Faghihian H, Bowman Robert S
Department of Chemistry, University of Isfahan, Darvazehshiraz, Isfahan, Iran New Mexico Institute of Mining and Technology, Socorro NM 87801-4796, USA.
Water Res. 2005 Mar;39(6):1099-104. doi: 10.1016/j.watres.2004.12.010.
Unmodified zeolite surfaces show no affinity for anions, due to the fact that zeolites are negatively charged. Thus, adsorption of anions by zeolites has not been given much attention. In this work, after modification of clinoptilolite by different cations, the mineral was found to adsorb a considerable amount of the divalent anion chromate. Chromate adsorption was proportional to the K(sp) of the chromate precipitate and the amount of the exchangeable cation. The amount of chromate adsorbed was maximized when the Pb-exchanged form was used. Chromate desorption in deionized water indicated that between 2.50% and 18.60% of the adsorbed chromate was released depending upon the exchangeable cation. Some of the exchanged forms are candidate materials for adsorption and immobilization of chromate.
未改性的沸石表面对阴离子没有亲和力，因为沸石带负电荷。因此，沸石对阴离子的吸附没有得到太多关注。在这项工作中，用不同阳离子对斜发沸石进行改性后，发现该矿物能吸附大量的二价阴离子铬酸盐。铬酸盐的吸附与铬酸盐沉淀物的K(sp)以及可交换阳离子的量成正比。当使用铅交换形式时，铬酸盐的吸附量最大。在去离子水中的铬酸盐解吸表明，根据可交换阳离子的不同，2.50%至18.60%的吸附铬酸盐会被释放。一些交换形式是吸附和固定铬酸盐的候选材料。
