Efficient uranium adsorbent with antimicrobial function: Oxime functionalized ZIF-90

Abstract

The anti-fouling performance of an adsorbent is important for its application in wastewater, because biological fouling severely reduces its adsorption capacity. A zeolitic imidazolate framework was synthesized and oxime-functionalized to produce an efficient uranium adsorbent with antimicrobial properties (ZIF-90-OM). Its adsorption performance for U (VI) was studied under different environmental parameters, including pH, initial uranium concentration, competitive ions, ionic strength, temperature, and contact time. Due to its porous structure and the strong chelation of oxime groups with U (VI), ZIF-90-OM showed a very high maximum adsorption capacity for U (VI) of 610 mg/g at pH = 5.0. The adsorption of uranium on ZIF-90-OM correlated well with the Langmuir model and the pseudo-second-order kinetic model. ZIF-90-OM showed high uranium selectivity even in the presence of competing metal ions. Besides, the adsorbent also exhibits good recyclability, the adsorption capacity was maintained after five adsorption/desorption cycles. Furthermore, ZIF-90-OM showed excellent antimicrobial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Our work shows that ZIF-90-OM is an efficient adsorbent for the removal of U (VI) from wastewater because of the presence of oxime groups and its anti-fouling properties. Moreover, due to its antimicrobial properties, ZIF-90-OM can be used to purify water.