Metal nanoparticles supported chitosan coated carboxymethyl cellulose beads as a catalyst for the selective removal of 4-nitrophenol

Design of switchable adsorbent based on chitosan and date palm endocarp film for adsorption of cationic and anionic dyes from aqueous solution

Discharging of industrial dyes to the water stream has led to significant toxicological and environmental issues that pose health risks. Therefore, there is a requirement for efficient and economical dyes removal technologies. This study examined the adsorption of crystal violet (CV) and eosin yellow (EY) using low-cost adsorbents made from date palm endocarp film (DPEF) and chitosan-coated date palm endocarp film (CS@DPEF). Adsorption efficiency was evaluated by varying different parameters in batch experiments. Results showed that pH 6 is optimal for CV adsorption, while for EY it was pH 8. The most effective adsorbent dosage for DPEF was 20 mg, resulting in a high CV removal of 90.05 % within 2 h and the EY removal percentage by 14.5 mg CS@DPEF was 91.34 % within 2 h. The equilibrium times for CV and EY removal were 90 and 120 min, respectively. Adsorption decreased with rising temperature and kinetic data indicated a pseudo-second-order model for both dyes. Isotherm analysis suggested that CV adsorption follows the Freundlich model, while EY follows the Langmuir model. Thermodynamic parameters indicated a spontaneous and exothermic process, with increased randomness for CV and decreased randomness for EY. The films could be recycled up to four times. Real sample tests confirmed the effectiveness of DPEF and CS@DPEF in adsorbing CV and EY. Thus, DPEF and CS@DPEF proved to be efficient low-cost adsorbents for treating industrial effluents.

Preparation and Properties of Sodium Carboxymethyl Cellulose Microspheres by Dropping Method

Sodium carboxymethyl cellulose (CMC) is the most extensively utilized derivative of cellulose. In this study, an innovative approach was employed to disperse a CMC aqueous solution into olive oil in the form of liquid droplets, resulting in the direct formation of CMC microspheres after drying. The effects of CMC concentration and needle aperture size on microsphere formation were systematically investigated, showing that the particle size of the microspheres decreased with an increase in CMC concentration and a decrease in needle aperture. The CMC-based microspheres exhibited a consistently uniform spheroid morphology with particle sizes ranging from 1.5 to 2.5 mm, and a three-dimensional uniform polymeric network structure. Furthermore, the drug loading efficiency of the CMC-based olive oil microspheres reached 82.18%, which was markedly superior to that of other cellulose-based microspheres for fat-soluble substances. The CMC-based vitamin C (VC) microspheres exhibited an ultimate drug loading efficiency of approximately 24%, and their maximum encapsulation efficiency was 78.57% at a VC concentration of 30%, which was significantly higher than that of starch-based VC microspheres. Additionally, the CMC-based VC microspheres realized a sustained and stable release rate in ethanol at 30 °C.

Copper oxide nanoparticles-decorated cellulose acetate: Eco-friendly catalysts for reduction of toxic organic dyes in aqueous media

In this study, we aimed to gain insight into the potential of catalytic reduction using copper oxide nanoparticles decorated cellulose acetate as a biosupport (CuxO@CA) for the removal of specific pollutants. The prepared catalyst was submitted to a series of spectroscopy techniques for characterization purposes. The results of the catalytic tests on methylene orange (MO) and methylene blue (MB) solutions suggest that the elimination efficiency may be influenced by several factors, including the catalyst dose and the concentration of the pollutant. Kinetic studies were also carried out, and the value of the rate constant Kapp derived from the pseudo-first-order kinetics was found to be highest for the prepared catalyst in a very short reaction time. The CuxO@CA catalyst was tested on a combination of MO/MB dyes, and the results indicated that it exhibited the highest catalytic activity in reducing and degrading these organic dyes in aqueous solutions, which is an encouraging outcome. Furthermore, the prepared catalyst demonstrated promising catalytic performance and exhibited the potential for recycling multiple times without significant loss of activity, which could be advantageous for large-scale production and practical use in water treatment.

Silver nanoparticle-decorated cellulose beads: Eco-friendly catalysts for efficient 4-nitrophenol reduction and antibacterial performance

This study presents an innovative and environmentally friendly method to produce fibrous cellulose beads by mechanically stirring natural fibers in an aqueous medium. Date palm fibers are transformed into uniform beads with a diameter of 1.5 to 2 mm through chemical treatment and mechanical agitation. These beads are then decorated with silver nanoparticles (Ag0 NPs) in a one-step synthesis, giving them catalytic capabilities for the reduction of 4-nitrophenol (4-NP) and antibacterial activities. Characterization techniques such as FTIR, XRD, SEM, EDX, and TGA confirmed the successful synthesis and deposition of Ag0 NPs on the cellulose beads. Tests showed complete conversion of 4-NP to 4-AP in just 7 min, with pseudo-first-order kinetics and a Kapp of 0.590 min-1. Additionally, Ag0@CB demonstrated exceptional recyclability and stability over five cycles, with minimal silver release. The beads also showed strong antibacterial activity against Escherichia coli and Staphylococcus aureus, effectively eradicating bacterial colonies in 30 min. In summary, Ag0@CB exhibits multifunctional capabilities for degrading organic pollutants and biomedical applications, offering promising potential for large-scale production and practical use in water treatment and antibacterial coatings.

Cellulose-based materials in environmental protection: A scientometric and visual analysis review

As sustainable materials, cellulose-based materials have attracted significant attention in the field of environmental protection, resulting in the publication of numerous academic papers. However, there is a scarcity of literature that involving scientometric analysis within this specific domain. This review aims to address this gap and highlight recent research in this field by utilizing scientometric analysis and a historical review. As a result, 21 highly cited articles and 10 mostly productive journals were selected out. The scientometric analysis reveals that recent studies were objectively clustered into five interconnected main themes: extraction of cellulose from raw materials and its degradation, adsorption of pollutants using cellulose-based materials, cellulose-acetate-based membrane materials, nanocellulose-based materials, and other cellulose-based materials such as carboxymethyl cellulose and bacterial cellulose for environmental protection. Analyzing the distribution of author keywords and thoroughly examining relevant literature, the research focuses within these five themes were summarized. In the future, the development of eco-friendly and cost-effective methods for extracting and preparing cellulose and its derivatives, particularly nanocellulose-based materials, remains an enduring pursuit. Additionally, machine learning techniques holds promise for the advancement and application of cellulose-based materials. Furthermore, there is potential to expand the research and application scope of cellulose-based materials for environmental protection.

Carboxymethyl Cellulose/Copper Oxide-Titanium Oxide Based Nanocatalyst Beads for the Reduction of Organic and Inorganic Pollutants

In this work, we have developed novel beads based on carboxymethyl cellulose (CMC) encapsulated copper oxide-titanium oxide (CuO-TiO2) nanocomposite (CMC/CuO-TiO2) via Al+3 cross-linking agent. The developed CMC/CuO-TiO2 beads were applied as a promising catalyst for the catalytic reduction of organic and inorganic contaminants; nitrophenols (NP), methyl orange (MO), eosin yellow (EY) and potassium hexacyanoferrate (K3[Fe(CN)6]) in the presence of reducing agent (NaBH4). CMC/CuO-TiO2 nanocatalyst beads exhibited excellent catalytic activity in the reduction of all selected pollutants (4-NP, 2-NP, 2,6-DNP, MO, EY and K3[Fe(CN)6]). Further, the catalytic activity of beads was optimized toward 4-nitrophenol with varying its concentrations and testing different concentrations of NaBH4. Beads stability, reusability, and loss in catalytic activity were investigated using the recyclability method, in which the CMC/CuO-TiO2 nanocomposite beads were tested several times for the reduction of 4-NP. As a result, the designed CMC/CuO-TiO2 nanocomposite beads are strong, stable, and their catalytic activity has been proven.

Multi-Compartmentalized Cellulose Macrobead Catalysts for In Situ Organic Reaction in Aqueous Media

This study reports a promising approach to fabricate bacterial cellulose (BC)-based macrobead catalysts with improved catalytic activities and recyclability for organic reactions in aqueous media. To this end, the consecutive extrusion and gelation of BC precursor fluids is conducted using a combined micronozzle device to compartmentalize the resulting BC macrobeads in a programmed manner. The use of BCs laden with Au and Pd nanoparticles (NPs), and Fe₃ O₄ NPs led to the production of catalytically and magnetically compartmentalized BC macrobeads, respectively. Through the model reduction reaction of 4-nitrophenol to 4-aminophenol using NaBH₄ , it is finally demonstrated that the BC macrobead catalysts not only enhance catalytic activities while exhibiting high reaction yields (>99%) in aqueous media, but also repeatedly retrieve the products with ease in response to the applied magnetic field, enabling the establishment of a useful green catalyst platform.

Chitosan@Carboxymethylcellulose/CuO-Co2O3 Nanoadsorbent as a Super Catalyst for the Removal of Water Pollutants

In this work, an efficient nanocatalyst was developed based on nanoadsorbent beads. Herein, carboxymethyl cellulose-copper oxide-cobalt oxide nanocomposite beads (CMC/CuO-Co2O3) crosslinked by using AlCl3 were successfully prepared. The beads were then coated with chitosan (Cs), Cs@CMC/CuO-Co2O3. The prepared beads, CMC/CuO-Co2O3 and Cs@CMC/CuO-Co2O3, were utilized as adsorbents for heavy metal ions (Ni, Fe, Ag and Zn). By using CMC/CuO-Co2O3 and Cs@CMC/CuO-Co2O3, the distribution coefficients (Kd) for Ni, Fe, Ag and Zn were (41.166 and 6173.6 mLg-1), (136.3 and 1500 mLg-1), (20,739.1 and 1941.1 mLg-1) and (86.9 and 2333.3 mLg-1), respectively. Thus, Ni was highly adsorbed by Cs@CMC/CuO-Co2O3 beads. The metal ion adsorbed on the beads were converted into nanoparticles by treating with reducing agent (NaBH4) and named Ni/Cs@CMC/CuO-Co2O3. Further, the prepared nanoparticles-decorated beads (Ni/Cs@CMC/CuO-Co2O3) were utilized as nanocatalysts for the reduction of organic and inorganic pollutants (4-nitophenol, MO, EY dyes and potassium ferricyanide K3[Fe(CN)6]) in the presence of NaBH4. Among all catalysts, Ni/Cs@CMC/CuO-Co2O3 had the highest catalytic activity toward MO, EY and K3[Fe(CN)6], removing up to 98% in 2.0 min, 90 % in 6.0 min and 91% in 6.0 min, respectively. The reduction rate constants of MO, EY, 4-NP and K3[Fe(CN)6] were 1.06 × 10-1, 4.58 × 10-3, 4.26 × 10-3 and 5.1 × 10-3 s-1, respectively. Additionally, the catalytic activity of the Ni/Cs@CMC/CuO-Co2O3 beads was effectively optimized. The stability and recyclability of the beads were tested up to five times for the catalytic reduction of MO, EY and K3[Fe(CN)6]. It was confirmed that the designed nanocomposite beads are ecofriendly and efficient with high strength and stability as catalysts for the reduction of organic and inorganic pollutants.