Mg-Al水滑石的改性机理和吸附性能  

Modification Mechanism of Mg-Al Hydrotalcites and Adsorption Performance

作　　者：张伟[1] 曾虹燕[1] 杨永杰[1] 肖华淼[1] 魏英民[1] 廖梦尘[1] 徐圣[1] 

机构地区：[1]湘潭大学化工学院,湘潭411105

出　　处：《材料研究学报》2012年第4期437-442,共6页Chinese Journal of Materials Research

基　　金：湖南省自科基金重点项目09JJ3021;12JJ2011;湖南省大学生创新性实验计划121253021资助项目~~

摘　　要：用硫酸铵对镁铝水滑石进行改性,研究了镁铝水滑石的溶解性及硫酸铵的改性机理。结果表明,镁铝水滑石在pH 1.0-11.0范围内呈现出完全溶解、部分溶解和基本不溶三种溶解特性。硫酸铵的改性即为镁铝水滑石的部分溶解过程,层板中镁以Mg^(2+)形态进入溶液,导致羟基铝(Al(OH)_6^(3-))进入溶液形成Keggin结构(Al_(13)聚集体),Al_(13)聚集体附着在镁铝水滑石层板表面形成无定形Al(OH)_3,从而阻止镁离子进一步溶出。改性镁铝水滑石对Pb^(2+)的吸附率提高了18.3%,是比表面积的增加、化学键合及静电吸附能力的提升所致。The modified Mg-Al hydrotalcite was prepared by using （NHa）2SO4 and characterized by XRD, FT-IR, SEM and EDS. The aqueous solubility and modified mechanism of Mg-Al hydrotalcite have been investigated. The results show that the solubility of Mg-Al hydrotalcite can be divided mainly into three dissolution behaviors： no solubility, partical and complete solubility. The modification of Mg-Al hydrotalcite is the partical dissolution process. In the corrosion of the Mg-Al hydrotalcite, Mg ions were dissoved from the brucite-like sheets and led Al ions into the reaction solution. Aquated ions Al（OH）3- in the solution aggregated to form Keggin structure Al13 cluster. The Al13 cluster was adsorbed rapidly on the surface of the sheets, and then formed amorphous Al（OH）3 which prevented the further solution of Mg ions from the sheet. The absorption performation on Pb2＋ was improved, and Pb2＋ removal rate of the modified products is raised by 18.3%. The improved adsoption property is mainly due to the increase of specific surface erea, chemical bonding and electrostatic adsorption ability.

关 键 词：无机非金属材料 镁铝水滑石 吸附 酸溶过程 

分 类 号：TB321[一般工业技术—材料科学与工程] TQ424[化学工程]