【摘要】 用共沉淀法合成了n(Mg)/n(Al)为2∶1的水滑石,通过在500℃下焙烧得到了其焙烧产物。研究了反应时间、pH及磷酸根浓度对磷酸根在水滑石及其焙烧产物上吸附量的影响。结果表明,水滑石对磷的吸附容量小于其焙烧产物,其吸附等温线都可以用Freundlich等温方程描述。在磷酸根浓度较低时(<0.05mmol/L),水滑石及其焙烧产物都可作为磷的高效吸附剂;当磷的浓度大于0.05mmol/L时,水滑石不能作为磷的高效吸附剂,但当磷酸根浓度在0.05～2.5mmol/L时,其焙烧产物仍可作为磷的高效吸附剂。在酸性环境下,水滑石及其焙烧产物在对阴离子的吸附过程中都有中和酸性溶液的作用。水滑石及其焙烧产物对磷的吸附具有不同的机理,并得到了X射线衍射的证实。更多还原

【Abstract】 In the present study, some hydrotalcite clays with a Mg/Al molar ratio of 2∶1 were synthesized using the co-precipitation method, and parts of the synthesized clays were calcined under 500 ℃ to obtain the corresponding mixed Mg-Al oxides. The influences of reaction time, pH,and the concentrations of phosphate on the adsorption of phosphate on hydrotalcite and its calcined products were studied. The results showed that the adsorption of phosphate on both hydrotalcite and its calcined products follows the Freundlich isotherm, and the sorption capacity of the former is much lower than that of the latter. Hydrotalcite is a highly efficient adsorbent for phosphate only when the concentrations of P are as low as 0.05 mmol/L. However, when the concentrations of P are higher than 0.05 mmol/L, the calcined product of hydrotalcite is a highly efficient adsorbent when the concentrations of P are as high as 2.5 mmol/L. In acidic aquatic environment, hydrotalcite and its calcined product can also play a role in neutralizing H⁺ions and sorbing anions. The mechanisms of phosphate sorption on hydrotalcite and its calcined product are different, which has been confirmed by X-ray diffraction examination.更多还原