生物炭对水中Pb(Ⅱ)和Zn(Ⅱ)的吸附特征  

Adsorption of Pb(Ⅱ),Zn(Ⅱ) from aqueous solution by biochars

作　　者：郭素华[1] 许中坚[1] 李方文[1] 许丹丹[1] 

机构地区：[1]湖南科技大学化学化工学院,湘潭411201

出　　处：《环境工程学报》2015年第7期3215-3222,共8页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(20577008);湖南省自然科学基金资助项目(05JJ30017)

摘　　要：选取花生壳和玉米秸秆为原材料,在不同温度下制备生物炭,与市售的银杉木炭一起作为吸附剂探究其对水溶液中Pb(Ⅱ)和Zn(Ⅱ)的吸附能力和特性。用FTIR和扫描电镜表征生物炭表面性质。实验考察了吸附时间、溶液初始pH、初始浓度对吸附的影响。结果表明,在室温25℃和pH 5.0条件下,生物炭对Pb(Ⅱ)、Zn(Ⅱ)的吸附量随时间的增加而增大,在24 h后基本达到平衡,并且生物炭对Pb(Ⅱ)、Zn(Ⅱ)的吸附动力学符合准二级动力学方程;溶液初始pH显著影响生物炭对Pb(Ⅱ)和Zn(Ⅱ)的吸附,其中对Pb(Ⅱ)和Zn(Ⅱ)的最佳吸附pH分别为5.0和6.0;花生壳生物炭和玉米秸秆生物炭对Pb(Ⅱ)的等温吸附符合Langmuir模型和Freundlich模型,而对Zn(Ⅱ)的等温吸附Freundlich模型拟合效果更佳;银杉木炭对Pb(Ⅱ)和Zn(Ⅱ)的等温吸附更适用于Langmuir模型。另外,随着生物炭制备时热解温度的升高,生物炭对Pb(Ⅱ)和Zn(Ⅱ)的吸附量增加,且各生物炭对Pb(Ⅱ)的最大吸附量远大于其对Zn(Ⅱ)的最大吸附量。不同生物炭对Pb(Ⅱ)的吸附能力有明显差异,表现为:花生壳生物炭>玉米秸秆炭>银杉木炭,而对Zn(Ⅱ)的吸附力差异不明显。In this study,peanut shell and corn stalk were used as raw materials to produce biochars by pyrolysis under different temperatures and the adsorption characteristics of Pb（Ⅱ） and Zn（Ⅱ） by these biochars were investigated.The effects of adsorption time,solution initial pH value and concentration of Pb（Ⅱ） and Zn（Ⅱ） on the adsorption were examined.The adsorption amounts of Pb（Ⅱ） and Zn（Ⅱ） by the biochars increased with adsorption time and basically reached equilibrium after 24 hours under the conditions of 25℃ and pH 5.0,and this adsorption process followed the pseudo-second-order kinetics model.Solution initial pH value significantly influenced the adsorption,and the optimum pH value for Pb（Ⅱ） and Zn（Ⅱ） were 5.0 and 6.0,respectively.The adsorption of Pb（Ⅱ） by biochars derived from peanut shells and corn stalk fitted both Langmuir and Freundlich adsorption isotherm model,but for the adsorption of Zn（Ⅱ）,Freundlich model was fitted better.Besides,the adsorption of Pb（Ⅱ） and Zn（Ⅱ） by silver fir charcoal were followed Langmuir model.Other findings showed the Pb（Ⅱ） and Zn（Ⅱ） adsorption amount of biochars increased with increasing of the pyrolysis temperature.And there were obvious differences in the adsorption amount for Pb（Ⅱ） by the biochars derived from different raw materials： peanut shell biochar displayed the best adsorption,followed by corn stalk,and silver fir charcoal ranked the weakest,but for the adsorption of Zn（Ⅱ） this difference was not observable.

关 键 词：生物炭 热解温度 铅 锌 吸附 

分 类 号：X53[环境科学与工程—环境工程]