共价有机框架(COFs)材料的结构控制及其在环境化学中的应用

近年来,共价有机框架(COFs)材料因其稳定的结构、高比表面积、大孔隙率、可修饰结构和易于功能化而受到了科学家们的广泛关注。通过控制COFs材料的孔径、形状和链接方式以及后合成修饰,功能性COFs材料在气体储存分离、传感器和药物传输等领域发挥了越来越重要的作用。尤其在环境化学领域,COFs材料的研究和应用已成为一热门课题。本文综述了COFs材料的结构控制、分类以及在环境污染物检测和去除中的应用,包括对重金属离子、放射性核素、有机污染物和气体污染物的吸附和催化等。通过改变构筑单体的大小和形状、引入特殊官能团和活性位点等方法,可以增强污染物与COFs材料的相互作用(氢键相互作用、π-π相互作用和范德华力等),使COFs材料在环境领域应用中有优异的表现。本文最后展望了COFs材料在环境领域的应用前景和今后的研究方向,希望能为该领域的研究提供参考。     

MXene二维无机材料在环境修复中的应用

MXenes是一类结构新颖的无机层状纳米材料,它是由几个原子层厚度的过渡金属碳化物、氮化物或碳氮化物构成,目前被广泛应用于能源、光学、催化和吸附等领域。由于其具有高亲水性、比表面积大、表面带负电和高离子交换力等特性,被作为一种优异的吸附剂材料。MXenes材料会通过静电吸引、配位螯合等相互作用去除环境中的重金属离子与放射性元素,有望成为吸附重金属离子与放射性元素的理想载体。本文介绍了MXene材料的结构与制备方法,其去除重金属离子(如铬(Cr)、汞(Hg)、铅(Pb)、镍(Ni))与放射性元素(如铀(U)、铯(Cs)、铕(Eu)、钡(Ba)、锶(Sr))的研究进展,并对其相关的吸附行为与相互作用机理进行了重点阐述。此外,还对MXene材料在该领域所面对的挑战和未来发展进行了展望。     

Highly Selective Recovery of Lanthanides by Using a Layered Vanadate with Acid and Radiation Resistance

It is of vital importance to capture lanthanides (nuclear fission products) from waste solutions for radionuclide remediation owing to their hazards. The effective separation of lanthanides are achieved by an acid/base‐stable and radiation‐resistant vanadate, namely, [Me₂NH₂]V₃O₇ ( 1 ). It exhibits high adsorption capacities for lanthanides (q_m^Eu=161.4 mg g^?1; q_m^Sm=139.2 mg g^?1). And high adsorption capacities are maintained over a pH range of 2.0–6.9 (q_m^Eu=75.1 mg g^?1 at low pH of 2.5). It displays high selectivity for Eu³⁺ (simulant of An³⁺) against a large excess of interfering ions. It can efficiently separate Eu³⁺ and Cs⁺ (or Sr²⁺) with the highest separation factor SF_Eu/Cs of 156 (SF_Eu/Sr of 134) to date. The adsorption mechanism is revealed by calculations and XPS, EXAFS, Raman, and elemental analyses. These merits combined with facile synthesis and convenient elution makes the title vanadate a promising lanthanide scavenger for environmental remediation.     

计算化学辅助无机化学课堂教学模式的探索

According to the characteristics of inorganic chemistry and in view of the current problems in classroom teaching of inorganic chemistry, the computational chemistry assisted teaching model has been introduced in this paper. The implementation of this innovative model is not only helpful for students to understand the difficult knowledge of inorganic chemistry, but also popularize the practical application of computational chemistry, which provides an opportunity for the establishment of the big data platform of chemistry in colleges and universities.     

Adsorption Properties of Hydrated Cr3+ Ions on Schiff‐base Covalent Organic Frameworks: A DFT Study

Considering the superior physiochemical property, increasing efforts have been devoted to exploiting the covalent organic frameworks (COFs) materials on the environmental remediation of heavy metal ions. Water pollution caused by Cr³⁺ metal ions is of special concern for scientists and engineers. Notwithstanding all the former efforts made, it is surprising that very little is known about the interaction mechanisms between the hydrated Cr³⁺ metal ions and COF materials. In present context, density functional theory (DFT) method is used to elucidate geometric and electronic properties with the purpose of putting into theoretical perspective the application values and interaction mechanisms for COF materials on Cr³⁺ capture. The results showed that all the five selected Schiff‐base COFs materials displayed good adsorption performance on Cr³⁺ removal while the phenazine‐linked and imine‐COFs possessed the most favorable adsorption capacity due to the optimal chemical units and frameworks. The hydration effect was found to play a two‐side role in the adsorption process and interaction mechanisms, involving coordination, hydrogen bonds, as well as weak non‐covalent interactions, have been illuminated to explain the observed different adsorption behaviors. This study provides a general guidance for the design and selection of efficient COF materials as high‐capacity Cr³⁺ adsorbents.