Specific ion effects in carboxymethyl cellulose adsorption on cellulose: A step towards modification of fibers in fiber line
Doctoral thesis, 2022
The increasing global demands for paper products have fuelled the research in developing new fibers from existing industrial processes. The adsorption of carboxymethyl cellulose (CMC) has been shown to improve the tensile properties of the paper significantly. One way to manufacture such modified fibers is to integrate the CMC adsorption step in current pulping mills. However, the mechanism behind the adsorption of CMC on cellulose surfaces is still not fully understood, even if the literature on this subject is extensive. This thesis discusses the controlling factors and mechanism behind the adsorption of CMC on cellulose surfaces, which can enable future integration of adsorption process within the pulping mill.
The adsorption studies have been carried out mainly on model cellulose surfaces using QCM-D and it was shown that the CMC absorption depends on the amount and type of added cations and anions. The ion specificity in CMC adsorption was explained by these ions' ability to induce dispersion forces and hydration regulated positioning of ions at the interface. The observation that CMC adsorption on the model system is ion-specific was confirmed in a study where CMC was absorbed on commercially available softwood kraft pulp. Furthermore, CMC adsorption on cellulose model surfaces in the presence of D2O or H2O revealed that this process is entropy driven, which was supported by temperature dependent adsorption experiments.
The adsorption studies have been carried out mainly on model cellulose surfaces using QCM-D and it was shown that the CMC absorption depends on the amount and type of added cations and anions. The ion specificity in CMC adsorption was explained by these ions' ability to induce dispersion forces and hydration regulated positioning of ions at the interface. The observation that CMC adsorption on the model system is ion-specific was confirmed in a study where CMC was absorbed on commercially available softwood kraft pulp. Furthermore, CMC adsorption on cellulose model surfaces in the presence of D2O or H2O revealed that this process is entropy driven, which was supported by temperature dependent adsorption experiments.
Carboxymethyl cellulose
Polymer adsorption
Cellulose
Specific ionic effects
Author
Vishnu Arumughan
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Fundamental aspects of the non-covalent modification of cellulose via polymer adsorption
Advances in Colloid and Interface Science,;Vol. 298(2021)
Review article
Specific ion effects in the adsorption of carboxymethyl cellulose on cellulose: The influence of industrially relevant divalent cations
Colloids and Surfaces A: Physicochemical and Engineering Aspects,;Vol. 626(2021)
Journal article
Calcium Ion-Induced Structural Changes in Carboxymethylcellulose Solutions and Their Effects on Adsorption on Cellulose Surfaces
Biomacromolecules,;Vol. 23(2022)p. 47-56
Journal article
Anion specific adsorption of carboxymethyl cellulose on cellulose
In our daily lives, we come across various paper-based products, ranging from traditional writing sheets to carry all bags. Compared to perhaps five years ago, we now witness an increase in paper-based products. This transition occurs due to growing environmental awareness and policymakers' efforts to promote sustainability. However, the need for new paper-based material applications necessitates enhanced functional diversity. So a variety of functionalization techniques have been developed, including chemical and physical methods. For example, polymer adsorption on the fiber surface is a common method for fiber modification. Recently, there has been a surge of interest in developing integrated modification steps for existing pulp mills to maximize resource utilization.
Carboxymethylcellulose (CMC) is a widely used negatively charged cellulose derivative. Adsorption of CMC on cellulose fiber has been shown to improve the mechanical properties of papers. CMC adsorption is also employed to aid the production of nanocellulose, the wonder material! The adsorption of CMC on cellulose serves a variety of advantages. Nonetheless, we do not know what drives the adsorption of negatively charged CMC on cellulose fibre's slightly 'negative' charged surface. This thesis looks into how this negatively charged cellulose derivative interacts with cellulose fiber surface. Furthermore, this thesis also discusses how different salts can tune the adsorption of CMCs. The findings of this thesis may enable the integration of the CMC adsorption step with current pulp mills to modify fibers during production and effectively utilize the resources.
Carboxymethylcellulose (CMC) is a widely used negatively charged cellulose derivative. Adsorption of CMC on cellulose fiber has been shown to improve the mechanical properties of papers. CMC adsorption is also employed to aid the production of nanocellulose, the wonder material! The adsorption of CMC on cellulose serves a variety of advantages. Nonetheless, we do not know what drives the adsorption of negatively charged CMC on cellulose fibre's slightly 'negative' charged surface. This thesis looks into how this negatively charged cellulose derivative interacts with cellulose fiber surface. Furthermore, this thesis also discusses how different salts can tune the adsorption of CMCs. The findings of this thesis may enable the integration of the CMC adsorption step with current pulp mills to modify fibers during production and effectively utilize the resources.
Subject Categories
Chemical Engineering
Chemical Sciences
ISBN
978-91-7905-616-2
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5082
Publisher
Chalmers