采用尿素法制备高结晶度Mg-Al 水滑石(MAH), 系统研究了Mg-Al水滑石“记忆效应”及其对Cr(VI) 阴离子吸附性能的影响. 通过XRD、FT-IR、SEM、DSC以及去卷积分析对MAH、重构“记忆”MAH (RMAH)以及MAH的金属氧化物(MAO)、RMAH的金属氧化物(RMAO)进行表征分析. 结果表明, 重构的“记忆”RMAH和前体MAH均具高结晶度水滑石层状晶体结构特征, 两者晶体结构和层板电荷密度几乎无差异. MAO仍保留层状结构, 而再次重构的RMAO中MgAl2O4尖晶石晶相增多, 仍有层状结构残留. 由于水滑石强结构“记忆效应”, 使Mg-A1 LDOs(MAO和RMAO)对Cr(VI)阴离子吸附能力大大强于Mg-A1 LDHs(MAH和RMAH). MAO对Cr(VI)阴离子吸附能力高于RMAO, 可能由于RMAH焙烧形成的RMAO中MgAl2O4尖晶石含量增多及层状结构消减, 导致其“记忆效应”重构能力衰减, 从而使RMAO对Cr(VI)阴离子吸附能力下降.
Mg-Al hydrotalcite (MAH) with high crystallinity was prepared using urea method. The “memory effect” and the chromium(VI) adsorption property of Mg-Al Hydrotalcites were studied. The MAH, reconstructed MAH (RMAH), calcined MAH (MAO) and calcined RMAH (RMAO) were characterized by XRD, FT-IR, SEM and DSC as well as self-deconvolution analyses. The results showed that the MAH and RMAH possessed a layered structure of hydrotalcites with high crystallinity, and there was little difference in crystal structures and charge density of brucite-like sheets between MAH and RMAH. The brucite-like sheets were still held in MAO, and a little remained in RMAO with more MgAl2O4. The adsorbility of Mg-A1 LDOs(MAO and RMAO) to Cr(VI) anions was substantially higher than that of Mg-A1 LDHs(MAH and RMAH), mainly because of the structure “memory effect” of hydrotalcites. The adsorbility of the MAO was higher than that of the RMAO. The adsorbility decrease of the RMAO might be due to the increase of the content of spinel MgAl2O4 phase and the decline of brucite-like sheets in RMAO that resulted in the descent of the “memory effect” reconstruction property. This newly discovery for anionic clays is useful for the decontamination of waste waters. The Mg-Al hydrotalcite can be considered as a potential material for sorption of anions in wastewater treatment systems.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | 陆 军, 刘晓磊, 史文颖, 等. 水滑石类插层组装功能材料. 石油化工, 2008, 37(6): 539-547.[2] 徐淑芬, 倪哲明, 夏盛杰, 等(XU Shu-Feng, et al). Mg/Al双金属氧化物吸附Cr(VI)的动力学和热力学机理. 硅酸盐学报(Journal of the Chinese Ceramic Society), 2009, 37(5): 773-777. [3] 臧运波, 侯万国, 王文兴. (ZANG Yun-Bo, et al) Cr(VI)在Mg-Al型类水滑石上的吸附-脱附性研究I. 吸附性. 化学学报(Acta Chim Sinica), 2007, 65(9): 773-778. [4] 叶 瑛, 杨帅杰, 郑丽波, 等(YE Ying, et al). 几种层状化合物对六价铬吸附性能的对比与讨论. 无机材料学报(Journal of Inorganic Materials), 2004, 19(6): 1379-1385.[5] 邓 欣, 曾虹燕, 冯 波. 固定化脂肪酶催化制备生物柴油条件优化. 天然产物研究与开发, 2008(1): 113-116.[6] 邹长军, 张丽颖, 姚伟宁. 超强碱催化剂碱强度(H-> |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%