Nanowires Reinforce Oriented Macroporous Aerogels for Rapid Uranium Removal from Acidic Radioactive Wastewater

Rapid uranium removal from acidic wastewater is significant for nuclear pollution treatment. Robust mechanical strength is necessary for practical applications. Herein, we design a "reinforced concrete" structural aerogel (NWs/SP-CSSB gel) with directional channels via nanowire-assisted directional freezing. Benefiting from interconnected microchannels and hydrophilic ligands, the gel has ultrafast water permeability. Owing to the padding of ultralong nanowires (HAP NWs), the mechanical strength of the gel increased 70.43 times compared with that without NWs. Most uranium is removed within 2 min, and the removal ratio reaches equilibrium within 30 min in the highly acidic environment of pH 3. Meanwhile, it can reduce U to 9.75 ppb from the contaminated groundwater, achieving the drinking water discharge standard. Furthermore, the gel possesses good anti-interference performance, even in a high-salt environment and the presence of interfering ions, including lanthanides, radioelements, and transition metal ions; the U removal ratios of NWs/SP-CSSB gel still maintain 84-96%. The adsorption mechanisms are carefully analyzed by using contrast experiments, kinetic and isotherm models, as well as FTIR and XPS spectra. Considering the high-performance properties and simple fabrication of NWs/SP-CSSB gel, we believe it has great potential in the application of radioactive wastewater treatment.