钙基胡敏酸改性生物炭的制备及其对镉污染的修复  

Preparation of biochar modified by calcium and humic acid for cadmium pollution remediation

作　　者：谭慧 王少锋 廉梅花 曾祥峰[3] 贾永锋[3] TAN Hui;WANG Shaofeng;LIAN Meihua;ZENG Xiangfeng;JIA Yongfeng(School of Environmental Science and Technology,Dalian University of Technology,Dalian 116024,Liaoning,China;School of Chemistry and Environmental Engineering,Shenyang Ligong University,Shenyang 110159,China;Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]大连理工大学环境学院,辽宁大连116024 [2]沈阳理工大学环境与化学工程学院,沈阳110159 [3]中国科学院沈阳应用生态研究所,沈阳110016

出　　处：《生态学杂志》2024年第9期2859-2870,共12页Chinese Journal of Ecology

基　　金：国家重点研发计划(2020YFC1807800);辽宁省兴辽英才计划项目(XLYC2007192);沈阳市科技计划项目(21⁃108⁃9⁃29);中央高校基本科研业务费(DUT22RC(3)074)资助。

摘　　要：生物炭是修复Cd污染土壤的常用材料,但效率总体不高。为提高生物炭对Cd^(2+)的吸附性能,采用稻杆生物炭作为原材料,通过负载Ca^(2+)和胡敏酸氧化浸渍对其进行活化改性,制备钙基胡敏酸改性生物炭材料。采用扫描电镜及能谱(SEM⁃EDS)、红外光谱(FTIR)、光电子能谱(XPS)对材料进行表征,并通过吸附实验和盆栽实验,探究钙基胡敏酸改性生物炭对Cd^(2+)的吸附固定性能和机理。结果表明:(1)生物炭与胡敏酸质量比为1∶1,碱性石灰水中Ca^(2+)浓度为1.5 g·L^(-1)的改性生物炭(RHB1⁃1)对Cd^(2+)的吸附性能最佳,最大吸附容量为74.46 mg·g^(-1),较改性前提高了61%;(2)钙基胡敏酸改性生物炭的表面酸性含氧官能团显著增加,并且新生成了游离态羟基,通过配位螯合、络合共离子交换作用,从而高效吸附Cd^(2+),吸附过程以化学吸附为主,符合Freundlich吸附等温模型;(3)钙基胡敏酸改性生物炭能够吸附固定土壤中Cd^(2+),促进Cd^(2+)由酸可提取态转化为残渣态,降低了土壤Cd^(2+)的生物有效性。Biochar is a commonly used material for remediation of cadmium contaminated soil,but its efficiency is not high.To improve the adsorption capacity of biochar for Cd^(2+),rice straw biochar was modified by loading Ca^(2+)and activating modification by humic acid oxidation impregnation.The materials were characterized by scanning electron microscopy(SEM)and energy dispersive X⁃ray spectroscopy(EDS),Fourier transform infrared spectros⁃copy(FTIR)and X⁃ray photoelectron spectroscopy(XPS).Batch adsorption experiments and pot experiments were carried out to explore the adsorption fixation properties and mechanism of the materials for Cd^(2+).The results showed that:(1)The best adsorption performance was observed when the mass ratio of biochar to humic acid was 1∶1 and the concentration of Ca^(2+)was 1.5 g·L^(-1)(referred to as RHB1⁃1),and the maximum adsorption capacity was 74.46 mg·g^(-1),which was 61%higher than that of original biochar.(2)The content of acidic oxygen⁃containing functional groups on the surface of calcium⁃humic acid modified biochar was significantly increased,and the free hydroxyl group was newly formed.Cd^(2+)was efficiently adsorbed by coordination chelation and complexation coion exchange.The adsorption of Cd^(2+)by calcium⁃humic acid modified biochar was mainly chemisorption,which was consistent with Freundlich adsorption isotherm model.(3)The materials can absorb Cd^(2+)in soil and promote the transformation of Cd^(2+)from an acid extractable state to a residual state,reducing the bioavailability of Cd^(2+)in soil.

关 键 词：生物炭 胡敏酸 CA^(2+) Cd^(2+) 

分 类 号：TQ424[化学工程] X53[环境科学与工程—环境工程]