摘要
为了探究不同炭基两性黏土材料对紫色土吸附Cu2+的影响,将0%、50%和100%CEC十二烷基二甲基甜菜碱(两性)修饰膨润土分别负载于旱生和水生空心莲子草生物炭上制得炭基两性黏土,然后将其以1%和2%(质量比)添加到紫色土中形成供试研究土样。批量处理法研究pH、离子强度和温度处理对各供试土样吸附Cu^2+的影响,并分析最适环境条件下土样对Cu^2+的等温吸附和热力学特征。结果表明:(1)pH在2~5范围内,各供试土样对Cu^2+的吸附量均与pH呈正相关关系。随着离子强度的增大,供试土样对Cu^2+的吸附量均先增加后减少,以0.1 mg/L最高。10℃~40℃范围内,土样对Cu^2+的吸附均表现为增温正效应。(2)在pH=5,离子强度0.1 mg/L和40℃条件下,土样对Cu^2+的吸附等温线符合Langmuir模型,最大吸附量(qm)保持在160.79~247.12 mmol/kg之间。添加1%和2%炭基两性黏土后土样qm分别为紫色土的1.35~1.74倍和1.57~2.02倍。选择旱生炭基两性黏土和2%材料添加比例下土样对Cu^2+的吸附量较大。(3)热力学参数结果显示各供试土样对Cu^2+的吸附是自发、吸热和熵增的反应过程。
To investigate the effect of biochar-based amphoteric clays(BAC)on the Cu2+adsorption by purple soil,different BAC are added into purple soil with a mass ratio of 1%and 2%to form mixed soil samples.BAC is prepared by loading 0%,50% and 100% CEC dodecyl dimethyl betaine modified bentonites on two biochars that derived from xerophilic and hydrophytic alternanthera philoxeroides.The effect of pH,ionic strength and temperature on Cu^2+ adsorption by the tested soils was studied using the batch method,and Cu^2+ adsorption and thermodynamic characteristics of tested samples under the optimal conditions were analyzed.The results showed that:(1)in the pH range of 2-5,the adsorption amount of Cu^2+ on each soil sample are positively correlated with the increasing pH.The adsorption amount of Cu^2+ on the tested samples increase first and then decrease with the increasing ionic strength,and presents the highest adsorption amount at 0.1 mol/L.Cu^2+ adsorption by tested samples enhance with increasing temperature in the range of 10-40℃.(2)under the optimum condition of pH=2,ionic strength of 0.1 mgl/L,and temperature of 40℃,the adsorption isotherms of Cu^2+ by different samples are all followed with the Langmuir model,and the maximum adsorption amount(qm)is between 160.79 and 247.12 mmol/kg.After addition of 1% and 2% BAC,qmof different soil samples is 1.35-1.74 times and 1.57-2.02 times than that of raw purple soil,respectively.Adding xerophilic biochar-based materials and a 2% addition ratio achieves the highest Cu^2+ adsorption.(3)Cu^2+ adsorption by each soil sample is a spontaneous,endothermic,and entropy-increasing reaction process.
作者
李文斌
叶勇
邓红艳
胡亚菲
王丹
陈星宇
何海霞
易会宇
LI Wenbin;YE Yong;DENG Hongyan;HU Yafei;WANG Dan;CHEN Xingyu;HE Haixia;YI Huiyu(College of Environmental Science and Engineering,China West Normal University,Nanchong Sichuan 637009,China)
出处
《地球与环境》
CAS
CSCD
北大核心
2020年第5期558-566,共9页
Earth and Environment
基金
四川省科技计划项目(2018JY0224)
四川省教育厅项目(18ZB0576)
西华师范大学基本科研业务费资金(17E057)。
