A Fenton-like System (Cu(II)/H₂O₂) for the Preparation of Cellulose Nanocrystals with a Slightly Modified Surface

Abstract

A preparation process of cellulose nanocrystals using a Fenton-like system was presented. Rod-shaped cellulose nanocrystals were isolated after treatment in the H2O2/acetic acid/2–6 mol % copper acetate system. The morphology and sizes of rod-shaped particles were determined by AFM (atomic force microscopy) and cryo-EM (cryo-electron microscopy). X-ray diffraction proves that the prepared particles have a natural polymorphic modification of cellulose I with a high crystallinity index. Thermogravimetry data indicates a slight decrease in thermal stability of the particles when compared to starting cellulose, correlating with an increase in the number of carbonyl groups determined by chemical analysis. Using pK spectroscopy, active acid–base surface sites (pK i 5.5 and 7.9) were quantitatively determined. The cellulose nanoparticles formed stable hydrosols. Using photometry and dynamic light scattering, it has been established that the critical concentration of coagulation of sols is 76 mM KCl.

The Physicochemical Method Uses Industrial Leftover Hemp Fibre Cellulose to Make Micron-Sized Hemp Powder

“…On the other hand, the HP had the highest roughness (d-h) because of The High-speed operation using different kinds of blade-focused powders, which were randomly sheared and crushed in various directions [26]. It was hard to ensure uniform crushing of each point on the surface of the powder [26,27].…”

Magnetic recoverable Cu/CuFe2O4 nanocomposite as an efficient catalyst for 4-nitrophenol reduction and methylene blue degradation

“…Những kết quả nghiên cứu gần đây nhất cho thấy, phản ứng khử 4-NP trong dung dịch nước khi sử dụng lượng dư natri borohydride (NaBH 4 ) và các chất xúc tác ferrite được xem là tối ưu do phản ứng đơn giản cùng hiệu quả khử 4-NP cao [16][17][18][19] . Riêng đối với MB, đã có rất nhiều phương pháp được đề nghị để xử lý loại phẩm nhuộm hữu cơ này trong nước thải [20][21][22][23][24] . Trong số đó, phương pháp đang được sử dụng khá phổ biến là phân hủy MB thông qua các quá trình oxi hóa nâng cao dựa trên các phản ứng có sử dụng xúc tác Fenton, cả Fenton đồng thể và dị thể [25][26][27] .…”

Efficient (Bio)emulsification/Degradation of Crude Oil Using Cellulose Nanocrystals

“…Additional treatment of CNC-that is, removal of sulfate groups from the surfaces of nanocrystals-leads to a reduction in the surface charge to −35 mW, which has a favorable effect on their emulsifying ability. Recently, there have also been methods developed for the direct extraction of CNCs with a composition and nanocrystal properties that are more suitable for these purposes [14].…”