Sorption of chromium(VI) from aqueous solution by cassava (Manihot sculenta Cranz.) waste biomass.
The sorption of highly toxic Cr(VI) ions by cassava waste biomass was quantitatively investigated. The sorption was found to be influenced by several physico-chemical factors such as agitation speed, temperature, contact time, pH, and sorbent/sorbate ratio. The adsorption data at equilibrium were fitted to Freundlich and Langmuir isotherms. The monolayer sorption capacity was found to be 61.79 mg of Cr(VI) per gram of biomass. The kinetics of Cr(VI) adsorption to pure cassava-tuber-bark wastes were determined based on a pseudo-second-order-rate model using the batch-sorption technique at a temperature of 30 degrees. The kinetics data suggest that the adsorption process is exothermic, and that the rate-limiting step is physisorption. Negative DeltaG(ads) values indicate that the adsorption is spontaneous and exothermic in nature. Also, under optimal conditions (in agitated 1M H(2)SO(4) at 30 degrees), the cassava waste biomass appears to be recyclable.
Horsfall
Michael
M
Department of Pure & Industrial Chemistry, University of Port Harcourt, Choba, Port Harcourt, Nigeria. horsfalljnr@yahoo.com
Ogban
Fred
F
Akporhonor
Eyitemi Emmanuel
EE
D000042:Absorption / Q000502:physiology; D018533:Biomass; D002857:Chromium / Q000737:chemistry / Q000378:metabolism*; D002365:Manihot / Q000378:metabolism*; D018514:Plant Structures / Q000378:metabolism; D035281:Plant Tubers / Q000378:metabolism; D012996:Solutions; D018505:Waste Management / Q000379:methods; D014867:Water / Q000737:chemistry / Q000378:metabolism*
D012996:Solutions; D014867:Water; D002857:Chromium