Preparation And Application Of Molybdenum Disulfide （MoS₂） With Widened Interlayer Spacing

Environmental pollution and excessive energy consumption are two major problems existing in the process of industrialization in China,which need to be solved in a timely manner.In this paper,the removal of Cr（Ⅵ）pollutants in water and the reduction of locomotive lubrication were studied.The main contents include MoS₂,especially the preparation method of MoS₂with widened interlayer spacing,the removal of Cr（Ⅵ）in water with widened MoS₂,and the performance study of MoS₂ as a friction reducer for solid lubricating materials.The specific work and results are as follows:1.A simple hydrothermal synthesis method was used to prepare oxygen-doped MoS₂nanosheets（O-MoS₂）by controlling reaction temperature with ammonium tetrahydrate(H₂₄Mo₇N₆O₂₄·4H₂O)and thiourea（CH₄N₂S）as precursors,and applied it to the removal of Cr（Ⅵ）in water.The characterization results showed that the interlayer spacing of the prepared O-MoS₂ was 9.52（?）,which was significantly wider than that of the traditional 2H-MoS₂（6.2（?））.O-MoS₂also showed excellent performance on the removal of Cr（Ⅵ）in water.When simulating the life and industrial waste water（pH is about 5 or so）,the removal rate of Cr（Ⅵ）remained at around 58.33%,adsorption capacity was up to 58.33 mg/g,and in the whole wide pH range（3～11）,it could still have a better removal effect of Cr（Ⅵ）.As the raw material is easy to be obtained,the preparation method is simple,the price is low,and it will not cause secondary pollution to the environment,thus,O-MoS₂ material has a good practical application prospect in water treatment.2.A PVP-intercalated MoS₂-based composite（MoS₂/PVP）was prepared by using a simple surfactant-assisted hydrothermal synthesis method with sodium molybdate（Na₂Mo O₄·2H₂O）and thioacetamide（CH₃CSNH₂）as the precursor by adjusting the amount of surfactant PVP added to the system,and was applied to the removal of Cr（Ⅵ）in water.Characterization results showed that the MoS₂/PVP interlayer spacing increased to 7.27（?）,and showed excellent performance in the removal of Cr（Ⅵ）in water.When simulating the life and industrial waste water（pH is about 5 or so）,the removal rate of Cr（Ⅵ）reached up to 71.15%,the adsorption capacity was up to 71.15mg/g,and compared with O-MoS₂,the removal rate of Cr（Ⅵ）increased by 12.82%.In the whole wide pH range（3～11）,it could still have a better removal effect of Cr（Ⅵ）.MoS₂/PVP material has a good practical application prospect in water treatment due to its simple preparation method,easy availability,low price and no secondary pollution to the environment.3.Single-component epoxy resin-based self-lubricating composite materials were prepared by simple blending and casting method,with epoxy E-51 as the matrix,MoS₂as the filler and 593 as the curing agent to cure and shape the resin at 60℃.When the filling ratio of MoS₂ is 30%,it shows the optimal wear-resistance effect,the weight wear rate is only 0.08 g/h.When the prepared lubricating block was applied to a real train,a lubricating block with a mass of 90 g can provide lubrication for a continuous section of about 120,000 kilometers.The O-MoS₂ nanosheets prepared by the modified preparation method was also used as a friction reducing agent to prepare the lubricating block,when the addition amount was 3%,the wear rate of the lubricating block obtained was only 0.30 g/h,and the wear-resistance effect was equivalent to that of 10%commercial grade MoS₂.