新型供体-受体g-C_(3)N_(4)有机半导体光催化铀分离技术

Novel Donor-Acceptor g-C_3N_(4) Organic Semiconductor Photocatalytic Separation of Uranium

从核废水中光催化提取铀是避免环境破坏和回收铀资源的一种可行方法,但设计具有快速迁移光生电荷和表面反应动力学的高效光催化剂用于去除含铀废水中的U(Ⅵ)仍然是一个重大挑战。采用无模板的自组装技术,成功构建了空心管状g-C_(3)N_(4)(TCN),并通过将间苯二酚引入TCN的骨架结构中,制备了管状供体-受体(D-A)有机半导体光催化剂B-TCN_(x),用于空气气氛下光催化去除U(Ⅵ)。分子内D-A体系的构建,使得电子和空穴分别聚集在受体和供体部分,这降低了电子-空穴对的复合。此外,电子和空穴在受体和供体部分的积累导致了内置电场的形成,从而促进了载流子的迁移。结果表明,B-TCN_(60)在120 min内对U(Ⅵ)的去除率达到96.8%,其动力学常数(0.031 14 min^(-1))是TCN (0.012 15 min^(-1))的2.58倍。并且在连续5次循环后变化不大,具有稳定性和可重复性。因此,D-A光催化剂具有很高的光催化铀分离效率。这项研究为深入了解光催化铀分离提供了启示和指导。

The extraction of uranium from nuclear wastewater through photocatalysis represents a highly viable,environmentally friendly,and sustainable approach,contributing significantly to mitigating environmental degradation while facilitating the efficient recovery of uranium resources.Nonetheless,the development of highly efficient photocatalysts with rapid charge carrier migration and surface reaction kinetics for the effective removal of U(Ⅵ) from uranium-containing wastewater remains a formidable challenge.This study successfully employed template-free self-assembly techniques to fabricate hollow tubular g-C_(3)N_(4)(TCN) and synthesized a tubular donor-acceptor(D-A) organic semiconductor photocatalyst,B-TCN_x,by incorporating hydroquinone into the framework of TCN.This innovative photocatalyst was utilized for the photocatalytic removal of U(Ⅵ) under ambient air conditions.The construction of an intramolecular D-A system enables the separate accumulation of electrons and holes in the acceptor and donor moieties,thereby significantly reducing electron-hole recombination.Furthermore,the spatial separation of electrons and holes in the acceptor and donor moieties leads to the formation of an intrinsic electric field,which facilitates the migration of charge carriers.The research findings indicate that B-TCN_(60) achieved a remarkable removal rate of 96.8% for U(Ⅵ) within 120 minutes,with a kinetic constant(0.031 14 min^(-1))that is 2.58 times higher than that of TCN(0.012 15 min^(-1)).Moreover,negligible performance variation was observed after five consecutive cycles,demonstrating the excellent stability and reproducibility of the photocatalyst.The enhanced performance of B-TCN_(60) can be attributed to its unique structural and electronic properties.The hollow tubular structure of TCN provides a high surface area,which is beneficial for the adsorption of uranium ions.Additionally,the incorporation of hydroquinone into the TCN framework not only improves the light absorption properties of the photocatalyst but also plays a crucial role in the formation of the D-A system.The effective separation of charge carriers within the D-A system minimizes recombination losses and maximizes the efficiency of the photocatalytic process.The study's findings underscore the potential of D-A organic semiconductor photocatalysts in addressing environmental challenges associated with nuclear waste,while also enhancing the recovery of valuable uranium resources.The novel approach of utilizing a D-A system in the photocatalyst design opens new avenues for the development of advanced materials with superior photocatalytic performance.The innovative use of template-free self-assembly techniques to fabricate hollow tubular g-C_(3)N_(4) and the successful synthesis of the B-TCN_(x) photocatalyst represent significant advancements in the field.The high removal efficiency,stability,and reproducibility of B-TCN_(60) highlight its potential for practical applications in environmental remediation.This work not only contributes to the field of environmental remediation but also offers a sustainable solution to the global issue of nuclear waste management.