A more efficient Fenton oxidation method with high shear mixing for the preparation of cellulose nanofiber (CNF) is investigated. The Fenton reaction is the reaction between Fe 2+ and H 2 O 2 to produce a series of free radicals that leads to oxidation of the cellulose. With the new technology, the Fe 2+ is preloaded into the kraft pulp by a high shear refining method to realize in situ oxidation of cellulose fibers. It is found that the carbonyl content in the fibers using high shear mixing process is 149.79 mol g −1 when the dosage of hydrogen peroxide is 0.08 g/g (weight of dry fibers), compared to the 126.40 mol g −1 of fiber without high shearing when the dosage of hydrogen peroxide is 0.15 g/g, which indicates that the new Fe 2+ pre-loading process has higher oxidation efficiency with lower H 2 O 2 consumption compared with traditional Fe 2+ preloading process. The 13 C NMR results show that the C 2 , C 3, and C 6 hydroxyl groups are oxidized to aldehyde and carboxyl groups, which is beneficial to increase the electrostatic repulsion between fibers and facilitate the subsequent homogenization treatment. The obtained CNF is uniform in size and slightly lower in thermal stability.
Cellulose and nanocellulose were used as carriers to prepare composites with antimicrobial and catalytic properties. In this reported study, di-aldehyde cellulose (DAC) was used as a raw material to prepare silver nanoparticles (AgNPs)/nano-DAC (DANC) aerogels. The AgNPs/DANC aerogels were loaded with 24.78% nanosilver. The experimental materials were characterised using ultraviolet-visible, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis. The test results showed that the AgNPs loaded on the DANC had particle sizes ranging from 3 to 14 nm, with an average particle size of 5.8 nm. The materials loaded onto the DANC were found to be elemental Ag. The specific surface area of AgNPs/DANC aerogels was 35.40 m 2 /g and the average pore diameter was 19.62 nm.
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