Wastewater Purification and All-Solid Z-Scheme Heterojunction ZnO-C/MnO2 Preparation: Properties and Mechanism

Abstract

Unlike many studies on the preparation of Z-scheme heterojunctions by doping precious metals, in this paper we first prepared a core-shell material obtained by C doping in ZnO and then composite with MnO2 to form a heterojunction; that is, a low-cost and highly catalytic ternary composite catalyst was prepared by a simple hydrothermal reaction. Meanwhile, a large amount of experimental data have enabled the heterostructure type as well as the mechanism of photocatalytic performance to be fully demonstrated. It is proven that C as an intermediate medium achieves electron transport while making up the deficiency of ZnO, and constitutes an all-solid state Z-scheme heterojunction, which enables the rapid transfer of photogenerated electron pairs and visible light irradiation to the stream to improve the photocatalytic performance of the composite photocatalyst. In terms of examination of degradation performance, this catalyst showed a high photodegradation rate of tetracycline hydrochloride (TC) of 92.6% within 60 min, and the surface ZnO-C/MnO2 catalysts also showed good degradation effect on practical petrochemical wastewater in CODcr degradation experiments.

Australia’s Spodumene: Advances in Lithium Extraction Technologies, Decarbonization, and Circular Economy

“…Overall, acidic digestion with H 2 SO 4 is considered to be a mature technology with the benefit of producing both technical grade (95%) and battery grade (99.5%) lithium products. 76,77 However, the following handicaps are also associated with the conventional sulfuric acid method: (i) the requirement of an excess H 2 SO 4 concentration, (ii) high temperature requirement for conversion of spodumene to more leachable form, (iii) formation of impurities into a leached solution requiring extra purification stages, and (iv) discharge of excessive waste. Additionally, the corrosion of equipment with excessive usage of H 2 SO 4 is also a matter of concern in this regard.…”

Special Issue on “Advanced Catalytic Material for Water Treatment”

“…Du et al made a high-energy TiO 2 nano photocatalyst with co-exposed {001} and {120} facets, and verified that the anatase structure, particle size and surface area and exposed facets of the nanocrystal all contributed to its photocatalytic performance [5]. Zhao et al fabricated a core-shell ZnO-C/MnO 2 material with an all-solid state Z-scheme heterojunction structure and a high photocatalytic reactivity [6].…”