Nishino Anzu, Taki Ayane, Asamoto Hiromichi, Minamisawa Hiroaki, Yamada Kazunori
Major of Applied Molecular Chemistry, Graduate School of Industrial Technology, Nihon University, 1-2-1 Izumi-cho, Narashino, Chiba 275-8575, Japan.
Department of Basic Science, College of Industrial Technology, Nihon University, 2-11-1 Shin-ei, Narashino, Chiba 275-8576, Japan.
Polymers (Basel). 2022 May 21;14(10):2104. doi: 10.3390/polym14102104.
The hexavalent chromium (Cr(VI)) ion adsorption properties were conferred to porous silica beads by introducing alkylamine chains through functionalization with an aminosilane coupling agent, [3-(2-aminoethylamino)propyl]triethoxysilane (AEAPTES), or with an epoxysilane coupling agent, (3-glycidyloxypropyl)triethoxysilane (GOPTES), and polyfunctional amine compounds or poly-ethylenimines (PEIs). The presence of amino groups on the silica beads was confirmed by XPS and the amount of amino groups increased to 0.270 mmol/g by increasing the AEAPTES concentration and/or reaction time. The adsorption capacity of the silica beads functionalized with AEAPTES was the maximum at the initial pH value of 3.0 and the initial adsorption rate increased with an increase in the temperature. The adsorption capacity increased with an increase in the amount of amino groups at pH 3.0 and 30 °C. The adsorption behavior obeyed the pseudo-second order kinetic model and was well expressed by the Langmuir isotherm. These results support that Cr(VI) ion adsorption is accomplished through the electrostatic interaction between protonated amino groups and HCrO ions. In addition, the adsorption capacity further increased to 0.192-0.320 mmol/g by treating the GOPTES-treated silica beads with triethylenetetramine, pentaethylenehexamine, or PEI. These empirical, equilibria, and kinetic aspects obtained in this study support that the porous silica-based adsorbents prepared in this study can be applied to the removal of Cr(VI) ions.
通过用氨基硅烷偶联剂[3-(2-氨基乙基氨基)丙基]三乙氧基硅烷（AEAPTES）或环氧硅烷偶联剂(3-缩水甘油氧基丙基)三乙氧基硅烷（GOPTES）以及多官能胺化合物或聚乙烯亚胺（PEIs）进行官能化，将烷基胺链引入多孔硅胶珠中，从而赋予其六价铬（Cr(VI)）离子吸附性能。通过XPS证实了硅胶珠上氨基的存在，并且通过增加AEAPTES浓度和/或反应时间，氨基的量增加到0.270 mmol/g。用AEAPTES官能化的硅胶珠的吸附容量在初始pH值为3.0时最大，并且初始吸附速率随温度升高而增加。在pH 3.0和30°C下，吸附容量随氨基量的增加而增加。吸附行为符合准二级动力学模型，并且用Langmuir等温线能很好地表示。这些结果表明，Cr(VI)离子吸附是通过质子化氨基与HCrO离子之间的静电相互作用实现的。此外，通过用三乙烯四胺、五乙烯六胺或PEI处理经GOPTES处理的硅胶珠，吸附容量进一步增加到0.192 - 0.320 mmol/g。本研究中获得的这些经验、平衡和动力学方面的结果表明，本研究中制备的多孔硅胶基吸附剂可用于去除Cr(VI)离子。
