title: Removal of fluoride from aqueous media by Fe3O4@Al(OH)3 magnetic nanoparticles.
abstract: A novel magnetic nanosized adsorbent using hydrous aluminum oxide embedded with Fe(3)O(4) nanoparticle (Fe(3)O(4)@Al(OH)(3) NPs), was prepared and applied to remove excessive fluoride from aqueous solution. This adsorbent combines the advantages of magnetic nanoparticle and hydrous aluminum oxide floc with magnetic separability and high affinity toward fluoride, which provides distinctive merits including easy preparation, high adsorption capacity, easy isolation from sample solutions by the application of an external magnetic field. The adsorption capacity calculated by Langmuir equation was 88.48 mg g(-1) at pH 6.5. Main factors affecting the removal of fluoride, such as solution pH, temperature, adsorption time, initial fluoride concentration and co-existing anions were investigated. The adsorption capacity increased with temperature and the kinetics followed a pseudo-second-order rate equation. The enthalpy change (Delta H(0)) and entropy change (DeltaS(0)) was 6.836 kJ mol(-1) and 41.65 J mol(-1)K(-1), which substantiates the endothermic and spontaneous nature of the fluoride adsorption process. Furthermore, the residual concentration of fluoride using Fe(3)O(4)@Al(OH)(3) NPs as adsorbent could reach 0.3 mg L(-1) with an initial concentration of 20 mg L(-1), which met the standard of World Health Organization (WHO) norms for drinking water quality. All of the results suggested that the Fe(3)O(4)@Al(OH)(3) NPs with strong and specific affinity to fluoride could be excellent adsorbents for fluoride contaminated water treatment.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhao
authors.forename: Jieming
authors.initials: J
authors.lastname: Wang
authors.forename: Fengchang
authors.initials: F
authors.lastname: Wu
authors.forename: Thanh
authors.initials: T
authors.lastname: Wang
authors.forename: Yaqi
authors.initials: Y
authors.lastname: Cai
authors.forename: Yali
authors.initials: Y
authors.lastname: Shi
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry*; D002852:Chromatography, Ion Exchange; D004574:Electromagnetic Fields; D005290:Ferric Compounds / Q000737:chemistry*; D005459:Fluorides / Q000302:isolation & purification*; D007202:Indicators and Reagents; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles; D010316:Particle Size; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014881:Water Supply / Q000032:analysis; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D007202:Indicators and Reagents; D014874:Water Pollutants, Chemical; C000499:ferric oxide; D000536:Aluminum Hydroxide; D005459:Fluorides