title: Application of a new adsorbent for fluoride removal from aqueous solutions.
abstract: Hydrous bismuth oxides (HBOs) have been investigated as a possible adsorbent for fluoride removal from water. Apart from bismuth trioxide (Bi2O3) compound, three additional HBOs, named as HBO1, HBO2, and HBO3 were synthesized in the laboratory and examined for their relative potentials for fluoride removal from aqueous solutions. HBO1 was observed to have highest fluoride removal at 10mg/L initial concentration in aqueous environment. Among competitive anions, sulfate and chloride affect the fluoride removal by HBO1 more adversely than bicarbonate. Characterization of HBOs using X-ray diffraction (XRD) pattern analyses indicated crystalline structures, and the broad chemical composition of materials showed successive increase of Bi(OH)3 from HBO1 to HBO3, with decrease of BiOCl in the same order. Fourier Transform Infrared (FTIR) spectroscopy analyses indicated presence of Bi-O bond and successively increasing number of peaks corresponding to OH ion from HBO1 to HBO3. Scanning Electron Microscopic (SEM) images of HBOs show rough and porous structure of the materials. Presence of higher proportion of chloride compound in HBO1 with respect to others appears to be the factor responsible for its better performance in fluoride removal from aqueous solutions.
authors.affiliation: Department of Applied Chemistry, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
authors.forename: Arun Lal
authors.initials: AL
authors.lastname: Srivastav
authors.forename: Prabhat K
authors.initials: PK
authors.lastname: Singh
authors.forename: Varsha
authors.initials: V
authors.lastname: Srivastava
authors.forename: Yogesh C
authors.initials: YC
authors.lastname: Sharma
mesh_terms: D000327:Adsorption; D000838:Anions; D001729:Bismuth / Q000737:chemistry*; D003460:Crystallization; D060766:Drinking Water / Q000737:chemistry; D004566:Electrodes; D005459:Fluorides / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D000838:Anions; D060766:Drinking Water; D007477:Ions; D014874:Water Pollutants, Chemical; D014867:Water; C033301:bismuth oxide; D005459:Fluorides; D001729:Bismuth
keywords: FTIR; Fluoride removal; Hydrous bismuth oxides; Isotherms; Kinetic studies; SEM; XRD