1Department of process engineering, Faculty of sciences and technology, University of Jijel PB 98 Ouled Aissa, Jijel, Algeria
2COVACHIMM, EA 3592 Laboratory, University of Antilles and Guyane, BP 250, 97157 Pointe a Pitre Cedex, Guadeloupe, France.
The biosorption of hexavelent chromium from saline solutions by Posidonia oceanica, a marine biomass, was studied as a function of pH, initial chromium (VI) and salt (NaCl) concentrations in batch system. The sorbent exhibited the maximal chromium (VI) uptake at pH 2 regardless of the presence of increasing salt concentration. Equilibrium uptake increased with chromium (VI) concentration up to 250 mg/ l and decreased slightly in the presence of increasing salt concentrations of salt up to 50 g/l. The biomass adsorbed 14.48 mg of metal per gram of biomass at 100 mg/l initial chromium concentration in the absence of salt. When 50 g/l salt concentration was added to the solution, the value diminished to 11.49 mg/g under the same conditions (i.e. a 20.6% decrease in the biosorption capacity). The equilibrium sorption data were analyzed using Freundlich, Langmuir and Redlich-Peterson models. The Langmuir equation was the most suitable adsorption model for describing the biosorption equilibrium data of chromium (VI) both in salt free and loaded media. The pseudo-second-order type kinetic model depicted the biosorption kinetics accurately at all chromium concentrations in absence and presence of increasing concentrations of salt.