关键词：
牛粪生物炭;核桃壳生物炭;Cd2+;Zn2+;吸附
摘 要：
为有效去除水溶液中Cd2+和Zn2+,以牛粪和核桃壳为原料,在不同热解温度下制取生物炭,采用等温吸附法和动力吸附法研究生物炭对水溶液中Cd2+和Zn2+的吸附效果和动力学特性,通过生物炭吸附前后的XRD和FTIR表征对比,探究其吸附机理.结果表明:生物质原材料的种类和热裂解温度是影响生物炭吸附效果的两大因素,牛粪生物炭比核桃壳生物炭吸附效果好,700℃制备的生物炭比300℃制备的生物炭吸附效果好;生物炭对Cd2+和Zn2+的吸附符合Langmuir方程;700℃制备的牛粪生物炭(DM700)对Cd2+和Zn2+的吸附性能最佳,饱和吸附量分别为117.5 mg·g-1和59.4 mg·g-1,其吸附过程由快速吸附和慢速吸附两个阶段组成,符合准二级动力学方程;吸附机理主要是生物炭中的羟基和羧基与Cd2+、Zn2+间发生离子交换和络合反应,Cd2+、Zn2+被吸附后进一步生成CdCO3和Zn3(PO4)2沉淀.这说明,DM700具备作为水溶液中Cd2+、Zn2+吸附剂的潜力,本研究为生物炭去除水中重金属和土壤重金属污染的修复提供了理论依据与应用参考.
作 者：
LIU Jian-nan;FENG Ji-meng;LI Dan;WANG Xin-ze;SHAN Ai-dang;School of Environmental Science and Engineering, Shanghai Jiao tong University;School of Agriculture and Biology, Shanghai Jiao Tong University;School of Materials Science and Engineering, Shanghai Jiao tong University;
单 位：
LIU Jian-nan%FENG Ji-meng%LI Dan%WANG Xin-ze%SHAN Ai-dang%School of Environmental Science and Engineering, Shanghai Jiao tong University%School of Agriculture and Biology, Shanghai Jiao Tong University%School of Materials Science and Engineering, Shanghai Jiao tong University
关键词：
dairy manure biochar;;walnut shell biochar;;Cd~(2+);;Zn~(2+);;adsorption
摘 要：
In order to remove Cd~(2+)and Zn~(2+)from aqueous solutions efficiently, using dairy manure and walnut shells as raw materials, biochar was prepared at different pyrolysis temperatures. The adsorption equilibrium method and dynamic adsorption method were used to study the kinetic characteristics of biochar and the adsorption effect of biochar on Cd~(2+)and Zn~(2+)in aqueous solutions. The adsorption mechanism was investigated by detecting biochar before and after adsorption using X-ray diffraction and Fourier transform infrared spectroscopy. The results showed that biomass materials and pyrolysis temperature were two major factors affecting the adsorption effect of biochar.The adsorption effect of dairy manure biochar was greater than that of walnut shell biochar, and the adsorption effect of biochar prepared at 700 ℃ was greater than that of biochar prepared at 300 ℃. Langmuir isotherms were more suitable for describing the Cd~(2+)and Zn~(2+)adsorp-tion mechanisms of biochar. Dairy manure biochar prepared at 700 ℃(DM 700)was the most effective adsorption material for Cd~(2+)and Zn~(2+), with maximum adsorption capacities of 117.5 mg·g~(-1) and 59.4 mg·g~(-1), respectively. The adsorption kinetics of DM700 fit better with pseudo-second order kinetics and included the rapid stage and slow stage. Ion exchange and the complex reaction between hydroxyl and carboxyl groups in biochar with Cd~(2+)and Zn~(2+)were the main adsorption mechanisms. CdCO_3 and Zn_3(PO_4)_2 precipitates were formed after Cd~(2+)and Zn~(2+)were adsorbed. Therefore, DM 700 has great potential as an adsorbent for Cd~(2+)and Zn~(2+).This study provides a theoretical basis and application reference for biochar removal of heavy metals from water and soil.
