KH-Fh的制备及其对Cd(Ⅱ)的吸附性能OA

The silane coupling agent 3-aminopropyltriethoxysilane(KH550)was employed to modify ferrihydrite(Fh).KH550-modified ferrihydrite(KH-Fh)was prepared and characterized.The adsorption ability and mechanism of KH-Fh for Cd(Ⅱ)in solution were investigated.The characterization results show that—Si—OH and—NH2 functional groups are successfully introduced onto the Fh surface after KH550 modification.Cd(Ⅱ)adsorption onto KH-Fh is a spontaneous and endothermic process.The adsorption isotherms are well fitted by both the Langmuir and Freundlich models.At 25℃,the saturated adsorption capacity of KH-Fh for Cd(Ⅱ)reaches 25.77 mg/g,2.32 times that of Fh(11.10 mg/g).The adsorption kinetics are well described by the pseudo-second-order kinetic model.Cd(Ⅱ)adsorption capacity increases with high NaNO3 concentration and pH.K+shows little effect on Cd(Ⅱ)adsorption capacity.The addition of Na+significantly promotes Cd(Ⅱ)adsorption,while Ca2+slightly decreases the Cd(Ⅱ)adsorption capacity.During the process of KH-Fh-Cd(Ⅱ)adsorption,Cd(Ⅱ)can complex with Fe—OH,Si—OH,and—NH2 to form stable complexes.