Department of Earth and Environmental Sciences and the Environmental Geosphere Research Lab (EGRL), Korea University, Seoul 136-701, Republic of Korea.
J Hazard Mater. 2010 Feb 15;174(1-3):307-13. doi: 10.1016/j.jhazmat.2009.09.052. Epub 2009 Sep 17.
Kinetic and equilibrium sorption experiments were conducted on removal of divalent heavy metals (Pb(II), Cu(II), Zn(II), Cd(II)) and trivalent arsenic (As(III)) from aqueous solutions by scoria (a vesicular pyroclastic rock with basaltic composition) from Jeju Island, Korea, in order to examine its potential use as an efficient sorbent. The removal efficiencies of Pb, Cu, Zn, Cd, and As by the scoria (size=0.1-0.2mm, dose=60gL(-1)) were 94, 70, 63, 59, and 14%, respectively, after a reaction time of 24h under a sorbate concentration of 1mM and the solution pH of 5.0. A careful examination on ionic concentrations in sorption batches suggested that sorption behaviors of heavy metals onto scoria are mainly controlled by cation exchange. On the other hand, arsenic appeared to be sensitive to specific sorption onto hematite (a minor constituent of scoria). Equilibrium sorption tests indicated that the removal efficiency for heavy metals increases with increasing pH of aqueous solutions, which is resulted from precipitation as hydroxides. Similarly, multi-component systems containing heavy metals and arsenic showed that the arsenic removal increases with increasing pH of aqueous solutions, which can be attributed to coprecipitation with metal hydroxides. The empirically determined sorption kinetics were well fitted to a pseudo-second order model, while equilibrium sorption data for heavy metals and arsenic onto scoria were consistent with the Langmuir and Freundlich isotherms, respectively. Natural scoria studied in this work is an efficient sorbent for concurrent removal of divalent heavy metals and arsenic.
采用来自韩国济州岛的浮石（一种具有玄武岩成分的泡沫状火山碎屑岩）进行了去除水溶液中二价重金属（Pb(II)、Cu(II)、Zn(II)、Cd(II)）和三价砷（As(III)）的动力学和平衡吸附实验，以考察其作为高效吸附剂的潜力。在吸附质浓度为 1mM 和溶液 pH 值为 5.0 的条件下，反应 24 小时后，浮石（粒径为 0.1-0.2mm，剂量为 60gL(-1))对 Pb、Cu、Zn、Cd 和 As 的去除效率分别为 94%、70%、63%、59%和 14%。对吸附批次中离子浓度的仔细检查表明，重金属在浮石上的吸附行为主要受阳离子交换控制。另一方面，砷似乎对赤铁矿（浮石的次要成分）的特定吸附很敏感。平衡吸附试验表明，随着水溶液 pH 值的升高，重金属的去除效率增加，这是由于形成了氢氧化物沉淀。同样，含有重金属和砷的多组分体系表明，随着水溶液 pH 值的升高，砷的去除率增加，这归因于与金属氢氧化物共沉淀。经验确定的吸附动力学很好地符合拟二级模型，而重金属和砷在浮石上的平衡吸附数据分别符合 Langmuir 和 Freundlich 等温线。本研究中研究的天然浮石是同时去除二价重金属和砷的有效吸附剂。
