Preparation Of ZnO And Composites And Photocatalytic Degradation Of Methyl Orange Dyes

The treatment of the pollution in water is vital to environmental protection in recent years.Among these the industrial waste such as coking waste-water metallurgical enterprises produced is one of the waste-water which is difficult to deal with.These stuff not only pollutes the ecological environment,but also does great harm to the human beings.Therefore,it is necessary to find a kind of industrial waste water treatment technology with low running cost,strong decontaminating ability,less prone to secondary pollution and wide range of use.Photocatalysis has provided a kind of green practically approach which has a wide application prospect in the field of energy and environmental to disposal of waste water depending on its wide applicability and sensitivity to toxic matter.Photocatalytic technology as a high-level oxidation technology can use sunlight to mineralize organic pollutants into H₂O and CO₂,will not cause secondary hazards to the environment.Among those photocatalysts,ZnO is widely studied due to its high catalytic activity,security,non-toxic,long life and other advantages.In this paper:?1?five kinds of ZnO were prepared by hydrothermal method,and then the influence of the photocatalytic properties of ZnO of the morphology,crystal structure,molecular oxygen,pH and other factors were studied.?2?Then the magnetic Fe₃O₄@ZnO-GO?graphene oxide?photocatalyst with visible light responseprepared were synthesis by hydrothermal method,and photocatalytic properties of the photocatalyst were discussed.The main results are as follows:?1?By controlling the content of complexing agent in the hydrothermal reaction,five kinds of morphology of ZnO materials were prepared with alkali content and reaction temperature,and the microstructure was explored by XRD?TEM?BET?XRD and UV-vis techniques.The catalyst degradation performance of methyl orange under ultraviolet show that:the ZnO belongs to the wurtzite type crystal;the five kinds of morphology of ZnO photocatalytic degradation reaction of the material is a first-order reaction.The MO photocatalytic degradation efficiency were as follows:nanorod?72.6%??nanoflower?77.5%??nanosheet?68.6%??nanopompon?84.4%??nanospherica?62.1%?;the degradation performance was more excellent rate when surface area is greater;five kinds of morphologies of ZnO photocatalytic materials in addition to the nano-sheet structure,crystallinity was positively correlated with the degradation efficiency.The photocatalyst dosage,initial dye concentration and the concentration of oxidant has inverted U type relation between the degradation efficiency of MO;pH value of the solution is on the contrary.ZnO photocatalyst light exists serious corrosion,and it was not easy to recover.So pure ZnO photocatalysts was not applicable to repeated use.?2?Fe₃O₄@ZnO-GO were preparation with different doping ratio by hydrothermal synthesis,Fe₃O₄@ZnO-GO was wurtzite type,indicate that the loading of GO,would not change the lattice constant.Photocatalytic degradation experiments draw the following conclusion:doped GO could greatly improve the photocatalytic properties of the photocatalyst.The photocatalytic reaction mainly occurs on the surface of Fe₃O₄@ZnO.GO was not directly involved in the photocatalytic reaction,but will reduce the photoinduced electron transfer electron recombination,thus improving the photocatalytic efficiency rate of the composite.When Fe₃O₄@ZnO and GO composite ratio was 0.8:0.2,the composite showed the best photocatalytic performance.At the same time,the magnetic properties of Fe₃O₄@ZnO-GO composite materials can be achieved by applying an external magnetic field separation,finite repeated use.Therefore,Fe₃O₄@ZnO-GO composites the photoelectrochemical properties of this enhanced is the ideal candidate materials for organic matter removal in wastewater.