Cotton Wastes Functionalized Biomaterials from Micro to Nano: A Cleaner Approach for a Sustainable Environmental Application

Assessment of the Effect of Multiple Processing of PHBV-Ground Buckwheat Hull Biocomposite on Its Functional and Mechanical Properties

The influence of the addition of ground buckwheat hulls on the properties of biocomposite on the basis of 3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) is presented here. The changes in the material after repeated reprocessing-up to five recycling cycles-are written in the paper. Analysis of the shrinkage, water adsorption, selected mechanical properties, tensile impact strength, hardness and the microstructure of the surface layer was performed. The results show that the application of the buckwheat hulls into the biopolymer decreases the material shrinkage. It improves the material dimensional stability, as well as increases the water adsorption in the wake of the hydrophobic properties of the filler. The addition of the natural filler also leads to an increase in composite stiffness. The decrease in the tensile impact strength and the elongation at break is also noted. The reprocessing of the biocomposite initially led to a decrease in its mechanical properties, but the results stabilized after further processing cycles. This indicates the improvement of the microstructure homogeneity. The microscopic analysis shows that buckwheat hull particles were better embedded in the matrix after recycling. The increase in hardness was also noted. The PHBV-ground buckwheat hull biocomposite is characterized by stable mechanical properties and by recycling resistance, which makes it a promising material in terms of the sustainable development.

Advances in the enhancement of mechanical and hydrophobic properties of nanocellulose-based packaging materials: A review

As environmental issues are hotly debated worldwide, finding suitable materials to replace petroleum-based materials as the next-generation packaging materials has become a research hotspot. Nanocellulose, as a biomass material widely available in nature, is favored for application in green packaging materials due to its environmentally friendly and bio-friendly characteristics. However, the unstable mechanical properties and strong hydrophilicity of nanocellulose limit its practical application in packaging materials. This paper starts with a discussion of nanocellulose-based packaging materials and focuses on methods to improve their mechanical and hydrophobic properties. The discussion on mechanical properties focuses on the contribution of carbon nanomaterials, which is then combined with hydrophobic modifications (including plant polyphenol modification, esterification, acetylation, in situ polymerization, etc.) to illustrate the impact on the performance of packaging materials in use. The relationship between the hydrophobic characteristics of packaging materials derived from nanocellulose and their comprehensive mechanical properties is meticulously elucidated. Furthermore, a theoretical framework is proposed, positing that enhancing the hydrophobicity of these materials can indirectly augment their mechanical attributes. This insight offers pivotal guidance for the advancement of next-generation, high-performance packaging materials based on nanocellulose.

Recycling the sediment of cotton spinning effluent for rigid polyurethane foams

Sediment from the effluent of cotton spinning industry was valorized as the renewable bio-based polyols substitute for the rigid polyurethane (RPUFs), targeting to generate the economic and environmental benefits. Before reaction with the isocyanate, the sediment was functionalized by hydroxymethylation, in order to increase the density of the active hydroxyl groups for higher reactivity. The structural characterization results of the functionalized sediment indicated the material exhibited narrow molecular weight distribution, high hydroxyl groups content, and highly aromatic skeleton, which can be qualified as the renewable polyols for the RPUFs. In the crosslinking process, the effect of the polyols substitute rate of the sediments on the physio-chemical properties and the thermo-resistant performances of the resulting RPUFs was investigated. Specifically, in the group with 30 wt% of polyols substitution, the received foam exhibited comprehensive superiorities in compressive strength (0.58 MPa), apparent density (58 kg m-3), and thermo-conductivity (0.032 W m-1 K-1). Attractively, the RPUFs also exhibited good flame retardancy. The burning time can be extended by 30 % compared to the control group that without the sediment's substitution. Moreover, the RPUF also possessed good degradability, allowing for harmless recycling. The current work provided a potential route for the valorization of the hazardous waste effluent from the cotton spinning industry.

Cloning and characterization of FMN-dependent azoreductases from textile industry effluent identified through metagenomic sequencing

Azo dyes, when released untreated in the environment, cause detrimental effects on flora and fauna. Azoreductases are enzymes capable of cleaving commercially used azo dyes, sometimes in less toxic by-products which can be further degraded via synergistic microbial cometabolism. In this study, azoreductases encoded by FMN1 and FMN2 genes were screened from metagenome shotgun sequences generated from the samples of textile dye industries' effluents, cloned, expressed, and evaluated for their azo dye decolorization efficacy. At pH 7 and 45°C temperature, both recombinant enzymes FMN1 and FMN2 were able to decolorize methyl red at 20 and 100 ppm concentrations, respectively. FMN2 was found to be more efficient in decolorization/degradation of methyl red than FMN1. This study offers valuable insights into the possible application of azoreductases to reduce the environmental damage caused by azo dyes, with the hope of contributing to sustainable and eco-friendly practices for the environment management. This enzymatic approach offers a promising solution for the bioremediation of textile industrial effluents. However, the study acknowledges the need for further process optimization to enhance the efficacy of these enzymes in large-scale applications.Implications: The study underscores the environmental hazards associated with untreated release of azo dyes into the environment and emphasizes the potential of azoreductases, specifically those encoded by FMN1 and FMN2 genes, to mitigate the detrimental effects. The study emphasizes the ongoing commitment to refining and advancing the enzymatic approach for the bioremediation of azo dye-containing effluents, marking a positive stride toward more sustainable industrial practices.

Unlocking the potential of cotton stalk as a renewable source of cellulose: A review on advancements and emerging applications

Cotton stalk (CS) is a global agricultural residue, with an annual production of approximately 50 million tons, albeit with limited economic significance. The utilization of cellulose derived from CS has gained significant attention in green nanomaterial technologies. This interest stems from its unique properties, including biocompatibility, low density, minimal thermal expansion, eco-friendliness, renewability, and its potential as an alternative source for chemicals, petroleum, and biofuels. In this review, we delve into various extraction and characterization methods, the physicochemical attributes, recent advancements, and the applications of cellulose extracted from CS. Notably, the steam explosion method has proven to yield the highest cellulose content (82 %) from CS. Moreover, diverse physicochemical properties of cellulose can be obtained through different extraction techniques. Sulfuric acid hydrolysis, for instance, yields nanocrystalline cellulose fibers measuring 10-100 nm in width and 100-850 nm in length. Conversely, the steam explosion method yields cellulose fibers with dimensions of 10.7 μm in width and 1.2 mm in length. CS-derived products, including biochar, aerogel, dye adsorbents, and reinforcement fillers, find applications in various industries, such as environmental remediation and biodegradable packaging. This is primarily due to their ready availability, cost-effectiveness, and sustainable nature.

Preparation of nanocellulose and its applications in wound dressing: A review

Nanocellulose, as a nanoscale polymer material, has garnered significant attention worldwide due to its numerous advantages including excellent biocompatibility, thermal stability, non-toxicity, large specific surface area, and good hydrophilicity. Various methods can be employed for the preparation of nanocellulose. Traditional approaches such as mechanical, chemical, and biological methods possess their own distinct characteristics and limitations. However, with the growing deterioration of our living environment, several green and environmentally friendly preparation techniques have emerged. These novel approaches adopt eco-friendly technologies or employ green reagents to achieve environmental sustainability. Simultaneously, there is a current research focus on optimizing traditional nanocellulose preparation methods while addressing their inherent drawbacks. The combination of mechanical and chemical methods compensates for the limitations associated with using either method alone. Nanocellulose is widely used in wound dressings owing to its exceptional properties, which can accelerate the wound healing process and reduce patient discomfort. In this paper, the principle, advantages and disadvantages of each preparation method of nanocellulose and the research findings in recent years are introduced Moreover, this review provides an overview of the utilization of nanocellulose in wound dressing applications. Finally, the prospective trends in its development alongside corresponding preparation techniques are discussed.

Use of copper-functionalized cotton waste in combined chemical and biological processes for production of valuable chemical compounds

Cotton textiles modified with copper compounds have a documented mechanism of antimicrobial action against bacteria, fungi, and viruses. During the COVID-19 pandemic, there was pronounced interest in finding new solutions for textile engineering, using modifiers and bioactive methods of functionalization, including introducing copper nanoparticles and complexes into textile products (e.g. masks, special clothing, surface coverings, or tents). However, copper can be toxic, depending on its form and concentration. Functionalized waste may present a risk to the environment if not managed correctly. Here, we present a model for managing copper-modified cotton textile waste. The process includes pressure and temperature-assisted hydrolysis and use of the hydrolysates as a source of sugars for cultivating yeast and lactic acid bacteria biomass as valuable chemical compounds.

Biochar‐C‐TETA as a superior adsorbent to acid yellow 17 dye from water: isothermal and kinetic studies

Adsorbents from local materials with high adsorption capacity (Qm) are strongly needed. In this study, mandarin peels (MP) as a local waste material were refluxed in 80% sulfuric acid (H2SO4) to produce a novel biochar, which was oxidized by boiling in 50% hydrogen perioxide (H2O2) and then aminated via refluxing in tetraacetic acid (TETA) to produce mandarin biochar‐C‐TETA (MBCT). Fourier transform infrared (FTIR), Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and thermgravimetric analysis (TGA) studied various characterizations of MBCT. The optimal pH for AY17 dye absorption was discovered to be 1.5 using 0.75 g L−1 MBCT, the maximum absorption capacity predicted for the MBCT was 1250 mg g−1. The high new absorption peaks at 1439.89 and 1362.38 cm−1 in MBCT imply that amino groups were successfully generated onto the surface of MBCT due to TETA treatment. The experimental data were examined using the Langmuir (LNR) and Freundlich (FRH) isotherm models. The FRH best explained the experimental MBCT data. The pseudo‐first‐order (PFOM) and pseudo‐second‐order (PSOM) models, intraparticle diffusion (INDM) and film diffusion (FDM) models were applied to calculate the kinetic data. The PFOM rate model ideally defined the absorption of AY17 dye to MBCT with a linear regression coefficient (R2 > 0.99). The key mechanism for absorbing AY17 dye molecules to MBCT was chemisorption, which entails the distribution or exchange of electrons between the absorbent and the dye due to the valency force. According to the findings, the novel MBCT adsorbent had a remarkable adsorption capacity (Qm = 1250 mg g−1) and could be reused without losing its absorption effectiveness. © 2023 Society of Chemical Industry (SCI).

Insights into the Applications of Natural Fibers to Metal Separation from Aqueous Solutions

There is a wide range of renewable materials with attractive prospects for the development of green technologies for the removal and recovery of metals from aqueous streams. A special category among them are natural fibers of biological origin, which combine remarkable biosorption properties with the adaptability of useful forms for cleanup and recycling purposes. To support the efficient exploitation of these advantages, this article reviews the current state of research on the potential and real applications of natural cellulosic and protein fibers as biosorbents for the sequestration of metals from aqueous solutions. The discussion on the scientific literature reports is made in sections that consider the classification and characterization of natural fibers and the analysis of performances of lignocellulosic biofibers and wool, silk, and human hair waste fibers to the metal uptake from diluted aqueous solutions. Finally, future research directions are recommended. Compared to other reviews, this work debates, systematizes, and correlates the available data on the metal biosorption on plant and protein biofibers, under non-competitive and competitive conditions, from synthetic, simulated, and real solutions, providing a deep insight into the biosorbents based on both types of eco-friendly fibers.

Nanocellulose reinforced lightweight composites produced from cotton waste via integrated nanofibrillation and compounding

Cotton is a natural fiber containing more than 95% of cellulose. With worldwide cotton consumption continuously increasing, the amount of cotton waste generated is enormous. Most of the cotton waste ends up in landfill or incinerators, resulting in a huge waste of this excellent natural resource. In this project, cotton waste was recycled to produce polypropylene nanocomposites. Instead of using the traditional two-step nanofiber extraction and compounding technique, an integrated process was adopted to combine nanofibrillation and compounding into one step. Results showed that cotton fibers with a slight prefibrillation and hydrophobic surface modification were successfully fibrillated into tens to hundreds of nanometers in width during compounding. The nanofibers reinforced polypropylene composites exhibited significantly enhanced tensile and flexural strength and moduli. For instance, when 30% fibers from bleached white and indigo-dyed denim fabrics were introduced, the tensile moduli of the resultant composites reached 4.57 and 4.59 GPa, respectively, compared to 1.60 GPa, the modulus of neat PP. Meanwhile, denim fabrics had a remarkable reinforcing effect on the composites' impact strength attributing to the hydrophobic indigo dyes that improved the interfacial bonding between cotton fibers and the matrix. The highest impact strength of denim reinforced composites was 4.96 kJ/m² with 20% fiber loading; while the impact strength of neat polypropylene was 2.46 kJ/m². The low water uptake of the composites further indicated the excellent adhesion at the filler/matrix interface. In general, a very promising processing technique to recycle cotton waste for high-value products was demonstrated.

Bacterial Cellulose and ECM Hydrogels: An Innovative Approach for Cardiovascular Regenerative Medicine

Cardiovascular diseases are considered the leading cause of death in the world, accounting for approximately 85% of sudden death cases. In dogs and cats, sudden cardiac death occurs commonly, despite the scarcity of available pathophysiological and prevalence data. Conventional treatments are not able to treat injured myocardium. Despite advances in cardiac therapy in recent decades, transplantation remains the gold standard treatment for most heart diseases in humans. In veterinary medicine, therapy seeks to control clinical signs, delay the evolution of the disease and provide a better quality of life, although transplantation is the ideal treatment. Both human and veterinary medicine face major challenges regarding the transplantation process, although each area presents different realities. In this context, it is necessary to search for alternative methods that overcome the recovery deficiency of injured myocardial tissue. Application of biomaterials is one of the most innovative treatments for heart regeneration, involving the use of hydrogels from decellularized extracellular matrix, and their association with nanomaterials, such as alginate, chitosan, hyaluronic acid and gelatin. A promising material is bacterial cellulose hydrogel, due to its nanostructure and morphology being similar to collagen. Cellulose provides support and immobilization of cells, which can result in better cell adhesion, growth and proliferation, making it a safe and innovative material for cardiovascular repair.

Recent Progress in Modification Strategies of Nanocellulose-Based Aerogels for Oil Absorption Application

Oil spills and oily wastewater have become a major environmental problem in recent years, directly impacting the environment and biodiversity. Several techniques have been developed to solve this problem, including biological degradation, chemicals, controlled burning, physical absorption and membrane separation. Recently, biopolymeric aerogels have been proposed as a green solution for this problem, and they possess superior selective oil absorption capacity compared with other approaches. Several modification strategies have been applied to nanocellulose-based aerogel to enhance its poor hydrophobicity, increase its oil absorption capacity, improve its selectivity of oils and make it a compressible and elastic magnetically responsive aerogel, which will ease its recovery after use. This review presents an introduction to nanocellulose-based aerogel and its fabrication approaches. Different applications of nanocellulose aerogel in environmental, medical and industrial fields are presented. Different strategies for the modification of nanocellulose-based aerogel are critically discussed in this review, presenting the most recent works in terms of enhancing the aerogel performance in oil absorption in addition to the potential of these materials in near future.

A comprehensive investigation on cellulose nanocrystals with different crystal structures from cotton via an efficient route

The crystal structures of cellulose nanomaterials play an important role in their morphologies and applications, however, there was still lacking systematic research on preparing various crystalline allomorphs of cellulose nanocrystals with high thermal stability. Herein, the efficient synthesis route was presented to design various crystalline allomorphs of cellulose from cotton. And then, cellulose nanocrystals with different crystal structures (CNC-I, CNC-II, CNC-III_II, CNC-IV_II) were prepared by hydrogen peroxide hydrolysis of resultant cellulose. Overall, needle-like CNC-I (length of 180 ± 25 nm, diameter of 12 ± 2 nm), near-spherical CNC-II (diameter of 101 ± 12 nm), and spherical CNC-III_II (diameter of 22 ± 3 nm) and CNC-IV_II (diameter of 21 ± 2 nm) all exhibited remarkable dispersibility and thermal stability (T_max > 357 °C). This work provides a simple and low-cost synthesis route for various crystalline allomorphs of CNCs with high thermal stability from the same raw materials (cotton).

Functional Properties of Antimicrobial Neem Leaves Extract Based Macroalgae Biofilms for Potential Use as Active Dry Packaging Applications

Antimicrobial irradiated seaweed–neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves’ extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed–neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem–seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed–neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.