title: Sequestration of hexavalent chromium from aqueous solutions by activated carbon derived from Macadamia nutshells.
abstract: The purpose of this study was to investigate the feasibility of activated carbons prepared from Macadamia nutshells as an efficient adsorbent for the removal of hexavalent chromium (Cr(VI)) from aqueous solutions. The activated carbon was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), CHNS analyzer and Brunauer-Emmett-Teller (BET). For effective removal of Cr(VI), the optimum parameters found were pH 2, 120 min of contact time and 0.2 g of sorbent. The adsorption data fitted well into the Freundlich model, suggesting a multilayer sorption process. The results demonstrated that Macadamia activated carbon could be used as cost-effective biosorbent for the treatment of aqueous solutions contaminated by Cr(VI) with an adsorption capacity of 22.3 mg g-1. The mode of removal involved adsorption and reduction of Cr(VI) to Cr(III).
authors.affiliation: Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Private Bag x 021, Vanderbijlpark 1900, South Africa E-mail: vusumzip@vut.ac.za.
authors.forename: V E
authors.initials: VE
authors.lastname: Pakade
authors.affiliation: Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Private Bag x 021, Vanderbijlpark 1900, South Africa E-mail: vusumzip@vut.ac.za.
authors.forename: O B
authors.initials: OB
authors.lastname: Nchoe
authors.affiliation: Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Private Bag x 021, Vanderbijlpark 1900, South Africa E-mail: vusumzip@vut.ac.za.
authors.forename: L
authors.initials: L
authors.lastname: Hlungwane
authors.affiliation: Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa.
authors.forename: N T
authors.initials: NT
authors.lastname: Tavengwa
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D039106:Macadamia / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; D002857:Chromium; D002606:Charcoal; C074702:chromium hexavalent ion