Xu He, Xie Tao, Ye Jinghong, Wu Qingchuan, Wang Dongfang, Cai Dongqing
College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
Langmuir. 2022 May 31;38(21):6579-6591. doi: 10.1021/acs.langmuir.2c00417. Epub 2022 May 16.
A novel nanocomposite [Fc-MIL-100(Fe)] was constructed by combining ferrocene (Fc) with the porous structural metal-organic framework [MIL-100(Fe)]. The proposed composite material could simultaneously and efficiently remove hexavalent chromium [Cr(VI)] and imidacloprid and reduced strongly noxious Cr(VI) to weakly noxious trivalent chromium [Cr(III)]. The removal efficiencies of the composite material for Cr(VI) and imidacloprid could reach 95% after 15 h. The adsorption process was determined by kinetics, isotherms, and thermodynamics. The results demonstrated that the adsorption kinetics of Cr(VI) followed the pseudo-second-order model mainly by chemisorption; meanwhile, the adsorption of imidacloprid by the material conformed to the pseudo-first-order kinetics, which indicated that physical adsorption was the main process. Additionally, the intraparticle diffusion model revealed that the uptake of imidacloprid and Cr(VI) occurred via intraparticle diffusion at the composite material. The adsorption procedure for Cr(VI) was fitted to the Langmuir model ( = 0.995) via monolayer adsorption, and that for imidacloprid was fitted to the Freundlich model ( = 0.995) due to multilayer or heterogeneous adsorption. The thermodynamic research confirmed that the adsorption procedure was exothermic and spontaneous. Infrared spectroscopy, X-ray photoelectron spectra, and the pH effect implied that intermolecular hydrogen bonding and electrostatic interaction played a crucial role during the removal process. Fc-MIL-100(Fe) also exhibited long-term stability and satisfactory regeneration and reusability. Therefore, this method may enhance an environmentally friendly and prospective approach for concurrently removing imidacloprid and Cr(VI) from wastewater.
通过将二茂铁（Fc）与多孔结构金属有机框架[MIL-100(Fe)]相结合，构建了一种新型纳米复合材料[Fc-MIL-100(Fe)]。所提出的复合材料能够同时高效去除六价铬[Cr(VI)]和吡虫啉，并将剧毒的Cr(VI)强烈还原为低毒的三价铬[Cr(III)]。该复合材料对Cr(VI)和吡虫啉的去除效率在15小时后可达到95%。吸附过程通过动力学、等温线和热力学进行测定。结果表明，Cr(VI)的吸附动力学主要遵循伪二级模型，以化学吸附为主；同时，该材料对吡虫啉的吸附符合伪一级动力学，这表明物理吸附是主要过程。此外，颗粒内扩散模型表明，复合材料对吡虫啉和Cr(VI)的摄取是通过颗粒内扩散发生的。Cr(VI)的吸附过程通过单层吸附拟合到Langmuir模型（ = 0.995），而吡虫啉的吸附过程由于多层或非均相吸附拟合到Freundlich模型（ = 0.995）。热力学研究证实吸附过程是放热且自发的。红外光谱、X射线光电子能谱和pH效应表明，分子间氢键和静电相互作用在去除过程中起关键作用。Fc-MIL-100(Fe)还表现出长期稳定性以及令人满意的再生和再利用性。因此，该方法可能为从废水中同时去除吡虫啉和Cr(VI)提供一种环境友好且有前景的方法。
