A new type of magnetic bioadsorbent (CDAB) was synthesized by reaction of amidoxime modified calix[6]arene derivative with the Aspergillus niger-Fe3O4 bio-nanocomposite, the bioadsorbent have been well characterized with FT-IR, SEM-EDS, XPS and VSM. The effects of various experimental parameters include pH, contact time, initial uranium(VI) concentration, adsorbent dosage and temperature on the bioadsorption of uranium(VI) were investigated in detail. Adsorption experimental results showed the adsorption process of CDAB was pseudo-second order ...