Guan Qingyu, Wu Deyi, Lin Yan, Chen Xuechu, Wang Xinze, Li Chunjie, He Shengbing, Kong Hainan
School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Rd., Minhang District, Shanghai, China.
J Hazard Mater. 2009 Aug 15;167(1-3):244-9. doi: 10.1016/j.jhazmat.2008.12.106. Epub 2008 Dec 31.
Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0M MgCl(2) at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na(+) and Ca(2+) with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates.
通过使用不同的NaOH/沉积物比例进行碱处理，从热处理后的沉积物中合成了沸石材料。通过XRD、FTIR、阳离子交换容量和比表面积对材料进行了表征。高NaOH/沉积物比例有利于沸石的形成。研究了沸石材料从水中保留三价铬的潜在价值。通过重复批次平衡法测定，沸石材料对Cr(III)的最大吸附量在38.9至75.8 mg/g之间，远高于热处理后的沉积物（6.3 mg/g）。在pH为7时，未观察到1.0M MgCl₂对吸附的Cr(III)有释放，但离子电解质对Cr(III)的解吸随pH降低而增加。即使在存在高浓度的Na⁺和Ca²⁺且剂量高于2.5 g/L的情况下，沸石材料也能完全从废水中去除Cr(III)。表面羟基位点的吸附和表面沉淀的形成解释了沸石材料对Cr(III)的pH依赖性解吸行为和高选择性。
