功能化多孔氮化碳材料对铀的吸附性能研究

The separation and enrichment of uranium from seawater and wastewater is of great significance to the sustainable development of energy and environmental protection. A porous carbon nitride adsorbent (d-g-CN) rich in cyano groups and hydroxyl groups was prepared through one-step alkalization and heat-condensation polymerization of melamine, and its adsorption performance for uranium was studied. The results of adsorption experiments showed that under the conditions of pH=6.0 and 298 K, the adsorption of uranium by d-g-CN reached equilibrium in about 3 h, and the saturated adsorption capacity was 2476.23 mg ∙ g^-1. The adsorption process conformed to the pseudo second order kinetic model and Freundlich isotherm model. In addition, d-g-CN had excellent selectivity and cyclicity. When there were many competitive ions in the solution, the adsorption distribution coefficient of d-g-CN for uranium reached 1.48×10⁴ ml∙g^-1. The adsorption efficiency remained about 89.5% after six cycles. Because the large specific surface area of d-g-CN provided more adsorption sites, and functional groups of cyano and hydroxyl had coordination effect with uranium, d-g-CN showed excellent adsorption performance, and had certain application potential in the extraction of low concentration uranium.