摘要
水洗处理在不影响生物质炭性质的前提下,可以去除附着在其表面的热解副产物,从而保证对重金属离子的去除能力。以小麦和玉米秸秆为原料,比较两种秸秆类生物质炭对溶液Cd^(2+)和Pb^(2+)的吸附解吸特点及其水溶性盐分含量的影响。结果表明,小麦和玉米秸秆生物质炭对Cd^(2+)和Pb^(2+)的吸附过程均更好地符合准二级动力学方程和Langmuir方程。小麦秸秆生物质炭对Cd^(2+)和Pb^(2+)的最大吸附量达12.82 mg g^(-1)和9.91 mg g^(-1),为玉米秸秆吸附量的1.31~1.76倍和1.06~1.53倍。洗脱水溶性盐分可以降低生物质炭对Cd^(2+)和Pb^(2+)的吸附,水洗后小麦秸秆和玉米秸秆生物质炭对Cd^(2+)的最大吸附量分别降低42.36%和60.13%,对Pb^(2+)的最大吸附量分别降低29.47%和62.72%。水洗处理提高了两种秸秆生物质炭对Cd^(2+)和Pb^(2+)的解吸率,其中小麦秸秆生物质炭提高幅度较大,由原来对Cd^(2+)的解吸率为1.84%~13.05%提高到7.88%~20.19%,对Pb^(2+)的解吸率为1.57%~11.82%提高到6.34%~16.94%。因此,可溶性盐分在秸秆生物质炭吸附Cd^(2+)和Pb^(2+)的过程中具有重要作用,该研究结果将为制备高效修复重金属污染土壤的生物质材料提供技术支撑。
Water washing could remove the pyrolysis by-products attached to the surface of biochar when the biochar properties remained unchanged,which would ensure the removal ability of heavy metal.The adsorption and desorption characteristics of Cd^(2+) and Pb^(2+) and the soluble salt contents by different biochar types derived from wheat and rice straw were compared in this study.Results showed that the adsorption processes of Cd^(2+)and Pb^(2+) by biochar were better fitted a pseudo second order kinetic model and a Langmuir equation.The maximum adsorption capacities of biochar from wheat straw on Cd^(2+) and Pb^(2+) were 12.82 mg g^(-1) and 9.91 mg g^(-1),which were 1.31-1.76 and 1.06-1.53 times than that from rice straw.Removing soluble salt with water washing decreased the adsorption capacities of Cd^(2+) and Pb^(2+) by biochar.After water washing,the maximum adsorption capacities of biochar derived from wheat and rice straw on Cd^(2+) decreased by 42.36%and 60.13%,and the sorption capacities on Pb^(2+)decreased by 29.47%and 62.72%.However,the desorption rates of Cd^(2+)and Pb^(2+)were higher by biochar from wheat straw than that from rice straw.The maximum desorption rates of the un-washed biochar on Cd^(2+) and Pb^(2+) were 1.84%-13.05%and 1.57%-11.82%,while those of the washed biochar were 7.88%-20.19%and 6.34%-16.94%,respectively.Therefore,water soluble salts in biochar play an important role in the adsorption/desorption of Cd^(2+) and Pb^(2+).These results would provide technical support to prepare biomass materials for remediation of heavy metal contaminated soil.
作者
来雪慧
王芳丽
张玉薇
赵婉辰
闫彬
吴宏梅
LAI Xue-hui;WANG Fang-li;ZHANG Yu-wei;ZHAO Wan-chen;YAN Bin;WU Hong-mei(Department of Environment and Safety Engineering,Taiyuan Institute of Technology,Taiyuan,China,030008;School of Geographic Sciences,Taiyuan Normal University,Jinzhong,030619,China;Qingdao Rural Environmental Engineering Research Center,School of Resources and Environment,Qingdao Agricultural University,Qingdao 266109,China)
出处
《土壤通报》
CAS
CSCD
北大核心
2021年第3期686-694,共9页
Chinese Journal of Soil Science
基金
国家自然科学基金项目(41701562)
山西省高等学校科技创新项目(2019L0917)
太原工业学院第三届青年学科带头人支持计划资助。
