Yili Xie,Chen Tian,Weiyi Chen,Can Wu,Zhangbin Liu,Ping Ning,Hong Deng,Zhang Lin
Manganese ferrite (MnxFe3−xO4) microspheres with a spinel structure are very effective adsorbents for arsenic (As) removal. In this study, highly ordered mesoporous MnxFe3−xO4 has been synthesized by a facile and convenient solvothermal method. By comparing the different doping amounts of manganese (Mn), the results show that Mn1.8Fe1.2O4 has a relatively higher efficiency for arsenate (As(V)) removal due to the modified surface complexes caused by the optimum Mn substitution. Rietveld XRD refinement reveals that Mn1.8Fe1.2O4 microspheres possess the highest distribution ratio of Mn/Fe situated between the octahedral (Oh) and the tetrahedral (Td) sites of the unit cell. The as-prepared Mn1.8Fe1.2O4 microspheres with MnO6Oh sites in Fdm symmetry exhibit a promising ability for toxic As(V) adsorption, which is mainly attributed to the increase of coordinated complexes. Extended X-ray absorption fine structure (EXAFS) analysis indicates that the coordination structures of As(V) on Mn1.8Fe1.2O4 are present as bidentate binuclear complexes with a regular distance of As–Fe = 3.41 Å. Apart from this, As(V) can also bind with Mn-doped sites through the monodentate coordination mode at a distance of As–Mn = 3.51 Å with a preferred coordination number (CN) of 4.4. This work discloses the correlation between the superior As(V) adsorption ability and MnO6Oh sites in Mn1.8Fe1.2O4 and provides an emerging and promising method to enhance the adsorption capacity of As via modifying Mn doping sites based on the pollutant structure to achieve synergistic adsorption effects.
Yoann de Rancourt de Mimérand,Kun Li,Cong Zhou,Xiaoyun Jin,Xiaoxian Hu,Yufei Chen,Jia Guo
Inorganic photocatalysts became an essential and powerful tool for the remediation of polluted water. However, important limitations of photocatalysts in their colloidal form, especially nanosized, remain. For instance, their separation from water after use and recovery, which can be particularly demanding, time- and energy-wise. Considering such aspects, supported catalysts bear significant advantages. However, efforts still have to be made to develop processes that allow the permanent and efficient immobilization of inorganic photocatalysts in sustainable conditions, in order to maintain the advantages of supported catalysts over colloidal ones. Herein, we report the use of an aqueous-phase plasma-aided grafting (APPAG) process to produce functional and efficient hybrid photocatalysts. More specifically, based on cold plasma discharge (CPD), ZnO/Bi2MoO6 heterojunctions were permanently immobilized on polymer supports generated by 3D-printing, with fractal-inspired designs. Three different approaches of the APPAG process have been successfully used for the immobilization of the inorganic phase, that is core–shell-assisted direct grafting, indirect grafting and in situ complexation-assisted precipitation (ISCAP). Noticeably, the latter technique has never been reported before to our knowledge. These three immobilization routes rely on different strategies and yield to distinct morphological specificities, but all allow using mild synthesis conditions and producing stable, active, permanently immobilized coatings of photocatalysts. Regarding the preparation of the organic supports, two sorts of additive manufacturing (AM) technologies were employed, namely fused-deposition modeling (FDM) and liquid crystal diode (LCD)-based SLA (stereolithography). The use of fractal geometries combined with AM permits the production of supports with relatively high surface areas, in a single processing step. Overall, the three plasma-based immobilization methods revealed to be efficient and the performance of the different hybrid photocatalysts have later been assessed through the photodegradation of Rhodamine B dye under simulated sunlight irradiation and visible light only, with promising results.
危险品化学品经营许可证（带存储）