Characterization And Preparation Of Nanocellulose-Based Hybrid Aerogels

In recent years, with the advancement of science and technology and the improvement of human living standard, environmental pollution has become increasingly serious, especially the water pollution. Under the background of sustainable development of the ecological environment, reasonably developing new biomass adsorption materials to solve current environmental pollution problems has attracted more and more attentions.Cellulose is the most widely distributed natural polymer materials in nature, which has the characteristics of biodegradability, reproducibility and low cost. With the cellulose as raw material, nanocellulose is prepared. Based on the high specific surface area and rich active functional group of cellulose, the functional hybrid aerogel, that has a three-dimensional network structure, has been designed, tailored and assembled to be used as environmental adsorption material, which has become research hotspot at present.In this research, nanocellulose has been prepared with Amorpha as the raw material through a combination method of chemical pretreatment and mechanical treatment. Then it has been used to hybridize with graphene oxide and ferriferrous oxide respectively to form aerogels on the basis of nanocellulose. Through TEM, SEM, AFM, FTIR, XRD, vibration magnetization test, the morphological features and chemical compositions of various components, the morphological features, chemical compositions and magnetic force of hybrid aerogels have been characterized and analyzed. On this basis, the adsorptions of nanocellulose-based hybrid aerogels on oil contamination, dyestuff and heavy metal ion have been further studied. Furthermore, this paper studies the effect of different proportion hybrid aerogels on adsorption performance, so as to determine the optimized ratio of materials.The main results are as follows:(1) With Amorpha as the raw material, nanocellulose with which the diameter distribution is 10-20 nm.(2) With the raw material of nanocellulose and graphene oxide prepared by improved Hummers, the nanocellulose/graphene oxide hybrid aerogel has been successfully prepared through hybridization. SEM observation indicates that nanocellulose is evenly distributed on the graphite oxide film layer, and there is no significant morphology change for them. They form the composite by physical adsorption between functional groups. When the mass ratio between nanocellulose and graphene oxide is 8:2, the hybrid aerogel has the best adsorption on the dyestuff methyl blue, and its maximum adsorption capacity is 265.6mg/g and it can be reused for many times. When a certain amount of hydrophobic agent is added to the aerogel, it will possess a certain hydrophobic oil absorption function. The static water contact angle is 132.5° and the aerogel has oil suction capacity of about 25.6 times its weight.(3) With nanocellulose and ferriferrous oxide as the raw material, the nanocellulose/ferriferrous oxide hybrid aerogel has been successfully prepared through hybrid composite. SEM result indicates that ferriferrous oxide attaches to the nanocellulose and gives a certain magnetic to the hybrid aerogel. Hysteresis curve analysis shows that the value of saturated magnetic for nanocellulose/ferriferrous oxide hybrid aerogel is 53.1emu/g, residual magnetism is 5.5emu/g and coercive force is 86 Oe, meaning that hybrid aerogel has a good ferromagnetism. When the mass ratio between nanocellulose and ferriferrous oxide is 1:1, adsorption efficiency of hybrid aerogel for Cr(?) reaches the maximum value of 52.63%.Above research results indicate that with nanocellulose as template to hybridize various functional inorganic materials, nanocellulose-based hybrid aerogel could have potential application in water pollution adsorption and purification. Based on this, designing and tailoring the advanced nanocellulose-based adsorption material, which has large specific surface area, good reproducibility and unique functions, will be the future research direction.