Continuous biosorption in rotating packed-bed contactor

Biosorption process has been studied in fixed-bed contactors where terrestrial gravity dictates attainable mass transfer rates. This work explored the mass transfer characteristics of continuous biosorption under centrifugal acceleration (many times earth's gravity) in a rotating packed-bed (RPB) contactor. The system studied was copper(II) ion adsorption on the packing of the contactor constituted by scales of Catla catla fish. Experiments were performed by continuously recycling a fixed volume of solution through the bed. The uptake of copper by the biosorbent increases with centrifugal force and liquid flow rate, but compaction of the bed negates the advantages of using high values of these. A low-packing-density bed demonstrated comparable efficiency in adsorbing copper as a bed nearly twice its packing density. Mass transfer rate per unit volume of packed bed was enhanced in the RPB by about 2.4 times compared to the fixed bed. A simple mass transfer model predicted the continuous biosorption experimental data in RPB fairly well.