Synthesis and adsorption characteristics of calix[6]arene derivative modified Aspergillus niger-Fe3O4 bio-nanocomposite for U(VI)

A new type of magnetic bioadsorbent (CDAB) was synthesized by reaction of amidoxime modified calix[6]arene derivative with the Aspergillus niger -Fe 3 O 4 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 kinetic model and Langmuir adsorption isotherm model. The maximum adsorption capacities of CDAB were calculated to be 77.04 mg g −1 for uranium(VI). The adsorption efficiency of CDAB towards U(VI) could reach at 83.6% with a considerable selectivity. In addition, the thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic.