Study On Preparation And Application Of Cuprous Oxide And Its Composite Film

Various new materials show great advantages in removing pollutants（heavy metals and dyes）from water bodies.How to obtain various new materials in batches at low cost is very important to solve the problem of environmental pollution.Cuprous oxide（Cu₂O）is a P-type semiconductor,which can be used as a photocatalyst to degrade organic pollutants in water.Polyvinyl alcohol（PVA）is a polymer material that is easy to form films.A large number of hydroxyl groups（-OH）on the molecular chain of PVA give it water solubility and chemical activity;Sodium carboxymethyl cellulose（CMCNa）has a large number of carboxyl groups（-COOH）,-OH and-COOH can be condensed and react with excess metal ions(such as Cu²⁺).Based on the above materials,firstly,the process parameters of Cu₂O powder preparation at room temperature were studied,and its removal performance of pollutants was explored.Then,PVA/CMCNa composite film was successfully prepared by blending the self-made amino（-NH₂）-PVA100 and CMCNa as raw materials,and the enrichment rule and possible mechanism of Cu²⁺were studied.Finally,PVA/CMCNa/Cu₂O composite film was successfully obtained by reducing and concentrating a certain amount of Cu²⁺with VC aqueous solution,and its photocatalytic removal performance of rhodamine B（Rh B）dye was explored.The main conclusions are as follows:1、At room temperature,hydrazine hydrate（HH）,ascorbic acid（VC）and lactose（LAC）can form soluble coordination ions with Cu²⁺,which can be reduced to Cu⁺（Cu₂O）.Among them,HH has the fastest reduction rate of Cu²⁺,and the size of Cu₂O octahedron obtained after reaction is about 80nm.VC reduced Cu²⁺quickly,resulting in irregular Cu₂O particles with an average size of 120nm.The reduction of Cu²⁺by LAC was the slowest,resulting in Cu₂O microsolids with a particle size of about 1.5μm.In comparison,Cuboscopic Cu₂O has higher visible light catalytic activity and regeneration ability.2、Different PVA/CMCNa composite films were prepared by flow casting method by controlling the proportion of aminated PVA100 and CMCNa.The results of batch adsorption experiments show that PVA/CMCNa composite membrane can rapidly enrich Cu²⁺,Ag⁺and other metal ions in water.The Cu²⁺enrichment kinetic process of PVA/CMCNa composite membrane satisfies the quasi-second-order kinetic equation,and the thermodynamic process conforms to Freundlich model.The coordination bonds between Cu²⁺and-NH₂,-OH and-COOH groups in the composite membrane may be the mechanism of Cu²⁺enrichment in the membrane.3、The results show that the coordinated Cu ions in PVA/CMCNa composite membrane can be quickly reduced by VC aqueous solution,and Cu₂O particles with different sizes（average size is 0.7μm）are formed in the membrane.The dispersion and binding force of Cu₂O particles formed in situ in PVA/CMCNa composite membrane are higher.The photocatalytic experiments showed that the composite film had excellent photocatalytic activity and the kinetic process of Rh B dye degradation in water was in accordance with the quasi-second-order kinetic equation.Synergetic regulation of photoelectron transfer between several phase interfaces in the composite film is a possible mechanism for the enhancement of photocatalytic activity of the composite film.