Wu Deyi, Sui Yanming, He Shengbing, Wang Xinze, Li Chunjie, Kong Hainan
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No 800, Dongchuan Road, Shanghai 200240, China.
J Hazard Mater. 2008 Jul 15;155(3):415-23. doi: 10.1016/j.jhazmat.2007.11.082. Epub 2007 Nov 29.
The capability of 14 zeolites synthesized from different fly ashes (ZFAs) to sequestrate Cr(III) from aqueous solutions was investigated in a batch mode. The influence of pH on the sorption of Cr(III) was examined. ZFAs had a much greater ability than fly ash to remove Cr(III), due to the high cation exchange capacity (CEC) and the high acid neutralizing capacity (ANC) of ZFAs. The mechanism of Cr(III) removal by ZFAs involved ion exchange and precipitation. A high-calcium content in both the fly ashes and ZFAs resulted in a high ANC value and, as a result, a high immobilization capacity for Cr(III). The pH strongly influenced Cr(III) removal by ZFAs. Inside the solubility range, removal of chromium increased with increasing pH. Hydroxysodalite made from a high-calcium fly ash had a higher sorptive capacity for Cr(III) than the NaP1 zeolite from medium- and low-calcium fly ashes. On the other hand, at pH values above the solubility range, the efficiency of chromium removal by the ZFAs approached 100% due to the precipitation of Cr(OH)3 on the sorbent surfaces. It is concluded that ZFAs and high-calcium fly ashes may be promising materials for the purification of Cr(III) from water/wastewater.
采用分批处理模式研究了由不同粉煤灰（ZFAs）合成的14种沸石从水溶液中螯合Cr(III)的能力。考察了pH值对Cr(III)吸附的影响。由于ZFAs具有高阳离子交换容量（CEC）和高酸中和容量（ANC），其去除Cr(III)的能力比粉煤灰强得多。ZFAs去除Cr(III)的机制包括离子交换和沉淀。粉煤灰和ZFAs中高钙含量导致高ANC值，从而对Cr(III)具有高固定能力。pH值对ZFAs去除Cr(III)有强烈影响。在溶解度范围内，铬的去除率随pH值升高而增加。由高钙粉煤灰制成的羟基方钠石对Cr(III)的吸附能力高于中低钙粉煤灰制成的NaP1沸石。另一方面，在pH值高于溶解度范围时，由于Cr(OH)3沉淀在吸附剂表面，ZFAs去除铬的效率接近100%。得出结论，ZFAs和高钙粉煤灰可能是从水/废水中净化Cr(III)的有前途的材料。
