Porous Cationic Electrospun Fibers with Sufficient Adsorption Sites for Effective and Continuous 99TcO4- Uptake

Removal of radioactive technetium-99 ((TcO4-)-Tc-99) from water by effective adsorbents is highly desired but remains a challenge. The currently used resin adsorbents possess several obstacles, such as slow adsorption kinetics and low adsorption capacity. To address these issues, herein a type of fibrous adsorbent with porosity and hyper-branched quaternary ammonium groups, namely porous cationic electrospun fibers (PCE fibers), is successfully prepared. PCE fibers can remove 97% of (TcO4-)-Tc-99 within 1 min and the equilibrium time of 99% removal is 20 min. The predicted maximum adsorption capacity toward the surrogate ReO4- can reach 826 mg g(-1), which is higher than the state of art anion-exchange resins and most of the other reported adsorbents. Furthermore, PCE fibers have good selectivity for ReO4- in the presence of competitive anions, and can retain ReO4- uptake under extreme conditions including high acid-base and gamma irradiation. Importantly, PCE fibrous adsorptive membrane is employed for dynamic ReO4- removal from simulated Hanford LAW stream with a processing capacity of 600 kg simulated stream per kilogram PCE fibers. The excellent performance highlights the advantages of PCE fibers over traditional resins in technetium removal.

Automated summary

A fibrous adsorbent, called porous cationic electrospun fibers (PCE fibers), was successfully prepared and exhibited excellent performance in removing radioactive technetium-99. It showed fast adsorption kinetics, high adsorption capacity, and good selectivity for the target pollutant.