title: Comparative study of differently treated animal bones for Co(2+) removal.
abstract: The objective of the present study was the evaluation of differently treated bovine bones for Co(2+) removal from aqueous media. Powdered bones (B), as well as samples prepared by H(2)O(2) oxidation (BH(2)O(2)) and annealing at 400-1000 degrees C (B400-B1000), were tested as sorbent materials. A combination of XRD, FTIR spectroscopies, DTA/TGA analyses, specific surface area (S(p)) and point of zero charge (pH(PZC)) measurements was utilized for physicochemical characterization of sorbents. Sorption of Co(2+) was studied in batch conditions as a function of pH, contact time and Co(2+) concentration. Initial pH values in the range 4-8 were found optimal for sorption experiments. Equilibrium time of 24h was required in all investigated systems. The maximum sorption capacities differ significantly from 0.078 to 0.495mmol/g, whereas the affinity towards Co(2+) decreased in the order: B400>BH(2)O(2)>B600>B>B800>B1000. The pseudo-second-order model and Langmuir theoretical equation were used for fitting the kinetic and equilibrium data, respectively. Ion-exchange with Ca(2+) and specific cation sorption were identified as main removal mechanisms. The amounts of Co(2+) desorbed from loaded bone sorbents increased with the decrease of pH as well as with the increase of Ca(2+) concentration. Heating at 400 degrees C was found to be an optimal treatment for the production of the Co(2+) removal agent.
authors.affiliation: Institute of Nuclear Sciences Vinca, P.O. Box 522, 11000 Belgrade, Serbia. sdimovic@vin.bg.ac.yu
authors.forename: S
authors.initials: S
authors.lastname: Dimović
authors.forename: I
authors.initials: I
authors.lastname: Smiciklas
authors.forename: I
authors.initials: I
authors.lastname: Plećas
authors.forename: D
authors.initials: D
authors.lastname: Antonović
authors.forename: M
authors.initials: M
authors.lastname: Mitrić
mesh_terms: D000327:Adsorption; D000818:Animals; D001842:Bone and Bones / Q000737:chemistry*; D002417:Cattle; D003035:Cobalt / Q000737:chemistry / Q000302:isolation & purification*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D003035:Cobalt; D006861:Hydrogen Peroxide