Preparation And Characterization Of Nano-silver Loaded Nanocellulose Aerogel

In this study,a kind of nanocellulose aerogel with high silver content was prepared.The aerogel was found to fix AgNPs for easy recycling of the AgNPs catalyst.Softwood bleached kraft pulp(SWBK)used as a raw material to prepare silver nanoparticles/nano-dialdehyde cellulose aerogels using a periodate oxidation pretreatment.The silver nanoparticles/dialdehyde cellulose were loaded with 24.78%nanosilver.Investigated the impacts of periodate oxidation pretreatment reaction time on the cellulose and fiber of SWBK.The surface morphology and structure of silver-loaded cellulose were characterized.SWBK was pretreated with sodium periodate oxidation.Investigated the effects of different oxidation time on SWBK and the cellulose.The fiber morphology analysis results show that the length and width of SWBK were descended as the time extension of sodium periodate oxidation.Decigrex of fibers were increased.The zero-distance tensile strength of the fiber was reduced because of fiber damage.With prolonged oxidation time,there was obvious stripes or crack on surface of fibers from SEM spectra.As the time extension of sodium periodate oxidation,the aldehyde group content of dialdehyde cellulose obtained after oxidation for 4 h was 3300 ?mol/g.The degree of polymerization of the fiber decreased rapidly from 1140 to 525.XRD spectra indicated that the crystallinity of the fibers decreased with the increase of oxidation time.SWBK maximum decomposition rate of temperature is 369.06? higher than that of dialdehyde cellulose decomposition rate of the largest temperature.Silver nanoparticles/dialdehyde cellulose(AgNPs/DAC)were characterized by UV-Vis spectroscopy,in which there was an absorption peak at 400 nm.The results show that the silver nanoparticles loaded on dialdehyde cellulose are spherical or quasi-spherical.The silver nanoparticles were 0.223-0.624?m with an average diameter of 0.371 ?m.Silver nanoparticles loaded on nano-dialdehyde cellulose had particle sizes ranging from 3 nm to 14 nm,with an average particle size of 5.8 nm.The silver content of dialdehyde fiber was related to the aldehyde group content,among which the silver content of AgNPs/DANC aerogel prepared by sodium periodate oxidation for 1 h and 4 h is 5.69%and 24.78%,respectively.AgNPs/DANC aerogel prepared from dialdehyde cellulose oxidized by sodium periodate for 4h was used as catalyst to catalyze methylene blue(MB)decolorization reaction.MB decolorizing reaction optimum reaction condition was:under 35?,add 0.15 g of AgNPs/DANC aerogel and 2 mL of H2O2 to 50 mL MB at a concentration of 100?mol/L.MB decolorization reaction conformed to the first order kinetic equation.The apparent rate constant of MB decolorization was affected by reaction temperature,H2O2 dosage,AgNPs/DANC aerogel quality and initial MB concentration.