title: Removal of chromium from aqueous solutions by diatomite treated with microemulsion.
abstract: In order to evaluate the sorption of heavy metals, a crude diatomite was impregnated with a microemulsion which showed remarkable increase in chromium sorption capacity as compared to untreated diatomite. Samples with two different granulometries were investigated, both yielding practically complete adsorption. The adsorption process is pH dependent and the best results for the initial Cr (III) concentration of 1.5 g/L were obtained at pH 2.95. The effect of the concentration of the chromium synthetic solution was also investigated. The adsorption isotherms were obtained (30. 40 and 50 degrees C) and the Freundlich and Langmuir models were used to determine the adsorption capacity of the adsorbent. Following the adsorption step, a desorption process was carried out using several eluant solutions. The best results were obtained using hydrochloric acid (100%) as eluant.
authors.affiliation: Universidade Federal do Rio Grande do Norte, UFRN/PPGEQ, Natal/RN, Brazil. tereza@linus.quimica.ufrn.br
authors.forename: T N
authors.initials: TN
authors.lastname: Dantas
authors.forename: A A
authors.initials: AA
authors.lastname: Dantas Neto
authors.forename: M C
authors.initials: MC
authors.lastname: Moura
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000302:isolation & purification*; D003300:Copper / Q000302:isolation & purification; D007692:Diatomaceous Earth; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D009532:Nickel / Q000302:isolation & purification; D010316:Particle Size; D012996:Solutions; D014865:Waste Disposal, Fluid / Q000379:methods; D014867:Water; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D004655:Emulsions; D007220:Industrial Waste; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; D007692:Diatomaceous Earth; C033787:diatomite; D003300:Copper; D009532:Nickel