CuO Nanosheets Modified with Amine and Thiol Grafting for High Catalytic and Antibacterial Activities

Dual functionalized copper nanoparticles for thermoplastics with improved processing and mechanical properties and superior antibacterial performance

The utilization of metal nanoparticles for antibacterial thermoplastic composites has the potential to enhance the safety of human and animal life by mitigating the spread and transmission of foodborne pathogenic bacteria. The dispersion, antioxidant and antimicrobial activities of metal nanoparticles directly affect the application performance of the composites. This study focused on achieving amine-carboxyl co-modified copper nanoparticles (Cu-AC) with excellent antioxidant properties and monodispersity through in situ grafting of amine and carboxyl groups onto the surface of copper nanoparticles via ligand interaction. Polyacrylic acid's extended carbon chain structure was utilized to improve its dispersion and antioxidant properties, and its antibacterial properties were synergistically enhanced using secondary amines. It was found that Cu-AC possesses high antibacterial properties, with a minimum inhibition concentration of 0.156 mg mL-1. Antibacterial masterbatches and their composites (polypropylene/Cu) manufactured by melt blending of polypropylene and Cu-AC exhibited excellent antibacterial rates of up to 90% and 99% at 300 ppm and 700 ppm Cu-AC, respectively. Additionally, Cu-AC bolstered the thermal degradation, processing and mechanical properties of polypropylene. The successful implementation of this product substantiates the potential applications of polypropylene/Cu composite materials across diverse industries.

Advances in Amine-Surface Functionalization of Inorganic Adsorbents for Water Treatment and Antimicrobial Activities: A Review

In the last decade, adsorption has exhibited promising and effective outcomes as a treatment technique for wastewater contaminated with many types of pollutants such as heavy metals, dyes, pharmaceuticals, and bacteria. To achieve such effectiveness, a number of potential adsorbents have been synthesized and applied for water remediation and antimicrobial activities. Among these inorganic adsorbents (INAD), activated carbon, silica, metal oxide, metal nanoparticles, metal–organic fibers, and graphene oxide have been evaluated. In recent years, significant efforts have been made in the development of highly efficient adsorbent materials for gas and liquid phases. For gas capture and water decontamination, the most popular and known functionalization strategy is the chemical grafting of amine, due to its low cost, ecofriendliness, and effectiveness. In this context, various amines such as 3-aminopropyltriethoxysilane (APTES), diethanolamine (DEA), dendrimer-based polyamidoamine (PAMAM), branched polyethyleneimine (PEI), and others are employed for the surface modification of INADs to constitute a large panel of resource and low-cost materials usable as an alternative to conventional treatments aimed at removing organic and inorganic pollutants and pathogenic bacteria. Amine-grafted INAD has long been considered as a promising approach for the adsorption of both inorganic and organic pollutants. The goal of this review is to provide an overview of surface modifications through amine grafting and their adsorption behavior under diverse conditions. Amine grafting strategies are investigated in terms of the effects of the solvent, temperature, and the concentration precursor. The literature survey presented in this work provides evidence of the significant potential of amine-grafted INAD to remove not only various contaminants separately from polluted water, but also to remove pollutant mixtures and bacteria.

Self-driven in situ facile synthesis of CuO/Cu2O for enhanced catalytic reduction of 4-nitrophenol by acetic acid

A series of CuO, Cu2O and CuO/Cu2O catalyst structures with different morphologies are synthesized in situ by controlling the anionic species of the copper salts in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).

Structural, Optical and Antibacterial Efficacy of Pure and Zinc-Doped Copper Oxide against Pathogenic Bacteria

Copper oxide and Zinc (Zn)-doped Copper oxide nanostructures (CuO-NSs) are successfully synthesized by using a hydrothermal technique. The as-obtained pure and Zn-doped CuO-NSs were tested to study the effect of doping in CuO on structural, optical, and antibacterial properties. The band gap of the nanostructures is calculated by using the Tauc plot. Our results have shown that the band gap of CuO reduces with the addition of Zinc. Optimization of processing conditions and concentration of precursors leads to the formation of pine needles and sea urchin-like nanostructures. The antibacterial properties of obtained Zn-doped CuO-NSs are observed against Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria via the agar well diffusion method. Zn doped s are found to have more effective bacterial resistance than pure CuO. The improved antibacterial activity is attributed to the reactive oxygen species (ROS) generation.

Carboxymethyl cellulose nanocomposite beads as super-efficient catalyst for the reduction of organic and inorganic pollutants

Carboxymethyl cellulose/copper oxide-nickel oxide (CMC/CuO-NiO) nanocomposite beads were prepared by facile, simple and environmentally friendly method. Initially, CuO-NiO was prepared and applied for the catalytic reduction of 4-nitrophenol (4-NP). The results showed that CuO-NiO demonstrate high catalytic activity toward the reduction of 4-NP to 4-aminophenol (4-AP) with a rate constant of 2.97 × 10^-2 s^-1. Further, CuO-NiO were well-dispersed in the polymeric matrix of carboxymethyl cellulose to prepare CMC/CuO-NiO beads. CMC/CuO-NiO nanocomposite beads were also applied to catalyze the reduction of potassium ferrocyanide (K₃Fe (CN)₆), 4-NP, Congo red (CR) and Eosin yellow (EY) in the presence of sodium borohydride. Experimental data indicated that CMC/CuO-NiO nanocomposite has higher catalytic activity and high rate constant compared to CuO-NiO. The rate constant found to be 6.88 × 10^-2, 6.27 × 10^-2, 1.89 × 10^-2 and 2.43 × 10^-2 for K₃Fe(CN)₆, 4-NP, CR and EY, respectively, using 5 mg CMC/CuO-NiO beads. FE-SEM, EDX, FTER, XRD and XPS were used to characterize the nanocomposites. CMC/CuO-NiO beads catalytically reduced up to 95-99% of K₃Fe(CN)₆, 4-NP, CR and EY within 40, 60, 120 and 120 s. CMC/CuO-NiO beads were found more selective for the reduction of 4-NP. The catalytic reduction performance of CMC/CuO-NiO beads was optimized by studying the influence of different parameters on the catalytic reduction of 4-NP. Hence, the effective and super catalytic performance toward the reduction of different organic and inorganic pollutants makes CMC/CuO-NiO beads a smart material and suitable for numerous scientific and industrial applications and may be used as an alternative to high-cost commercial catalysts.

Fine Characterization of Natural SiO2-Doped Catalyst Derived from Mussel Shell with Potential Photocatalytic Performance for Organic Dyes

In this work, a SiO2-doped natural photocatalyst derived from waste mussel shell (HAS) was prepared by acidification. The as-prepared sample was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible diffuse-reflectance spectrum (UV-vis DRS), and Differential scanning and thermogravimetric analyses (DTA/TGA). The results exhibited that HAS was mesopores nanomaterial consisting of uneven arranged rod-like structure, the dominant component of HAS was SiO2 with a large number of hydroxyl groups, and a variety of transition metals uniformly distributed in HAS. Rhodamine B (RhB) and methylene blue (MB) removal efficiencies (equal to 92.59% and 99.14%, respectively) were observed under the HAS presence when exposed to the visible light. The degradation products were analyzed using liquid Chromatograph Mass Spectrometer (LC-MS) and Total Organic Carbon (TOC), among which, MB was degraded by demethylation and deamination, and RhB was degraded by N-deethylation and conjugate structure destruction. After four successive recycles, the removal efficiency of RhB and MB are still reach 86.103% and 75.844%. This study indicated that the mussel shells might be suggested as a novel natural photocatalyst in the application of dye wastewater treatment.

Modification of fibrous membrane for organic and pathogenic contaminants removal: from design to application

In this study, a flexible multifunctional fibrous membrane for heterogeneous Fenton-like removal of organic and pathogenic contaminants from wastewater was developed by immobilizing zerovalent iron nanoparticles (Fe-NPs) on an amine/thiol grafted polyester membrane. Full characterization of the resulting polyester membranes allowed validation of successful grafting of amine/thiol (NH₂ or SH) functional groups and immobilization of Fe-NPs (50–150 nm). The Fenton-like functionality of iron immobilized fibrous membranes (PET–Fe, PET–Si–NH₂–Fe, PET–NH₂–Fe, and PET–SH–Fe) in the presence of hydrogen peroxide (H₂O₂) was comparatively studied in the removal of crystal violet dye (50 mg L⁻¹). The effect of pH, amount of iron and H₂O₂ concentration on dye removal was systematically investigated. The highest dye removal yield reached 98.87% in 22 min at a rate constant 0.1919 min⁻¹ (R² = 95.36) for PET–SH–Fe providing 78% toxicity reduction assessed by COD analysis. These membranes could be reused for up to seven repeated cycles. Kinetics and postulated mechanism of colour removal were proposed by examining the above results. In addition, the resultant membranes showed substantial antibacterial activity against pathogenic bacteria (Staphylococcus epidermidis, Escherichia coli) strains studied through disc diffusion-zone inhibitory and optical density analysis. These findings are of great importance because they provide a prospect of textile-based flexible catalysts in heterogeneous Fenton-like systems for environmental and green chemistry applications.

Multifunctional fibrous membrane for heterogeneous Fenton-like removal of organic and pathogenic contaminants from wastewater was developed by immobilizing zerovalent iron nanoparticles (Fe-NPs) on an amine/thiol grafted polyester membrane.

Facile fabrication of functional cellulose paper with high-capacity immobilization of Ag nanoparticles for catalytic applications for tannery wastewater

Abstract

It has been a research goal to develop macroscopic materials with an optimized surface structure to affix silver nanoparticles which could contaminate water and maximize their practical functions. Cellulose paper is a versatile biomass material valued for its abundance, low cost, biocompatibility, and natural composition. Until now, its potential application in water purification has not been adequately explored. In this study, gallic acid-modified silver nanoparticles (GA@AgNPs) were loaded onto commercial cellulose filter paper using a simple lipoic acid modification process (GA@AgNPs-LA-CP). Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used to characterize the GA@AgNPs-LA-CP. The catalytic activity of the GA@AgNPs-LA-CP was evaluated by the reduction reaction of methylene blue (MB), Rhodamine B (RhB), and 4-nitrophenol (4-NP) with sodium borohydride (NaBH4). The GA@AgNPs-LA-CP exhibited excellent catalytic activity toward MB, RhB, and 4-NP, taking advantage of its high specific surface area generated by the cellulose fiber network structure. Interestingly, due to the electrostatic interactions between the cationic dyes and the GA@AgNPs, the as-prepared catalytic composite material serves as a better catalyst for MB and RhB, suggesting dual applications of the composite materials for organic wastewater treatment and the removal of harmful dyes. This implies that the immobilization of AgNPs on cellulose papers is an effective method and can be applied to efficient wastewater treatment applications.

Graphical abstract

Economical, green and rapid synthesis of CDs-Cu2O/CuO nanotube from the biomass waste reed as sensitive sensing platform for the electrochemical detection of hydrazine

Reeds live widely in swamp and wetland and have an important ecological balance functions in environmental protection. However, the use of reeds is not effectively. The carbon dots (CDs) have been developed as the family of 0D nanocarbon materials and have all the advantages of the carbon family. In this work, we prepared CDs via hydrothermal method using reed. It is surprising that the reed-derived CDs are an effective reducing agent. A highly catalytically active composite material CDs-Cu₂O/CuO was synthesized using economical, green, one-step ultrasonic method and used for the detection of hydrazine. The electrochemical detection of hydrazine was investigated by cyclic voltammetry. The result shows that the CDs-Cu₂O/CuO exhibited good electrocatalytic activity for the oxidation of hydrazine. The fabricated sensor presented a wide linear range from 0.99 μM to 5903 μM and a detection limit of 0.024 μM. In addition, the CDs-Cu₂O/CuO exhibited good sensitivity, stability and repeatability. Therefore, the CDs-Cu₂O/CuO provides a new idea for the utilization of reed and low-cost electrocatalytic nanocomposite.

Dopamine Grafted Iron-Loaded Waste Silk for Fenton-Like Removal of Toxic Water Pollutants

Dispersion of iron was achieved on waste silk fibers (wSF) after grafting of polydopamine (PDA). The catalytic activity of the resulting material (wSF-DA/Fe) was investigated in Fenton-like removal of toxic aromatic dyes (Methylene Blue, Cationic Violet X-5BLN, and Reactive Orange GRN) water. The dye removal yield reached 98%, 99%, and 98% in 10–40 min for Methylene Blue, Cationic Violet X-5BLN, and Reactive Orange GRN, respectively. The catalytic activity was explained in terms of the effects of temperature, dyes, and electrolytes. In addition, the kinetic study showed that the removal of dyes followed pseudo-1st order adsorption kinetics. These findings allow envisaging the preparation of fiber-based catalysts for potential uses in environmental and green chemistry.