Biosorption potential of dead and living Arthrobacter viscosus biomass in the removal of Cr(VI): Batch and column studies

Batch experiments were conducted with dead and living Arthrobacter viscosus biomass for Cr(VI) removal from aqueous solution. Both dead and living cells successfully reduced Cr(VI) to Cr(III) from aqueous solution in highly acidic pH (pH 1 and 2) with an efficiency of 100% for aqueous solutions having the initial concentrations of Cr(VI) lower than 100 mg/L. Langmuir isotherm and kinetic models based on reduction could simulate chromium removal at 5 and 8 g/L biosorbent dosages and in highly acidic pH conditions (pH = 1-2). Further, the potential use of the Arthrobacter viscosus biomass was examined in an open system, where Cr(VI) removal from aqueous solution was performed by a bacterial biofilm supported on a new type of polyethylene supports. The experiment showed a favorable uptake of chromium ions bound to the biomass, of 20.37 mg/g, with high potential for scaling up. This study showed that the reduction of toxic Cr(VI) to the less toxic Cr(III) by Arthrobacter viscosus, in batch and continuous modes is an efficient and promising technique for wastewaters polluted with chromium.This paper was elaborated with the support of BRAIN project Doctoral scholarships as an investment in intelligence - ID 6681, financed by the European Social Found and Romanian Government and with the support of a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0559, Contract 265/2011. H. Figueiredo is thankful to “FCT – Fundação para a Ciência e Tecnologia” for the financial support through the concession of PhD grant SFRH/BD/28201/2006.