title: Adsorption of Cd(II) and Pb(II) by in situ oxidized Fe3O4membrane grafted on 316L porous stainless steel filter tube and its potential application for drinking water treatment.
abstract: Removing heavy metal ions from aqueous solutions is one of the most challenging separations. In situ oxidized Fe3O4membranes using 316L porous stainless steel filter tube have shown great potential for removing anion Cr(VI). Here we report the performances of the in situ oxidized Fe3O4membranes for removing two toxic cations Cd(II) and Pb(II) commonly existing in water and their potential applications for drinking water purification. The membranes exhibited high removal efficiency: 97% at pH 9.0 for Cd(II) of 1.0 mg/L initial concentration and 100% at pH 5.0-6.0 for Pb(II) of 5.0 mg/L initial concentration. The maximum adsorption capabilities were estimated at 0.800 mg/g and 2.251 mg/g respectively for Cd(II) and Pb(II) at 318 K by the Langmuir model. Results of batch tests revealed the existence of electrostatic attraction and chemisorption. XRD and FT-IR analyses indicated that the chemisorption might be the insertion of Cd(II) and Pb(II) into the Fe3O4crystal faces of 311 and 511 to form mononuclear or binuclear coordination with O atoms of Fe-O6groups. Competitive adsorption of Cd(II) and Pb(II) in binary solutions revealed a preferential adsorption for Pb(II). Na2EDTA solution was used to regenerate the membranes, and the maximum desorption ratio was 90.29% and 99.75% respectively for Cd(II) and Pb(II). The membranes were able to efficiently lower Cd(II) and Pb(II) concentrations to meet the drinking water standards recommended by the World Health Organization and are promising for engineering applications aimed at drinking water purification.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Mengfei
authors.initials: M
authors.lastname: Zhu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhu
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Tianli
authors.initials: T
authors.lastname: Yue
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China. Electronic address: steveli@nwsuaf.edu.cn.
authors.forename: Zhonghong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000327:Adsorption; D002104:Cadmium; D006863:Hydrogen-Ion Concentration; D007854:Lead; D017550:Spectroscopy, Fourier Transform Infrared; D013193:Stainless Steel; D014874:Water Pollutants, Chemical; D018508:Water Purification
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D013193:Stainless Steel; D007854:Lead
keywords: Adsorption; Adsorption mechanism; Competitive adsorption; Heavy metal; Inorganic membrane; Membrane separation