title: Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its ion-association complex with cetyltrimethylammoniumbromide on an alumina column.
abstract: A simple approach has been developed for the solid phase extraction of chromium(VI) based on the adsorption of its ion-association complex with cetyltrimethylammoniumbromide (CTABr) on an alumina column. The effect of various parameters such as acidity, stability of the column, sample volume, effect of diverse ions, etc. have been studied in detail. The adsorbed complex could be eluted using sodium hydroxide and the concentration of chromium has been established using visible spectrophotometry after complexation with diphenyl carbazide. The calibration graph was linear in the range 0-0.5 microg mL(-1) chromium(VI) with a detection limit of 5 microg L(-1). A highest preconcentration factor of 25 could be obtained for 250 mL sample volume. The data from the column studies were also studied using the Thomas model of adsorption. The experimental results obtained were correlated with the proposed model of adsorption. The Thomas rate constant k was found to be 0.0025 L/min mg and the maximum adsorption capacity q(o) was found to be 0.36 mgCr/g alumina at an initial chromium(VI) concentration of 1 mg L(-1). The validity of the method has been checked by applying it to study the recovery of chromium in spiked water samples and electroplating wastewater.
authors.affiliation: Department of Chemistry, Birla Institute of Technology and Science, Pilani 333031, India. rajesh@bits-pilani.ac.in
authors.forename: N
authors.initials: N
authors.lastname: Rajesh
authors.forename: B
authors.initials: B
authors.lastname: Deepthi
authors.forename: Archana
authors.initials: A
authors.lastname: Subramaniam
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D004595:Electroplating; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D012972:Sodium Hydroxide / Q000737:chemistry; D052616:Solid Phase Extraction; D012996:Solutions; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D002593:Cetrimonium Compounds; D007220:Industrial Waste; D012996:Solutions; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D012972:Sodium Hydroxide; D000537:Aluminum Oxide; D000077286:Cetrimonium