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.

The fashion industry significantly impacts the environment, mainly through the substantial generation of waste textiles fostered by fast fashion business models. This study introduces an innovative approach to textile waste management by recycling waste textiles without the use of chemical or mechanical treatments. Herein, we developed a method adhering to the principles of circular economy to transform these textile wastes into high-quality construction panels using a papermaking process. This method not only provides a sustainable solution to reduce landfill dependency but also enhances resource efficiency in the construction industry. The fabricated panels, composed of a blend of 45% textile waste microfibres and 55% fire-retardant fibres, exhibit several advantageous properties. They feature a low apparent density ranging between 170–180 kg/m3 and a low thermal conductivity coefficient of 0.047 W/m∗K at 50 kPa. It revealed that phosphorylated fibres not only provide flame-retardant properties, but they also significantly improve the mechanical properties of the panels. For example, load at break increases from 12.4 to 81.1 N, stress at break from 0.44 to 3.59 MPa, and E-modulus from 29.2 to 198.8 MPa after the addition of these 55% fibres. Moreover, these panels successfully met the criteria set by international standards for construction products satisfying the fire test, EN ISO 11925-2. These characteristics make the panels superior options for sustainable construction materials, offering enhanced fire resistance and insulation properties, which are critical to meet modern building standards. They mark a pivotal step towards sustainable construction and waste reduction in the fashion industry.

Metallogels are a class of materials produced by the complexation of polymer gels with metal ions that can form coordination bonds with the functional groups of the gel. Hydrogels with metal phases attract special attention due to the numerous possibilities for functionalization. Cellulose is preferable for the production of hydrogels from economic, ecological, physical, chemical, and biological points of view since it is inexpensive, renewable, versatile, non-toxic, reveals high mechanical and thermal stability, has a porous structure, an imposing number of reactive OH groups, and good biocompatibility. Due to the poor solubility of natural cellulose, the hydrogels are commonly produced from cellulose derivatives that require multiple chemical manipulations. However, there is a number of techniques of hydrogel preparation via dissolution and regeneration of non-derivatized cellulose of various origins. Thus, hydrogels can be produced from plant-derived cellulose, lignocellulose and cellulose wastes, including agricultural, food and paper wastes. The advantages and limitations of using solvents are discussed in this review with regard to the possibility of industrial scaling up. Metallogels are often formed on the basis of ready-made hydrogels, which is why the choice of an adequate solvent is important for obtaining desirable results. The methods of the preparation of cellulose metallogels with d-transition metals in the present state of the art are reviewed.

Metallogels represent a class of composite materials in which a metal can be a part of the gel network as a coordinated ion, act as a cross-linker, or be incorporated as metal nanoparticles in the gel matrix. Cellulose is a natural polymer that has a set of beneficial ecological, economic, and other properties that make it sustainable: wide availability, renewability of raw materials, low-cost, biocompatibility, and biodegradability. That is why metallogels based on cellulose hydrogels and additionally enriched with new properties delivered by metals offer exciting opportunities for advanced biomaterials. Cellulosic metallogels can be either transparent or opaque, which is determined by the nature of the raw materials for the hydrogel and the metal content in the metallogel. They also exhibit a variety of colors depending on the type of metal or its compounds. Due to the introduction of metals, the mechanical strength, thermal stability, and swelling ability of cellulosic materials are improved; however, in certain conditions, metal nanoparticles can deteriorate these characteristics. The embedding of metal into the hydrogel generally does not alter the supramolecular structure of the cellulose matrix, but the crystallinity index changes after decoration with metal particles. Metallogels containing silver (0), gold (0), and Zn(II) reveal antimicrobial and antiviral properties; in some cases, promotion of cell activity and proliferation are reported. The pore system of cellulose-based metallogels allows for a prolonged biocidal effect. Thus, the incorporation of metals into cellulose-based gels introduces unique properties and functionalities of this material.

The incorporation of the metal phase into cellulose hydrogels, resulting in the formation of metallogels, greatly expands their application potential by introducing new functionalities and improving their performance in various fields. The unique antiviral, antibacterial, antifungal, and anticancer properties of metal and metal oxide nanoparticles (Ag, Au, Cu, CuxOy, ZnO, Al2O3, TiO2, etc.), coupled with the biocompatibility of cellulose, allow the development of composite hydrogels with multifunctional therapeutic potential. These materials can serve as efficient carriers for controlled drug delivery, targeting specific cells or pathogens, as well as for the design of artificial tissues or wound and burn dressings. Cellulose-based metallogels can be used in the food packaging industry to provide biodegradable and biocidal materials to extend the shelf life of the goods. Metal and bimetallic nanoparticles (Au, Cu, Ni, AuAg, and AuPt) can catalyze chemical reactions, enabling composite cellulose hydrogels to be used as efficient catalysts in organic synthesis. In addition, metal-loaded hydrogels (with ZnO, TiO2, Ag, and Fe3O4 nanoparticles) can exhibit enhanced adsorption capacities for pollutants, such as dyes, heavy metal ions, and pharmaceuticals, making them valuable materials for water purification and environmental remediation. Magnetic properties imparted to metallogels by iron oxides (Fe2O3 and Fe3O4) simplify the wastewater treatment process, making it more cost-effective and environmentally friendly. The conductivity of metallogels due to Ag, TiO2, ZnO, and Al2O3 is useful for the design of various sensors. The integration of metal nanoparticles also allows the development of responsive materials, where changes in metal properties can be exploited for stimuli-responsive applications, such as controlled release systems. Overall, the introduction of metal phases augments the functionality of cellulose hydrogels, expanding their versatility for diverse applications across a broad spectrum of industries not envisaged during the initial research stages.

During recent decades, the interest in renewable, biodegradable, non-fossil materials has been exponentially increasing. Thus, cellulose and cellulose-derived products have been extensively considered for a wide variety of new potential uses. Due to the sustainability of cellulosic raw materials and their excellent properties, the use and modification of cellulose-based materials can be versatile in the material science and technology community. In this featured article, the fundamentals and background of cellulose-based gels are presented, and approaches, prospects and developments in the field, including their potential future applications, are discussed.

Abstract The authors have requested that this preprint be removed from Research Square.

Aim . To evaluate in vitro the antibacterial effect of a paper made of silver phosphate cellulose fibers (SPCF) on Staphylococcus aureus , the most common diabetic foot ulceration (DFU) pathogen when compared with other common commercial products. Methods . The antibacterial activity of SPCF samples was evaluated through time with cell counting on agar plates. SPCF samples were then compared with commercial wound care products currently in use in DFU treatments (Silvercel™, Acticoat 7, and Aquacel Ag Extra TM ) through time on agar plates (growth inhibition zones). Results . After 6 hours, there was no viable bacterial cell detected on either plate (p<0.05). There was a net growth inhibition zone for SPCF samples but no significant difference between the two silver concentrations. Compared with common commercial products, SPCF paper provides results equal to Acticoat 7 (p<0.05) and superior to Aquacel AG Extra TM and Silvercel™ at lower silver concentrations (p<0.001). Conclusions . These results have shown the efficiency of SPCF paper to eliminate Staphylococcus aureus in these conditions. SPCF papers are effective when compared with other common commercial products and could have an industrial potential in wound care. Infected DFU could benefit from the antibacterial effectiveness of SPCF, but more relevant experimentations related to foot ulcers are needed.

The removal of Cd(II) ions from aqueous solution was carried out using a new nanofibrous electrospun non-woven sorbent made from Chitosan (CS) and Phosphorylated Nanocellulose (PNC). The sorbent material was characterized using SEM, EDX, AFM and FTIR. The sorption capacity reached 62.3 mg/g at pH 5.5 and 25 degrees C. The Cd(II) adsorption occurred rapidly and achieved equilibrium within 120 min. The pseudo-second order kinetic model best fitted experimental data. The sorption isotherm was also best described by the Langmuir model. The maximum adsorption capacity of Langmuir was 232.55 mg/g at 25 degrees C, and increased with temperature, which can be explained by the high affinity of amine and phosphate groups with cadmium on the surface of the nanofibrous mats. The thermodynamic study showed that the adsorption is a spontaneous endothermic reaction. This work confirmed that an electrospun nanofibrous mats based on CS and PNC can be used as an alternative material for the removal of cadmium ions, contributing to water sustainability.

A novel approach to modifying native cellulosic fibers by phosphorylation, glycerol grafting and further cross-linking by citric acid had been successfully investigated. The conductivity of the resulting cellulose-based material was measured to be 3 × 10−3 S cm−1, approximately 105 times as large as that in the initial fibers, while the volumetric mass density was 0.40 ± 0.03 g cm−3, similar with wood and wood products. These special properties and the capability to assemble these modified fibers into a paper sheet-like structure without altering the fiber morphology would boost the application of this new bio-based material, including its potential use as a conductive polymer for energy devices.

Due to their flame retardant behavior, phosphorylated cellulosic fibers could be interesting candidates for use in the composite material field. However, because of the phosphate groups, the fiber network is highly charged and hydrophilic reducing its compatibility towards synthetic resins. An effective hydrophobization method for phosphorylated cellulosic fibers was therefore developed in order to enhance their hydrophobic behavior. The best results were obtained with a straightforward addition of tosylated fatty alcohols. The influence of the carbon chain length on the reaction efficiency, the thermal degradation and the hydrophobic behavior are reported. The success of the alkylation reaction was confirmed by FTIR analyses and the degree of substitution by elemental analysis. Contact angle with water of more than 100° were obtained after alkylation. The cellulosic samples were furthermore characterized by means of SEM, fiber length distribution, NMR spectroscopy and thermo gravimetric analysis.

The objective of this study is to develop a low cost bio-based sorbent for the removal of nickel ions from aqueous solutions. Chitosan/Polyethylene oxide (Cs/PEO) nanofibers were prepared by electrospinning technique and characterized. Batch adsorption experiments were then carried out to investigate the effect of contact time and Cs/PEO mass ratio on adsorption efficiency of nickel ions. Results indicate that a maximum nickel adsorption (q(m)) of 227.27 mg/g was achieved at 75 degrees C. Pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to fit kinetic adsorption data. Batch adsorption equilibrium tests were also carried out at different temperatures. Langmuir, Freundlich, Redlich-Peterson and Dubinin-Radushkevich models were fitted to experimental data. It was found that the pseudo-second order and the Langmuir models provided a high degree of correlation (R-2 > 0.99) with experimental data. Adsorption was then assumed to be a spontaneous endothermic chemical process. (C) 2016 Elsevier Ltd. All rights reserved.

The properties of phosphorylated kraft fibers, including their flame retardancy and behavior in water, such as electrical charge and swelling capacity, were investigated in this study. Two different phosphorus contents and three forms of phosphorylated fibers (ammonium, acid, and sodium) were analyzed. All types of phosphorylated fibers exhibited high char formation and limiting oxygen index (LOI) values, indicating good flame retardancy. In particular, the ammonium form exhibited the best flame retardancy behavior and the highest LOI value. The charge density and swelling capacity of the kraft fibers were significantly increased by phosphorylation. Alkaline treatment following the phosphorylation reaction further increased the water retention value (WRV) and surface charge of the kraft fibers. Compared to unmodified kraft fibers, the phosphorylated fibers had lower absolute values of the negative zeta potentials, and these values were less affected by conductivity.

Phosphate esters, derived from two different long-chain aliphatic alcohols, were used as phosphorylating reagents for Kraft pulp fibers. High phosphorus contents and almost non-degraded fibers were obtained by following this pathway. The phosphorylation efficiency was influenced by the alkyl chain length of PEs since the phosphorus content in modified fibers was higher for the shorter chain reagent. Due to the heterogeneous reaction environment, the amount of grafted phosphorus was found to be almost three times higher at the surface than in the bulk of the fibers. Analyses also indicated that the phosphorus was bonded to fibers as a phosphate-like structure. Furthermore, the situation seemed to be different for the fiber surface where significant amounts of phosphorus were present in more complex structures like pyrophosphate or even oligo-phosphate.

Release paper is a special paper grade with one or both sides coated with non-sticking materials. Silicone is currently the only material used to produce release paper at the industrial level. Its remarkable properties and availability ensure product quality and sustainability of the industrial production. Meanwhile, the stability of silicone polymers raises serious environmental problems in terms of paper substrate recyclability. Studies are currently under way to evaluate the ability of phosphate esters as a new class of compounds capable of developing non-adhesive surface properties. This paper presents initial attempts to coat the paper with phosphate esters and to assess phosphate ester / fibrous substrate and phosphate ester / adhesive interactions. The results show that this class of compounds exhibits non-adhesive properties and, when coated on paper under certain conditions, can lead to a non-sticking surface. Despite the fact that there is a long way to achieve ester anchoring to surface fibers and to control the peeling force from an adhesive tape, preliminary results are encouraging.

Advanced closing of paper machine circuits results in the accumulation of the dissolved and colloidal substances (DCS) in the process water. At a critical concentration, the DCS are destabilizing even by small variations in paper machine parameters, producing operational and product quality problems. This article presents results of lab experiments simulating the process water recycling in short circuit of paper machine, without and with addition of fixing agents. Tests were performing with a 100% OCC recycled fibre stock, using two cationic polymers - PDADMAC and Chitosan as coagulants. The results have shown that the interactions between polymers and the DCS are depending on the size and ionic charge of particulates, as well as on polymers characteristics. Both polymers can easily precipitate fine dispersed and colloidal particles, leading to consistent reduction of water turbidity, but they have low influence on dissolved polysaccharides or no effects on dissolved inorganic - the conductivity and total hardness increase by water recycling. Despite of low global effectiveness, tested polymers proved to be very effectively in the precipitating and removing the most detrimental substances from process water, such as the extractives, lignin fractions, or starch.

Actual trends in papermaking concern on the use of recycled fibers and minimizing effluent volume by closing water circuit. Beside environmental and economic advantages, both trends can lead to serious problems in papermaking processes due to contaminants introduced with recycled fibers and their accumulation in closed water system. A key factor to avoid disturbances in the papermaking is to prevent the accumulation of detrimental compounds. In this respect, first it is necessary to find out methods to obtain and characterize process water model for different papers grade. This paper presents preliminary experiments for building and characterization process water model using 100% OCC (old corrugated containers) fiber furnish. The results have shown that proposed model clearly evidences the accumulation of dissolved and colloidal substances (DCS) and suspended solids (SS) by water recycling. Methods used for quantification of individual compounds have shown significant differences in accumulation rate, depending mainly of their hydrophilic / hydrophobic character.