In-Situ Generation Of H₂O₂ In Cu₂O/TiO₂ Heterojunction And Its Application In Algae Removal

The large-scale seasonal outbreak of blue-green algae blooms poses a variety of threats to human life and production.Therefore,the in-depth study of the natural conditions of Algae blooms and algae outbreaks explores the use of natural conditions for algae growth to inhibit and kill algae blooms.It is of great theoretical and practical value to control algae pollution in eutrophic water bodies.Water bloom outbreak is affected by light intensity,temperature,nitrogen,phosphorus nutrients,algae is the use of photosynthesis for growth,so the general blue-green algae outbreak season has strong light,photosynthesis oxygen production,but also make the water body The dissolved oxygen?DO?concentration increases.The illumination and DO are important hotspots for the application of semiconductor photocatalysis technology in the environmental field.Therefore,it is a meaningful attempt in the field of water bloom pollution control to study the new technology of photocatalytic algae removal that can fully utilize light conditions and supersaturated DO.In this paper,a series of Cu₂O/TiO₂ composites were prepared by liquid phase reduction method based on Cu₂O.The p-type semiconductor Cu₂O and the n-type semiconductor TiO₂ can form a heterojunction.On the basis of ensuring the visible light response property of Cu₂O,it can also improve the shortcomings of easy photocomposition and easy photo-corrosion of photogenerated carriers,thereby effectively improving the photocatalytic production of H₂O₂ performance,and H₂O₂ is the green oxidant commonly used in algae removal studies.A sufficient amount of DO and proper light in the photocatalytic system are the key to the generation of H₂O₂.At the same time,we use hydrotalcite and rectorite clay minerals as carriers to prepare ternary materials,and study the effects of clay mineral doping on the heterostructure and the properties of H₂O₂ produced.This paper studies the effects of different light intensity,DO,etc.on the photocatalytic H₂O₂ properties of Cu₂O,Cu₂O/TiO₂,and lays a foundation for the establishment of photocatalytic algae removal system under natural water.In order to achieve the goal of better removal of algae by using the natural conditions of the outbreak season of water bloom under conditions of no light and no oxygen,we conducted the following research:1.Cu₂O,Cu₂O/TiO₂,hydrotalcite Cu₂O/TiO₂ and rectorite Cu₂O/TiO₂ composites wereprepared by liquid phase reduction method.The morphology of the as-synthesizedmaterials was characterized by SEM,TEM,XRD,XPS and PL.Characterization of structure,structure,purity and optical properties.Through the analysis of the morphology,band gap and bonding energy of Cu₂O and TiO₂ before and after recombination,it is shown that Cu₂O and TiO₂ form a heterogeneous structure, which can theoretically improve its photocatalytic activity,and the addition of clay minerals is only possible.It has a small effect on the morphology of Cu₂O without affecting other properties.In addition,Uv-vis DRS tests show that all materials synthesized on the basis of Cu₂O have visible light response performance.2.Through the determination of H₂O₂ concentration in different systems,the propertiesof Cu₂O and Cu₂O/TiO₂ heterojunctions are continuously and stably supplied toH₂O₂.In order to study the mechanism,H₂O₂ was produced from Cu₂O and Cu₂O/TiO₂ under non-O₂ system and the adding of electron donors system.Under the same conditions,the best performance of H₂O₂ is that binary material with nCu₂O:nTiO₂ is 1:2,and Cu₂O/2TiO₂ is stable and continues to supply H₂O₂ system. The results of the H₂O₂ properties of ternary materials show that suitable clay minerals do not affect the performance of H₂O₂ produced by Cu₂O/2TiO₂ heterojunctions.3.The photosynthetic algae-removing performance of Cu₂O/2TiO₂ stabilized H₂O₂ system was studied by using photosynthetic microalgae aeruginosa as the object of photocatalytic degradation.By changing the light intensity,the amount of oxygen,and other conditions,the effects of changes in natural and environmental factors such as light and oxygen on the algicidal performance of Cu₂O/2TiO₂ were studied.4.The photocatalytic removal of algae from Cu₂O/2TiO₂ was performed in an O2-free system and an electron donor-added system respectively.The mechanism of photocatalytic removal of algae was explored,and a photocatalytic algae removal system capable of fully utilizing the natural conditions of algae outbreaks was established.