Department of Civil Engineering, VIT University, Vellore, 632014, India.
Environ Sci Pollut Res Int. 2013 Mar;20(3):1327-43. doi: 10.1007/s11356-012-0981-2. Epub 2012 May 30.
The main aim of this study is to investigate the combined effect of different operating parameters like adsorbent dose, initial Cr(6+) concentration and pH on the removal of Cr(6+) from aqueous solution using neem bark powder (NBP). A series of batch experiments were performed to find out the adsorption isotherms and kinetic behaviour of Cr(6+) in the aqueous solution. The adsorption process was examined with three independent variables viz. NBP dosage, initial Cr(6+) concentrations and pH. Seventeen batch experiments designed by Box-Behnken using response surface methodology were carried out, and the adsorption efficiency was modelled using polynomial equation as the function of the independent variables. Based on the uptake capacity and economic use of adsorbent, the independent variables were optimized by two procedures. The desirability of first and second optimization procedures were found to be 1.00 and 0.84, respectively, which shows that the estimated function may well represent the experimental model. The kinetic study indicated that the rate of adsorption confirms to the pseudo-second-order rate equation. Thermodynamics study indicated that the adsorption process was spontaneous and endothermic in nature. The surface texture changes in NBP were obtained from FT-IR analysis. The optimized result obtained from RAMP plots revealed that the NBP was supposed to be an effective and economically feasible adsorbent for the removal of Cr(6+) from an aqueous system.
本研究的主要目的是研究不同操作参数（如吸附剂用量、初始 Cr(6+)浓度和 pH 值）对使用印楝树皮粉（NBP）从水溶液中去除 Cr(6+)的综合影响。进行了一系列批处理实验，以找出 Cr(6+)在水溶液中的吸附等温线和动力学行为。该吸附过程通过三个独立变量进行了检验，即 NBP 用量、初始 Cr(6+)浓度和 pH 值。使用响应面法设计了 17 个 Box-Behnken 批次实验，并使用多项式方程作为自变量的函数对吸附效率进行建模。基于吸附剂的吸附容量和经济利用，通过两种程序对自变量进行了优化。两种优化程序的理想性分别为 1.00 和 0.84，这表明估计函数可以很好地代表实验模型。动力学研究表明，吸附速率符合准二级速率方程。热力学研究表明，吸附过程是自发的和吸热的。通过傅里叶变换红外光谱分析获得了 NBP 的表面纹理变化。从 RAMP 图得出的优化结果表明，NBP 是一种有效且经济可行的吸附剂，可用于从水溶液中去除 Cr(6+)。
