title: Rapid and efficient removal/recovery of molybdenum onto ZnFe2O4 nanoparticles.
abstract: An efficient method for removing and recovering molybdenum (Mo) from water was developed by using ZnFe2O4 nanoparticles. The Mo adsorption displayed a nonlinear isotherm that fitted well with the Langmuir isotherm, showing limited adsorption sites on the surface of ZnFe2O4. The adsorption of Mo(VI) was dependent on solution pH. With increasing pH, the build-up of negative charges of both adsorbent and adsorbate led to enhanced electric repulsion between them. The K-edge XANES spectra for the adsorbents collected after Mo adsorption revealed that Mo(VI) was the predominant oxidation state sorbed on ZnFe2O4, indicating that the reduction of Mo(VI) did not occur on ZnFe2O4. The different peak positions of k-space and R-space shown in K-edge EXAFS spectra demonstrated that the adsorbed Mo could be bound on the surface or be slipped in the vacancy position of the ZnFe2O4 crystal. Importantly, Mo could be efficiently adsorbed from photoelectric industrial wastewater and these adsorbed Mo anions were rapidly replaced by OH(-) ions, implying the potential for Mo removing and recovering in industrial wastewater.
authors.affiliation: Institute of Urban Study, Shanghai Normal University, No. 100, Guilin Rd., Shanghai 200234, China. Electronic address: todojen@163.com.
authors.forename: Yao-Jen
authors.initials: YJ
authors.lastname: Tu
authors.affiliation: National Synchrotron Radiation Research Center (NSRRC), No 101, Hsin-Ann Road, Hsincho 30076, Taiwan. Electronic address: chan.ts@nsrrc.org.tw.
authors.forename: Ting-Shan
authors.initials: TS
authors.lastname: Chan
authors.affiliation: National Synchrotron Radiation Research Center (NSRRC), No 101, Hsin-Ann Road, Hsincho 30076, Taiwan.
authors.forename: Hao-Wei
authors.initials: HW
authors.lastname: Tu
authors.affiliation: Department of Agricultural Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Shan-Li
authors.initials: SL
authors.lastname: Wang
authors.affiliation: Earth Dynamic System Research Center, National Cheng-Kung University, No. 1, University Road, Tainan City 701, Taiwan; Department of Earth Sciences, National Cheng-Kung University, No. 1, University Road, Tainan City 701, Taiwan.
authors.forename: Chen-Feng
authors.initials: CF
authors.lastname: You
authors.affiliation: Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Science, No. 415, Chien Kung Road, Kaohsiung 807, Taiwan.
authors.forename: Chien-Kuei
authors.initials: CK
authors.lastname: Chang
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D007220:Industrial Waste; D008982:Molybdenum / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D015032:Zinc / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D007220:Industrial Waste; D008982:Molybdenum; D062065:Wastewater; D014874:Water Pollutants, Chemical; D015032:Zinc
keywords: EXAFS; Kinetics and isotherms; Molybdenum; XANES; ZnFe(2)O(4)