Hydroxyl Groups Of Cellulose Research Articles

Fully Bio-Based Ionic Liquids for Green Chemical Modification of Cellulose in the Activated-State.

Biopolymers, especially cellulose, are vital to transitioning to a circular economy and reducing our reliance on fossil fuels. However, for many applications a high degree of cellulose hydroxyl modification is necessary. The challenge is that the chemical features of the hydroxyls of cellulose and water are similar. Therefore, chemical modification of cellulose is often explored under non-aqueous conditions with systems that result in high hydroxyl accessibility and reduce cellulose aggregation. Unfortunately, these systems depend on hazardous and complex solvents from fossil resources, which diverge from the initial sustainability objectives. To address this, we developed three new betaine-based ionic liquids that are fully bio-based, scalable, and green. We found that a specific ionic liquid had the perfect chemical features for the chemical activation of cellulose without disturbing its crystalline ordering. The high activation in heterogeneous conditions was exemplified by reacting cellulose with succinic anhydride, resulting in more than 30 % conversion of all hydroxyls on cellulose. Overall, this work opens new perspectives for the derivatization of cellulosic materials while simultaneously "keeping it green".

Simple Protein Analysis by Droplet Paper Spray Ionization Mass Spectrometry with Polyolefin Silica-Based Paper.

Paper spray ionization mass spectrometry (PSI MS) has emerged as a notable method for the rapid analysis of biological samples. However, the typical cellulose-based paper tip is incompatible with protein detection due to the strong interaction between cellulose hydroxyl groups and proteins. In this study, we utilized a commercially available polyolefin-based synthetic paper, Teslin®, as an alternative PSI substrate for simple protein analysis. We have named this method "droplet PSI" MS, as the aqueous protein solution droplet retains its shape on the Teslin® paper tip. For droplet PSI, no further chemical pretreatment was necessary for the Teslin® substrate; the only required preparation was shaping the Teslin® paper into a triangular tip. In droplet PSI MS, protein ion signals were instantly detected from a protein solution droplet upon applying a spray solvent in situ along with high voltage (HV). When compared with conventional PSI MS, our method demonstrated superior sensitivity. The droplet PSI MS utilizing Teslin® also showcased flexibility in real-time observation of protein alterations induced by an acid additive. Additionally, the effects of spray solvent composition and the application method were discussed.

A Density Functional Theory Study on the Interaction of Cellulose Biopolymer and Atomic Arsenic

Here we provide a description of arsenic (As) adsorption on the cellulose biopolymer using first-principles density functional theory. In all studied configurations, the process of As adsorption on the cellulose is an exothermic process indicated by the negative binding energy. The cellulose's hydroxyl and hydroxymethyl groups significantly interact with As atom, characterized by the binding energy. In all optimized configurations, the interactions are mainly described as chemical bonding. This claim is supported by the overlap of the electron localization function (ELF) in the interface of As and cellulose in all studied adsorption sites. The adsorption of As on the cellulose introduces new states in the vicinity of the Fermi energy, leading to the lower bandgap of the cellulose-As systems. Overall, these results imply that the As atom can be trapped and detected using cellulose-based material. These findings offer an explanation of earlier research works on cellulose-As systems. This work will also serve as a reference for fabricating cellulose-based material for sensing and removing As.

Facile fabrication of functionalized wood evaporator through deep eutectic solvent delignification for efficient solar-driven water purification

Solar-driven sewage purification was considered to be a promising technique for the alleviation of freshwater scarcity issues globally. However, most steam generation devices focused on ultrahigh photothermal conversion and also neglected to develop the potential functions of natural creatures. Here, a deep eutectic solvent (DES) functionalized wood was designed as the supported substrate decorated with black polypyrrole (PPy) to construct low-cost and efficient solar interfacial evaporator. DES modification selectively removed most of the lignin, which enhanced the hydrophilic wetness of wood for the efficient transportation of water from the bottom to the solar interface. The lignin selective removal lowered the thermal conductivity of the evaporator, facilitating the heat location on the gas-liquid interface for efficient steam generation. Most importantly, more cellulose hydroxyl was exposed on the wood surface by the DES process, which was conducive to the in-situ polymerization of pyrrole on the wood surface by hydrogen bond interaction. The prepared PPy-DES wood evaporator achieved a considerable water evaporation rate of about 1.94 kg m−2 h−1 with a corresponding photothermal conversion efficiency of about 83.4% in one sun, arising from the functionalized design of DES wood and efficient photothermal conversion. For seawater desalination and sewage purification, the prepared evaporator exhibited excellent salt self-cleaning ability and stable wastewater purification performance. It was envisioned that the strategy of functionalized design of natural evaporators would motivate a large-scale application of biomaterials for efficient wastewater purification.

Preparation and characterization of corn cob cellulose acetate for potential industrial applications

Background: Locally generated biopolymers are amenable to further processing to widen their industrial applications. The study was aimed at generating low-cost cellulose acetate from corn cob residue and its characterizations for potential applications in biopolymer industries. Methods: Cellulose was extracted from the corn cob residue using the sodium hydroxide method. Acetylation of the cellulose to obtain corn cob cellulose acetate was carried out by adding appropriate quantities of a glacial acetic and acetylating mixture of acetic anhydride and sulphuric acid. The corn cob native cellulose and corn cob cellulose acetate were characterized using scanning electron microscopy (SEM) to examine their morphology, Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD) for structural elucidation while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were employed to investigate their thermal properties. Results: - Two corn cellulose acetate samples with degree of substitutions 1.87 and 2.65 for samples CDA and CA respectively were obtained. They had improved solubilities in some organic solvents compared to the corn cob cellulose. The SEM examination showed the surface of the corn cob native cellulose (NC) was smooth and had a regular bundle-like structure while acetylation destroyed the original cellulose structure. Cellulose acetate samples showed a cluster-like structure with different sizes and a rough flake-like surface. FTIR and XRD studies showed that acetyl groups substituted cellulose hydroxyl groups. While FTIR study showed that the cellulose acetates had sharp bands between 1728 cm-1 to 1733 cm-1 and around 1368 cm-1 wavenumber unlike the corn cob cellulose sample, the data generated from XRD study indicated that acetylation of the corn cob cellulose led to 47% and 77% decrease in the crystallinity of CDA and CA samples respectively. The thermal analysis data from DSC and TGA studies confirmed that the acetylation improved the corn cob cellulose's thermal stability as indicated by the degradation of cellulose acetate samples at higher temperatures. Conclusion: The study concluded that low-cost cellulose acetate generated from corn cob residue could be potentially employed as a renewable, biodegradable, biocompatible polymer for industrial applications.

Interactions between cellulose and lignin during pyrolysis: Evolutions of condensed-phase functional groups and gas-phase volatile fraction

Understanding cellulose-lignin interactions during biomass pyrolysis is important to improve the overall product distribution and quality. In the current study, the condensed-phase cellulose-lignin interactions during biomass pyrolysis from 100° to 600°C were systematically investigated with in-situ diffuse reflectance infrared Fourier transform spectroscopy and modified perturbation correlation moving-window two-dimensional correlation spectroscopy. It was found that compared to the individual component pyrolysis, the decomposition peak, evident by thermogravimetric analysis, of cellulose-lignin co-pyrolysis became wider and shifted to higher temperature range. The cellulose-lignin interactions further promoted the formations of char, and H2O, CH3/CH2, CO, aromatic-containing compounds. With simultaneous IR identification of gaseous products and condensed-phase remaining, the detailed interaction mechanism was elucidated as: 1) hydrogen donation from cellulose hydroxyl to lignin Cα could promote the lignin rearrangement at low temperature range through quinone methide structure; 2) the reactive species from homolytic cracking of lignin could abstract hydrogen from CH/CH2 groups of cellulose to generate phenolic compounds; 3) dehydration reactions of cellulose was therefore enhanced to promote char formation.

Experimental and theoretical studies on dissolution and regeneration of microcrystalline cellulose with dihydroxyl ionic liquids

Ionic liquids (ILs) have emerged as a promising class of green solvents suitable for cellulose dissolution. In this study, two dihydroxyl-functionalized ionic liquids, 1-methyl-3-(2,3-dihydroxypropyl)-imidazolium chloride ([DPmim]Cl) and 1-butyl-3-(2,3-dihydroxypropyl)-imidazolium chloride ([DPbim]Cl), were prepared for microcrystalline cellulose (MCC) dissolution. The physical properties of [DPmim]Cl and [DPbim]Cl, such as relative viscosity, density, electrical conductivity, and Kamlet-Taft parameters (β and π*), were evaluated. The dissolution and regeneration properties of MCC in [DPmim]Cl and [DPbim]Cl were investigated. The regenerated MCC was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). Density functional theory (DFT) simulations were used to investigate the interactions between ionic liquid and cellobiose. [DPmim]Cl and [DPbim]Cl, with higher β-values (0.975 and 1.098) respectively, exhibited stronger hydrogen bonding alkalinity. This increased alkalinity enhanced their ability to accept hydrogen bonds from cellulose, which in turn weakened the inter- and intra-molecular hydrogen bonds within cellulose. As a result, the dissolution of MCC was promoted. The dissolution of MCC in [DPmim]Cl was faster than [DPbim]Cl at same temperature. FTIR, TGA, and XRD characterizations showed that the hydrogen bonding network of microcrystalline cellulose was disrupted during ionic liquid dissolution. DFT simulations unveiled the formation of strong hydrogen bonds between the hydroxyl groups of ILs and the hydroxyl or ether linkages in cellulose. These hydrogen bonds have been identified as a potential crucial factor in facilitating the dissolution of cellulose.

Mechanistic insight into homogeneous catalytic crosslinking behavior between cellulose and epoxide by explicit solvent models

Inspired by recent advances on functional modification of cellulosic materials, the crosslinking behaviors of epoxide with cellulose under the catalysis of different homogeneous catalysts including H2O, Brønsted acid, Brønsted base, Lewis acid and neutral salt were systematically investigated using density functional theory (DFT) methods with hybrid micro-solvation-continuum approach. The results showed that catalytic activity, reaction mechanism and regioselectivity are determined by the combined effect of catalyst type, electronic effect and steric hindrance. All the homogeneous catalysts have catalytic activity for the crosslinking reaction, which decreases in the order of NaOH > HCl > NCl3 > MCl2 > CH3COOH > NaCl (N = Fe3+, Al3+; M = Zn2+, Ca2+). Upon the catalysis of NaOH, hydroxyl group of cellulose is firstly deprotonated to form a carbanion-like intermediate which will further attack the less sterically hindered C atom of epoxide showing excellent regioselectivity. Acidic catalysts readily cause epoxide protonated, which suffers from nucleophilic attack of cellulose and forms the carbocation-like intermediate. Brønsted acid exhibits poor regioselectivity, however, Lewis acid shows an interesting balance between catalytic activity and regioselectivity for the crosslinking reaction, which may be attributed to the unique catalysis and stabilization effects of its coordinated H2O on the transition state structure.

Nanozyme-immobilized cellulose membranes designed by a simple hydrogen bond-dominated for colorimetric detection of hydrogen peroxide and uric acid

Nanozymes are considered promising replacement materials for natural enzymes. The application limitations of nanozymes in separation and purification, quantitative utilization, and recycling can be solved by immobilization technology. Herein, a cellulose membrane-based nanozyme immobilization platform was designed and successfully applied for the colorimetric detection of hydrogen peroxide (H2O2) and uric acid (UA). Gold nanoclusters (AuNCs), which can mimic peroxidase and catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2, were immobilized on cellulose membranes (CMs) by hydrogen bonding to prepare AuNCs functionalized CMs (Au@CMs) with firm immobilization and uniform dispersion. TMB (colorless) in solution was oxidized to oxTMB (blue) after collision with hydroxyl radicals (∙OH) formed by H2O2 decomposition on the surface of Au@CMs. The oxTMB generated on Au@CMs was immediately in-situ immobilized under the combined action of cellulose hydroxyl groups and AuNCs. This enabled the dispersion of the colored molecules on the Au@CMs without diffusing into the solution, therefore the colorimetric response was retained to the maximum. Au@CMs were used to effectively colorimetric H2O2 with high selectivity and sensitivity, its visual limit of detection (VLOD) was 7 μM. Experiment results proved that Au@CMs were stable, convenient, and recyclable. It was worth noting that in the presence of uricase, the sensor could also be used for the colorimetric detection of UA, which had a gradient colorimetric response to UA in the concentration range of 50–500 μM. The design and preparation of Au@CMs provided an effective method for immobilizing nanozymes, promising for early-warning and semi-quantitative analysis.

Extraction and characterization of modified algae derivative cellulose and its mixtures for dye removal

A new bio-sorbent derived from green algae biomass, Arthrospira platensis (Spirulina), was found to be economically practical for water decontamination. This biosorbent comprised of microalgae cellulose, poly(lactic acid) (PLA), Dabai activated carbon (AC), and montmorillonite (MMT), each plays a distinctive role in removing methylene blue (MB) dye. The presence of hydroxyl and carbonyl functional groups in algae cellulose, confirmed by the FTIR analysis, offered binding sites for dye removal. Scanning electron microscopy demonstrated the morphological structure of the biosorbent, highlighting the combined effect of microalgae cellulose, PLA, Dabai AC, and MMT mixtures. The inclusion of Dabai AC and MMT improved micropores and mesopores, enhancing adsorption reactions. The Brunauer-Emmett-Teller (BET) analysis confirmed that the sample containing microalgae cellulose, Dabai AC, and MMT clay in PLA had a specific surface area of 0.784 m2/g, three times higher than the PLA + cellulose sample. Additionally, adding 1% MMT to the sample improved the particle dispersion on the surface of the hydrophobic PLA, thereby improving its thermal properties. Remarkably, the biosorbent effectively eliminated 86.8% of MB dye from an initial concentration of 50 mg/L after 60 min of Vis-light irradiation using Ultraviolet-visible spectroscopy.

Effect of different electronegative oxygen atoms of cellulose nanofibrils on the formation and photocatalytic property of ZnO/cellulose composite

Cellulose is widely employed as a template in supporting and dispersing ZnO. The oxygen atom of the hydroxyl (–OH) groups of cellulose have a significant impact on the morphology and photocatalytic property of ZnO. This work aims to investigate the effect of different electronegative oxygen atoms of cellulose nanofibrils (CNF) on the formation and photocatalytic properties of ZnO/cellulose composites. The interaction between cellulose and ZnO has been achieved by controlling cellulose fiber size and regulating the electronegativity of oxygen atoms on the CNF surface. The results indicate that etherized CNF (ECNF) with the highest degree of etherification substitution (1.7) and the best electronegativity (−34.6 mV) can synthesize the ZnO/cellulose composite with the largest loading content of ZnO (58.9%) and the best photocatalytic activity for MO degradation (91.1%). It can be concluded that the intenser electrostatic interaction between oxygen atoms on the CNF surface and ZnO can facilitate the fixation and growth of more high-quality ZnO nanoflowers, thus improving the photocatalytic property. In a word, this work can provide a novel perspective for the efficient preparation of ZnO/cellulose composites with designable morphology and structure.

TEMPO‐Oxidized Cellulose Nanofibers as Pseudocatalysts for in Situ and on‐Demand Hydrogen Generation via Aluminum Powder/Pure Water Reactions at a Temperature below 50 °C

Cellulose nanofibers (CNFs) prepared via 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐mediated oxidation of the C6 primary hydroxyls of native cellulose to carboxylates are used as pseudocatalysts for enhancing the aluminum powder/pure water reactions. The Al powder/pure water reaction is a stepwise reaction. It starts from hydration of the outmost native Al2O3 thin layer and then the reaction of the inner metallic Al with water. At lower temperatures (<50 °C), OH− and Al3+ ions are the preliminary products of the native Al2O3 thin layer hydration. Once Al powders are mixed with pure water containing 0.1–0.5 wt% TEMPO‐CNFs, condensed networks consisting of TEMPO‐CNFs self‐establish over the native Al2O3 thin layer. Al3+ ions are captured by TEMPO‐CNFs via the formation of insoluble Al3+/TEMPO‐CNFs complexing nanostructures and the conjugated OH− ions are being restricted nearby the native Al2O3‐based thin layer via electrostatic repulsion. A highly alkaline condition (pH > 11) is dynamically generated, and as a result, the native Al2O3 thin layer dissolves rapidly via the reaction with OH− ions. The OH− ions function also as catalysts, accelerating the reaction of metallic Al with water. Al powders (2–200 μm) react promptly and a nearly 100% Al/H2 conversion is obtained at the reaction temperature below 50 °C.

Efficient Cellulose Dissolution and Film Formation Enabled by Superbase Amino Acid Ionic Liquids.

Cellulose is a promising feedstock for the production of sustainable materials. To fully utilize its potential, exploring efficient cellulose solvents is a paramount prerequisite. In this study, ten superbase amino acid ionic liquids (SAAILs) are synthesized using 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with different amino acid anions via a simple neutralization method. The properties of these SAAILs, such as viscosity and glass transition temperature, varied with their cation and anion structures. The ability of the SAAILs to dissolve cellulose is related to their Kamlet-Taft parameters, particularly hydrogen bond basicity (β). The main driving force for cellulose dissolution in SAAILs is thought to be hydrogen bonding interactions between SAAILs and cellulose hydroxyl groups. Four SAAILs composed of DBN or DBU cations and proline, or aspartic acid anions are identified as promising solvents for preparing regenerated cellulose films (RCFs). The RCF prepared from [DBN]Proline(Pro) showed a favorable combination of high tensile strength (76.9MPa), high Young's modulus (5201.2MPa), good transparency (≈70% at 550nm), and smooth surface morphology. These halogen- and metal-free SAAILs show the potential to provide a new avenue for cellulose processing.

The Light Fastness of the Reactive Dyes on Cationized Cellulose

ABSTRACT Conventional dyeing of cellulose with reactive dyes requires the use of huge quantities of electrolytes and alkalis and the temperature between 60–90°C. Using the above conditions a stable covalent bond is formed between the reactive group of the dye and the hydroxyl group of cellulose. Cationization of cellulose allows to carry out reactive dyeing without electrolytes and alkalis even at room temperature. The dye, depending on the cationic modifier used, can form only ionic bond between sulfonic group of the dye and quaternary group of the modifier or also covalent bond between reactive group of the dye and hydroxyl group of the modifier. In this work we investigate how light fastness is affected by the type of bond with which the dye bound to the cationized cellulose. So far, such research has not been published. We found that the light fastness of the reactive dyeings on cationized cellulose was lower compared to non-cationized cellulose and depends on the kind of modifier used: chlorocholine chloride, 3-chloro-2-hydroxy-propyltrimethylammonium chloride and copolymer [(chloro-methyl)oxirane +1 H-Imidazole]. Density electron changes of ionic bonds between quaternary group of modified cellulose and sulfonic group of reactive dyes were analyzed in relation to the fading process.

Selective preparation of crystalline or fibrous nano-cellulose carboxylate to fabricate an anti-bacterial hydrogel in co-operation with ZnO and recycled gelatin

Bio-polymeric based nano-composites and hydrogels are newsworthy nano-biomaterials. Herein, crystalline or fibrous nano-cellulose carboxylate (NCCC and NCCF) were selectively prepared via the controllable direct oxidative-hydrolysis of MC in alkaline NaClO2 at 1:2 mol ratio, 90 °C, and 24 h for NCCC and at 1:1 mol ratio, 70 °C, and 20 h for NCCF. Characterization of NCCC and NCCF were performed by comparative Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and energy dispersive X-ray spectroscopy (EDS). Then, NCCC was cross-linked to the recycled gelatin (Gel) from the medicine capsules and the as-prepared nano-ZnO by maleic anhydride (MA) to give the novel hydrogel Gel/MA/NCCC/nano-ZnO. Nano-ZnO plays multi-roles in this hydrogel preparation, as either catalyst for the esterification of cellulose hydroxyls and amidation of gelatin amino groups or as the anti-bacterial part of hydrogel. The in vitro anti-bacterial activity results against the three gram-negative and gram-positive bacteria by well diffusion method confirmed Gel/MA/NCCC/nano-ZnO as an antibacterial agent with the activity order of P. aeruginosa > S. aureus > E. coli. The top anti-bacterial activity of this hydrogel against the gram-negative resistant bacteria of P. aeruginosa suggests its potential for biomedical applications.

Silver Nanoparticle-Embedded Conductive Hydrogels for Electrochemical Sensing of Hydroquinone.

In this work, a conductive hydrogel was successfully synthesized, taking advantage of the high number density of active amino and hydroxyl groups in carboxymethyl chitosan and sodium carboxymethyl cellulose. These biopolymers were effectively coupled via hydrogen bonding with the nitrogen atoms of the heterocyclic rings of conductive polypyrrole. The inclusion of another biobased polymer, sodium lignosulfonate (LS), was effective to achieve highly efficient adsorption and in-situ reduction of silver ions, leading to silver nanoparticles that were embedded in the hydrogel network and used to further improve the electro-catalytic efficiency of the system. Doping of the system in the pre-gelled state led to hydrogels that could be easily attached to the electrodes. The as-prepared silver nanoparticle-embedded conductive hydrogel electrode exhibited excellent electro-catalytic activity towards hydroquinone (HQ) present in a buffer solution. At the optimum conditions, the oxidation current density peak of HQ was linear over the 0.1-100 μM concentration range, with a detection limit as low as 0.12 μM (signal-to-noise of 3). The relative standard deviation of the anodic peak current intensity was 1.37% for eight different electrodes. After one week of storage in a 0.1 M Tris-HCl buffer solution at 4 °C, the anodic peak current intensity was 93.4% of the initial current intensity. In addition, this sensor showed no interference activity, while the addition of 30 μM CC, RS, or 1 mM of different inorganic ions does not have a significant impact on the test results, enabling HQ quantification in actual water samples.

One-Step Treatment for Upgrading Bleached Bamboo Pulp to Dissolving Pulp High Solvency in Green Alkali/Urea Aqueous Solution.

Bleached bamboo pulp, as a kind of natural cellulose, has received significant attention in the field of biomass materials due to its advantages of environmental protection and the abundance of raw materials. Low-temperature alkali/urea aqueous system is a green dissolution technology for cellulose, which has promising application prospects in the field of regenerated cellulose materials. However, bleached bamboo pulp, with high viscosity average molecular weight (Mη) and high crystallinity, is difficult to dissolve in an alkaline urea solvent system, restraining its practical application in the textile field. Herein, based on commercial bleached bamboo pulp with high Mη, a series of dissolvable bamboo pulps with suitable Mη was prepared using a method of adjusting the ratio of sodium hydroxide and hydrogen peroxide in the pulping process. Due to the hydroxyl radicals being able to react with hydroxyls of cellulose, molecular chains are cut down. Moreover, several regenerated cellulose hydrogels and films were fabricated in an ethanol coagulation bath or a citric acid coagulation bath, and the relationship between the properties of the regenerated materials and the Mη of the bamboo cellulose was systematically studied. The results showed that hydrogel/film had good mechanical properties, as the Mη is 8.3 × 104 and the tensile strength of a regenerated film and the film have values up to 101 MPa and 3.19 MPa, respectively. In this contribution, a simple method of a one-step oxidation of hydroxyl radicals to prepare bamboo cellulose with diversified Mη is presented, providing an avenue for a preparation of dissolving pulp with different Mη in an alkali/urea dissolution system and expanding the practical applications of bamboo pulp in biomass-based materials, textiles, and biomedical materials.

Complete valorization of bamboo biomass into multifunctional nanomaterials by reactive deep eutectic solvent pretreatment: Towards a waste-free biorefinery

The introduction of nanotechnology into conventional biorefinery will facilitate complete valorization of lignocellulosic biomass. In this work, a microwave-assisted deep eutectic solvent (DES) pretreatment was developed for one-pot fractionation of bamboo biomass into three scalable fractions (cellulose-rich residue, lignin and recovered DES), which were then respectively upgraded to three value-added bio-based nanomaterials, namely lignin-containing cellulose nanofibrils (LCNFs), lignin nanoparticles (LNPs) and carbon quantum dots (CDs). After the mild and rapid DES pretreatment (130 °C, 20 min), 51.0% cellulose-rich residue was recovered accompanied by 90.6% delignification ratio. The cellulose-rich residues were mechanically fibrillated into LCNFs with a width of 5–20 nm. In-situ esterification of carboxylic acid groups from DES with cellulose hydroxyl groups improved the hydrophobicity of LCNFs. The LCNFs film prepared exhibited excellent hydrophobic (water contact angle of 103.3°). In-situ esterification, condensation and cleavage reactions of lignin during DES fractionation enhanced its amphiphilicity and facilitated lignin self-assembly into LNPs with diameters of 30–75 nm. Furthermore, using the recovered DES as carbon precursors, CDs were successfully prepared by a typical hydrothermal method, which provides a new approach for the disposal of waste DES. In short, the proposed waste-free biorefinery scheme realizes the complete valorization of bamboo biomass into bio-based multifunctional nanomaterials, which can be further applied in various downstream fields.

Application of nata de coco as a biodegradable material for the aqueous adsorption of toxic metal cations

The bacterial fermentation of coconut water at ambient conditions produced bacterial cellulose in a jelly-like form which is widely known as nata de coco. X-ray diffraction, scanning electron microscopy and isothermal nitrogen sorption measurements confirmed that bacterial cellulose in nata de coco was arranged in a three-dimensional complex network with a high crystallinity and high porosity, which are highly promising for adsorption applications. In this study, as-synthesized nata de coco was directly applied as a bio-adsorbent for the removal of heavy metal ions from aqueous solutions without any further modification. The presence of numerous hydroxyl groups in cellulose could lead to strong affinities of nata de coco towards positively charged species. Upon a series of experiments screening the adsorption conditions for the single-metal solutions containing Cd(II) and Cr(III), respectively, it was found that the trapping process reached an equilibrium state after 60–120 min. Importantly, reducing the size of nata de coco via grinding for 6 min led to significant enhancements in the adsorption capacity of Cd(II) and Cr(III) to approx. 14 and 17 mg/g, respectively. Furthermore, in the solution containing 8 metal cations including Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II), Fe(III) and Cr(III), nata de coco could adsorb all of these cations with the uptakes in the range of 6.0–10.4 mg/g. The utilization of the biodegradable material facilely prepared from an abundant biomass resource, no chemical modifications required for the material, and trapping performances achieved for many different metal cations are highlights of this contribution.

Tunable Hydrophobic Octadienyl-Ether Nanocelluloses by In Situ Ultrasonication for Reinforced Polymers and Water-Resistant Paper

One-pot syntheses and in situ ultrasonication have been optimized to generate tunable and highly hydrophobic 2,7-octadienyl-ether (ODE) cellulose nanofibrils (CNFs). Using only butadiene sulfone to serve as dual reaction medium and precursor to 1,3-butadiene (1,3-BD) for telomerization with cellulose hydroxyls, the OH-to-ODE conversion significantly improved from ca. 0.7 to 1.2, 1.8, 3.1, and 4.1 mmol of ODE/g-cellulose at 103–110 °C for 1–2 h. Ultrasonication was highly effective and versatile in the direct disintegration of ODE-cellulose (ODE-cell) in nonpolar organic solvents and plant oils into ODE-CNFs as well as pretreating cellulose for improved functionalization. Mixing 2 wt % in situ ultrasonicated 1.2 mmol of ODE/g-cell improved the modulus of polybutadiene six times and the strength of poly(styrene-b-isoprene-b-styrene) three times, whereas in situ ultrasonication of 1.8 mmol/g-cell directly with linseed oil at merely 0.07 wt % created holistic biobased hydrophobic cellulose paper to resist water penetration while also significantly improving the tensile strength. This optimized telomerization and streamlined in situ ultrasonication approach has presented a sustainable synthesis and processing strategy to generate highly hydrocarbon-compatible nanocelluloses previously unattainable.