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

•Removal of Cr(VI) from aqueous solutions by A. viscosus biomass is studied.•Both dead and living biomass can reduce Cr(VI) to Cr(III) in highly acidic conditions.•Cr(III) is bonded by biomass functional groups through an ion-exchange mechanism.•Uptake capacity of living and dead A. viscosus is similar under optimum conditions.•Langmuir model fitting suggested a monolayer sorption of total Cr bound to biomass. 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 100mg/L. Langmuir isotherm and kinetic models based on reduction could simulate chromium removal at 5 and 8g/L biosorbent dosages and in highly acidic pH conditions (pH 1–2). Further, the potential use of the A. 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 20.37mg/g, with high potential for scaling up. This study showed that the reduction of toxic Cr(VI) to the less toxic Cr(III) by A. viscosus, in batch and continuous modes is an efficient and promising technique for wastewaters polluted with chromium.