热解温度对不同生物炭吸附铅和镉性能的影响  

Effect of pyrolysis temperature on adsorption of lead and cadmium on different biochar

作　　者：王敏 杨锟鹏 张斌[3] 祁超[3] 金志鹏[3] 张亚平 WANG Min;YANG Kunpeng;ZHANG Bin;QI Chao;JIN Zhipeng;ZHANG Yaping(Xuzhou Environmental Monitoring Center of Jiangsu Province,Xuzhou 221002,China;Key Laboratory of Energy Thermal Conversion and Control,Ministry of Education,School of Energy and Environment,Southeast University,Nanjing 210096,China;Geological Exploration Technology Institute of Jiangsu Province,Nanjing 210008,China)

机构地区：[1]江苏省徐州环境监测中心,江苏徐州221002 [2]东南大学能源与环境学院能源热转换及其过程测控教育部重点实验室,江苏南京210096 [3]江苏省地质勘查技术院,江苏南京210008

出　　处：《化工环保》2024年第1期138-145,共8页Environmental Protection of Chemical Industry

基　　金：徐州市社会发展重点专项基金项目(KC21150);江苏省地质矿产勘查局科研项目(2021KY15)。

摘　　要：以芦苇、花生壳和稻杆为原料,分别在300℃和600℃下制备生物炭,考察不同生物炭对溶液中Pb^(2+)和Cd^(2+)的吸附性能,探讨其吸附机理。实验结果表明:准二级动力学模型和Langmuir等温吸附模型能够更好地拟合不同生物炭对Pb^(2+)和Cd^(2+)的吸附过程,生物炭对Pb^(2+)和Cd^(2+)的吸附均为化学吸附;3种生物炭对Pb^(2+)和Cd^(2+)吸附能力的顺序为稻杆生物炭(DBC)>花生壳生物炭(HBC)>芦苇生物炭(LBC);600℃制备的生物炭(DBC600)对Pb^(2+)和Cd^(2+)的吸附性能更好;25℃时,DBC600对Pb^(2+)和Cd^(2+)的饱和吸附量分别为91.06 mg/g和44.15 mg/g。3种生物炭吸附Pb^(2+)和Cd^(2+)过程的ΔG小于0,表明该吸附过程是自发的。3种生物炭吸附Pb^(2+)和Cd^(2+)的主要机理为矿物沉淀作用和离子交换作用,随热解温度的升高,离子交换作用在Pb^(2+)和Cd^(2+)吸附过程中的贡献率减小,金属阳离子与π电子间的配位作用的贡献率增大,而金属阳离子与含氧官能团间的配位作用的贡献率较小。Reed,peanut shell,and rice stalk were used as raw materials to prepare biochar at 300℃ and 600℃respectively.The adsorption capability of biochar for Pb^(2+)and Cd^(2+)in solution was investigated and the adsorption mechanism was discussed.The experimental results show that:The adsorption processes of Pb^(2+)and Cd^(2+)on the three kinds of biochar fit the quasi-second-order kinetic model and Langmuir isothermal adsorption model better,and all the adsorption processes are chemisorptions;The order of adsorption capacity of the three kinds of biochar for Pb^(2+)and Cd^(2+)is rice stalk biochar(DBC)>peanut shell biochar(HBC)>reed biochar(LBC);The biochar prepared at a pyrolysis temperature of 600℃(DBC600)possessed the best adsorption capability for Pb^(2+)and Cd^(2+);At 25℃,the saturated adsorption capacity of DBC600 for Pb^(2+)and Cd^(2+)is 91.06 mg/g and 44.15 mg/g,respectively;The adsorption process of Pb^(2+)and Cd^(2+)on the three kinds of biochars is spontaneous.The main mechanisms for the adsorption of Pb^(2+)and Cd^(2+)on the three kinds of biochar are mineral precipitation and ion exchange.With the increase of pyrolysis temperature,the contribution of ion exchange to the adsorption of Pb^(2+)and Cd^(2+)gradually decreases,and the contribution of coordination between metal cations andπelectrons gradually increases,however,the coordination between metal cations and oxygen-containing functional groups is small.

关 键 词：生物炭 重金属 热解温度 吸附机理 生物质 

分 类 号：X52[环境科学与工程—环境工程]