Inbaraj B Stephen, Sulochana N
Department of Chemistry, National Institute of Technology, Tiruchirappalli, India.
J Hazard Mater. 2006 May 20;133(1-3):283-90. doi: 10.1016/j.jhazmat.2005.10.025. Epub 2005 Dec 1.
A carbonaceous sorbent derived from the fruit shell of Indian almond (Terminalia catappa) by sulfuric acid treatment was used for the removal of mercury(II) from aqueous solution. Sorption of mercury depends on the pH of the aqueous solution with maximum uptake occurring in the pH range of 5-6. The kinetics of sorption conformed well to modified second order model among the other kinetic models (pseudo first order and pseudo second order) tested. The Langmuir and Redlich-Peterson isotherm models defined the equilibrium data precisely compared to Freundlich model and the monolayer sorption capacity obtained was 94.43 mg/g. Sorption capacity increased with increase in temperature and the thermodynamic parameters, DeltaH degrees , DeltaS degrees and DeltaG degrees , indicated the Hg(II) sorption to be endothermic and spontaneous with increased randomness at the solid-solution interface. An optimum carbon dose of 4 g/l was required for the maximum uptake of Hg(II) from 30 mg/l and the mathematical relationship developed showed a correlation of 0.94 between experimental and calculated percentage removals for any carbon dose studied. About 60% of Hg(II) adsorbed was recovered from the spent carbon at pH 1.0, while 94% of it was desorbed using 1.0% KI solution.
一种通过硫酸处理从印度杏仁（Terminalia catappa）果壳衍生而来的碳质吸附剂被用于从水溶液中去除汞（II）。汞的吸附取决于水溶液的pH值，在pH值为5 - 6的范围内吸附量最大。在所测试的其他动力学模型（伪一级和伪二级）中，吸附动力学与修正的二级模型拟合良好。与弗伦德利希模型相比，朗缪尔和雷德利希 - 彼得森等温线模型能更精确地定义平衡数据，获得的单层吸附容量为94.43 mg/g。吸附容量随温度升高而增加，热力学参数ΔH°、ΔS°和ΔG°表明汞（II）的吸附是吸热的且自发的，在固 - 液界面处随机性增加。从30 mg/l的汞（II）溶液中实现最大吸附量需要的最佳碳剂量为4 g/l，所建立的数学关系表明，对于所研究的任何碳剂量，实验去除率和计算去除率之间的相关性为0.94。在pH值为1.0时，从废碳中回收了约60%吸附的汞（II），而使用1.0%的KI溶液可解吸出94%的汞（II）。
