Adsorption characteristics and the kinetics of the Cr(VI) on the Thuja oriantalis
Adsorption characteristics and the kinetics of the Cr(VI) on the Thuja oriantalis
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DOI：
10.1016/j.colsurfa.2004.10.004
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发表时间：
2005-01
期刊：
影响因子：
--
通讯作者：
E. Oguz
中科院分区：
文献类型：
--
作者：
E. Oguz
崖柏球果生物质本身是一种废弃物，在自然界中是一种容易获得的吸附剂。崖柏对Cr（VI）的吸附动力学研究表明，崖柏对Cr（VI）的吸附速度快，在20 min内达到吸附平衡，符合准二级动力学方程。研究了搅拌速率、pH值和温度对崖柏吸附Cr（VI）的影响。采用Langmuir Freundlich、Radke-Prausnitz、Brunauer、埃米特和Teller（BET）和Dubininin-Radushkevich（D-R）吸附等温线对结果进行了分析。根据D-R吸附等温线计算出平均吸附能为38.3kJmol− 1。计算了289、315和333 K下的反应速率常数，并利用Arhenius方程推导了反应活化能Ea。根据lnKD与1/T的线性关系曲线的斜率和截距计算了热力学参数ΔH°、ΔS°和ΔG°。崖柏对Cr（VI）的吸附ΔH°和ΔG°值为吸热吸附。但自由能值为负值，说明高温有利于Cr（VI）的吸附过程。
The cone biomass of Thuja oriantalis is a waste itself and a readily available adsorbent in nature. The kinetics of adsorption of Cr(VI) by the Thuja oriantalis was found fast, and reached equilibrium in 20min and followed pseudo second order rate equation. The adsorption behavior of Cr(VI) on the Thuja oriantalis has been studied as a function of the solution agitation rate, pH and temperature. Results have been analyzed by Langmuir Freundlich, Radke-Prausnitz, Brunauer, Emet and Teller (BET) and Dubinin–Radushkevich (D–R) adsorption isotherms. The mean energy of adsorption was calculated as 38.3kJmol−1from the D–R adsorption isotherm. The rate constants have been calculated for 289, 315 and 333K, and the activation energy (Ea) was derived using the Arhenius equation. Thermodynamic parameters such as ΔH°, ΔS° and ΔG° were calculated from the slope and intercept of linear plot of lnKDagainst 1/T. The ΔH° and ΔG° values of Cr(VI) adsorption on the Thuja oriantalis show endothermic heat of adsorption. But negative free energy value, indicating that the process of Cr(VI) adsorption is favored at high temperatures.