Fabrication of phosphate-containing mesoporous carbon for fast and efficient uranium (VI) extraction

Abstract

Uranium has been recognized as one of the most desired radionuclides that has long been used in reactor. The efficient extraction of uranyl (VI) ions from radioactive effluents and seawater is an ideal way to collect uranium, however it is always a challenge to develop high-efficiency adsorbents for effective uranium uptake. In this paper, a series of phosphate-containing mesoporous carbon (PC) are fabricated by the carbonization of sucrose and phytic acid upon using nanosized silica as hard template. The obtained PC have high-content phosphate group, large specific surface area and tunable mesoporous structure. The PC can efficiently adsorb uranium at a wide pH conditions. The maximum uptake capacity of PC for uranium reaches 928 mg g −1, ranking as one of the most highly effective adsorbents. The mesopores of PC enables them to quickly reach the adsorption equilibrium within 60 s and meantime PC show excellent adsorption selectivity. Investigations of adsorption mechanism reveals that uranyl (VI) ions tend to bind with the surface P-OH groups to form P-O-U complexes, leading to the effective uranium extraction. Moreover, PC displays good recyclability and can be further used for dynamic column adsorption of uranyl (VI) ion from uranium-containing solution. The excellent adsorption performances of PC highlight their great potential in uranium extraction.