Wang Shaobin, Zhu Z H
Department of Chemical Engineering, Curtin University of Technology, G.P.O. Box U1987, Perth, WA 6845, Australia.
J Hazard Mater. 2006 Aug 25;136(3):946-52. doi: 10.1016/j.jhazmat.2006.01.038. Epub 2006 Feb 28.
An Australian natural zeolite was collected, characterised and employed for basic dye adsorption in aqueous solution. The natural zeolite is mainly composed of clinoptiloite, quartz and mordenite and has cation-exchange capacity of 120 meq/100g. The natural zeolite presents higher adsorption capacity for methylene blue than rhodamine B with the maximal adsorption capacity of 2.8 x 10(-5) and 7.9 x 10(-5)mol/g at 50 degrees C for rhodamine B and methylene blue, respectively. Kinetic studies indicated that the adsorption followed the pseudo second-order kinetics and could be described as two-stage diffusion process. The adsorption isotherm could be fitted by the Langmuir and Freundlich models. Thermodynamic calculations showed that the adsorption is endothermic process with Delta H(0) at 2.0 and 8.7 kJ/mol for rhodamine B and methylene blue. It has also found that the regenerated zeolites by high-temperature calcination and Fenton oxidation showed similar adsorption capacity but lower than the fresh sample. Only 60% capacity could be recovered by the two regeneration techniques.
收集了一种澳大利亚天然沸石，对其进行了表征，并将其用于水溶液中碱性染料的吸附。该天然沸石主要由斜发沸石、石英和丝光沸石组成，阳离子交换容量为120 meq/100g。该天然沸石对亚甲基蓝的吸附容量高于罗丹明B，在50℃时，对罗丹明B和亚甲基蓝的最大吸附容量分别为2.8×10(-5)和7.9×10(-5)mol/g。动力学研究表明，吸附遵循准二级动力学，可描述为两阶段扩散过程。吸附等温线可用Langmuir和Freundlich模型拟合。热力学计算表明，吸附是吸热过程，罗丹明B和亚甲基蓝的ΔH(0)分别为2.0和8.7 kJ/mol。还发现，通过高温煅烧和芬顿氧化再生的沸石显示出相似的吸附容量，但低于新鲜样品。两种再生技术只能恢复60%的容量。
