Nanocellulose-Graphene Derivative Hybrids: Advanced Structure-Based Functionality from Top-down Synthesis to Bottom-up Assembly

A critical review of microplastics in aquatic ecosystems: Degradation mechanisms and removing strategies

Plastic waste discarded into aquatic environments gradually degrades into smaller fragments, known as microplastics (MPs), which range in size from 0.05 to 5 mm. The ubiquity of MPs poses a significant threat to aquatic ecosystems and, by extension, human health, as these particles are ingested by various marine organisms including zooplankton, crustaceans, and fish, eventually entering the human food chain. This contamination threatens the entire ecological balance, encompassing food safety and the health of aquatic systems. Consequently, developing effective MP removal technologies has emerged as a critical area of research. Here, we summarize the mechanisms and recently reported strategies for removing MPs from aquatic ecosystems. Strategies combining physical and chemical pretreatments with microbial degradation have shown promise in decomposing MPs. Microorganisms such as bacteria, fungi, algae, and specific enzymes are being leveraged in MP remediation efforts. Recent advancements have focused on innovative methods such as membrane bioreactors, synthetic biology, organosilane-based techniques, biofilm-mediated remediation, and nanomaterial-enabled strategies, with nano-enabled technologies demonstrating substantial potential to enhance MP removal efficiency. This review aims to stimulate further innovation in effective MP removal methods, promoting environmental and social well-being.

On the versatility of graphene-cellulose composites: An overview and bibliometric assessment

Practical benefits of graphene-cellulose composites (GCC) are categorical. Diverse salient features like thermal and electrical conductivity, mechanical strength, and durability make GCC advantageous for widespread applications. Despite extensive studies the basic understanding of various fundamental aspects of this novel complex remains deficient. Based on this fact, a critical overview and bibliometric analysis involving the overall prospects of GCC was made wherein a total of 1245 research articles from the Scopus database published during the year 2002 to 2020 were used. For the bibliometric assessment, various criteria including the publication outputs, co-authorships, affiliated countries, and co-occurrences of the authors' keywords were explored. Environmental amiability, sustainability, economy, and energy efficiency of GCC were emphasized. In addition, the recent trends, upcoming challenges, and applied interests of GCC were highlighted. The findings revealed that the studies on GCC related to the energy storage, adsorption, sensing, and printing are ever-increasing, indicating the global research drifts on GCC. The bibliometric map analysis displayed that among the researchers from 61 countries/territories, China alone contributed about 50 % of the international publications. It is asserted that the current article may offer taxonomy to navigate into the field of GCC wherein stronger collaboration networks can be established worldwide through integrated research activities desirable for sustainable development.

A comprehensive review on processing, characteristics, and applications of cellulose nanofibrils/graphene hybrid-based nanocomposites: Toward a synergy between two-star nanomaterials

Nanostructured materials are fascinating since they are promising for intensely enhancing materials' performance, and they can offer multifunctional features. Creating such high-performance nanocomposites via effective and mild approaches is an inevitable requirement for sustainable materials engineering. Nanocomposites, which combine two-star nanomaterials, namely, cellulose nanofibrils (CNFs) and graphene derivatives (GNMs), have recently revealed interesting physicochemical properties and excellent performance. Despite numerous studies on the production and application of such systems, there is still a lack of concise information on their practical uses. In this review, recent progress in the production, modification, properties, and emerging uses of CNFs/GNMs hybrid-based nanocomposites in various fields such as flexible energy harvesting and storage, sensors, adsorbents, packaging, and thermal management, among others, are comprehensively examined and described based on recent investigations. Nevertheless, numerous challenges and gaps need to be addressed to successfully introduce such nanomaterials in large-scale industrial applications. This review will certainly help readers understand the design approaches and potential applications of CNFs/GNMs hybrid-based nanocomposites for which new research directions in this emerging topic are discussed.

From Forces to Assemblies: van der Waals Forces-Driven Assemblies in Anisotropic Quasi-2D Graphene and Quasi-1D Nanocellulose Heterointerfaces towards Quasi-3D Nanoarchitecture

In the pursuit of advanced functional materials, the role of low-dimensional van der Waals (vdW) heterointerfaces has recently ignited noteworthy scientific interest, particularly in assemblies that incorporate quasi-2D graphene and quasi-1D nanocellulose derivatives. The growing interest predominantly stems from the potential to fabricate distinct genres of quasi-2D/1D nanoarchitecture governed by vdW forces. Despite the possibilities, the inherent properties of these nanoscale entities are limited by in-plane covalent bonding and the existence of dangling π-bonds, constraints that inhibit emergent behavior at heterointerfaces. An innovative response to these limitations proposes a mechanism that binds multilayered quasi-2D nanosheets with quasi-1D nanochains, capitalizing on out-of-plane non-covalent interactions. The approach facilitates the generation of dangling bond-free iso-surfaces and promotes the functionalization of multilayered materials with exceptional properties. However, a gap still persists in understanding transition and alignment mechanisms in disordered multilayered structures, despite the extensive exploration of monolayer and asymmetric bilayer arrangements. In this perspective, we comprehensively review the sophisticated aspects of multidimensional vdW heterointerfaces composed of quasi-2D/1D graphene and nanocellulose derivatives. Further, we discuss the profound impacts of anisotropy nature and geometric configurations, including in-plane and out-of-plane dynamics on multiscale vdW heterointerfaces. Ultimately, we shed light on the emerging prospects and challenges linked to constructing advanced functional materials in the burgeoning domain of quasi-3D nanoarchitecture.

Self-Assembled CNF/rGO/Tannin Composite: Study of the Physicochemical and Wound Healing Properties

In this study, a conductive composite material, based on graphene oxide (GO), nanocellulose (CNF), and tannins (TA) from pine bark, reduced using polydopamine (PDA), was developed for wound dressing. The amount of CNF and TA was varied in the composite material, and a complete characterization including SEM, FTIR, XRD, XPS, and TGA was performed. Additionally, the conductivity, mechanical properties, cytotoxicity, and in vitro wound healing of the materials were evaluated. A successful physical interaction between CNF, TA, and GO was achieved. Increasing CNF amount in the composite reduced the thermal properties, surface charge, and conductivity, but its strength, cytotoxicity, and wound healing performance were improved. The TA incorporation slightly reduced the cell viability and migration, which may be associated with the doses used and the extract's chemical composition. However, the in-vitro-obtained results demonstrated that these composite materials can be suitable for wound healing.

Nanocellulose-based electrodes and separator toward sustainable and flexible all-solid-state supercapacitor

Nanocellulose, as the most abundant natural nanomaterial with sustainability, biodegradability, and excellent mechanical properties, has been widely applied in modern electronic systems, particularly, in the flexible electrochemical energy storage devices. Herein, a reduced graphene oxide (RGO)/cellulose nanocrystal/cellulose nanofiber (RCC) composite membrane was prepared by using a one-pot method. Compared to the pure RGO membranes, the RCC composite membranes exhibited better mechanical properties and hydrophilicity. Furthermore, due to the synergistic effect of nanocellulose and RGO sheets, the RCC composite membrane exhibited a specific capacitance as high as 171.3 F·cm^-3. Consequently, a nanocellulose-based symmetric flexible all-solid-state supercapacitor (FASC) was constructed, in which two RCC composite membranes served as electrodes and a porous cellulose nanofiber membrane acted as separator. This fabricated FASC demonstrated a high volumetric specific capacitance of 164.3 F·cm^-3 and a satisfactory energy density of 3.7 mW·h·cm^-3, which exceeded that of many other FASCs ever reported. This work may open a new avenue in design of next-generation nanocellulose based, sustainable and flexible energy storage device.

Cellulose nanofibrils-graphene hybrids: recent advances in fabrication, properties, and applications

With the fast-developing social economy and the acceleration of industrialization, seeking effective renewable, sustainable, and environmentally friendly resources that show promising properties is an urgent task and a crucial means to achieve sustainable progress in the face of the growing depletion of non-renewable resources and the deterioration of environmental issues. Cellulose nanofibrils (CNFs) are natural polymeric nanomaterials with excellent biocompatibility, biodegradability, good mechanical features, high strength, low density, high specific surface area, and tunable chemistry. Their combination with other nanomaterials, such as graphene derivatives (GNMs), has been demonstrated to be effective since they produce hybrids with outstanding physicochemical properties, tailorable functionality, and high performance. In this review, recent advances in the preparation, modification, and emerging application of CNFs/GNMs hybrids are described and discussed using the latest studies. First, the concise background of nanocellulose and graphene derivatives is provided, followed by the interfacial interactions between CNFs and GNMs. The different hybrids exhibit great promise in separation, adsorption, optics, flexible electronics, energy storage, thermal management, barrier and packaging, and electromagnetic shielding. The main challenges that inhibit the applicability of these hybrids are finally highlighted, and some perspectives for future research directions are provided.