Cationic cellulosic derivatives as flocculants in papermaking

Abstract

7 Abstract Water-soluble cationic cellulose deriva-8 tives were synthesized by three different procedures, 9 cationizing bleached hardwood kraft pulp with (3-10 chloro-2-hydroxypropyl) trimethylammonium chlo-11 ride. The first procedure involved a previous depoly-12 merization step with orthophosphoric acid. The 13 second one consisted on dissolving cellulose in 14 NaOH/urea before cationization. For the third proce-15 dure, the reaction medium was heterogeneous since it 16 was carried out with a part of cellulose with high 17 degree of polymerization. Oppositely to the common 18 methods, cationization occurred under mild condi-19 tions. Differences among the three derivatives are 20 illustrated by X-ray diffraction patterns of pretreated 21 samples, infrared spectra, and determinations of the 22 degree of substitution, the zeta potential, the charge 23 density and the molecular weight. The performance of 24 these polyelectrolytes for the flocculation of mineral 25 fillers used in papermaking was tested by laser 26 diffraction spectrometry. The flocculant with the 27 highest degree of polymerization and charge origi-28 nated the best results, particularly when the filler used 29 was kaolin, proving that water-soluble cationic cellu-30 lose derivatives can aid in the flocculation of fillers 31 used in papermaking. On the contrary, the shortest-32 chained derivative was not effective. The results were 33 interpreted in terms of the characteristics of the 34 cellulose derivatives flocculants and of the fillers, 35 and neutralization and patching were proposed as the 36 dominant mechanisms. 37Keywords Cationization Á Cellulose Á Fillers for 38 papermaking Á Flocculation Á Laser diffraction 39 spectrometry 40 Introduction 41 Non-renewable and scarcely biodegradable polymeric 42 aids, such as cationic polyacrylamides (CPAM) or 43 polyethyleneimine (PEI), are often applied in paper 44 mills to achieve good retention of mineral fillers. The 45 particle size of these fillers is generally much smaller 46 than the wire mesh at the forming and drainage section 47 of the paper machine, and thus mechanical retention A1 Electronic supplementary material The online version of A2 this article

Cationization of Eucalyptus wood waste pulps with diverse lignin contents for potential application in colored wastewater treatment

“…The reaction vessel was covered with aluminium foil to prevent the photo-induced decomposition of periodate and placed in an oil bath. 7.2 g of LiCl and 8.2 g of NaIO 4 were then added to initiate the reaction. The reaction mixture, at pH 3.0 (measured at 25 C), was stirred with a magnetic stirrer and kept at the desired temperature of 75 C for 3 h. Aerwards, the suspension was cooled, and the product was ltered off and washed thoroughly with distilled water to remove iodine-containing compounds.…”

“…NaOH/ urea, NaOH/thiourea or LiOH/urea, which are pre-cooled to zero degrees, followed by (ii) cationization in homogeneous medium with (3-chloro-2-hydroxypropyl)trimethylammonium chloride (CHPTAC), as described in the literature. 4,5 Another approach refers to cationization of pre-modied cellulose, by using dialdehyde cellulose 6,7 or cellulose acetate, 8 among other materials. The third approach involves introduction of monomeric or polymeric cationizing agents into the cellulose backbone by gra copolymerization.…”

Industrial Application of Nanocelluloses in Papermaking: A Review of Challenges, Technical Solutions, and Market Perspectives

“…It can avoid or minimize the requirements of other synthetic retention systems and flocculants. This would make the process more cost-efficient by improving both the retention of NC and mineral fillers and the mechanical properties [81]. There are numerous methods to cationize NC, as shown in Table 2.…”

The relevance of the pretreatment on the chemical modification of cellulosic fibers

“…Modified starches are widely used as wet-end additives, but fibers are always essentially composed of native cellulose, even though they could also attain interesting functionalities. For instance, inserting cationic functional groups, commonly quaternary ammonium, into the structure of cellulose fibers and/or fines can compensate their negative charge density (Sood et al 2010), improve the internal bond strength of paper (Montplaisir et al 2006), diminish the dependence on poorly biodegradable polymeric aids (Aguado et al 2017), and decrease drainage time during sheet forming (Mayr et al 2017). Sehaqui et al (2016) produced cationic cellulose nanofibers with quaternary ammonium groups, and proved their usefulness in water treatment processes, as they could retain fluoride, nitrate, and other anions.…”