“Bridging hydrogen bonds” from guanidine and amidoxime groups on natural bamboo strips as a superantibacterial and knitted adsorbent to efficiently adsorb uranium from simulated seawater

Uranium adsorption from seawater can provide a sustainable development path for the future raw material supply of nuclear energy. However, in the process of uranium extraction from seawater, biofouling adheres to the surface of the adsorbent, wasting the adsorption sites and seriously affecting the adsorption capability of the adsorbent. Herein, inspired by the superanti-biofouling property of guanidine groups, a superantibacterial and knitted adsorbent with guanidine and amidoxime groups cografted on natural bamboo strips (G-AOBS) is synthesized to adsorb uranium from simulated seawater. The intrinsic structure of bamboo is not destroyed by the whole grafting process, and G-AOBS still maintains the porous and cellulose crystalline structure. The grafting of guanidine groups improves the hydrophilicity and significantly enhances the anti-biofouling performance, thereby increasing the adsorption capacity for uranium (q_e = 201.4 ± 13.23 mg g⁻¹ at pH = 4 with C₀ = 100 mg L⁻¹ and q_e = 1.04 ± 0.12 mg g⁻¹ in simulated seawater with C₀ = 500 μg L⁻¹). According to the results of DFT, the guanidine and amidoxime groups can not only replace one carbonate in uranyl tricarbonate alone to form a more stable coordination structure but also have a synergistic effect between the two, that is, using three “bridging hydrogen bonds” to form the most stable chelation mode with uranyl dicarbonate.