Preparation Of Molybdenum Disulfide/sepiolite Composite And Its Application In Water Treatment

As a typical semiconductor material,Mo S₂ is widely used in the degradation of dye wastewater due to its excellent photocatalytic properties.However,nano-Mo S₂ is easy to reunite,which leads to recombination of electron-hole pairs and low photocatalytic efficiency.The sepiolite mineral nanofibers are suitable as a carrier for the catalyst due to large specific surface area,high porosity,and good adsorption,dispersion and stability.The sepiolite mineral nanofibers as a functional carrier of molybdenum disulfide can save costs,improve photocatalytic performance,and broaden the application range of sepiolite mineral materials.In this work,using ammonium molybdate and thiourea as molybdenum source and sulfur source respectively.The molybdenum disulfide/sepiolite composite was synthesized by microwave hydrothermal method.At the same time,the changes of different process parameters about the crystal structure,micro morphology and properties of the composites were analyzed by XRD,FTIR,SEM,TEM,STEM and N₂ adsorption-desorption.The reasons for the improvement of photocatalytic performance were analyzed,and the photocatalytic mechanism was also discussed.On this basis,the microstructure of the composites were regulated and the performance was optimized.The experimental results showed that the optimal process conditions of the composites were as follows:microwave hydrothermal temperature of 220°C,hydrothermal time of 3 h,and sepiolite content of 8%（total mass ratio to molybdenum source and sulfur source）.The photocatalytic performance of the composites was the best for rhodamine B（Rh B）solution,and the degradation rate was 90%.,which was about 2.5 times that of pure molybdenum disulfide.On the basis,the composites prepared by SDBS with a concentration of 1.0 mmol/L had the best morphology,structure and photocatalytic activity,and the degradation rate of Rh B reached 93%.In order to further explore the photocatalytic mechanism of composite materials,different trapping agents were used to capture holes and free radicals.The results showed that h⁺and·O₂^-were the main active substances in the photocatalytic degradation of Rh B,and played a major role in the degradation.In addition,the porous structure and good adsorption properties of sepiolite can provide more surface active sites for the adsorption of Rh B,which is beneficial to the photocatalytic reaction.The new structure formed by the molybdenum disulfide/sepiolite composite generates an interaction between charges and promotes the separation of photogenerated charges,which has potential application value in the preparation of molybdenum disulfide composites for the degradation of dye wastewater by using one-dimensional mineral as carrier.