Preparation And Properties Of Functionalized Dialdehyde Cellulose

High-crystalline cellulose spheres?Ces?were used as original materials,which were first cross-linked with citric acid to produce cross-linked cellulose?CACes?,and then oxidized by periodic acid to break the C2-C3 bonds on the ring of glucose units to form dialdehyde cellulose spheres?DACes?.Schiff base reaction could occur by aldehyde groups on DACes with other substances,producing a series of derivatives with specific properties.The natural polysaccharide composites could be prepared by combination between the modified cellulose and the amino groups of the chitosan matrix through the C=N double bond.CACes and DACes fillers were incorporated into chitosan matrices resulting in improved mechanical and moisture barrier properties of the composites at different relative humidities.DACes with 65%aldehyde performed well among the CACes and DACes fillers,and enhanced the tensile strength from26.8 MPa for the chitosan film to 58.2 MPa for the composite with 6%filler,while the water vapor permeability?WVP?decreased to 0.98×10^-6 from 1.37×10^-6 g·m^-1·h^-1·Pa^-1 at relative humidity of 75%.The composites also exhibited better barrier properties against UV light.Urease was respectively immobilized on DACes with 19%,31%and 45%aldehyde contents to obtain three kinds of immobilized ureases?UrCes?.The maximum removal capacities of them for urea were 243.3,276.2 and 187.6 mg·g^-1,while only 10.71,15.08 and 20.50 mg·g^-1 L-phenylalanine were adsorbed,respectively.UrCes had both a greater adsorption capacity for urea and a greater specific selective adsorption than DACes,as well as easier separation from the reaction system and good reusability.Amino-functionalized cellulose?ADAC?was prepared by DACes grafting with ethylenediamine.Zeta potential of ADAC was significantly affected by the pH value.It was positive at low pH and became negative in the alkaline region.As an adsorbent,ADAC could remove anionic dye?MO?and cationic dye?MB?in solution at different pH,showing good adsorption capacity.Adsorption of dyes on ADAC surface followed the pseudo-second-order kinetics model and the Langmuir isotherm model.The maximum adsorption capacity of ADAC for MB and MO were 70.77 mg·g^-1 and42.92 mg·g^-1,respectively.