Nanocellulose: Structure, modification, biodegradation and applications in agriculture as slow/controlled release fertilizer, superabsorbent, and crop protection: A review

Tunable NPK Release from Surface-Esterified Nanocellulose-Based Prills

Polysaccharides represent an ideal delivery platform for agrochemicals due to their biodegradability, biocompatibility, and abundance. However, hydrophilicity renders native polysaccharides ineffective at controlling the release of water-soluble agrochemicals. To overcome this limitation, we used a solvent-free, vapor-phase modification strategy to generate hydrophobic shells on the surface of nanofibrillated cellulose (CNF) prills and evaluated the effects of these tunable diffusion barriers on fertilizer release behavior. Hydrophobic shells of different thicknesses were created on CNF prills by esterification with acyl chlorides of varying alkyl chain lengths, although esterification did not hinder the inherent biodegradability of the CNFs. Fertilizer release rates were largely invariable to pH and NPK loading but were tunable over 3 orders of magnitude by varying the alkyl chain length and the degree of substitution (i.e., shell thickness). However, NPK release rates did not increase monotonically with increasing shell thickness; for long-chain (6 carbons or longer) esters, increases in shell thickness beyond optimal values increased release rates; SEM revealed that this originated from the introduction of fractures to the prills which act as diffusion channels. This work demonstrates the potential of controlled surface modification to generate a mineralizable and tunable NPK release platform from naturally sourced and sustainable feedstocks.

Nanocellulose - metal-organic framework (MOF) composites for efficient carbon dioxide capture and sequestration: a review

Air pollution, a major global challenge, poses significant risks to human health and the environment. While various porous materials have been used to reduce pollutants, they have limitations. Metal-organic frameworks (MOFs) stand out due to their unique combination of organic and inorganic components, allowing precise tuning of their structure and functionality. With remarkable properties such as tunable pore sizes and high porosity, MOFs are highly effective for CO2 separation. However, their fragility has led to the integration of bio-based materials such as nanocellulose. Nanocellulose, known for its abundance, non-toxicity, renewability, excellent hydrophilicity, flexibility, strength and low cost, offers a promising support matrix for MOFs. Functionalising nanocellulose with MOFs (NC-MOFs) shows great promise in CO2 adsorption and separation, presenting a valuable approach to mitigate carbon dioxide emissions. This review summarises the properties and synthesis methods involving NC-MOFs, focusing on various types of nanocellulose and their efficiency in CO2 capture. It also explores the adsorption mechanisms and factors influencing the stability and capacity of NC-MOFs in gas capture. Furthermore, we discuss the current limitations and future opportunities of NC-MOFs in addressing global carbon emissions, emphasising their potential role in tackling one of the most critical environmental challenges of our time.

Sustainable Agriculture Solutions: Biodegradable Coatings for Enhanced-Efficiency Fertilizers Using Cellulose and Lignin

Current challenges in sustainable development and environmental protection are driving scientists and engineers to innovate and mitigate the negative impact of human activities on ecosystems. Strict legal requirements in the European Union (EU) underscore the need for changes to materials used in fertilizers because all components must be biodegradable by July 2024. The EU has published new guidelines for biodegradable materials based on ISO 17556, which assesses degradability in soil. One of the main directions to meet these expectations is the use of enhanced-efficiency fertilizers made from biodegradable materials. This review critically analyses recent advances in using natural raw materials as mineral fertilizer coatings, addressing a significant gap in the evaluation of their commercial viability. The properties of cellulose and lignin as coating materials and their modifications are discussed, including cellulose acetate, ethylcellulose, cellulose acetate butyrate, and phenolated and oxypropylated lignin. These findings provide practical guidance for fertilizer manufacturers seeking to comply with upcoming regulations while maintaining product efficacy.

Effect of eucalyptus nanofibril as reinforcement in biodegradable thermoplastic films based on rice starch (Oryza sativa): Evaluation as primary packaging for crackers

This study investigated the incorporation of eucalyptus nanocellulose (CNF) into rice starch-based thermoplastic (TPS) films, evaluating the effects of four CNF concentrations (0 %, 2 %, 4 %, and 6 %, w/w) on the physicochemical properties of the films. The analyses included scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), solubility, mechanical properties, optical properties, biodegradability, and application for cookie preservation. Atomic force microscopy (AFM) confirmed good CNF dispersion at 4 %, while higher concentrations caused agglomeration. FTIR analysis revealed effective interactions between CNF and the starch matrix. The TPS + 4 % CNF film showed reductions in water solubility (44 %), solubility in acidic (34 %) and basic (32 %) conditions, water vapor permeability (51 %), and water retention capacity (27 %) compared to pure TPS. Tensile strength increased from 3 MPa (pure TPS) to 6.5 MPa (TPS with 4 % CNF), while elongation at break ranged from 38 % (pure TPS) to 65 % (TPS with 2 % CNF). At 6 % CNF, elongation decreased to 45 %, with increased rigidity. The TPS + 4 % CNF film demonstrated good performance in mechanical strength and water vapor barrier properties, while higher CNF concentrations resulted in stiffer, less flexible films due to restricted polymer chain mobility. Higher CNF concentrations also increased the film's opacity. With 90 % biodegradability after 15 days, the reinforced film showed environmental potential. In cookie preservation, TPS + 4 % CNF demonstrated promising performance, with moisture barrier and texture preservation capabilities comparable to oriented polypropylene (BOPP). The combination of biodegradable primary packaging with non-biodegradable secondary packaging offers an innovative solution for food protection with reduced environmental impact.

Advancing agricultural efficiency and sustainability: Bio-inspired superabsorbent hydrogels for slow and controlled release fertilizers

Bio-inspired superabsorbent hydrogels (BiSAHs) represent a versatile polymeric material class that has garnered significant interest due to their multifunctional attributes and extensive range of applications. A thorough examination of the literature and patents on BiSAHs highlights their critical role across diverse sectors. This review provides an in-depth analysis of BiSAHs, focusing on their classification, synthesis methodologies, and potential applications in agriculture. It critically examines biopolymer-based SAHs as soil conditioners and slow and controlled, focusing on their classification, synthesis methodologies, and potential applications in agriculture. It critically examines biopolymer-based SAHs as soil conditioners and slow and controlled-release fertilizers, elucidating the mechanisms governing water retention, swelling capacity, and nutrient release kinetics. The review further presents detailed case studies illustrating the enhancement of crop growth and productivity facilitated by BiSAHs and their effectiveness as agrochemical carriers. Moreover, it explores the role of SAHs in crop protection, particularly in mitigating adverse abiotic stresses such as heavy metal toxicity, salinity, and drought. The ecological, economic, and societal impacts of BiSAH-based controlled-release fertilizers are evaluated, providing a balanced perspective on their sustainability. Ultimately, the review offers insights into future directions and emerging advancements in the development and application of BiSAHs in agricultural settings.

Comparative Study on the Effects of Silicon Nanoparticles and Cellulose Nanocrystals on Drought Tolerance in Tall Fescue (Festuca arundinacea Schreb.)

Tall fescue (Festuca arundinacea Schreb.) is a herbaceous species that is commonly used for ecological slope restoration in China. However, water scarcity often constrains its growth due to the unique site conditions of steep slopes and climate-induced drought stress. This study aims to compare the ameliorative effects of silicon nanoparticles (Si NPs) and cellulose nanocrystals (CNCs) on drought stress in tall fescue and to elucidate their underlying mechanisms of action. The results indicated that drought stress impaired photosynthesis, restricted nutrient absorption, and increased oxidative stress, ultimately reducing biomass. However, Si NPs and CNCs enhanced drought tolerance and promoted biomass accumulation by improving photosynthesis, osmotic regulation, and antioxidant defense mechanisms. Specifically, Si NP treatment increased biomass by 48.71% compared to drought-stressed control plants, while CNCs resulted in a 33.41% increase. Transcriptome sequencing further revealed that both nanomaterials enhanced drought tolerance by upregulating genes associated with photosynthesis and antioxidant defense. Additionally, Si NPs improved drought tolerance by stimulating root growth, enhancing nutrient uptake, and improving leaf structure. In contrast, CNCs play a distinct role by regulating the expression of genes related to cell wall synthesis and metabolism. These findings highlight the crucial roles of these two nanomaterials in plant stress protection and offer a sustainable strategy for the maintenance and management of slope vegetation.

Recent progress of multifunctional nanocellulose-based pharmaceutical materials: A review

In the pharmaceutical industry, ongoing research and development focus on discovering new drug formulations that align with regulatory approvals. Recently, innovative drug delivery systems have been used to maximize therapeutic efficacy with a precision of sustained drug delivery in the disease management system. Nanocellulose (NCs) synthesized from abundant cellulose, have attracted wide attention for potential pharmaceutical applications due to their unique properties, such as biocompatibility, high surface area-to-volume ratio, extensive drug loading and binding capacity, controlled drug release efficiency, strength, and availability with various treatments and modification ability. Nevertheless, research on nanocarriers (NCs) in the pharmaceutical field faces several limitations and challenges. Key areas requiring further exploration include chemical consumption, energy intensity, effluent management, recovery processes from acid hydrolysis, reaction times, ecotoxicology, and overall development progress. This overview provides the applications of emerging nanocellulose. It gives a clue on the synthesis of sustainable NCs related to their different sources, pre- and post-modifications of NCs, and key properties in pharmaceutical sectors. Furthermore, it gives an overview of the current advancements, life cycle analysis, biosafety, and key property performance with a summary of challenges and future perspectives.

Nanocellulose-hydrogel hybrids: A review on synthesis and applications in agriculture, food packaging and water remediation

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NC-HHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Ginger residue-derived nanocellulose as a sustainable reinforcing agent for composite films

Nanocellulose extracted from agricultural waste for the development of reinforced sustainable composites is needed, due to a greater environmental responsibility and awareness of environmental pollution. In this work, the extraction of nanocellulose (GNC) from ginger residue was conducted via acid hydrolysis without complicated pretreatments. The potential application of GNC as a reinforcing agent for sustainable composite films was also explored. The results showed that the obtained GNC exhibited a rod-like shape with a high aspect ratio (15.75 ± 4.25). X-ray diffraction patterns revealed a cellulose II structure with a crystallinity index of 88.47 %. The reinforcing effects of GNC were evaluated in composite films made from different matrices, including sodium alginate (SA) and chitosan (CS), to assess its performance in enhancing material properties. The incorporation of 5 % of GNC significantly improved the tensile strength of SA and CS by 94 % and 64 %, respectively. Notably, the addition of GNC also enhanced the elongation at break of the SA-based films. This study demonstrates that ginger residue is a promising and sustainable feedstock for extracting nanocellulose, which can serve as an effective reinforcing agent in biocomposite films.

Advancing nanocellulose-based biosensors: pioneering eco-friendly solutions for biomedical applications and sustainable material replacement

The escalating demand for sustainable and high-performance biosensing technologies has intensified interest in nanocellulose-based biosensors as eco-friendly alternatives to conventional materials. Nanocellulose, derived from abundant natural sources, offers remarkable properties such as high surface area, mechanical strength, biocompatibility, and chemical versatility, making it highly suitable for biosensing applications. This review delves into the synthesis, functionalization, and diverse applications of nanocellulose materials, particularly bacterial nanocellulose (BNC) and cellulose nanofibrils (CNFs), in the development of advanced biosensors. Innovative functionalization techniques, including polymer grafting and TEMPO oxidation, have been employed to enhance the specificity, stability, and sensitivity of these biosensors. These advancements lay the foundation for a sustainable and efficient biosensing framework, positioning nanocellulose-based technologies at the forefront of developing eco-friendly and accessible biosensors for biomedical applications and beyond.

Perspective of nanocellulose production, processing, and application in sustainable agriculture and soil fertility enhancement: A potential review

Nanocellulose, a promising green material derived from various bio-sources, has potentiality on and off-site in the agricultural sector. Due to its special qualities, which include high strength, hydrophilicity, and biocompatibility, it is a material that may be used in a variety of industries, especially agriculture. This review explores in this article production processes, post-processing procedures, and uses of nanocellulose in soil fertility increment and sustainable agriculture. A variety of plant materials, agricultural waste, and even microbes can be used to isolate nanocellulose. Nanocellulose is produced using both top-down and bottom-up methods, each of which has benefits and limitations of its own. It can be applied as nano-biofertilizer in agriculture to enhance beneficial microbial activity, increase nutrient availability, and improve soil health. Moreover, nanocellulose can be used in fertilizer and pesticide formulations with controlled releases to increase efficacy and lessen environmental effects. Innovative approaches to sustainable agriculture are provided by nanocellulose technologies, which also support the UN's Sustainable Development Goals (SDGs), especially those pertaining to eradicating hunger and encouraging responsible consumption. Nanocellulose promotes climate action and ecosystem preservation by increasing resource efficiency and decreasing dependency on hazardous chemicals, ultimately leading to the development of a circular bioeconomy. Nonetheless, there are still issues with the high cost of production and the energy-intensive isolation procedures. Despite its various potentialities, challenges such as high production costs, environmental concerns, and regulatory issues must be addressed for nanocellulose to be widely adopted and effectively integrated into farming practices.

Research progress on improving dispersion stability of nanocellulose in different media: A review

Nanocellulose has been widely used in various fields due to its good biocompatibility, mechanical properties, large specific surface area and environmental friendliness. Among these applications, uniformly dispersing nanocellulose in various media to improve its performance is an application with good development prospects. However, due to the presence of surface hydroxyl groups, nanocellulose tends to form aggregates between molecular chains and is less compatible with nonpolar solvents, thus making it difficult to be stably dispersed in solvents. How to break the aggregation between cellulose and improve its compatibility with the medium has become a challenging issue. In this paper, the dispersion system is classified into polar medium, nonpolar medium and polymer matrix according to the polarity and state of the medium, and a review is presented on how to improve the dispersion stability of nanocellulose in different media. The methods of using surface modification to improve the dispersion stability of nanocellulose in different media, such as carboxylation, amidation, and grafting of long-chain molecules to reduce the aggregation among nanocellulose and to improve the compatibility with solvents, are highlighted. Finally, suggestions are made for future research directions.

Sustainable Biopolymer Colloids: Advances in Morphology for Enhanced Functionalities

Biobased polymers such as cellulose, chitin/chitosan, starch, alginate, and lignin are making inroads as sustainable, environmentally safe and biodegradable alternatives to synthetic colloidal materials. This perspective summarizes recent developments in preparation techniques, identifies critical barriers, and proposes future directions for improving the performance and applicability of biopolymer colloidal structures. A major focus is the sustainable colloids morphology as a means of introducing functionality without chemical modification. We discuss the strategies for fabrication of four distinct classes of colloidal morphologies from biobased materials: spherical and nonspherical particles, fibers/fibrils, and films. Their preparation methods can be categorized into physical and chemical approaches. Despite advancements in these methods, challenges persist regarding uniformity, scalability, desired properties, and the need to enhance environmental sustainability. Addressing these challenges is essential for facilitating the transition from synthetic polymers to greener, more sustainable, and microplastic-free colloidal alternatives.

Biodegradable composite films of barley fibers for food packaging applications: A review

The conventional food packaging is creating a significant cause of environmental hazards, posing challenges in disposal and recycling. Lignocellulose fibers possess remarkable biodegradable properties and can be modified or blended with other polymers. Thus, using lignocellulose biocomposite films derived from barley, a renewable source can mitigate and potentially transform into sustainable, innovative packaging material in the food sectors. Hence, this review focuses on barley lignocellulose fibers incorporated into different film matrix phases, showing promising enhanced mechanical, and functional properties. Barley biocomposites provide the necessary protective functions to replace traditional plastic for food packaging applications and that could reduce the negative effects on the environment. In addition, we highlighted various recently developed barley lignocellulose-based biocomposite films for a variety of food packaging applications. Furthermore, an overview of the environmental impact of plastic pollution and its effects on ecological niches has been emphasized. Additionally, aspects of different sustainable goals (SDGs 9, 12, 13) are discussed. Based on the existing research gaps, this article is concluded with the challenges and discussed further perspectives of biocomposites enriched with barley lignocellulose fibers.

A Comprehensive Review on Cellulose Nanofibers, Nanomaterials, and Composites: Manufacturing, Properties, and Applications

Cellulose nanofibers (CNFs), cellulose nanomaterials (CNMs), and cellulose-based composites represent a convergence of material science, sustainability, and advanced engineering, paving the way for innovative and eco-friendly materials. This paper presents a comprehensive review of these materials, encompassing their extraction, preparation methods, properties, applications, and future directions. The manufacturing of CNFs and CNMs leverages diverse techniques-chemical, mechanical, and enzymatic-with each offering distinct advantages in tailoring material characteristics to meet specific needs. Strategies for functionalization and surface modification are detailed, highlighting their role in enhancing the properties of CNFs and composites while addressing challenges in scaling production to industrial levels. The structural, mechanical, thermal, optical, electrical, and biocompatibility properties of CNFs, CNMs, and their composites are explored, underscoring their versatility for applications across various industries. Cellulose-based composites, in particular, demonstrate exceptional tunable properties for specific uses, although achieving uniform dispersion remains a key technical hurdle. These materials have applications in packaging, automotive, aerospace, biomedical devices, energy storage, and environmental remediation. Emerging research trends emphasize the integration of CNFs and CNMs with advanced manufacturing technologies, promoting sustainable practices and life cycle considerations while advancing their commercialization potential. This rapidly evolving field holds immense promise for addressing global challenges by creating high-performance, and sustainable materials. This review is crucial in advancing the understanding of cellulose nanofibers, nanomaterials, and cellulose-based composites, providing valuable insights that will drive the development of sustainable, high-performance materials for a wide range of applications, ultimately addressing key global challenges.

Carboxymethyl Cellulose Surface Modification Alleviates the Toxicity of Fe-MOFs to Rice and Improves Iron Absorption

Iron-based metal-organic frameworks (Fe-MOFs) are widely used for agricultural chemical delivery due to their high loading capacity, and they also have the potential to provide essential iron for plant growth. Therefore, they hold significant promise for agricultural applications. Evaluating the plant biotoxicity of Fe-MOFs is crucial for optimizing their use in agriculture. In this study, we used the natural biomacromolecule carboxymethyl cellulose (CMC) to encapsulate the Fe-MOF NH2-MIL-101 (Fe) (MIL). Through hydroponic experiments, we investigated the biotoxic effects of Fe-MOFs on rice before and after CMC modification. The results show that the accumulation of iron in rice is dependent on the dose and the exposure concentration of Fe-MOFs. CMC modification (MIL@CMC) can reduce the release rate of Fe ions from Fe-MOFs in aqueous solutions with different pH values (5 and 7). Furthermore, MIL@CMC treatment significantly increases the absorption of iron by both the aboveground and root parts of rice. MIL@CMC significantly alleviated the growth inhibition of rice seedlings and increased the aboveground biomass of rice under medium- to high-exposure conditions. Specifically, in rice roots, MIL induced a more intense oxidative stress response, with significant increases in the activities of related antioxidant enzymes (CAT, POD, and SOD) and MDA content. Our results demonstrated that the encapsulation of NH2-MIL-101(Fe) using CMC effectively alleviated oxidative damage and promoted the uptake and growth of iron in rice. These findings suggest that rational modification can have a positive effect on reducing the potential phytotoxicity of MOFs and improving their biosafety in agricultural applications.

Structure-property relations in rheology of cellulose nanofibrils-based hydrogels

Hydrogels prepared from self-assembled cellulose nanofibrils (CNFs) are widely used in biomedicine, electronics and environmental technology. Their ability to serve as inks for extrusion-based 3D printing is conventionally evaluated by means of rheological tests. A model is developed that describes the response of CNF gels in small- and large-amplitude oscillatory tests in a unified manner. The model involves a reasonably small number of material parameters, ensures good agreement between results of simulation and observations in oscillatory tests and correctly predicts the stress-strain Lissajous curves, experimental data in hysteresis loop tests, and measurements of the steady-state viscosity. The model is applied to analyze how composition and preparation conditions for CNF gels affect transition from shear thinning to weak strain overshoot in large-amplitude shear oscillatory tests. Based on the model, simple relations are derived for the fractal dimension of CNF clusters and the storage modulus of gels prepared in aqueous solutions of multivalent salts. The validity of these equations is confirmed by comparison of their predictions with observations in independent tests.

Nanocellulose: A novel pathway to sustainable agriculture, environmental protection, and circular bioeconomy

Nanocellulose, obtained from natural cellulose, has attracted considerable interest for its distinctive properties and wide-ranging potential applications. Studies suggest that nanocellulose improves the thermal, mechanical, and barrier properties of conventional cellulose. This review investigates the production, properties, approach, and application of nanocellulose from various sources in agriculture. The main role play of cellulose-nanocomposite is discussed as a seed coating agent to improve seed dispersal, germination, protection against fungi and insects, plant growth promoter, adsorption of targeted pollutants, providing water and nutrient retention, and other advantages. As a nobility, we included all mechanical, chemical, and static culture approaches to the production procedure of nanocellulose and its application as a nanocarrier in soil, including the unique properties of nanocellulose, such as its high surface area, inherent hydrophilicity, and ease of surface modification. Here, methods such as melt compounding, solution casting, and in situ polymerization were evaluated to incorporate nanoparticles into cellulose materials and produce nanocellulose and cellulose-nanocomposites with improved strength, stability, water resistance, and reduced gas permeability. The commercialization faces challenges such as high production costs, scalability issues, and the need for more research on environmental impacts and plant interactions. Despite these hurdles, this field is promising, with ongoing advancements likely to yield new and improved agricultural materials. This review thoroughly examines the innovative application of nanocellulose in slow and controlled-release fertilizers and pesticides, to transform nutrient management, boost crop productivity, and minimize the environmental impact.

Synthesis and application of a multifunctional poly (vinyl pyrrolidone)-based superabsorbent hydrogel for controlled fertilizer release and enhanced water retention in drought-stressed Pisum sativum plants

Water scarcity poses a significant challenge to agricultural production, prompting the development of sustainable technologies to optimize water resource utilization. This study focuses on the synthesis and application of a multifunctional poly (vinylpyrrolidone); PVP-based superabsorbent hydrogel (SAH) for controlled release of essential fertilizers (nitrogen, phosphorus, and potassium) and enhanced water retention in soil. The hydrogel was prepared via a facile one-step approach and compared to a control soil without hydrogel amendment. The reaction was initiated in the presence of poly(vinylpyrrolidone) (PVP) to produce a PVP-based copolymer hydrogel. The hydrogel was then subjected to a basic treatment using either sodium hydroxide (hydrogel #1) or potassium hydroxide (hydrogel #2). The PVP-based SAH exhibited excellent swelling capacity, water retention, and fertilizer release properties. When applied to Pisum sativum plants under drought stress, the hydrogel significantly improved soil moisture levels, nutrient availability, and plant growth parameters compared to the control. The hydrogel #2-amended plants demonstrated enhanced biomass, chlorophyll content, and photosynthetic efficiency, highlighting the hydrogel's effectiveness in mitigating the adverse effects of drought stress. These findings demonstrate the potential of the PVP-based SAH as a promising strategy for sustainable agriculture, offering using readily available and inexpensive raw materials, suggesting a relatively low-cost and scalable production process. Furthermore, the hydrogel facilitates water conservation, controlled nutrient delivery, and improved plant performance under drought stress conditions.

Evaluating the Effectiveness of Cellulose-Based Surfactants in Expandable Graphite Wood Coatings

This study deals with the design of modern environmentally friendly and non-toxic flame retardants based on expandable graphite 25 K + 180 (EG) modified by cellulose ethers (Lovose TS 20, Tylose MH 300, Klucel H) and nanocellulose (CNC) that are biocompatible with wood and, therefore, are a prerequisite for an effective surfactant for connecting EG to wood. The effectiveness of the formulations and surfactants was verified using a radiant heat source test. The cohesion of the coating to the wood surface and the cohesion of the expanded graphite layer were also assessed. The fire efficiency of the surfactants varied greatly. Still, in combination with EG, they were all able to provide sufficient protection-the total relative mass loss was, in all cases, in the range of 7.38-7.83% (for untreated wood it was 88.67 ± 1.33%), and the maximum relative burning rate decreased tenfold compared to untreated wood, i.e., to 0.04-0.05%·s-1. Good results were achieved using Klucel H + EG and CNC + EG formulations. Compared to Klucel H, CNC provides significantly better cohesion of the expanded layer, but its high price increases the cost of the fireproof coating.

Preparation and characterization of starch carbamate modified natural sodium alginate composite hydrogel blend formulation and its application for slow-release fertilizer

The exploration of environmentally friendly slow-release fertilizer (SRF) based on natural bio-polymers is of great importance in the development of modern agriculture and horticulture. Herein, a novel starch carbamate (SC) modified sodium alginate (SA) hydrogel (SC/SAH) was prepared utilizing as-synthesized SC and natural SA through the cationic ions crosslinking method and ultimately the corresponding slow-release fertilizer (SC/SAH-SRF) was successfully developed by immersing the dried SC/SAH matrix into saturated urea solution. Due to the low gelation temperature and high viscosity of the synthesized SC, the formed SC/SAH exhibits significantly enhanced properties including excellent water absorbency up to 8.02 g/g with considerable repeatability, abundant pore structure and high hydrophilicity compared with the neat SAH and natural starch based hydrogel (NS/SAH). Accordingly, the SC/SAH leads to higher urea loading amount ∼ 1.28 g/g. Importantly, the resultant SC/SAH-SRF also shows superior slow-release performance, yielding a cumulative urea release of only 61.6 % within 10 h and almost completely release >16 h in water, what's more, only 58.5 % of the urea releases within 25 days and exceeding 50 days for complete release in soil column assays. The slow-release of urea from SC/SAH-SRF well complies for the first-order kinetics and accomplishes via a non-Fickian diffusion process. Moreover, the pot experiment demonstrates that the SC/SAH-SRF has higher growth promotion role for the maize seedlings than those of others. Consequently, this work provides a novel strategy for preparing environmentally friendly SRF by blending modified starch and hydrogel.

Recent trends in the phytoremediation of radionuclide contamination of soil by cesium and strontium: Sources, mechanisms and methods: A comprehensive review

This comprehensive review examines recent trends in phytoremediation strategies to address soil radionuclide contamination by cesium (Cs) and strontium (Sr). Radionuclide contamination, resulting from natural processes and nuclear-related activities such as accidents and the operation of nuclear facilities, poses significant risks to the environment and human health. Cs and Sr, prominent radionuclides involved in nuclear accidents, exhibit chemical properties that contribute to their toxicity, including easy uptake, high solubility, and long half-lives. Phytoremediation is emerging as a promising and environmentally friendly approach to mitigate radionuclide contamination by exploiting the ability of plants to extract toxic elements from soil and water. This review focuses specifically on the removal of 90Sr and 137Cs, addressing their health risks and environmental implications. Understanding the mechanisms governing plant uptake of radionuclides is critical and is influenced by factors such as plant species, soil texture, and physicochemical properties. Phytoremediation not only addresses immediate contamination challenges but also provides long-term benefits for ecosystem restoration and sustainable development. By improving soil health, biodiversity, and ecosystem resilience, phytoremediation is in line with global sustainability goals and environmental protection initiatives. This review aims to provide insights into effective strategies for mitigating environmental hazards associated with radionuclide contamination and to highlight the importance of phytoremediation in environmental remediation efforts.

Regulation of the Degradation Properties of Tyrosinase-Catalyzed Crosslinking Silk Membranes for Superficial Wound Repair

Appropriate biodegradability to meet the demands of wound repair is critical for superficial wound repair membrane applications. Tyrosinase-catalyzed crosslinking SF (c-SF) membranes were constructed and regulated the degradation behavior in this study. The crosslinking degree of the c-SF membranes could be adjusted by reaction ratios of tyrosinase against SF (TYR/SF). Upon reaching a TYR/SF ratio of 20/6000, the degree of crosslinking increased to 88.17 ± 0.20%, without obvious changes in the crystal structure. The degradation behavior was regulated by the TYR/SF ratio and the degradation environment. All c-SF membranes remained stable after immersion without collagenase but showed an adjustable degradation behavior in the presence of collagenase. As the TYR/SF ratio increased, the residual weights increased from 23.31 ± 1.35% to 60.12 ± 0.82% after 7 days of degradation, occurring with low increased amounts of β-sheet structure and free amino acids. This work provides a new c-SF membrane with controllable rapid degradability and favorable cytocompatibility, which can help to meet requirements for biodegradable superficial wound repair membranes.

Urea-rich sodium alginate-based hydrogel fertilizer as a water reservoir and slow-release N carrier for tomato cultivation under different water-deficit levels

In this study, a new eco-friendly urea-rich sodium alginate-based hydrogel with a slow-release nitrogen property was prepared, and its effectiveness was evaluated in the cultivation of tomato plants under different water stress levels. The structure and performance of the hydrogel were investigated by FTIR, XRD, TGA, DTG, and SEM. The swelling and release experiments showed that prepared urea-rich hydrogel exhibited a high-water holding capacity (412 ± 4 g/g) and showed a sustained and slow nitrogen release property. A greenhouse pot experiment was conducted using two hydrogel levels (0.1 and 0.5 wt%) under two water deficit levels (30 and 70 % based on required water irrigation). Germination tests indicated that the developed hydrogel fertilizer has no phytotoxicity and has a positive impact on the germination rate even under water deficit conditions. The application of hydrogel fertilizer at 0.5 wt% significantly (p > 0.05) enhanced plant growth parameters such as leaf number, chlorophyll content, stem diameter, and plant length compared to the control treatment. The magnitude of the responses to the hydrogel fertilizer application depended on the concentration of applied hydrogel fertilizer and stress severity with the most positive effects on the growth and yield of tomato observed at a level of 0.5 %. Tomato yield was significantly enhanced by 19.58 %-12.81 %, 18.58 %-22.02 %, and 39.38 %-43.18 % for the plant amended with hydrogel at 0.1-0.5 wt% and grown under water deficit levels of 0, 30, and 70 %, respectively, compared to the control treatment.

Agriculture 4.0: Polymer Hydrogels as Delivery Agents of Active Ingredients

The evolution from conventional to modern agricultural practices, characterized by Agriculture 4.0 principles such as the application of innovative materials, smart water, and nutrition management, addresses the present-day challenges of food supply. In this context, polymer hydrogels have become a promising material for enhancing agricultural productivity due to their ability to retain and then release water, which can help alleviate the need for frequent irrigation in dryland environments. Furthermore, the controlled release of fertilizers by the hydrogels decreases chemical overdosing risks and the environmental impact associated with the use of agrochemicals. The potential of polymer hydrogels in sustainable agriculture and farming and their impact on soil quality is revealed by their ability to deliver nutritional and protective active ingredients. Thus, the impact of hydrogels on plant growth, development, and yield was discussed. The question of which hydrogels are more suitable for agriculture-natural or synthetic-is debatable, as both have their merits and drawbacks. An analysis of polymer hydrogel life cycles in terms of their initial material has shown the advantage of bio-based hydrogels, such as cellulose, lignin, starch, alginate, chitosan, and their derivatives and hybrids, aligning with sustainable practices and reducing dependence on non-renewable resources.

Construction of cellulose-based hybrid hydrogel beads containing carbon dots and their high performance in the adsorption and detection of mercury ions in water

Cellulose-based adsorbents have been extensively developed in heavy metal capture and wastewater treatment. However, most of the reported powder adsorbents suffer from the difficulties in recycling due to their small sizes and limitations in detecting the targets for the lack of sensitive sensor moieties in the structure. Accordingly, carbon dots (CDs) were proposed to be encapsulated in cellulosic hydrogel beads to realize the simultaneous detection and adsorption of Hg (II) in water due to their excellent fluorescence sensing performance. Besides, the molding of cellulose was beneficial to its recycling and further reduced the potential environmental risk generated by secondary pollution caused by adsorbent decomposition. In addition, the detection limit of the hydrogel beads towards Hg (II) reached as low as 8.8 × 10-8 M, which was below the mercury effluent standard declared by WHO, exhibiting excellent practicability in Hg (II) detection and water treatment. The maximum adsorption capacity of CB-50 % for Hg (II) was 290.70 mg/g. Moreover, the adsorbent materials also had preeminent stability that the hydrogel beads could maintain sensitive and selective sensing performance towards Hg (II) after 2 months of storage. Additionally, only 3.3% of the CDs leaked out after 2 weeks of immersion in water, ensuring the accuracy of Hg (II) evaluation. Notably, the adsorbent retained over 80% of its original adsorption capacity after five consecutive regeneration cycles, underscoring its robustness and potential for sustainable environmental applications.

Recent advances in nano-fertilizers: synthesis, crop yield impact, and economic analysis

The escalating global demand for food production has predominantly relied on the extensive application of conventional fertilizers (CFs). However, the increased use of CFs has raised concerns regarding environmental risks, including soil and water contamination, especially within cereal-based cropping systems. In response, the agricultural sector has witnessed the emergence of healthier alternatives by utilizing nanotechnology and nano-fertilizers (NFs). These innovative NFs harness the remarkable properties of nanoparticles, ranging in size from 1 to 100 nm, such as nanoclays and zeolites, to enhance nutrient utilization efficiency. Unlike their conventional counterparts, NFs offer many advantages, including variable solubility, consistent and effective performance, controlled release mechanisms, enhanced targeted activity, reduced eco-toxicity, and straightforward and safe delivery and disposal methods. By facilitating rapid and complete plant absorption, NFs effectively conserve nutrients that would otherwise go to waste, mitigating potential environmental harm. Moreover, their superior formulations enable more efficient promotion of sustainable crop growth and production than conventional fertilizers. This review comprehensively examines the global utilization of NFs, emphasizing their immense potential in maintaining environmentally friendly crop output while ensuring agricultural sustainability.

Design of Bismuth Tungstate Bi2WO6 Photocatalyst for Enhanced and Environmentally Friendly Organic Pollutant Degradation

In this study, a chemical precipitation approach was adopted to produce a photocatalyst based on bismuth tungstate Bi2WO6 for enhanced and environmentally friendly organic pollutant degradation. Various tools such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), optical spectroscopy and X-ray photoelectron spectroscopy, were employed to assess the structural and morphological properties. Hence, the XRD profiles showed a well crystallized Bi2WO6 orthorhombic phase. The photocatalytic performance of the resulting photocatalyst was assessed by the decomposition of Rhodamine B (RhB) and methyl orange (MO) with a decomposition efficiency of 97 and 92%, along with the highest chemical oxygen demand of 82 and 79% during 120 min of illumination, respectively. The principal novelty of the present work is to focus on the changes in the crystalline structure, the morphology, and the optical and the photoelectrochemical characteristics of the Bi2WO6, by tuning the annealing temperature of the designed photocatalyst. Such physicochemical property changes in the as-prepared photocatalyst will affect in turn its photocatalytic activity toward the organic pollutant decomposition. The photocatalytic mechanism was elaborated based on electrochemical impedance spectroscopy, photocurrent analysis, photoluminescence spectroscopy, and radical trapping measurements. The overall data indicate that the superoxide O2•- and holes h+ are the principal species responsible for the pollutant photodegradation.