title: Mechanism of hexavalent chromium removal by dead fungal biomass of Aspergillus niger.
abstract: When synthetic wastewater containing Cr(VI) was placed in contact with the dead fungal biomass of Aspergillus niger, the Cr(VI) was completely removed from aqueous solution, whereas Cr(III), which was not initially present, appeared in aqueous solution. Desorption and X-ray photoelectron spectroscopy (XPS) studies showed that most of the Cr bound on the biomass was in trivalent form. These results indicated that the main mechanism of Cr(VI) removal was a redox reaction between Cr(VI) and the dead fungal biomass, which is quite different from previously reported mechanisms. The influences of contact time, pH, Cr(VI) concentration, biomass concentration and temperature on Cr(VI) removal were also evaluated. The Cr(VI) removal rate increased with a decrease in pH and with increases in Cr(VI) concentration, biomass concentration and temperature. Although removal kinetics was dependent on the experimental conditions, Cr(VI) was completely removed in the aqueous solution. In conclusion, a new mechanism of Cr(VI) removal by the dead fungal biomass has been proposed. From a practical viewpoint, this abundant and inexpensive dead fungal biomass has potential application in the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).
authors.affiliation: Advanced Environmental Biotechnology Research Center, Department of Chemical Engineering, School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang, Republic of Korea.
authors.forename: Donghee
authors.initials: D
authors.lastname: Park
authors.forename: Yeoung-Sang
authors.initials: YS
authors.lastname: Yun
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Jo
authors.forename: Jong Moon
authors.initials: JM
authors.lastname: Park
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D002274:Carcinogens, Environmental / Q000302:isolation & purification; D002857:Chromium / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D013995:Time; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D002274:Carcinogens, Environmental; D002857:Chromium; C074702:chromium hexavalent ion