Defluorination performance of lanthanum and zirconium modified aluminum hydroxide in zinc sulfate electrolyte
To address the problems of poor fluoride removal effect and low adsorption capacity of industrial adsorbents,a mesoporous Al-La-Zr composite adsorption material was prepared by co-precipitation method to effectively remove fluoride ions in zinc sulfate solution.Firstly,the effects of the type and proportion of doped metals on the fluoride removal rate were investigated,and the optimum doping ratio was obtained.Secondly,the adsorbent was characterized by BET,XRD and SEM to understand the main phase,specific surface area and morphology of the adsorbent.Thirdly,the effects of adsorbent dosage,adsorption temperature,contact time and pH on adsorption efficiency and adsorption capacity were studied,and the process optimization conditions were determined.Finally,the adsorption mechanism of mesoporous Al-La-Zr composite adsorbent was further revealed by kinetic and thermodynamic analysis of the adsorption process and the characterization results of the adsorbent before and after adsorption.The results show that the main phase of the material is Al(OH)3.The surface of the material has rich pore structure,which is conducive to improving the specific surface area of the material(127.16 m2/g)and increasing the adsorption capacity.When the adsorption temperature is 30℃,the pH is 4.7,the adsorption time is 3 h,the adsorbent dosage is 5 g/L,the adsorption equilibrium defluorination efficiency is 78.32%,and the equilibrium capacity is 15.66 mg/g.The adsorption process conforms to the pseudo-second-order kinetic model.The linear Freundlich can well describe the adsorption isotherm,and the adsorption process is a spontaneous exothermic process.The adsorption mechanism involves ion exchange,electrostatic adsorption and metal complexation of fluorine.
万方数据
维普
