生物炭改良黄土对Pb(Ⅱ)吸附特性的宏细观试验和内在影响机理研究  

Investigating adsorption properties of Pb(Ⅱ)of biochar-amended loess using macroscopic and microscopic methods

作　　者：李东风 郑文杰 文少杰 胡文乐 LI Dongfeng;CHENG Wenchieh;WEN Shaojie;HU Wenle(Xi'an University of Architecture and Technology,School of Civil Engineering,Xi'an 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi'an 710055,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]陕西省岩土与地下空间工程重点实验室,陕西西安710055

出　　处：《岩土工程学报》2025年第5期977-986,共10页Chinese Journal of Geotechnical Engineering

基　　金：中共中组部“国家海外高层次人才引进计划”青年项目(2019)。

摘　　要：垃圾渗滤液中含有大量重金属离子,在渗滤液的长期渗流作用下,垃圾填埋场衬里材料吸附阻滞重金属的能力因其自身的劣化问题而逐渐退化。为了改善衬里材料对重金属的长期吸附阻滞能力,在天然黄土中添加生物炭,并以Pb(NO_(3))_(2)作为污染源,通过渗透试验研究生物炭改良黄土对Pb^(2+)的吸附阻滞能力,通过XRD、FTIR等细观试验阐明黄土、生物炭改良黄土吸附Pb^(2+)前后矿物成分与官能团变化情况。结果表明:黄土试样吸附Pb^(2+)主要通过方解石矿物的界面沉淀作用生成白铅矿和石英矿物的专性吸附。通过SEM可看出白铅矿的生成附着于黄土颗粒表面,严重阻碍了黄土对Pb^(2+)的吸附,导致渗透试验后期黄土试样对Pb^(2+)去除效率仅为45%;FTIR试验在生物炭改良黄土试样中检测到大量含氧官能团,为官能团通过络合来吸附Pb^(2+)提供佐证;XRD试验证实生物炭表面磷酸盐矿物吸附Pb^(2+)界面沉淀占有主导地位。生物炭改良黄土衬里材料通过多重作用优先吸附Pb^(2+),缓解了黄土中方解石矿物的消耗,延长了Pb^(2+)吸附时间,使得渗透试验后期Pb^(2+)去除效率提升至85%。Landfill leachate contains many heavy metal ions,and under the long-term seepage of leachate,the capability of landfill liners to adsorb and retain heavy metals is gradually degraded due to their deterioration problems.To improve the long-term adsorption and retention capacity of the liner materials for heavy metals,in this study,biochar is added to loess,and Pb(NO_(3))_(2)is used as a pollution source to study the adsorption and retention capacity of the biochar-amended loess for Pb^(2+)through the seepage tests.The changes in mineral composition and functional groups before and after adsorption of Pb^(2+)on the biochar-amended loess are elucidated through the XRD and FTIR microscopic tests.The results indicate that the adsorption of Pb^(2+)of the loess is mainly through the interfacial precipitation of calcite minerals,resulting in the obligatory adsorption of cerussite and quartz minerals.The SEM test results show that the generation of cerussite attached to the surface of loess particles prevents the adsorption of Pb^(2+)on the loess,which leads to the removal efficiency of Pb^(2+)on the loess specimens at the late stage of the seepage tests is only 45%.The FTIR tests detect many oxygen-containing functional groups in the biochar-amended loess specimens,which provides evidence for the adsorption of Pb^(2+)by functional groups through complexation.The XRD tests confirm the predominance of phosphate minerals on the surface of biochar for the adsorption of Pb^(2+)through interfacial precipitation.The liner materials of the biochar-amended loess relieve the depletion of calcite minerals in the loess by preferential adsorption of Pb^(2+)through oxygen-containing functional groups and phosphate minerals,which prolongs the Pb^(2+)adsorption time,resulting in an increase of removal efficiency of Pb^(2+)to 85%at the late stage of the seepage tests.

关 键 词：黄土 生物炭 重金属 吸附 阻滞 界面沉淀 

分 类 号：TU443[建筑科学—岩土工程]