，重金属废水处理的方法主要有生物吸附法、化学沉淀法、离子交换法和膜分离技术[1，2]。生物吸附剂具有金属吸附选择性高、适应范围广、耐受有机负荷高、再生能力强、吸附迅速等优点，尤其是在低浓度下具有良好的重金属吸附能力[3-5]。……