The ethylenediamine-modified Aspergillus niger (EMAN) and amidoxime-modified A. niger (AMAN) had been successfully prepared and then characterized by means of FTIR and SEM–EDX. The selective adsorption features of raw A. niger (RAN), EMAN, and AMAN for UO2 2+ over other coexistent heavy metal ions, such as Fe3+, Pb2+, Cu2+, Zn2+, Cd2+, and Co2+ had been investigated in a multi-metal system and a binary system. At the optimum pH which was 5, the orders of selectivity biosorption of EMAN and AMAN in a multi-metal system were UO2 2+ ≫ Fe3+ > ...