Studies on accumulation of uranium by fungus Lentinus sajor-caju.

The untreated, heat- and alkali-treated Lentinus sajor-caju mycelia were used for the recovery of uranium from aqueous solutions. The effect of pH, temperature, initial concentration of UO(2)(2+) ions and contact time parameters were investigated in a batch system. The particles sizes of the fungal mycelia were ranging from 100 to 200 microm. Biosorption equilibriums were established in about 30 min and the correlation regression coefficients show that the adsorption process can be well defined by the Freundlich equation. The alkali treated form had a high biosorption capacity (378 mg/g) than those of the untreated (268 mg/g) and heat-treated fungal mycelia (342 mg/g). Optimum biosorption was observed at pH 4.5 for all the tested fungal preparations and was independent of temperature (5-35 degrees C). In addition, the polarity and surface energy of the fungal biomass film preparations were determined by contact angle measurement. The fungal biomass could be regenerated using 10mM sodium carbonate, with up to 93% recovery. The biosorbents were used in six biosorption-desorption cycles and no considerable loss in the biosorption capacity was observed.