硝酸镧改性锌铝水滑石复合材料的制备及性能研究

Preparation of lanthanum nitrate modified zinc aluminum hydrotalcite and its properties

通过共沉淀法在一定温度下合成硝酸镧改性锌铝水滑石复合材料。利用XRD、SEM、FTIR等对其进行表征。采用单因素实验探究吸附磷酸盐时影响因素(初始pH、吸附反应时间、溶液初始浓度),考察了复合材料的循环吸附性能。并研究吸附动力学模型和吸附等温模型。结果表明,当pH=4,处理25 mg/L磷酸二氢钾模拟废水,吸附反应时间11 h后,该复合材料对磷酸盐的吸附量达到最大值60.4 mg/g,去除率为96%。经过3次循环再生后,该复合材料对磷酸盐的吸附量仍保持在46 mg/g以上。经拟合结果发现硝酸镧改性锌铝水滑石复合材料吸附磷酸盐符合拟二级动力学方程和Freundlich吸附等温模型。该吸附过程的吸附机理为化学吸附。

The lanthanum nitrate modified zinc-aluminum hydrotalcite composite material was synthesized at a certain temperature by co-precipitation method.The materials were characterised by XRD,SEM,FTIR.The influence of factors such as the initial pH value of the solution,the adsorption reaction time,and the initial concentration of the solution on the adsorption performance was investigated using single-factor experiments,and the cyclic regeneration performance of the adsorbent was explored.The adsorption kinetic model and adsorption isotherm model were also studied.The results showed that when pH=4,25 mg/L potassium dihydrogen phosphate simulated wastewater was treated,and the adsorption reaction time was 11 h,the adsorption capacity of the composite material for phosphate reached the maximum of 60.4 mg/g,and the removal rate was 96%.After three cycles of regeneration,the adsorption capacity of ZnAlLa hydrotalcite composite material to phosphate remained above 46 mg/g.The fitting results showed that the adsorption of phosphate by the lanthanum nitrate modified zinc-aluminum hydrotalcite composite material conforms to the pseudo-second-order kinetic equation and the Freundlich adsorption isotherm model.The adsorption mechanism of this adsorption process is chemical adsorption.