As the most abundant natural polymer, cellulose is a prime candidate for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from oil-based synthetic polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Both fundamental and applied aspects of cellulose dissolution remain active areas of research and include mechanistic studies on solvent–cellulose interactions, the development of novel solvents and/or solvent systems, the optimization of dissolution conditions, and the preparation of various cellulose-based materials. In this review, we build on existing knowledge on cellulose dissolution, including the structural characteristics of the polymer that are important for dissolution (molecular weight, crystallinity, and effect of hydrophobic interactions), and evaluate widely used non-derivatizing solvents (sodium hydroxide (NaOH)-based systems, N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl), N-methylmorpholine-N-oxide (NMMO), and ionic liquids). We also cover the subsequent regeneration of cellulose solutions from these solvents into various architectures (fibers, films, membranes, beads, aerogels, and hydrogels) and review uses of these materials in specific applications, such as biomedical, sorption, and energy uses.

Synthetic dyes have become an integral part of many industries such as textiles, tannin and even food and pharmaceuticals. Industrial dye effluents from various dye utilizing industries are considered harmful to the environment and human health due to their intense color, toxicity and carcinogenic nature. To mitigate environmental and public health related issues, different techniques of dye remediation have been widely investigated. However, efficient and cost-effective methods of dye removal have not been fully established yet. This paper highlights and presents a review of recent literature on the utilization of the most widely available biopolymers, specifically, cellulose, chitin and chitosan-based products for dye removal. The focus has been limited to the three most widely explored technologies: adsorption, advanced oxidation processes and membrane filtration. Due to their high efficiency in dye removal coupled with environmental benignity, scalability, low cost and non-toxicity, biopolymer-based dye removal technologies have the potential to become sustainable alternatives for the remediation of industrial dye effluents as well as contaminated water bodies.

Petroleum-based synthetic plastics play an important role in our life. As the detrimental health and environmental effects of synthetic plastics continue to increase, the renewable, degradable and recyclable properties of cellulose make subsequent products the “preferred environmentally friendly” alternatives, with a small carbon footprint. Despite the fact that the bioplastic industry is growing rapidly with many innovative discoveries, cellulose-based bioproducts in their natural state face challenges in replacing synthetic plastics. These challenges include scalability issues, high cost of production, and most importantly, limited functionality of cellulosic materials. However, in order for cellulosic materials to be able to compete with synthetic plastics, they must possess properties adequate for the end use and meet performance expectations. In this regard, surface modification of pre-made cellulosic materials preserves the chemical profile of cellulose, its mechanical properties, and biodegradability, while diversifying its possible applications. The review covers numerous techniques for surface functionalization of materials prepared from cellulose such as plasma treatment, surface grafting (including RDRP methods), and chemical vapor and atomic layer deposition techniques. The review also highlights purposeful development of new cellulosic architectures and their utilization, with a specific focus on cellulosic hydrogels, aerogels, beads, membranes, and nanomaterials. The judicious choice of material architecture combined with a specific surface functionalization method will allow us to take full advantage of the polymer’s biocompatibility and biodegradability and improve existing and target novel applications of cellulose, such as proteins and antibodies immobilization, enantiomers separation, and composites preparation.

Biopolymers are polymeric materials derived from biological sources. Due to their renewability, abundance, biodegradability and other unique properties such as high adsorption capabilities and ease of functionalization they have been investigated for several industrial applications including sorption. Polysaccharides especially cellulose, chitin and chitosan are important biopolymers because of their high abundance, wide distribution and low cost of production. This chapter provides an overview of properties, common processing methods, and material characterization of three commonly studied biopolymers namely cellulose, chitin and chitosan. It provides a thorough review on recent developments on utilization of cellulose, chitin, and chitosan-based materials for various sorption applications. Specifically, their application and efficiency in organic dye removal, heavy metals removal, oil and solvent spillage cleanup, and CO2 adsorption are presented and discussed.

This study investigated the effect of acid hydrolysis of cellulose on its dissolution under mild conditions in ionic liquid, 1-butyl-3-methylimidazolium acetate/N,N-dimethylacetamide (BMIMAc/DMAc). Acid hydrolysis of high molecular weight (MW) cotton cellulose (DP > 4000) was carried out to produce hydrolyzed cotton (HC) samples for dissolution. The HC samples were characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), and the dissolution process was monitored using polarized light microscopy (PLM). It was found that the drastic decrease of the MW of cellulose did not result in improvement of its dissolution at room temperature. As compared to original cotton cellulose, the high amount of undissolved fibers in HC solutions led to unstable rheological behavior of HC solutions. Agglomeration and inhomogeneous dispersion of HC, and increased crystallinity, in this case, likely made the diffusion of BMIMAc/DMAc more difficult to the inside of the polymeric network of cellulose at ambient temperature, thereby hindering the dissolution. However, increasing the temperature from room temperature to 35 °C and 55 °C, led to a significant improvement in cellulose dissolution. This phenomenon implies that reducing the MW of cellulose might not be able to improve its dissolution under certain conditions. During the dissolution process, the physical properties of cellulose including fiber aggregation status, solvent diffusivity, and cellulose crystallinity may play a critical role compared to the MW, while the MW may not be an important factor. This finding may help further understand the mechanism of cellulose dissolution and seek better strategies to dissolve cellulose under mild conditions for industrial applications.