URANIUM(VI) BIOSORPTION BY DRIED ROOTS OF EICHHORNIA CRASSIPES (WATER HYACINTH)

Uranium uptake by dried roots of Eichhornia crassipes was rapid and the biomass could remove 54% of the initial uranium present within 4 min of contact time. The process was favored at pH 5–6 and was least influenced by temperature. Biosorption data fitted to both Langmuir and Freundlich isotherm. The maximum loading capacity obtained was 371 mg U/g dry biomass. Distribution coefficient of 9336 ml/g was observed at a residual concentration of 4.9 mg U/L. Uptake increased at higher dose of biomass and reached a plateau beyond the concentration of 6 g/L. The specific metal ion uptake decreased with increasing initial uranium concentration. Anions (0.1 M) inhibited the uptake and followed the trend acetate > sulphate > nitrate > chloride. However presence of carbonate had no effect on uranium biosorption.