Study On Preperation And Adsorption Properties Of Functionalized Cellulose Composite Aerogel

With the rapid development of printing and dyeing technology,a variety of complex industrial synthetic dyes have been widely utilized.They are difficult to biodegrade,which impair the health of lives on earth.Dye wastewater purification has become one of the urgent problems to be solved for protecting the environment.The adsorption technology has attracted much attention due to its advantages of high efficiency,simple operation and low cost.Compared to synthetic polymer materials,cellulose,as the most abundant natural renewable polymer material on earth,has the unique advantage of being environmentally friendly,which is an ideal material for adsorbents for sewage treatment.Cellulose aerogel has been proven to be used for the adsorption and removal of dyes in printing and dyeing wastewater,but due to the negatively charged hydroxyl groups on its surface,the adsorption capacity of cellulose aerogel in anionic dyes is limited.To improve the adsorption capacity of cellulose to anionic dyes and take environmental protection and economy into account,cationic cellulose(CCEs)are prepared through dissolving and grafting from natural cotton linter cellulose in this work.SEM,TG and XPS characterizations confirm the successful grafting of cationic groups.Zeta potential shows that the prepared CCEs have a stable positive surface charge.On this basis,CCEs were prepared into cationic cellulose aerogels(CCAs)through chemical cross-linking and freeze-drying processes.SEM,FTIR and NMR characterizations confirm the formation of chemical crosslinks.CCAs have stable mechanical properties.The dye adsorption test finds that the removal rate of CCAs for anionic dye Eosin Y increase from 5.31%of CA to 99.58%,and it can selectively remove anionic dyes from mixed dyes,which is due to the electrostatic attraction between the positive charge of CCAs and anionic dyes.The adsorption process of CCAs towards dyes conforms to the pseudo-second-order kinetic model,Langmuir isotherm model and Weber-Morris intraparticle diffusion model.As a new type of cationic cellulose aerogel,CCAs not only has a high adsorption capacity for anionic dyes(364.22 mg/g)but also possesses resistance to a fickle environment and reusability.As-prepared aerogel is a promising candidate for the decontamination of anionic dyes from industrial wastewater.