共沉淀法合成锌铝类水滑石化合物的焙烧产物及其磷吸附

采用共沉淀法合成ZnAl类水滑石化合物,并于400℃焙烧4h,研究焙烧产物对含NaH2PO4、Na2SO4、NaNO3、NaCl的混合溶液中磷的选择性吸附行为.发现该产物表现出对磷具有高选择性,吸附量随着吸附时间的增加而增加而后趋于饱和,可达35mg.g-1,该值比采用均匀沉淀法合成的该材料的吸附量增加了1倍;且随着吸附量的增大,溶液的pH变大,验证了该体系对磷的吸附机制很可能是磷酸根与吸附剂进行表面络合.本工作提供了一条增大比表面积从而提高磷吸附量的途径,同时该合成方法简洁且产量大.

PRODUCT OF CALCINED ZINC-ALUMINIUM HYDROTALCITE-LIKE COMPOUNDS PREPARED BY COPRECIPITATION AND ITS PHOSPHATE ADSORPTION

Zinc-aluminium hydrotalcite-like compounds were prepared by co-precipitation and calcination at 400℃ for 4 h,and for the calcinated product,selective adsorption toward phosphate in an aqueous solution of NaH2PO4,Na2SO4,NaNO3,and NaCl was investigated.Data showed that it had high selective adsorption for phosphate,and adsorption increased with increasing time and reaching saturation with an phosphate uptake of 35 mg·g-1.This amount was almost double of that showed by materials prepared using homogenous precipitation method.The pH values became higher with increasing adsorptions,verifying that adsorption mechanism could be ligand complexation between phosphate and adsorbent.This work provides a route to increase phosphate-adsorption by increasing specific surface area of adsorbents,and synthesis method had the advantages of simplicity and high yield.