| Vermiculite and layered double hydroxide(LDH),both layered structure with variable materials,attracted much attention of researchers in recent years,due to its advantages of surface adsorption,environmental friendly,high adsorption capacity.In this paper,we synthesized and characterized three kinds of functional materials including magnetic vermiculite(MVER),sodium carboxymethylcellulose intercalated hydrotalcite(CMC-LDH)and calcinations of CMC-LDH(R/CMC-LDH),and used to remove Pb(II)from aqueous solution by batch adsorption experiments.Based on the adsorption properties of the three kinds of adsorption materials,the development and application of the adsorption materials for Pb(II)were investigated.The results were as follows:(1)The MVER,CMC-LDH and R/CMC-LDH were prepared via a facile one-pot solvothermal method,low saturation coprecipitation method and calcination method,respectively.The VER and MVER were characterized by XRD(X-ray diffraction),SERS(surface-enhanced Raman scattering),FTIR(Fourier transform infrared)spectroscopy,SEM(Scanning electron microscopy),TEM(transmission electron microscope)and Zeta potential.The CMC-LDH and R/CMC-LDH were characterized by XRD(X-ray diffraction),FTIR(Fourier transform infrared),BET(Brunner-Emmet-Teller)measurements and XPS(X-ray photoelectron spectroscopy).The results showed that the three kinds of materials have good lamellar structure,large specific surface area and good physical and chemical properties.(2)Batch equilibrium experiments were conducted to study the Pb(II)adsorption performance onto the MVER and VER.The saturated adsorption capacities were 37.0 mg/g and 70.4 mg/g for 20 m L 100 mg/L solution of Pb(II),respectively at the conditions of 0.05 g MVER and 0.12 g VER,the contact time of 20 min.The adsorption kinetics fit the pseudo-second order kinetic models well and isotherms correspond to Langmuir model strictly.The MVER and VER were reused for five times,and the adsorption rateio of Pb(II)were all kept above 85%,suggested that the VER and MVER had relatively good reusability for Pb(II)removal from aqueous solution.And the powdered adsorbents can be quickly and easily separated from the solution under magnetic field.(3)Batch equilibrium experiments were conducted to study the Pb(II)adsorption performance onto the CMC-LDH and R/CMC-LDH.the saturated adsorption capacities were 196 mg/g and 333 mg/g for 20 mL 500 mg/L solution of Pb(II),respectively conditions of 0.07 g CMC-LDH,0.03 g R/CMC-LDH,and the contact time of 60 min.The adsorption kinetics fit the pseudo-second order kinetic models well and isotherms correspond to Langmuir model strictly. |
