title: Dispersion-precipitation synthesis of nanosized magnetic iron oxide for efficient removal of arsenite in water.
abstract: Nanosized magnetic iron oxide was facilely synthesized by a dispersion-precipitation method, which involved acetone-promoted precipitation of colloidal hydrous iron oxide nanoparticles and subsequent calcination of the precipitate at 250°C. Characterization by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, nitrogen sorption, and vibrating-sample magnetometry revealed that the material was a composite of α-Fe2O3 and γ-Fe2O3 with primary particle size of 15-25 nm and specific surface area of 121 m(2)/g, as well as superparamagnetic property. The material was used as adsorbent for the removal of arsenite in water. Batch experiments showed that the adsorption isotherms at pH 3.0-11.0 fit the Langmuir equation and the adsorption obeys pseudo-second-order kinetics. Its maximum sorption capability for arsenite is 46.5 mg/g at pH 7.0. Coexisting nitrate, carbonate, sulfate, chloride, and fluoride have no significant effect on the removal efficiency of arsenite, while phosphate and silicate reduce the removal efficiency to some extent. The As(III) removal mechanism is chemisorption through forming inner-sphere surface complexes. The efficiency of arsenic removal is still maintained after five cycles of regeneration-reuse.
authors.affiliation: School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cheng
authors.affiliation: School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wu
authors.affiliation: China National Environmental Monitoring Centre, Beijing 100012, China.
authors.forename: Xiuyan
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Resources and Environmental Sciences, Hubei Key Lab of Bioresources and Environmental Biotechnologies, Wuhan University, Wuhan 430079, China. Electronic address: ljjcbacademy@163.com.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Li
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000302:isolation & purification*; D011232:Chemical Precipitation; D005290:Ferric Compounds / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; D014874:Water Pollutants, Chemical; C000499:ferric oxide; D001151:Arsenic
keywords: Adsorption; Arsenic; Iron oxide; Nanoparticle; Water purification