| Layered Double Hydroxides (LDH) have peculiar structure and properties , so they have become an important class of inorganic functional materials with applications in the fields of adsorption, ion exchange, catalysis and functional materials and have attracted considerable attention at home and overseas.This thesis relates to a systemic study on the preparation of Mg/Al-LDH, and discusses the feasibility of preparation LDH by the wastewater of acid activated palgorskite clay and the effect of removing Cr (VI) in Cr(VI)-bearing Wastewate by using in-situ synthesized LDH. A preliminary investigation has also been carried out on the relationship between the composition, the structure and the property of adsorption Cr(â…¥) of the products thereby obtained.We have systemically investigated the dependence of synthesis LDH on such reaction as pH value, temperature, Mg/Al molar ration by orthogonal experiments. The results show that, by controlling the reaction conditions, a series of Mg/Al-LDH can be successfully obtained. We can synthesize LDH using the wastewater of acid activated palygorskite clay, and which has a outstanding adsorption capability to Cu(â…¥). The removal efficiency of Cr(â…¥) is very high by using the method of in-situ synthesized LDH and the maximal removal efficiency of Cr(â…¥) can be reached when pH values are between 8.5 and 9, Mg/Al ratios are between 1:1 and 2:1 and reaction temperature are 60 C, Meanwhile, the use of Mg and Al at the optimized conditions is also very efficient.The crystal structure and outward appearance, IR property and thermal stability of Mg/Al-LDH, synthesized LDH using the wastewater of acid activated palygiwskite clay and synthesized LDH by the in-situ method have been studied by XRD, FT-IR and TEM. The results show that, by controlling the reaction conditions, the outcomes have similar crystal appearances to LDH, with a high degree of anion exchange. The thermal stability of synthesized LDH varies regularly when LDH is calcined.
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