Separation Of Cellulose From Corncob Fermenting Ethanol Bioresidues And Preparation Of Nano-cellulose

Recently, the incompatibilities of shorting fossil resource with increasing energy need have made ligno-cellulosic ethanol become the one of most effective ways to ease the energy pressure. In the process of producing ethanol from ligno-cellulosic materials, a large amount of residues will be generated inevitably. The bioethanol production residues contains the two main components of cellulose and lignin, and lignin can be extracted to make its derivatives, thus how to utilize the cellulose to obtain valued products can be a worthy project to explore. In this paper, highly purified cellulose was separated from corn cob ethanol bioresidues by suitable purification, and the cellulose fibers fibrillated into cellulose nanocellulose after carboxymethylation-assisted mechanical action, then the influence of nanocellulose on paper properties was studied.Firstly, the whiteness of cellulose was taken as the index to determine the conditions of alkaline and bleaching treatments, then the samples of materials before and after purification were analyzed on appearance color, micro morphology and chemical composition. After purification, the cellulose content increased to 81.24%and lignin was removed almostly.Secondly, the influence of alkaline and etherifying agent dosage on degree of substitution (DS) in carboxymethylated reaction and the influence of DS on Zeta potential, particles size, nano-content yield, viscosity and transparency of cellulosic products after mechanical action were studied. The results showed that the Zeta potential, viscosity and transparency of cellulosic products increased with DS. In addition, some degree of carboxymethylation can facilitate the fibrillation of cellulose fibers, but the cellulose fibers will be water-soluble after mechanical treatment when DS exceeds a value limit, so the DS of carboxymethylated cellulose was choosed to be 0.1.Thirdly, the changes of cellulose fibers on morphology, crystallinity and thermal stability from initial state to nanocellulose were analyzed. The results showed that prepared nanocellulose had the dimensions of 5～20 nm in width and mostly 100～300 nm in length; The carboxymethylation can reduce the crystallinity and thermal stability of cellulose, and the crystallinity of nanocellulose was 61.9%, and the started degradation temperature and maximum degradation rate temperature were 250 ℃ and 320 0C, respectively.Finally, compared to eucalyptus chemical pulp nanocellulose, corn cob residues nanocellulose or PAE/nanocellulose system were added into paper pulp to investigate their effects on paper properties. The results proved that PAE/nanocellulose bicomponent system was better than individual nanocellulose in enhancing paper strength. For individual nanocellulose, the enhancement effect of pulp nanocellulose on paper properties was better than residues nanocellulose, and for PAE/nanocellulose bicomponent system, the enhancement effect of PAE/residues nanocellulose bicomponent system was better than PAE/pulp nanocellulose system. When the PAE and residues nanocellulose usage were 0.5, 5 percent of dry pulp weight, the tensile,burst and tear index of paper were increased by 88.0%, 179.4% and 59.2% than referenced paper.