Short-range conjugated nitrogen-rich porous polymers for uranium(vi) photocatalysis†

The recovery of uranium from uranium-containing wastewater is crucial for the nuclear energy industry. Despite the effectiveness of photocatalytic reduction of uranium from U(VI) to U(IV) in treating uranium-containing wastewater, conventional organic conjugated semiconductors face challenges due to their high cost and reliance on inert gases. This study introduces an economical and eco-friendly approach using trimeric cyanuric chloride to construct a nitrogen-rich porous polymer (Py-NPP) with a short-range conjugated π unit and a pyrrole end-cap. Py-NPP demonstrated a remarkable removal efficiency of 93% in a 100 mg L⁻¹ U(VI) solution, even reaching 89% under ambient air. Py-NPP demonstrated good stability, with a uranium removal rate still over 80% after being cycled four times. Moreover, it still exhibited a good removal rate under 500-fold salt concentration. The nitrogen-containing functional groups enhanced chelation with U(VI), while the triazine structure and short-range conjugation of the π unit boosted photocatalytic activity, facilitating charge separation and transfer. This study offers a promising strategy for efficient U(VI) reduction using short-range conjugated catalysts under ambient conditions.