Biosorption of Rare Earth Elements by Two Fungal Genera from Lower Carboniferous Carbonaceous Shales, Southwestern Sinai, Egypt

This work aims to test the ability of two fungal genera A. niger and A. flavus, for sorption of rare earth elements (REEs) during bioleaching process,from Sinai carbonaceous shales. The sorption of heavy metals and REEs was found to be influenced by initial ore concentration, contact time and temperature. The maximum biosorption efficiency by using A. flavus and A. niger was observedat 5% ore concentration, 9 days of contact time and 40 oC. It is noticed that the A. flavus has higher biosorption efficiency than A. niger. The Environmental Scanning electron microscopeand EDX analysis indicate the selectivity of both fungi for Cerium (Ce) from other REEs. Transmission electron microscope analysis of A. niger showed that elements were accumulated and precipitated aroundits cell wall and form black dense area around it.By increasing ore concentration the cell wall starts to hydrolysis and metal ions interto the resulting cell large vacuole.