| Water plays an important role in the maintenance of human life and the development of a sustainable society.However,water pollution is becoming more and more serious with the rapid growth of the population and the rapid development of industry.Recently,more and more oily wastewater,the discharge of dyes wastewater is not conducive to the protection of water resources,and must be well treated.Among various sources of water pollution,insoluble（e.g.oil and aromatic compounds）and soluble（e.g.,dye）organics are major pollutants.Also,there are a lot of bacteria or other contaminants in practical wastewater environment,easy to form biofouling on the surface of the materials,resulting in oil/water separation materials to be contaminated,thus reducing the separation efficiency.Therefore,facing the complex wastewater environment,it is more urgent and important to research and develop multifunctional wastewater treatment materials.As the most abundant biological matrix material on the earth,cellulose has the merits of good chemical stability,hydrophilicity and biodegradability.Cellulose-based aerogels is porous,which can be used as oil-water separation materials,and can also adsorb dyes in wastewater.Based on this,the main object of this thesis is the following three aspects:（1）Using cellulose as the raw material,NaOH/urea/water solution as solvent,first,the cellulose-based aerogels were prepared by sol-gel and freeze drying.Then a functional monomer（2-（Dimethylamino）ethyl methacrylate,DMAEMA）was introduced on the surface of cellulose-based aerogel by ATRP（atom transfer radical polymerization）.The cellulose-based aerogel has high selectivity,and exhibit switchable wettability.The material can be transformed between superhydrophilicity with a water contact angle（WCA）of 0°and hydrophobicity（WCA 130°）by modulating pH or temperature,so it can be well applied to oil/water separation.The functionalized cellulose-based aerogels could be used to absorb the water under 60oC（pH=7.0）or pH is 1.0（T=25oC）,while absorb oil underwater when the temperature is above 60 oC（pH=7.0）or pH is 13.0（T=25oC）,and it is reusable.This pH,temperature intelligent response surface,has a double switch to control the wettability of the material surface.（2）In this experiment,similarly,using cellulose as the raw material,cellulose（CE）/quaternary cellulose（QCE）composite aerogels were prepared,and then polydopamine（PDA）/polyethylenimine（PEI）was co-deposited on the surface of CE/QCE composite aerogels.The modified aerogels is superhydrophilic（WCA=0°）and underwater superoleophobic（underwater oil contact angle>150o）,and have antifouling and antibacterial properties,can not only be used in oil-water separation,after repeated filtration for 10 times,the aerogel still has a good separation efficiency（>99%）,it can also separate the oil-in-water emulsion,meanwhile,it has good adsorption effect on dye,taking alizarin red as a model dye,its maximum adsorption capacity is 454.545 mg g-1.This kind of material with many functions has a good prospect in the field of water treatment.（3）With cellulose as raw material,preparation of CE/QCE composite aerogels,One step polymerizationofacrylatemonomer（[2-（Methacryloyloxy）ethyl]dimethyl-（3-sulfopropyl）ammonium hydroxide,SBMA）under the initiation of dopamine and co deposition on the surface of composite aerogel,PDA/PSBMA coating gives the aerogel superhydrophilic（WCA=0°）and underwater superoleophobic（underwater oil contact angle>150o）properties,the oil/water mixture can be separated efficiently,after repeated 10 times,the separation efficiency of aerogel is still up to99%.The existence of QCE materials with the function of dye adsorption（choose Congo Red as the model dye,the maximum adsorption capacity is 833.333mg g-1）and antibacterial.The multifunctional material,which can adsorb dye,oil/water separation,and antibacterial,has good practicability for complex operation conditions and complicated sewage environment in wastewater treatment. |
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