With increasing environmental and ecological concerns due to the use of petroleum-based chemicals and products, the synthesis of fine chemicals and functional materials from natural resources is of great public value. Nanocellulose may prove to be one of the most promising green materials of modern times due to its intrinsic properties, renewability, and abundance. In this review, we present nanocellulose-based materials from sourcing, synthesis, and surface modification of nanocellulose, to materials formation and applications. Nanocellulose can be sourced from biomass, plants, or bacteria, relying on fairly simple, scalable, and efficient isolation techniques. Mechanical, chemical, and enzymatic treatments, or a combination of these, can be used to extract nanocellulose from natural sources. The properties of nanocellulose are dependent on the source, the isolation technique, and potential subsequent surface transformations. Nanocellulose surface modification techniques are typically used to introduce e...

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Nanocellulose, a Versatile Green Platform: From Biosources to Materials and Their Applications

The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass ...

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability

Recent advances in regenerated cellulose materials

Cellulose nanocrystals, a class of fascinating bio-based nanoscale materials, have received a tremendous amount of interest both in industry and academia owing to its unique structural features and impressive physicochemical properties such as biocompatibility, biodegradability, renewability, low density, adaptable surface chemistry, optical transparency, and improved mechanical properties. This nanomaterial is a promising candidate for applications in fields such as biomedical, pharmaceuticals, electronics, barrier films, nanocomposites, membranes, supercapacitors, etc. New resources, new extraction procedures, and new treatments are currently under development to satisfy the increasing demand of manufacturing new types of cellulose nanocrystals-based materials on an industrial scale. Therefore, this review addresses the recent progress in the production methodologies of cellulose nanocrystals, covering principal cellulose resources and the main processes used for its isolation. A critical and analytical examination of the shortcomings of various approaches employed so far is made. Additionally, structural organization of cellulose and nomenclature of cellulose nanomaterials have also been discussed for beginners in this field.

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Recent progress in cellulose nanocrystals: sources and production

Lignocellulosic biomass (LCB) is the most abundantly available bioresource amounting to about a global yield of up to 1.3 billion tons per year. The hydrolysis of LCB results in the release of various reducing sugars which are highly valued in the production of biofuels such as bioethanol and biogas, various organic acids, phenols, and aldehydes. The majority of LCB is composed of biological polymers such as cellulose, hemicellulose and lignin, which are strongly associated with each other by covalent and hydrogen bonds thus forming a highly recalcitrant structure. The presence of lignin renders the bio-polymeric structure highly resistant to solubilization thereby inhibiting the hydrolysis of cellulose and hemicellulose which presents a significant challenge for the isolation of the respective bio-polymeric components. This has led to extensive research in the development of various pretreatment techniques utilizing various physical, chemical, physicochemical and biological approaches which are specifically tailored towards the source biomaterial and its application. The objective of this review is to discuss the various pretreatment strategies currently in use and provide an overview of their utilization for the isolation of high-value bio-polymeric components. The article further discusses the advantages and disadvantages of the various pretreatment methodologies as well as addresses the role of various key factors that are likely to have a significant impact on the pretreatment and digestibility of LCB.

/pdf/recent-trends-in-the-pretreatment-of-lignocellulosic-biomass-27tds25s66.pdf

Recent Trends in the Pretreatment of Lignocellulosic Biomass for Value-Added Products

Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

https://www.rsc.org/suppdata/cc/c2/c2cc17795a/c2cc17795a.pdf

Magnetic cellulose–chitosan hydrogels prepared from ionic liquids as reusable adsorbent for removal of heavy metal ions

http://ir.qibebt.ac.cn/bitstream/337004/6110/1/A%20novel%20approach%20for%20the%20preparation%20of%20nanocrystalline%20celluloseby%20using%20phosphotungstic%20acid.pdf

A novel approach for the preparation of nanocrystalline cellulose by using phosphotungstic acid.

Cellulose nanopaper (CNP) is of great interest to researchers mainly due to its renewability, excellent mechanical properties and optical properties. However, CNP is usually sensitive to water, resulting in the loss of strength and durability. To overcome this issue, in this work, an efficient and sustainable route, which involved ammonium sulfite cooking and formic acid hydrolysis, was reported to isolate lignin-containing cellulose nanofibrils (CNFs) from tobacco stalk. The resultant CNFs were directly used to fabricate strong, flexible, and water resistant CNP without any complex chemical modification. The residual lignin was found to act as a reinforcing agent between CNFs in CNP. The tensile strength and toughness of the lignin-containing CNP (255 MPa and 19.7 MJ m−3) were much higher compared with those of the one without lignin (179 MPa and 12.8 MJ m−3). The water-resistance of the CNP was also improved extraordinarily, and its maximum wet tensile strength reached up to 83 MPa which is the highest value in comparison with the reported CNP. Compared to the lignin-free CNP, the lignin-containing CNP also showed the better thermal stability and excellent UV-blocking properties. The present work designed a new route to prepare lignin-containing CNFs and CNP, which are potential candidates to replace petroleum-based materials in many advanced applications.

Flexible cellulose nanopaper with high wet tensile strength, high toughness and tunable ultraviolet blocking ability fabricated from tobacco stalk via a sustainable method

Magnetic Fe3O4–cellulose–chitosan hybrid gel microspheres were prepared by sol–gel transition technology using ionic liquids as solvent for cellulose and chitosan dissolution and regeneration. The synthesized microspheres were characterized by XRD, FTIR, SEM, and vibrating sample magnetometer (VSM). The XRD and FTIR results showed that chitosan and cellulose had been successfully coated onto the surface of Fe3O4 after the preparation. SEM presented that the synthesized microspheres were regular sphere with a mean diameter of about 10 μm. Furthermore, it was found that glucose oxidase (GOx) could be successfully immobilized on the hybrid gel microspheres via glutaraldehyde technique. The immobilized enzyme presented higher thermostability, wider range of pH optima and improved storage stability in comparison with free GOx. The glucose conversion could reach 91.5% within 4 h and retained 84.2% of the initial activity after 15 cycles of use. These results demonstrate their potential applications in the field of biocatalysis.

Guang Yu

Papers

Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

Magnetic cellulose–chitosan hydrogels prepared from ionic liquids as reusable adsorbent for removal of heavy metal ions

A novel approach for the preparation of nanocrystalline cellulose by using phosphotungstic acid.

Flexible cellulose nanopaper with high wet tensile strength, high toughness and tunable ultraviolet blocking ability fabricated from tobacco stalk via a sustainable method

Biocompatible magnetic cellulose–chitosan hybrid gel microspheres reconstituted from ionic liquids for enzyme immobilization