Limin Zhang,Yunyan Wang,Yong Ke,Zhumei Sun,Yun Li,Cong Peng,Mingfei Zhu,Yongjian Luo,Xiaobo Min
Zinc ferrite is a dominant phase in mass solid wastes generated from zinc or iron production, which causes the obstacle of metal recovery and recycling. A facile and efficient sulfuric acid leaching process of zinc ferrite assisted by copper powder was proposed in this study. The effects of factors on the leaching of zinc ferrite and copper were investigated. The results showed that zinc ferrite and copper were coupled and leached. The complete dissolution of zinc ferrite was obtained with wide ranges of leaching conditions. The shortest time for the complete dissolution of zinc ferrite was 10 min at 80 ℃ under the conditions: copper to zinc ferrite molar ratio of 1.5, sulfuric acid concentration of 100 g/L, liquid to solid ratio of 30 mL/g, and copper powder of + 38.5–20 μm. The least consumption of copper to realize the complete dissolution of zinc ferrite was 27.15%. The leaching kinetics was studied by the shrinking core model. It was found that zinc ferrite leaching assisted by copper was controlled by surface chemical reaction. The apparent activation energies for zinc, iron, and copper are 56 kJ/mol, 56 kJ/mol, and 50 kJ/mol, respectively. Characterization of the leaching residues and determination of iron and copper species in the leaching solution showed galvanic corrosion took place between zinc ferrite and copper, enhancing their acid dissolution.
Li Lv,Pengfei Cheng,Yinglin Wang,Luping Xu,Bao Zhang,Chao Lv,Jian Ma,Yue Zhang
In this paper, the preparation process and gas sensing performance of Sb-doped three-dimensional spinel ferrite (3D ZnFe 2 O 4 ) with well-assembled macroporous spherical structure have been investigated. Sb-doped 3D ZnFe 2 O 4 macroporous spheres (MPs) were prepared through a one-step ultrasonic spray pyrolysis (USP) method by sacrificing self-assembly sulfonated polystyrene spheres (S-PSs). The interconnected macropores (an average pore size about 200 nm) can be observed in the as-prepared materials by SEM and TEM characterization, which provided the dual functions of accelerating the diffusion of gas molecules and providing more reactive sites. The XPS analysis showed that the element Sb existed as Sb 5+ in doped samples. Compared with the pure 3D ZnFe 2 O 4 MPs (response = 18), 0.5 % Sb-doped sample presented the response of 35.5–100 ppm n-butanol at 250 °C, and also revealed excellent selectivity and long-term stability to n-butanol. The greatly enhanced sensing performance of Sb-doped simples can be attributed to the construction of 3D spheres with interconnected macroporous structures and the modification of Sb doping. The formation of p-n junctions at interface through Sb doping also improved the sensing performance for n-butanol. In addition, the relative sensing mechanism of Sb-doped 3D ZnFe 2 O 4 MPs for n-butanol sensing has been discussed in detail.
Engineering semiconductors with porous hierarchical micro-/nanostructures is a feasible strategy to obtain high solar-light utilization efficiency and strong photocatalytic performance. In this work, an integrated strategy of solvent evaporation and morphology-inherited annealing for the Fe-based metal–organic framework was developed to prepare the hierarchical spinel zinc ferrite (ZnFe2O4) micro-/nanostructure. The morphology and porosity of the hierarchical ZnFe2O4 structures can be adjusted by optimizing the annealing temperatures. Benefitting from magnetic separation performance, these highly visible light-responsive hierarchical ZnFe2O4 micro-/nanostructures are demonstrated to be multifunctional photocatalytic materials, and their photocatalytic activity and reproducibility were analyzed, and the photocatalytic mechanism was also investigated. This work provides a controlled and generic route for constructing novel hierarchical semiconductors with specific compositions and intriguing structures.
危险品化学品经营许可证（带存储）