摘要
采用惰性电解质滴定法和静态吸附实验,研究了磁性海泡石表面零电荷点和吸附Cd2+特性.实验结果表明,海泡石经过磁改性后所对应的pHpzc值由8.0升高到8.5,吸附体系pH的提高,有利于对重金属阳离子Cd2+的吸附.在pH值大于3时,磁性海泡石对Cd2+吸附量和去除率随pH值的升高而增大且趋于稳定,其吸附量为16.10 mg.g-1,约为海泡石的3.9倍,去除率为98%,约为海泡石的2.2倍.磁性海泡石对Cd2+的吸附量与离子强度有较大的相关性,随离子强度的增加而减小;对Cd2+的吸附量随反应温度的升高而增加,吸附等温式符合Langmuir方程.吸附机理以表面配合吸附和表面沉淀为主.
Surface point of zero charge of magnetic sepiolite and adso sepiolite were studied through inert electrolyte titration and static rption characteristics of Cd2~ onto magnetic adsorption experiment. Results showed that the point of zero charge pHpzo increased from 8.0 to 8.5 after magnetically modified. The high pH value of adsorption system contributed to adsorption of heavy metal cation Cd2~ onto magnetic sepiolite. When the pH value was above 3, the adsorbed amount of Cd2＋ and the removal rate of Cd2 ~ for magnetic sepiolite increased and tended to be stable with the pH increasing. The maximum adsorption capacity was 16.10 mg.g-lCd2＋ for magnetic sepiolite, which is about 3.9 times of sepiolite. The removal rate of Cd2~ was 98% for magnetic sepiolite, which is about 2.2 times of sepiolite. The adsorbed amount of Cd2~ onto magnetic sepiolite has a great relevance with ionic strength, decreasing with increasing of ionic strength. The adsorbed amount increased with reaction temperature. Langm onto magnetic sepiolite with a good fitness. importance role in adsorption mechanism of uir isotherm model was applied to describe the adsorption of Cd2~ Surface complexation and surface precipitation played the most Cd2＋ onto magnetic sepiolite.
出处
《环境化学》
CAS
CSCD
北大核心
2012年第11期1691-1696,共6页
Environmental Chemistry
基金
水体污染控制与治理科技重大专项(2010ZX07212-008)
湖南省科学技术厅科技计划重点项目(2011SK2016)资助
关键词
磁性海泡石
零电荷点
吸附
镉
magnetic sepiolite, point of zero charge, adsorption, Cd2 ＋.
