Preparation Of Cellulose-Based Hydrophilic/Hydrophobic Materials And Their Application In Oil-Water Separation

The industrial production process will produce a large amount of oily wastewater,which will cause great harm to the environment.Therefore,it is very important to develop efficient oil-water separation methods.However,it is still difficult to achieve efficient separation of small droplets oil-water emulsions from the micron to nanometer range.Cellulose has a porous structure with rich physicochemical properties,making it easy to chemically modify into a wettable material for oil-water separation.A variety of cellulose separation membranes with different wetting properties demonstrate their high performance in oil-water separation.For the preparation of cellulose separation membranes with special wetting properties for separating oil-water emulsions,the following works have been done.1.For the water-in-oil emulsion,four kinds of MOFs,UIO-66,MOF-199,ZIF-8and MIL-101,were synthesized in situ on ordinary quantitative filter paper to obtain cellulose-compliant CFP@MOFs with micro-level and nano-level ordered structures.Further,the low surface energy compound octadecyltrichlorosilane（OTS）is modified on the surface of the filter paper by hydrolysis impregnation.The paper-based materials CFP@MOFs@C₁₈with higher hydrophobicity were obtained.The results of material surface morphology tests and compositions analysis shew that several MOFs were successfully synthesized on the surface of the filter paper and long-chain silanes were also successfully modified on the surface of CFP@MOFs.The wetting performance test of several paper-based matrix materials shows that they have good hydrophobic properties.Subsequently,the separation effects of four membrane materials on various water-in-oil emulsions were tested,and found that the highest separation rate could reach 99.93%.2.For oil-in-water emulsion,it proposed to use hydrogel to modify the traditional filter paper to make it wettable,so that the hydrogel modified filter paper can separate pure water from the oil-in-water emulsion.Polyvinyl alcohol（PVA）-chitosan（CS）composite hydrogels and calcium alginate（CaAlg）-protocatechuic acid（PCA）were used as surface materials to form FP@PVA-CS and FP@CaAlg-PCA hydrogel filter paper composites,respectively.The performances of FP@PVA-CS and FP@CaAlg-PVA hydrogel filter materials were also investigated for the removal of organic solvents from oil-water emulsions,with separation efficiencies of up to 99.95%and reusability of more than 6 times.