A More Efficient Fenton Oxidation Method with High Shear Mixing for the Preparation of Cellulose Nanofibers

Abstract

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.

One-Step Treatment for Upgrading Bleached Bamboo Pulp to Dissolving Pulp High Solvency in Green Alkali/Urea Aqueous Solution

“…A schematic diagram of the bleached bamboo pulp upgrades to a high-solvency bamboo pulp in the alkali system by regulating M η with OH originating from NaOH/H 2 O 2 is shown in Figure 2 a. As shown in Figure 2 b, hydroxyl radicals are able to react with hydroxyl groups at C6, C3, C2, and C1 of the cellulose chains in the alkaline solution system [ 51 , 52 , 53 ] and form various cellulose oxidation products ( Figure 2 c). [ 37 , 54 ].…”

Pine sawdust modification using Fenton oxidation for enhanced production of high-yield lignin-containing microfibrillated cellulose

“…In thermomechanical pulping (TMP), an interstage treatment between primary and secondary refiners with Fenton's reagent has been found to decrease the refining energy consumption by up to 35 % (Walter, 2013). Fenton chemistry has also been studied as a pre-treatment method to enhance the production of microfibrillated cellulose (Hellström et al, 2014) and cellulose nanofibrils (Duan et al, 2020;Q. Li et al, 2019) from bleached kraft pulp, i.e.…”