缓冲体系评价老化作用对生物炭吸附重金属影响  

Influence of Aging Effect on Metal Adsorption by Biochar with Buffered System

作　　者：辜建强 王水[1] 宋敏[2] GU Jianqiang;WANG Shui;SONG Min(Jiangsu Provincial Key Laboratory of Environmental Engineering,Jiangsu Provincial Academy of Environment Science,Nanjing 210000,China;School of Energy and Environment,Dongnan University,Nanjing 210000,China)

机构地区：[1]江苏省环境科学研究院,江苏省环境工程重点实验室,江苏南京210000 [2]东南大学能源与环境学院,江苏南京210000

出　　处：《环境科学与技术》2022年第9期43-48,共6页Environmental Science & Technology

基　　金：国家重点研发项目(2019YFC1804004);江苏省环境工程重点实验室开放课题(ZX2018009)。

摘　　要：生物炭吸附重金属受p H影响巨大,利用非缓冲体系评价生物炭重金属吸附性能可能准确性不足。该研究探索了2-(N-吗啡啉)乙磺酸(MES)缓冲体系评价生物炭对Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)等的吸附性能及老化作用影响。研究结果发现,吸附前后非缓冲体系pH变化在3~5个单位,且随着pH上升(5.5→7.3),生物炭对Zn(Ⅱ)和Cd(Ⅱ)的饱和吸附量上升1.51~1.58倍,证明非缓冲体系评价准确性不足。而缓冲吸附体系能很好地稳定体系p H(±0.2),当体系p H相同时,2种体系对Cu(Ⅱ)的吸附无显著差异,表明MES不会与生物炭及重金属发生相互作用。老化作用对重金属在不同p H条件下吸附影响差异较大,这可能与不同pH条件下生物炭主导吸附机制有关。综上,MES缓冲体系可以准确评价生物炭的重金属吸附性能,更适用于指导生物炭在土壤污染修复中的应用。Biochar adsorption of heavy metals was greatly affected by the pH of the environment,and using conventional unbuffered system to estimate the adsorption capacity of biochar for heavy metal could lead to inaccurate results.In this study,we investigated the application of MES buffer system to evaluate adsorption capacity of biochar for three kinds of divalent metal cations(Cu,Zn,Cd),as well as the aging effect(freeze-thaw cycle aging and soil aging)on the adsorption behavior.Results showed that the pH of unbuffered system changed 3~5 units during the adsorption experiment,and the saturated adsorption capacity of biochar for Zn(Ⅱ)and Cd(Ⅱ)increased by 1.51~1.58 times with the p H of system increased from5.5 to 7.3,which proved that the evaluation accuracy of unbuffered system was insufficient.Otherwise,the pH of MES buffer system kept steady(±0.2).When the pH of adsorption systems was similar(5.5±0.1),there was no significant difference in the adsorption capacity between two adsorption systems for Cu,indicating that MES had no direct reaction with neither biochar nor heavy metals cations.In addition,the aging effects on the adsorption of heavy metals at different pH conditions are quite different,which may be related to the different critical adsorption effect under different pH conditions.In general,MES buffer system can accurately evaluate the adsorption performance of biochar for heavy metals under specific pH conditions,and is more suitable for guiding biochar remediation of heavy metal pollution in soil environment which generally have strong buffer capacity.

关 键 词：生物炭 缓冲吸附体系 老化作用 

分 类 号：X53[环境科学与工程—环境工程]