Efficiency of Chitosan and their Combination with Bentonite as Retention Aids in Papermaking

BioResources

Angeles Blanco¹  Raluca Nicu²  Ruben Miranda³  Elena Bobu⁴ 

[1] Romania;Spain;Department of Chemical Engineering, Faculty of Chemistry, Complutense University of Madrid, Av. Complutense s/n, 28040, Madrid, Spain;Department of Natural and Synthetic Polymers, “Gheorghe Asachi” Technical University of Iasi, Prof. Doc. Dimitrie Mangeron 73, Iasi, 700050, Romania;

关键词: Chitosan;    Retention;    Drainage;    Bentonite;    Flocculation;    Retention aids;   

DOI  :  10.15376/biores.11.4.10448-10468

来源: DOAJ

【 摘 要 】

In a previous work (Nicu et al. 2013), the flocculation efficiency of three chitosans differing by molecular weight and charge density were evaluated for their potential use as wet end additives in papermaking. According to the promising results obtained, chitosan (single system) and its combination with bentonite (dual system) were evaluated as retention aids, and their efficiency was compared with poly(diallyl dimethyl ammonium chloride) (PDADMAC) and polyethylenimine (PEI). In single systems, chitosan was clearly more efficient in drainage rate than PDADMAC and PEI, especially those with the lowest molecular weights; however, retention is considerably lower. This drawback can be overcome by using dual systems with anionic bentonite microparticles, with the optimum ratio of polymer:bentonite being 1:4 (wt./wt.). In dual systems, the differences in retention were almost negligible, and the difference in drainage rate was even higher, together with better floc reversibility. The most efficient chitosan in single systems was Ch.MMW, while Ch.LMW was the most efficient in dual systems. The flocculation mechanism of chitosan was a combination of patch formation, charge neutralization, and partial bridge formation, and the predominant mechanism depended on the molecular weight and charge density of the chitosan.

【 授权许可】

Unknown