Pb(Ⅱ)在天然土壤纳米颗粒上的吸附-解吸：pH和离子强度的影响  

Adsorption-desorption of Pb(Ⅱ)on natural soil nanoparticles:Effects of p H and ionic strength

作　　者：安伟强[1] 孙慧敏[1,2] 吕家珑[1,2] 殷宪强[1,2] 韦革宏[3] 李俊[1] 

机构地区：[1]l西北农林科技大学资源环境学院,陕西杨凌712100 [2]农业部西北植物营养与农业环境重点实验室,陕西杨凌712100 [3]西北农林科技大学生命科学学院,陕西杨凌712100

出　　处：《农业环境科学学报》2016年第3期463-470,共8页Journal of Agro-Environment Science

基　　金：国家高技术研究发展计划(863计划,2012AA101402);国家自然科学基金(21207106,21207107);陕西省自然科学基础研究计划项目(2012JQ5012,2014JQ5184);中央高校基本科研业务专项(QN2011151,QN2011017)

摘　　要：选择提取自四种典型土壤的天然纳米颗粒作为吸附材料,研究了p H及离子强度(IS)对Pb(Ⅱ)在四种天然纳米颗粒上的吸附-解吸的影响,旨在为有效地控制土壤铅的环境行为提供依据。结果表明:在低p H时,四种土壤纳米颗粒Pb(Ⅱ)吸附量随p H的增大而增大,当p H>5后吸附量达到最大且趋于稳定。相同初始浓度下,四种吸附材料对Pb(Ⅱ)的吸附能力依次为黄绵土纳米颗粒>塿土纳米颗粒>风沙土纳米颗粒>黑垆土纳米颗粒。且四种土壤纳米颗粒的吸附量与离子强度(IS)有关,当IS为0.01 mol·L^(-1)Na Cl时,Pb(Ⅱ)吸附量最大,而0.1 mol·L^(-1) Na Cl时吸附效果最差,吸附在低IS时形成内表面络合物,高IS时形成外表面络合物。Pb(Ⅱ)解吸率随p H的增大而减小,p H为3时解吸率最大,p H>5后四种土壤纳米颗粒的解吸率降低。在不同IS的解吸液中,IS越大Pb(Ⅱ)的解吸率越大,解吸液为蒸馏水时解吸率最小。四种土壤纳米颗粒解吸率大小顺序为风沙土纳米颗粒>塿土纳米颗粒>黑垆土纳米颗粒>黄绵土纳米颗粒。Nanoparticles may play an important role in adsorption-desorption of heavy metals because of small sizes and huge surface area.In this study, natural soil nanoparticles were extracted from four typical soils, and adsorption and desorption of Pb（Ⅱ） by natural soil nanoparticles were investigated under different pH and ionic strengths（IS）. Results showed that amount of adsorbed Pb（Ⅱ）on four different soil nanoparticles increased along with increases of pH when pH was lower than 3. Amount of Pb adsorption by four soil nanoparticles was in order of loessal soil〉lou soil〉aeolian sandy soil〉black loam soil nanoparticles. Under different IS, adsorption rates of Pb by four soil nanoparticles varied greatly. The adsorption amount of Pb（Ⅱ） in 0. 01 mol·L^-1 NaCl solution was highest, but lowest in 0. 1 mol·L^-1NaCl solution. The inner surface adsorption complex was formed at low IS, while the outer surface complex happened at high IS. The desorption rates of Pb decreased as pH values increased, with the highest desorption found at pH 3. In different IS solutions, the Pb desorption rates increased with increasing IS. The Pb desorption rates in four soil nanoparticles decreased in order of aeolian sandy soil colloid lou soil colloid 〉black loam soil colloid 〉loessal soil colloid.

关 键 词：PH 离子强度 天然土壤纳米颗粒 吸附 解吸 

分 类 号：X131.3[环境科学与工程—环境科学]