Preparation And Adsorption Properties Of Chitosan/Cellulose Composite Microspheres

Chitosan is non-toxic, biodegradable environmentally friendly materials with excellentadsorption performance, due to its special chemical structures. However, there are manydisadvantages about chitosan such as likely to cause dust pollution due to its small powderparticles, lack of rigidity, hard to recycle. In this paper, the composite of chitosan andcellulose was dissolved in ionic liquids ([EMIM] Ac),using anhydrous ethanol as thecoagulation bath, prepared chitosan/cellulose composite microspheres and characterized itsstructure. The adsorption performance of congo red(CR) water extract of Chinese herbalmedicine and heavy metal ions on chitosan/cellulose composite microspheres were furtherresearchd. The results of the study are as follows:1.(1)The formability and adsorption ability of chitosan/cellulose composite microsphereswere taken into consideration and concluded that, the ratio of raw materials for chitosan:cellulose=1:1, selected anhydrous ethanol as coagulation bath;(2)IR and XRD studiesshowed that chitosan/cellulose composite microspheres did not generate new chemical groupin the process of forming, belonged to physical crosslinking;(3)SEM and BET studies showedthat chitosan/cellulose composite microspheres’ surface and cross sections were full ofnumerous holes and ravines structures which could provide a large number of adsorption sites.Meanwhile, the average adsorption pore size was about15nm.2.(1)The initial concentration of CR, the contact time time, the dosage of adsorbent(chitosan/cellulose composite microsphere) and pH were all very important factors ofadsorption process. When the initial concentration of CR was30mg/L, adsorbent dosage was2.0g/L, the equilibrium of adsorption was reached at115min, removal rate was up to89.6%;(2)The maximum adsorption capacity of chitosan/cellulose composite microspherescould reach40mg/g;(3)The adsorption of CR on chitosan/cellulose composite microspheresfitted Langmuir isotherm equation well; Adsorption kinetic was well accorded withPseudo-second-order kinetic equation:roj=i.5o.[+icloer[; adsorption mechanism of CR onchitosan/cellulose composite microspheres was part dispersion.3. Chitosan/cellulose composite microspheres are mainly applied in the decoloration ofwater extract of Chinese herbal medicine and removal of heavy metal ions. The results showed that:(1)chitosan/cellulose composite microspheres had good decoloration effect onprunus cistena, momordica grosvenori, dark plum fruit, polygonum multiflorum thunb andlonicera japonica. In the process of decoloring water extract of lonicera japonica, its activeingredients (chlorogenic acid and galuteolin) could be retained well.(2)Chitosan/cellulosecomposite microspheres had different degrees adsorption ability of Zn2+Cu2+Cr3+Pb2+andCd2+. Especially for Zn2+and Cu2+, its adsorption effect was excellent. Removal rate couldreach96.58%and80.65%respectively. Moreover, adsorption capacity were7.20mg/g and6.77mg/g, respectively.