College of Resources and Environmental Sciences, University of Jinan, Jinan 250022, PR China.
J Hazard Mater. 2010 Jul 15;179(1-3):244-50. doi: 10.1016/j.jhazmat.2010.02.086. Epub 2010 Mar 3.
Phosphorus removal is important for the control of eutrophication, and adsorption is an efficient treatment process. In this study, three modified inorganic-bentonites: hydroxy-aluminum pillared bentonite (Al-Bent), hydroxy-iron pillared bentonite (Fe-Bent), and mixed hydroxy-iron-aluminum pillared bentonite (Fe-Al-Bent), were prepared and characterized, and their phosphate adsorption capabilities were evaluated in batch experiments. The results showed a significant increase of interlayer spacing, BET surface area and total pore volume which were all beneficial to phosphate adsorption. Phosphate adsorption capacity followed the order: Al-Bent>Fe-Bent>Fe-Al-Bent. The adsorption rate of phosphate on the adsorbents fits pseudo-second-order kinetic models (R(2)=1.00, 0.99, 1.00, respectively). The Freundlich and Langmuir models both described the adsorption isotherm data well. Thermodynamic studies illustrated that the adsorption process was endothermic and spontaneous in nature. Finally, phosphate adsorption on the inorganic pillared bentonites significantly raised the pH, indicating an anion/OH(-) exchange reaction.
除磷对于控制富营养化非常重要，而吸附是一种有效的处理工艺。本研究制备并表征了三种改性无机膨润土：羟基铝柱撑膨润土（Al-Bent）、羟基铁柱撑膨润土（Fe-Bent）和混合羟基铁铝柱撑膨润土（Fe-Al-Bent），并通过批量实验评估了它们对磷酸盐的吸附能力。结果表明，层间距、BET 表面积和总孔体积均显著增加，这都有利于磷酸盐的吸附。磷酸盐吸附容量的顺序为：Al-Bent＞Fe-Bent＞Fe-Al-Bent。磷酸盐在吸附剂上的吸附速率符合准二级动力学模型（分别为 R(2)=1.00、0.99、1.00）。Freundlich 和 Langmuir 模型均很好地描述了吸附等温线数据。热力学研究表明，吸附过程本质上是吸热和自发的。最后，无机柱撑膨润土对磷酸盐的吸附显著提高了 pH 值，表明存在阴离子/OH(-)交换反应。
