Inorganic Chemistry Department, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
Environ Sci Pollut Res Int. 2017 Jul;24(20):16958-16970. doi: 10.1007/s11356-017-9328-3. Epub 2017 Jun 3.
Removal of cationic dye, Azur II, and anionic dye, Reactive Red 2 (RR-2) from aqueous solutions, has been successfully achieved by using a modified agricultural biomaterial waste: cocoa shell husk (Theobroma cacao) treated by gliding arc plasma (CPHP). The biomass in its natural form CPHN and modified form CPHP was characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and point of zero charge (pH). Experimental variables such as initial pH, contact time, and temperature were optimized for adsorptive characteristics of CPHN and CPHP. The results show that the removal of the Azur II dye was favorable in the basic pH region (pH 10) while the Reactive Red 2 dye was favorable in the acidic pH region (pH 2). The minimum equilibrium time for Azur II and RR-2 dye was obtained after 40 and 240 min, respectively. The adsorption kinetics and isotherm data obtained were best described by a pseudo-second-order kinetic rate model and a combination of Langmuir-Freundlich isotherm models. This work indicates that the plasma-treated raw materials are good alternative multi-purpose sorbents for the removal of many coexisting pollutants from aqueous solutions.
采用滑动弧等离子体（CPHP）处理的可可壳（Theobroma cacao）农业生物材料废料成功实现了从水溶液中去除阳离子染料亚甲蓝（Azur II）和阴离子染料活性红 2（RR-2）。天然形式的生物质 CPHN 和改性形式的 CPHP 用红外光谱（FTIR）、热重分析（TGA）、扫描电子显微镜（SEM）和零电荷点（pH）进行了表征。实验变量，如初始 pH 值、接触时间和温度，优化了 CPHN 和 CPHP 的吸附特性。结果表明，Azur II 染料的去除在碱性 pH 区域（pH 10）是有利的，而 RR-2 染料在酸性 pH 区域（pH 2）是有利的。分别在 40 和 240 min 后获得了 Azur II 和 RR-2 染料的最小平衡时间。获得的吸附动力学和等温线数据最好由伪二阶动力学速率模型和 Langmuir-Freundlich 等温线模型的组合来描述。这项工作表明，等离子体处理的原材料是从水溶液中去除许多共存污染物的良好替代多用途吸附剂。
