Wang Tianning, Yang Yunfei, Wang Jinshu, Wu Junshu, Sun Lingmin, Du Yucheng, Li Yongli, Li Hongyi
The Key Lab of Advanced Functional Materials, Ministry of Education China, School of Materials Science and Engineering, Beijing University of Technology Beijing 100022 China
RSC Adv. 2019 Jan 29;9(7):3816-3827. doi: 10.1039/c8ra10186h. eCollection 2019 Jan 25.
A general solution-phase strategy is developed to synthesize nanostructure niobates such as MnNbO, SnNbO and ZnNbO on natural mineral diatomite for water environmental remediation. (NH)CO aqueous solution is the key to achieve a scalable and controllable synthesis of niobate/diatomite hybrid systems, which generates NH·HO for surface etching activation of diatomite, and HCO for complexation dissolution of NbO, enabling the heterogeneous crystallization process to proceed with controllable growth kinetics. First principle calculations indicate that both niobium atom and niobium-oxygen species have the lowest adsorption energy on SiO surface, and then induce the nucleating process of Nb-O-Mn (or Zn, Sn) networks. Cr(vi), Fe(iii), and Pb(ii) ions are taken as target pollutants to evaluate the water-cleaning ability of the niobate-modified diatomite. Possible mechanisms for the photoreduction of Cr(vi), physical adsorption of Fe(OH) colloids, and chemisorption of Pb(ii) ions are proposed on the basis of experimentally investigations. The possibility of combining the advantages of natural mineral diatomite and nanostructured niobates provides a highly robust and potential material system with versatile functionalities of heavy metal ion removal, demonstrating great promise for a wide range of water purification.
开发了一种通用的溶液相策略，用于在天然矿物硅藻土上合成纳米结构铌酸盐，如MnNbO、SnNbO和ZnNbO，用于水环境修复。(NH)CO水溶液是实现铌酸盐/硅藻土杂化体系可扩展和可控合成的关键，它产生NH·HO用于硅藻土的表面蚀刻活化，产生HCO用于NbO的络合溶解，使非均相结晶过程能够以可控的生长动力学进行。第一性原理计算表明，铌原子和铌-氧物种在SiO表面具有最低的吸附能，进而诱导Nb-O-Mn（或Zn、Sn）网络的成核过程。以Cr(vi)、Fe(iii)和Pb(ii)离子作为目标污染物，评估铌酸盐改性硅藻土的水净化能力。在实验研究的基础上，提出了Cr(vi)光还原、Fe(OH)胶体物理吸附和Pb(ii)离子化学吸附的可能机制。结合天然矿物硅藻土和纳米结构铌酸盐优势的可能性提供了一种具有去除重金属离子多功能性的高度稳健且有潜力的材料体系，在广泛的水净化方面展现出巨大前景。
