Preparation And Properties Of Multi-walled Carbon Nanotubes Supported On Activated Carbon-based Microporous Carbon Films

Adsorption technology is widely used in the treatment of dye wastewater due to its cost-effective advantages.Carbon nanotubes have become one of the main applications of adsorbents due to their high specific surface area.Carbon nanotubes are used as adsorbents to be dispersed in the solution.After the adsorption is saturated,solid-liquid separation is required to achieve dye removal.Therefore,the preparation of carbon nanotubes into membrane can reduce the process of solid-liquid separation,but pure carbon nanotube membrane has problems such as easy breakage of the membrane and low flexural strength.In view of the problems in the process of removing dyes from carbon nanotubes,this paper proposed to use activated carbon-based microporous carbon membrane with high flexural strength(hereinafter referred to as C membrane)as the base membrane,and first use magnetron sputtering to grow on the C membrane Ni catalyst,where Ni₃N was prepared by introducing NH₃.Then,a chemical vapor deposition(Chemical Vapor Deposition,CVD)method was used to grow multi-walled carbon nanotubes on the surface of the C membrane supporting the catalyst to prepare the C membrane(MWCNTs/C membrane)supporting the multi-walled carbon nanotubes.Under the magnetron sputtering power with 80 W,the magnetron sputtering time with 25 s,ammonia gas was introduced for 15 min at 650?,Acetylene serving as the carbon source,and the growth time was 20 min,the I_D/I_G of multi-walled carbon nanotubes was 0.83,the least defects,the highest purity.The MWCNTs/C membrane was immersed and acidified in concentrated nitric acid for 12 hours to prepare the MWCNTs/C-ac membrane.C membrane,MWCNTs/C membrane and MWCNTs/C-ac membrane were used for the adsorption of methylene blue wastewater,and the mechanism of adsorption and separation was studied.Through the optimization of process parameters(initial concentration,Multi-walled carbon nanotube growth time and p H),The removal rates of methylene blue by the C membrane,MWCNTs/C membrane and MWCNTs/C-ac membrane were 56%,96%and 96%,respectively,and showed good stability.Using the adsorption isotherm model(Langmuir and Freundlich)and kinetic model to analyze the adsorption process of methylene blue on the above three membranes,it was found that the adsorption process of methylene blue by the three membranes was more in line with the Langmuir isotherm adsorption model and the quasi-secondary kinetic model.Finally,the C membrane and MWCNTs/C-ac membrane were used to construct a membrane module for membrane adsorption and separation of methylene blue.Through optimization of process parameters(initial concentration,residence time and p H),the COD removal rate of C membrane and MWCNTs/C-ac membrane for methylene blue reached 80%and 86%,and they also showed good stability.