Batch and continuous flow studies of adsorptive removal of Cr(VI) by adapted bacterial consortia immobilized in alginate beads

摘要

The adsorptive removal of Cr(VI) by alginate beads containing Cr(VI)-adapted Acinetobacter junii, Escherichia coli and Bacillus subtilis in batch and continuous packed bed column reactors was investigated. Under optimized conditions (pH 3.0; contact time, 180. min; 30°C; initial Cr(VI) concentration of 100. mg/L), 65.86. mg/g adsorption capacity was recorded in the batch study. When an adsorbent dosage of 1. g/L, a flow rate of 5. mL/min, a bed height of 20. cm, an initial Cr(VI) concentration of 300. mg/L was employed, a capacity of 657. mg/g was noted for the continuous column assay. The batch sorption data followed the Langmuir isotherm and pseudo second order kinetics. Five sorption/desorption cycles yielded 100%, 99.63%, 95.31%, 80.7% and 74.22% regeneration, respectively. Cr(VI) adsorption studies using spiked ground water, freshwater and domestic wastewater in a packed bed reactor demonstrated Cr(VI) removals of 64.8%, 55.08%, 56.86% respectively. Cr(VI) sorption on immobilized bacteria was confirmed with Fourier-transform infrared and Energy dispersive X-ray spectroscopy.