Cellulose Nanomaterials for Oil Exploration Applications

Defective h-BNs-Supported Pd Nanoclusters: An Efficient Photocatalyst for Selective Oxidation of 5-Hydroxymethylfurfural

5-hydroxymethylfurfural (HMF) is one of the most promising biomass-based chemicals that is used to produce many kinds of important compounds. Especially, the selective conversion of HMF to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), an important chemical feedstock, has high industrial significance but is technically challenging. In this study, we present a high-performance photocatalyst for selective oxidation of HMF to HMFCA. By integrating an ultrasmall amount of palladium (Pd) nanoclusters (1.12‰ in weight) on defective hexagonal boron nitride nanosheets (Pd/defective h-BN nanosheets (dh-BNs)), outstanding photocatalytic performance can be achieved, resulting in up to a 95% HMF conversion ratio with an 82% HMFCA selectivity. The performance is considerably higher than that of pristine dh-BNs and Pd on defect-free h-BNs. More importantly, this Pd/dh-BNs catalyst maintains a high catalytic activity after eight cycles, demonstrating robust catalytic stability. Density functional theory calculations indicate that Pd/dh-BNs can lower the energy barrier for HMF oxidation and facilitate the desorption of HMFCA, which contributes to the high selectivity catalytic performance. This study not only introduces a promising photocatalyst for sustainable chemical transformations but can also provide valuable insights into the design of advanced photocatalytic material for biorefinery applications.

A review of cellulose nanomaterial-stabilized Pickering foam: Formation, properties, and emerging oilfield applications

The rapid development of the petroleum industry has led to increasing demands for high-performance oilfield working fluids, such as drilling fluids, fracturing fluids, and fluids for enhanced oil recovery. Liquid foam is widely utilized as the oilfield working fluids due to its advantages, including low density, high mobility, superior cutting suspending ability, excellent fluid diversion capacity, and outstanding sweep efficiency. However, the short lifespan of foam limits its broad application in the oilfield. Considering the advantages of environmental protection, renewability, high specific surface area, tailorable surface chemistry, and excellent rheological properties of cellulose nanomaterials (CNMs), Pickering foams stabilized by CNMs offer improved eco-friendliness and foam stability. In this review, the classification and preparation methods of CNMs are briefly introduced. Subsequently, the preparation methods, properties, and application prospects of CNM-stabilized Pickering foams as oilfield working fluids are summarized. Finally, the challenges and prospects of CNM-stabilized Pickering foam are outlined, aiming to pave the way for the development of petroleum industry in an eco-friendlier manner.

Cellulose derivatives as environmentally-friendly additives in water-based drilling fluids: A review

The application of cellulose derivatives including carboxymethyl cellulose (CMC), polyanionic cellulose (PAC), hydroxyethyl cellulose (HEC), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) has gained enormous interest, especially as environmentally friendly additives for water-based drilling fluids (WBDFs). This is due to their sustainable, biodegradable, and biocompatible nature. Furthermore, cellulose nanomaterials (CNMs), which include both CNFs and CNCs, possess unique properties such as nanoscale dimensions, a large surface area, as well as unique mechanical, thermal, and rheological performance that makes them stand out as compared to other additives used in WBDFs. The high surface hydration capacity, strong interaction with bentonite, and the presence of a complex network within the structure of CNMs enable them to act as efficient rheological modifiers in WBDFs. Moreover, the nano-size dimension and facilely tunable surface chemistry of CNMs make them suitable as effective fluid loss reducers as well as shale inhibitors as they have the ability to penetrate, absorb, and plug the nanopores within the exposed formation and prevent further penetration of water into the formation. This review provides an overview of recent progress in the application of cellulose derivatives, including CMC, PAC, HEC, CNFs, and CNCs, as additives in WBDFs. It begins with a discussion of the structure and synthesis of cellulose derivatives, followed by their specific application as rheological, fluid loss reducer, and shale inhibition additives in WBDFs. Finally, the challenges and future perspectives are outlined to guide further research and development in the effective utilization of cellulose derivatives as additives in WBDFs.

Cellulose-derived raw materials towards advanced functional transparent papers

Pulp and paper are gradually transforming from a traditional industry into a new green strategic industry. In parallel, cellulose-derived transparent paper is gaining ground for the development of advanced functional materials for light management with eco-friendly, high performance, and multifunctionality. This review focuses on methods and processes for the preparation of cellulose-derived transparent papers, highlighting the characterization of raw materials linked to responses to different properties, such as optical and mechanical properties. The applications in electronic devices, energy conversion and storage, and eco-friendly packaging are also highlighted with the objective to showcase the untapped potential of cellulose-derived transparent paper, challenging the prevailing notion that paper is merely a daily life product. Finally, the challenges and propose future directions for the development of cellulose-derived transparent paper are identified.

Carbon-based single-atom catalysts derived from biomass: Fabrication and application

Single-atom catalysts (SACs) with active metals dispersed atomically have shown great potential in heterogeneous catalysis due to the high atomic utilization and superior selectivity/stability. Synthesis of SACs using carbon-neutral biomass and its components as the feedstocks provides a promising strategy to realize the sustainable and cost-effective SACs preparation as well as the valorization of underused biomass resources. Herein, we begin by describing the general background and status quo of carbon-based SACs derived from biomass. A detailed enumeration of the common biomass feedstocks (e.g., lignin, cellulose, chitosan, etc.) for the SACs preparation is then offered. The interactions between metal atoms and biomass-derived carbon carriers are summarized to give general rules on how to stabilize the atomic metal centers and rationalize porous carbon structures. Furthermore, the widespread adoption of catalysts in diverse domains (e.g., chemocatalysis, electrocatalysis and photocatalysis, etc.) is comprehensively introduced. The structure-property relationships and the underlying catalytic mechanisms are also addressed, including the influences of metal sites on the activity and stability, and the impact of the unique structure of single-atom centers modulated by metal/biomass feedstocks interactions on catalytic activity and selectivity. Finally, we end this review with a look into the remaining challenges and future perspectives of biomass-based SACs. We expect to shed some light on the forthcoming research of carbon-based SACs derived from biomass, manifestly stimulating the development in this emerging research area.

A review of cellulose-based catechol-containing functional materials for advanced applications

With the increment in global energy consumption and severe environmental pollution, it is urgently needed to explore green and sustainable materials. Inspired by nature, catechol groups in mussel adhesion proteins have been successively understood and utilized as novel biomimetic materials. In parallel, cellulose presents a wide class of functional materials rating from macro-scale to nano-scale components. The cross-over among both research fields alters the introduction of impressive materials with potential engineering properties, where catechol-containing materials supply a general stage for the functionalization of cellulose or cellulose derivatives. In this review, the role of catechol groups in the modification of cellulose and cellulose derivatives is discussed. A broad variety of advanced applications of cellulose-based catechol-containing materials, including adhesives, hydrogels, aerogels, membranes, textiles, pulp and papermaking, composites, are presented. Furthermore, some critical remaining challenges and opportunities are studied to mount the way toward the rational purpose and applications of cellulose-based catechol-containing materials.

Nanocellulose-graphene composites: Preparation and applications in flexible electronics

In recent years, the pursuit of high-performance nano-flexible electronic composites has led researchers to focus on nanocellulose-graphene composites. Nanocellulose has garnered widespread interest due to its exceptional properties and unique structure, such as renewability, biodegradability, and biocompatibility. However, nanocellulose materials are deficient in electrical conductivity, which limits their applications in flexible electronics. On the other hand, graphene boasts remarkable properties, including a high specific surface area, robust mechanical strength, and high electrical conductivity, making it a promising carbon-based nanomaterial. Consequently, research efforts have intensified in exploring the preparation of graphene-nanocellulose flexible electronic composites. Although there have been studies on the application of nanocellulose and graphene, there is still a lack of comprehensive information on the application of nanocellulose/graphene in flexible electronic composites. This review examines the recent developments in nanocellulose/graphene flexible electronic composites and their applications. In this review, the preparation of nanocellulose/graphene flexible electronic composites from three aspects: composite films, aerogels, and hydrogels are first introduced. Next, the recent applications of nanocellulose/graphene flexible electronic composites were summarized including sensors, supercapacitors, and electromagnetic shielding. Finally, the challenges and future directions in this emerging field was discussed.

The catalytic hydrodeoxygenation of bio-oil for upgradation from lignocellulosic biomass

The increasing depletion of oil resources and the environmental problems caused by using much fossil energy in the rapid development of society. The bio-oil becomes a promising alternative energy source to fossil. However, bio-oil cannot be directly utilized, owing to its high proportion of oxygenated compounds with low calorific value and poor thermal stability. Catalytic hydrodeoxygenation (HDO) is one of the most effective methods for refining oxygenated compounds from bio-oil. HDO catalysts play a crucial role in the HDO reaction. This review emphasizes the description of the main processing of HDO and various catalytic systems for bio-oil, including noble/non-noble metal catalysts, porous organic polymer catalysts, and polar solvents. A discussion based on recent studies and evaluations of different catalytic materials and mechanisms is considered. Finally, the challenges and future opportunities for the development of catalytic hydrodeoxygenation for bio-oil upgradation are looked forward.

Green remediation of cadmium-contaminated soil by cellulose nanocrystals

Cellulose nanocrystals (CNC) were used as a novel, green eluent to remediate Cd-contaminated soil in this study. The influence of washing conditions on the removal of Cd, including CNC concentration, pH value, liquid/solid (L/S) ratio, contact time and temperature were investigated. The effect of CNC remediation of Cd-contaminated soil on soil health and the possible remediation mechanism were also explored. The results showed that CNC concentration, pH value and contact time had a significant effect on the removal efficiency of Cd. CNC rapidly removed heavy metals in soil within 30 min. When the pH value of the eluent was 9.0, the removal efficiency of Cd could reach 86.3 %. The eluent mainly removed exchangeable and reducible fractions of Cd, which could effectively reduce the bioavailability of heavy metals. CNC washing had no negative effects on seed growth, species abundance and Shannon index. C-O, -COO^- groups on CNC played an important role in the reaction between CNC and soil Cd, and other oxygen-containing functional groups on CNC could also assist in adsorption, ion exchange and chemical complexation processes. Therefore, cellulose nanocrystals had the potential to remediate heavy metal-contaminated soils in a green and efficient manner.

Hemicellulose-based hydrogels for advanced applications

Hemicellulose-based hydrogels are three-dimensional networked hydrophilic polymer with high water retention, good biocompatibility, and mechanical properties, which have attracted much attention in the field of soft materials. Herein, recent advances and developments in hemicellulose-based hydrogels were reviewed. The preparation method, formation mechanism and properties of hemicellulose-based hydrogels were introduced from the aspects of chemical cross-linking and physical cross-linking. The differences of different initiation systems such as light, enzymes, microwave radiation, and glow discharge electrolytic plasma were summarized. The advanced applications and developments of hemicellulose-based hydrogels in the fields of controlled drug release, wound dressings, high-efficiency adsorption, and sensors were summarized. Finally, the challenges faced in the field of hemicellulose-based hydrogels were summarized and prospected.

Strong, flexible, and highly conductive cellulose nanofibril/PEDOT:PSS/MXene nanocomposite films for efficient electromagnetic interference shielding

Flexible and light weight electromagnetic interference (EMI) shielding materials with high electromagnetic shielding efficiency (SE) and excellent mechanical strength are highly demanded for wearable and portable electronics. In this work, for the first time, a freestanding and flexible cellulose nanofibril (CNF)/PEDOT:PSS/MXene (Ti₃C₂T_x) nanocomposite film with a ternary heterostructure was manufactured using a vacuum-assisted filtration process. The results show that compared with pure MXene films, the tensile strength of the optimized nanocomposite film increases from 8.88 MPa to 59.99 MPa, and the corresponding fracture strain increases from 0.87% to 4.60%. Intriguingly, the optimized nanocomposite film exhibited an impressive conductivity of 1903.2 S cm^-1, which is among the highest values reported for MXene and cellulose-based nanocomposites. Owing to the superior conductivity and unique heterostructure, the nanocomposite film exhibits a high EMI SE value of 76.99 dB at a thickness of only 58.0 μm. Taking into account the robust mechanical properties and remarkable EMI shielding performance, the CNF/PEDOT:PSS/MXene nanocomposite film could be a prospective EMI shielding material for a variety of high-end applications.

Nanocellulose/two dimensional nanomaterials composites for advanced supercapacitor electrodes

With the emerging of the problems of environmental pollution and energy crisis, the development of high-efficiency energy storage technology and green renewable energy is imminent. Supercapacitors have drawn great attention in wearable electronics because of their good performance and portability. Electrodes are the key to fabricate high-performance supercapacitors with good electrochemical properties and flexibility. As a biomass based derived material, nanocellulose has potential application prospects in supercapacitor electrode materials due to its biodegradability, high mechanical strength, strong chemical reactivity, and good mechanical flexibility. In this review, the research progress of nanocellulose/two dimensional nanomaterials composites is summarized for supercapacitors in recent years. First, nanocellulose/MXene composites for supercapacitors are reviewed. Then, nanocellulose/graphene composites for supercapacitors are comprehensively elaborated. Finally, we also introduce the current challenges and development potential of nanocellulose/two dimensional nanomaterials composites in supercapacitors.

Lignin-silver triggered multifunctional conductive hydrogels for skinlike sensor applications

Conductive hydrogels have attracted tremendous attention as a novel generation of wearable devices and body monitoring due to their great stretchability and high flexibility. Here, a multifunctional cellulose nanocrystal @sodium lignosulfonate-silver-poly(acrylamide) nanocomposite hydrogel was prepared by radical polymerization within only a few minutes. This polymerization rapidly occurred by lignosulfonate-silver (Ls-Ag) dynamic catalysis that efficiently activated ammonium persulfate (APS) to initiate the free-radical polymerization. In particular, the hydrogel exhibited excellent tensile strength (406 kPa), ultrahigh stretchability (1880 %), self-recovery, and fatigue resistance. Furthermore, due to the inclusion of Ls-Ag metal ion nanocomposite in the hydrogels, the composite hydrogel presented repeated adhesion to various objects, excellent conductivity (σ ∼ 9.5 mS cm^-1), remarkable UV resistance (100 % shielding of the UV spectral region), and high antibacterial activity (above 98 %), which enabled the hydrogel to be applied to epidermal sensors. In addition, the high-sensitivity (gauge factor of 2.46) sensor constructed of the hydrogel monitored the large and subtle movements of the human body and was used as a biological electrode to collect human electromyography and electrocardiographic signals. This work provided a novel strategy for the high-value utilization of lignin, which had potential application prospects in many fields such as wearable bioelectrodes.

Successive organic solvent fractionation and homogenization of technical lignin for polyurethane foam with high mechanical performance

This work demonstrates an organic solvent fractionation method for lignin homogenization, which can effectively reduce the lignin heterogeneity and use each lignin fraction to prepare polyurethane foams (PUFs) with excellent mechanical properties. Such fractions were fully characterized by GPC, NMR (³¹P, 2D-HSQC), FTIR, and TG to obtain a detailed description of the structures and properties. The properties of PUFs from each lignin fraction showed higher compatibility than that from unfractionated industrial lignin, as studied by morphology and DSC analysis. The improvement of compatibility between the fractionated lignin fractions and polyethylene glycol can effectively enhance the mechanical properties of the prepared PUFs. The hysteresis loss (43.10%-51.85%) and resilience (95.81%-98.81%) of the fractionated lignin polyurethane foams (LPUFs) were better than that from the unfractionated LPUFs (hysteresis loss 41.64%, resilience 94.67%) at the lignin content of 5%. Subsequently, the strong relationships between lignin structures and PUF properties were demonstrated in detail. The suggested approach provides greater possibilities to prepare LPUFs with tunable properties based on real industrial lignin fractions, rather than modified lignin.

Effects of taxifolin from enzymatic hydrolysis of Rhododendron mucrotulatum on hair growth promotion

Flavonoid aglycones possess biological activities, such as antioxidant and antidiabetic activities compared to glycosides. Taxifolin, a flavonoid aglycones, is detected only in trace amounts in nature and is not easily observed. Therefore, in this study, to investigate the hair tonic and hair loss inhibitors effect of taxifolin, high content of taxifolin aglycone extract was prepared by enzymatic hydrolysis. Taxifolin effectively regulates the apoptosis of dermal papilla cells, which is associated with hair loss, based on its strong antioxidant activities. However, inhibition of dihydrotestosterone (DHT), which is a major cause of male pattern hair loss, was significantly reduced with taxifolin treatment compared with minoxidil, as a positive control. It was also confirmed that a representative factor for promoting hair growth, IGF-1, was significantly increased, and that TGF-β1, a representative biomarker for hair loss, was significantly reduced with taxifolin treatment. These results suggest that taxifolin from enzymatic hydrolysis of RM is a potential treatment for hair loss and a hair growth enhancer.

Cellulose Nanopaper: Fabrication, Functionalization, and Applications

Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices, food packaging, biomedical application, and so forth, owing to their various advantages such as good flexibility, tunable light transmittance, high thermal stability, low thermal expansion coefficient, and superior mechanical properties. Herein, recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies. We begin with a brief introduction of the three types of nanocellulose: cellulose nanocrystals, cellulose nanofibrils and bacterial cellulose, recapitulating their differences in preparation and properties. Then, the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared. Furthermore, the advanced applications of cellulose nanopaper including energy storage, electronic devices, water treatment, and high-performance packaging materials were highlighted. Finally, the prospects and ongoing challenges of cellulose nanopaper were summarized.

Lignin-Based/Polypyrrole Carbon Nanofiber Electrode With Enhanced Electrochemical Properties by Electrospun Method

Tailoring the structure and properties of lignin is an important step toward electrochemical applications. In this study, lignin/polypyrrole (PPy) composite electrode films with microporous and mesoporous structures were designed effectively by electrostatic spinning, carbonization, and in situ polymerization methods. The lignin can not only reduce the cost of carbon fiber but also increase the specific surface area of composite films due to the removal of carbonyl and phenolic functional groups of lignin during carbonization. Besides, the compact three-dimensional (3D) conductive network structures were constructed with PPy particles densely coated on the lignin nanofibers, which was helpful to improve the conductivity and fast electron transfer during the charging and discharging processes. The synthesized lignin carbon fibers/PPy anode materials had good electrochemical performance in 1 M H2SO4 electrolyte. The results showed that, at a current density of 1 A g−1, the lignin carbon nanofibers/PPy (LCNFs/PPy) had a larger specific capacitance of 213.7 F g−1 than carbon nanofibers (CNFs), lignin carbon nanofibers (LCNFs), and lignin/PPy fiber (LPAN/PPy). In addition, the specific surface area of LCNFs/PPy reached 872.60 m2 g−1 and the average pore size decreased to 2.50 nm after being coated by PPy. Therefore, the independent non-binder and self-supporting conductive film is expected to be a promising electrode material for supercapacitors with high performance.