Manufacturing of macroporous cellulose monolith from green macroalgae and its application for wastewater treatment

Phosphorylating Tannin in Urea System: A Simple Approach for Enhanced Methylene Blue Removal from Aqueous Media

Tannin, after lignin, is one of the most abundant sources of natural aromatic biomolecules. It has been used and chemically modified during the past few decades to create novel biobased materials. This work intended to functionalize for the first time quebracho Tannin (T) through a simple phosphorylation process in a urea system. The phosphorylation of tannin was studied by Fourier transform infrared spectroscopy (FTIR), NMR, inductively coupled plasma optical emission spectroscopy (ICP-OES), and X-ray fluorescence spectrometry (XRF), while further characterization was performed by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and thermogravimetric analysis (TGA) to investigate the morphology, composition, structure, and thermal degradation of the phosphorylated material. Results indicated the occurrence of phosphorylation, suggesting the insertion of phosphate-containing groups into the tannin structure, revealing a high content of phosphate for modified tannin (PT). This elevated phosphorus content serves as evidence for the successful incorporation of phosphate groups through the functionalization process. The corresponding PT and T were employed as adsorbents for methylene blue (MB) removal from aqueous solutions. The results revealed that the Langmuir isotherm model effectively represents the adsorption isotherms. Additionally, the pseudo-second-order model indicates that chemisorption predominantly controls the adsorption mechanism. This finding also supports the fact that the introduced phosphate groups via the phosphorylation process significantly contributed to the improved adsorption capacity. Under neutral pH conditions and at room temperature, the material achieved an impressive adsorption capacity of 339.26 mg·g-1 in about 2 h.

Copper phosphorylated cellulose nanofibers mediated azide-alkyne cycloaddition click reaction in water

Heterogenous copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC) was performed by using the phosphorylated carbohydrate-based cellulose nanofibers loaded with copper(II) ions. The copper-containing phosphorylated cellulose nanofibers (here after noted Cu(II)-PCNFs) were prepared in two different morphologies, namely the paper and foam ones and characterized by different techniques, including Scanning Electronic Microscopy (SEM), Energy Dispersive X-ray (EDX), Brauner-Emmett-Teller (BET), FT-IR spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), X-ray Photoelectron spectroscopy (XPS) and Atomic Force Microscopy (AFM). Cu(II)-PCNFs showed high activity in the CuAAC reaction when applied to the ligation of various organic azides and terminal alkynes without any reducing agent, resulting in the regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles in water at room temperature. These nanofibers were recovered and reused with no significant loss of catalytic activity or selectivity. A carbohydrate-based bio-support cellulose as reliable heterogenous catalyst was efficiently developed in view of taking the click chemistry concept to sustainable chemistry.

Increasing the efficiency of agricultural fertilizers using cellulose nanofibrils: A review

Developing new agricultural products, such as new fertilizers with high use efficiency and less negative impact on the environment, is required in sustainable agriculture. In this vein, controlled-release fertilizers (CRFs) have been designed to decrease nutrient waste and increase nutrients' availability to plants. Various CRFs have been developed based on petroleum-derived polymers with many advantages over conventional fertilizers. Although, their use is limited due to their adverse effects on the soil and environment. To overcome these issues, CRFs based on biopolymers represent a new generation of fertilizers developed by encapsulating nutrients with cellulose nanofibrils (CNFs). CNFs and the hydrogels based on CNFs have great potential to be applied as CRFs matrix as they are biodegradable, minimize environmental pollution, and exhibit a great controlled-release potential and water/nutrient retention capacity. In order to gain a better understanding of the potential benefits of these new fertilizers in agricultural systems, this review summarizes the recent advances in CNFs in CRFs, the coating methods, hydrogel preparation techniques, and their impact on plant growth and soil. By examining these factors in depth, a better understanding can be gained on how these novel fertilizers can help improve agricultural productivity and sustainability.

Bio-based functionalized adsorptive polymers for sustainable water decontamination: A systematic review of challenges and real-world implementation

The overwhelming concerns of water pollution, industrial discharges and environmental deterioration by various organic and inorganic substances, including dyes, heavy metals, pesticides, pharmaceuticals, and detergents, intrinsically drive the search for urgent and efficacious decontamination techniques. This review illustrates the various approaches to remediation, their fundamentals, characteristics and demerits. In this manner, the advantageous implementation of nature-based adsorbents has been outlined and discussed. Different types of lignocellulosic compounds (cellulose, lignin, chitin, chitosan, starch) have been introduced, and the most used biopolymeric materials in bioremediation have been highlighted; their merits, synthesis methods, properties and performances in aqueous medium decontamination have been described. The literature assessment reveals the genuine interest and dependence of academic and industrial fields to valorize biopolymers in the adsorption of various hazardous substances. Yet, the full potential of this approach is still confined by certain constraints, such as the lack of reliable, substantial, and efficient extraction of biopolymers, as well as their modest and inconsistent physicochemical properties. The futuristic reliance on such biomaterials in all fields, rather than adsorption, is inherently reliable on in-depth investigations and understanding of their features and mechanisms, which can guarantee a real-world application and green technologies.

Application of cellulose to chromatographic media: Cellulose dissolution, and media fabrication and derivatization

As the cornerstone of chromatographic technology, the development of high-performance chromatographic media is a crucial means to enhance the purification efficiency of biological macromolecules. Cellulose is a popular biological separation medium due to its abundant hydroxyl group on the surface, easy modification and, weak non-specific adsorption. In this paper, the development of cellulosic solvent systems, typical preparation methods of cellulosic chromatographic media, and the enhancement of chromatographic properties of cellulosic chromatographic media by polymeric ligand grafting strategies and their mechanism of action are reviewed. Ultimately, based on the current research status, a promising outlook for the preparation of high-performance cellulose-based chromatographic media was presented.

Essential characteristics improvement of metallic nanoparticles loaded carbohydrate polymeric films - A review

Petroleum-based films have contributed immensely to various environmental issues. Developing green-based films from carbohydrate polymers is crucial for addressing the harms encountered. However, some limitations exist on their property, processibility, and applicability that prohibit their processing for further developments. This review discusses the potential carbohydrate polymers and their sources, film preparation methods, such as solvent-casting, tape-casting, extrusion, and thermo-mechanical compressions for green-based films using various biological polymers with their merits and demerits. Research outcomes revealed that the essential characteristics improvement achieved by incorporating different metallic nanoparticles has significantly reformed the properties of biofilms, including crystallization, mechanical stability, thermal stability, barrier function, and antimicrobial activity. The property-enhanced bio-based films made with nanoparticles are potentially interested in replacing fossil-based films in various areas, including food-packaging applications. The review paves a new way for the commercial use of numerous carbohydrate polymers to help maintain a sustainable green environment.

Hybrid carbonaceous adsorbents based on clay and cellulose for cadmium recovery from aqueous solution

The current work describes the synthesis of carbonaceous composites via pyrolysis, based on CMF, extracted from Alfa fibers, and Moroccan clay ghassoul (Gh), for potential use in heavy metal removal from wastewater. Following synthesis, the carbonaceous ghassoul (ca-Gh) material was characterized using X-ray fluorescence (XRF), Scanning Electron Microscopy coupled with Energy Dispersive X-ray (SEM-EDX), zeta-potential and Brunauer-Emmett-Teller (BET). The material was then used as an adsorbent for the removal of cadmium (Cd²⁺) from aqueous solutions. Studies were conducted into the effect of adsorbent dosage, kinetic time, initial concentration of Cd²⁺, temperature and also pH effect. Thermodynamic and kinetic tests demonstrated that the adsorption equilibrium was attained within 60 min allowing the determination of the adsorption capacity of the studied materials. The investigation of the adsorption kinetics also reveals that all the data could be fit by the pseudo-second-order model. The Langmuir isotherm model might fully describe the adsorption isotherms. The experimental maximum adsorption capacity was found to be 20.6 mg g^-1 and 261.9 mg g^-1 for Gh and ca-Gh, respectively. The thermodynamic parameters show that the adsorption of Cd²⁺ onto the investigated material is spontaneous and endothermic.

Methylcellulose/lignin biocomposite as an eco-friendly and multifunctional coating material for slow-release fertilizers: Effect on nutrients management and wheat growth

To obviate adverse effects from the non-biodegradability of certain polymer-based slow-release fertilizers (SRFs) and to offset higher operational costs, the use of biopolymers as coating material has recently caught interest in the research circles. The present work aims to design a sustainable coating material based on biodegradable polymers. To this end, Alfa plant was initially exploited as a viable sustainable source for the extraction of lignin (LGe), which was in turn integrated into the development of a three-dimensional cross-linked network, including methylcellulose (MC) as a matrix and citric acid (CA) as a cross-linking agent. Then, the designed coating material was applied onto Di-ammonium Phosphate (DAP) and Triple Superphosphate (TSP) water-soluble fertilizers in a rotating pan machine. Chemical, physical, and biodegradation studies have confirmed that the coating material is environmentally-friendly. Nutrients release experiments in water as well as in soil environments have proved the effectiveness of the MC and MC/LGe coating layers in delaying the nutrients discharge. Besides, the nutrients release from coated DAP and TSP lasted longer than 30 days. Furthermore, the coating film enhanced the fertilizers mechanical resistance and boosted the soil water retention capacity. The agronomic evaluation has also confirmed their remarkable potential in enhancing wheat leaf area, chlorophyll content and biomass, in addition to the roots architecture and the final fruiting efficiency. These results showed that this hybrid composite could be used as an efficient coating material to produce slow-release fertilizers with multifunctional performances.

Beneficiation of cactus fruit waste seeds for the production of cellulose nanostructures: Extraction and properties

Cactus fruit waste seeds (CWS) are a by-product of the cactus fruit processing industry. Until now, CWS are not recoverable in any sector. The valorization of these residues may reduce their volume in the environment and transform them into valuable products. In this work, CWS have been identified for the first time as a sustainable lignocellulosic source. Cellulose microfibers (CMFs) and nanocrystals (CNCs) were successfully produced via alkali and bleaching treatments followed by sulfuric acid hydrolysis. It was found that the extracted CMFs showed an average diameter of 11 μm, crystallinity of 72%, and a yield of 25%. The as-produced CNCs exhibited a needle-like shape with a diameter of 13 ± 3 nm and length of 419 ± 48 nm, giving rise to an aspect ratio of 30.7, with a zeta potential value of - 30 mV and a charge content of sulfate groups of 287.8 mmol·kg^-1. Herein, the obtained cellulosic derivatives with excellent properties from this underutilized waste can draw the attention of researchers towards CWS as a new type of biomass with virtually no hemicellulose, which could be of great interest to isolate and study the effects of how lignin interacts with cellulose.