1. Locust bean gum adsorption onto softwood kraft pulp fibres: isotherms, kinetics and paper strength
- Author
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Jingqian Chen, Heather L. Trajano, and Rodger P. Beatson
- Subjects
Softwood ,Polymers and Plastics ,Chemistry ,Adsorption isotherms ,Pulp (paper) ,Locust bean gum ,Langmuir adsorption model ,engineering.material ,Northern bleached softwood kraft ,Hemicellulose ,Northern bleached softwood kraft pulp ,symbols.namesake ,chemistry.chemical_compound ,Adsorption kinetics ,Adsorption ,Paper strength additive ,Chemical engineering ,Kraft process ,Chemisorption ,symbols ,engineering ,Original Research - Abstract
The adsorption of locust bean gum (LBG) onto Northern Bleached Softwood Kraft (NBSK) pulp improved paper tensile and burst strength and lowered refining energy by strengthening inter-fibre bonding. Adsorption kinetics and isotherms were investigated to develop a fundamental understanding of the adsorption mechanism. The adsorption rate followed pseudo-second-order kinetics and the activation energy was 99.34 kJ·mol−1, suggesting chemisorption. The adsorption rate constant increased rapidly with temperature from 25 to 45 °C (k = 1.93 to 24.03 g·mg−1·min−1), but the amount adsorbed at equilibrium decreased (qe = 1.91 to 0.48 mg·g−1 o.d. fibre). LBG adsorption to NBSK at 25 °C was consistent with the Langmuir adsorption model for LBG n = 5.00, and the equilibrium constant Kf = 2.57 mg·g−1·(mg·L−1)−1/n at 25 °C. Favorable adsorption conditions for negatively charged LBG were identified: 25 °C for 10 min, low dosage level ( 150 r.p.m.), acidic or neutral conditions (pH 2–7) without salt addition. Graphic abstract
- Published
- 2021