摘要
深入研究成本低廉的膨润土对水溶液中Pb(Ⅱ)的吸附特性,采用Batch试验方法,分析了土水比、pH、离子强度、反应时间、温度及Pb(Ⅱ)的初始浓度对Pb(Ⅱ)在膨润土上吸附性能的影响,并对吸附动力学和吸附平衡试验进行了探讨。Pb(Ⅱ)在膨润土上去除率与pH、离子强度有很强的依赖性。当pH<7时,膨润土对Pb(Ⅱ)的吸附主要是离子交换,而当7<pH<10时,内表面络合是主要的吸附机理。膨润土对Pb(Ⅱ)的吸附非常迅速,15 min去除率就达到50%,120 min内可达到平衡。动力学数据符合伪二级动力学模型,吸附速率常数均随Pb(Ⅱ)的浓度增加而减小。Langmuir模型可成功的拟合等温吸附数据,膨润土对Pb(Ⅱ)的吸附量可达27.45 mg/g,升温有利于膨润土对Pb(Ⅱ)的吸附。试验结果表明:膨润土可作为防污屏障和降低水环境中重金属污染物的吸附剂。
The adsorption of lead on bentonite is studied by means of the Batch experiment due to its low cost and easy availability. The effects of soil-water content, solution pH, ionic strength, reaction time, temperature and initial Pb（II） concentration on the removal of Pb（II） by use Of bentonite, kinetic process and adsorption equilibrium are investigated. The removal of Pb（II） from aqueous solutions by use of bentonite is strongly dependent on pH and ionic strength. When pH〈7, the removal of Pb（II） is dominated by ion-exchange on soil surfaces, whereas inner-sphere surface complexation is the main adsorption meehanism when 7〈pH〈10. The adsorption of Pb（II） on bentonite is a fast process, 50% of the Pb（II） is removed in 15 minutes, and the equilibrium can be attained within 120 minutes. The kinetic data fit the pseudo-second order kinetics very well and the rate constants decrease with the increase of the initial concentration. The adsorption isotherms are best-fit with the Langmuir isotherm. The saturated adsorption capacity of Pb（II） on bentonite is 27.45 mg/g, and higher temperature favors the adsorption process. The results show the bentonite can be used as containment barrier system and as adsorbent removing heavy metal contamination in aquatic environment.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2013年第1期117-123,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(51179023)
关键词
铅
膨润土
吸附
动力学
平衡
lead
bentonite
adsorption
kinetics
equilibrium
