Preparation Of Three Layers Of Grapene Oxide Membrane And Its Removal Performance For Methylene Blue

The GO membranes can remove dyes and salts by adsorption,but its flux tends to be low.In this study,the multi-walled carbon nanotubes were filtering on a CA membrane,and the GO layer was then filtered.MCG membrane of the three layers was formed,and the presence of the insertion layer greatly improved the s than that of MG membrane,and its hydrophilicity increases.With the increase of GO dosage,the rejection rate of MCG increases,but the flux decreases.The optimal GO dosage is recommended to be 217.39 mg·-2,and the MCG flux is about 180 L·m-2·h-1·bar-1.The rejection rate for methylene blue is more than 95%,and the rejection rate for sodium sulfate is less than 20%,which shows that MCG membrane can play a good separation effect of dyes and salts.The removal rates of different charged dyestuff on MCG membrane are slightly different,indicating that the covalent bond adsorption of GO layer functional groups plays a major role in dye removal,and electrostatic action can promote dye removal to a certain extent.For MCG membrane,the removal effect of positive dye is better than that of negative dye.The effect of MCG membrane on methylene blue removal is different under different pH.In the range of pH 2～12,the larger the pH,the more negative the Zeta potential of GO,and the better the removal effect of methylene blue by MCG membrane,but the smaller the flux.Partially reduced Graphene Oxide(rGO)was prepared by low dose(1～10 kGy)irradiation of GO and partial reduction of GO.Compared with GO,rGO has fewer carboxyl groups with smaller layer spacing.XKMCG membranes were prepared using rGO instead of GO.The GO dosage of XKMCG membrane is 86.96 mg·m-2,but the removal effect of methylene blue can reach more than 98%,while the removal effect of sodium sulfate can reach the lowest 18.2%.Compared with MCG membranes,XKMCG membranes prepared with irradiated GO can achieve better removal effect with less GO amount.The optimal irradiation dose is 2 kGy.However,the hydrophilicity of XKMCG membrane is slightly lower than that of MCG membrane permeability and flux of the membrane.The surface of MCG membrane is rougher.In this study,the GO membrane prepared by vacuum filtration can effectively separate dyes and salts,and the membrane flux and the rejection rate of methylene blue can be improved by adding MWCNTs as the intermediate layer.By replacing GO with rGO prepared by y-ray irradiation,it was found that XKMCG films prepared with less amount of rGO could get the same removal effect on methylene blue.