Mn^(2+)调控制备ZnO、ZnMn-LDHs及其对磷酸盐的吸附研究

Studies on preparation regulated by Mn^(2+)and phosphate adsorption of ZnO,ZnMn-LDHs

含磷废水的大量排放使水体富营养化,最终导致区域水质恶化。为有效去除水中的磷酸盐,以硝酸锌、硝酸锰为原料,三乙醇胺/水为溶剂体系,采用水热法合成ZnO和层状锌锰氢氧化物(ZnMn-LDHs)纳米吸附材料,利用SEM、XRD、Zeta电位仪、FT-IR对纳米材料进行表征,并考察了纳米吸附材料对磷酸盐的去除性能。结果表明:n_(Zn)∶n_(Mn)是影响ZnMn-LDHs向ZnO纳米材料转变的主要因素;ZnO和ZnMn-LDHs对磷酸根的吸附均符合Freundlich等温吸附模型及准二级动力学模型;相同条件下,ZnMn-LDHs对磷酸根的吸附性能优于ZnO;通过0.01 mol/L的NaOH脱附可实现材料的再生,6次循环利用后,ZnO和ZnMn-LDHs对磷酸根的去除率仍可达80%以上。

The discharge of phosphorus-containing wastewater has led to eutrophication of water bodies,ultimately resulting in the deterioration of regional water quality.To effectively remove phosphates from water,ZnO and lay⁃ered zinc-manganese hydroxide(ZnMn-LDHs)nano-adsorption materials were synthesized using zinc nitrate and manganese nitrate as raw materials and triethanolamine/water as the solvent system by hydrothermal method.The nano-materials were characterized by SEM,XRD,Zeta potentiometer,and FT-IR.The removal performance of nanoadsorption materials for phosphates was investigated.The results showed that the ratio of n_(Zn)to n_(Mn)was the main fac⁃tor affecting the transformation of ZnMn-LDHs to ZnO nano-materials.The adsorption of phosphate by ZnO and ZnMn-LDHs both conformed to the Freundlich isothermal adsorption model and pseudo-second-order kinetic model.Under the same conditions,the adsorption performance of ZnMn-LDHs for phosphate was better than that of ZnO.The regeneration of the materials could be achieved through desorption with 0.01 mol/L NaOH.After six cycles of utilization,the removal rates of phosphate by ZnO and ZnMn-LDHs could still reach over 80%.