Preparation And Application Of Highly Dispersive CdS Composite Photocatalyst

Cadmium sulfide（CdS）is considered as an ideal photocatalyst due to its advantages of good light absorption and high activity.However,the serious agglomeration and photo-corrosion problems of the CdS catalyst also restrict its development.By designing and preparing novel catalyst structures,the use of CdS catalysts can be effectively solved.On this basis,coupled biological treatment systems can also help improve the defect of low mineralization rate of photocatalytic treatment technology.The in-situ CdS/PAN fibrous composite photocatalyst was successfully prepared by electrostatic spinning and hydrothermal method.Scanning electron microscope,X-ray diffraction,and transmission electron microscopy tests confirmed that CdS nanoparticles in CdS/PAN composite photocatalysts were dispersed and grown in situ on the surface and internal channels of PAN fibers,which overcomes the shortcomings of CdS particles easily agglomerated.UV diffuse reflection and photocatalytic degradation experiments prove that the highly dispersed CdS/PAN composite catalyst has enhanced light absorption capacity and excellent photocatalytic effect.In addition,the CdS/PAN composite catalyst has a three-dimensional fiber felt structure in a macroscopic view,which is soft and deformable,and has the characteristics of easy recycling.The CdS/g-C₃N₄ composite photocatalyst was prepared by a simple hydrothermal method using cadmium acetate,thiourea and melamine as raw materials.The results show that CdS nanoparticles are dispersedly attached to the surface of the g-C₃N₄ material,the particle agglomeration phenomenon is improved,and the layered structure of g-C₃N₄ is retained.The photocurrent experiments and fluorescence spectrum tests show that the synergistic effect between the binary composite structure of CdS and g-C₃N₄ makes the CdS/g-C₃N₄ composite photocatalyst exhibit excellent optical properties.In the photocatalytic degradation experiment with p-chlorophenol as the target pollutant,it was found that the CdS/g-C₃N₄ composite photocatalyst exhibited enhanced photocatalytic activity and excellent photostability under visible light irradiation.A new set of photocatalytic-biological integration system（PBIS）was designed to enhance the treatment of p-chlorophenol（4-CP）simulated wastewater,and the photocatalytic and biodegradation reactions were successfully coupled into the same reactor system.The results show that the CdS/g-C₃N₄ catalyst material is successfully supported on the surface of the graphite felt carrier,and the dense biofilm is inoculated and cultivated inside the carrier.This special structure strengthens the degradation and mineralization effect of 4-CP by the PBIS reactor.Properly increasing the amount of electron donors can improve the degradation performance of PBIS,but when the amount of sodium acetate continues to increase to 1000mg/L,excessive electron donors will have a certain inhibition effect on PBIS.After a long period of operation,the degradation of 4-CP by the PBIS reactor remained relatively stable,and the system’s mineralization performance showed a certain improvement.The stable degradation effect provided the possibility for the practical application of PBIS in the future.