采用批次平衡实验法,研究了胡麻秸秆生物炭、黄土及加炭黄土吸附重金属Cu(Ⅱ)的特性,考察了吸附时间、溶液pH值、溶液初始浓度、吸附温度和离子强度对吸附效果的影响.结果表明:生物炭、黄土及加炭黄土对重金属Cu(Ⅱ)的吸附符合准二级动力学方程;溶液初始pH值在2~6时,三者对Cu(Ⅱ)的吸附量随pH值的增大而逐渐增大;在25℃时,生物炭和加炭黄土对Cu(Ⅱ)的吸附符合Langmuir方程,而黄土对Cu(Ⅱ)的吸附符合Freundlich方程;当温度在20~40℃时,吸附量均随着温度的升高而逐渐增加,且三者对Cu(Ⅱ)的吸附是一个自发的吸热过程;一定浓度的无机盐Ca2+对生物炭、黄土和加炭黄土吸附重金属Cu(Ⅱ)的影响不大.
The adsorption of Cu(Ⅱ)onto the benne straw biochar,loess and loess with biochar was investigated.The effects of time,pH values,initial Cu(Ⅱ)concentration,temperature and thermodynamics on adsorption were studied.The results showed that the adsorption kinetics of Cu(Ⅱ)from the biochar,loess and the loess with biochar were well described by the pseudo-secondorder-kinetic model and the corresponding coefficients R2 were 0.974,0.996 and 0.996,respectively.When the pH ranged from 2to 6,the adsorption of Cu(Ⅱ)was greater.At 25℃,the isotherm adsorption of the biochar and the biochar with loess followed the isothermal model of Langmuir,but the loess fitted the isothermal model of Freundlich.The adsorption kinetics of Cu(Ⅱ)from the biochar,loess and the loess with biochar were spontaneous,and the capacity increased with increase of temperature from 20℃~40℃.The existence of inorganic salts with the certain concentrations could not influence the adsorption capacity of copper.