Fabrication of copper oxide dumbbell-like architectures via the hydrophobic interaction of adsorbed hydrocarbon chains

Synthesis of nanomagnetite/copper oxide/potassium carrageenan nanocomposite for the adsorption and Photo-Fenton degradation of Safranin-O: kinetic and thermodynamic studies

In the current study, a novel nanomaterial called nanomagnetite/copper oxide/potassium carrageenan nanocomposite (MKCO) was fabricated to include Fenton (nanomagnetite, NM) and Fenton-like reagent (copper oxide nanoparticles, NCO) in a matrix of potassium carrageenan biopolymer. The prepared solid materials were characterized by different physicochemical techniques, such as TGA, N2 adsorption/desorption, SEM, TEM, XRD, DRS, pHPZC, and FTIR. The prepared MKCO showed unique properties like higher specific surface area of 652.50 m2/g, pore radius of 1.19 nm, pHPZC equals 7.80, and the presence of different surface chemical functional groups. Under various application conditions, comparative experiments between Safranin-O dye (SO) adsorption and Photo-Fenton catalytic degradation were conducted. After 24 h, MKCO had a maximum adsorption capacity of 384.61 mg/g at 42 °C, while the Photo-Fenton oxidation process took only 10 min to totally decompose 93% of SO at 21 °C. Based on the higher values of correlation coefficients, Langmuir’s adsorption model is the best-fitted adsorption model for SO onto all the prepared solid materials. Studies on SO adsorption’s kinetics and thermodynamics show that it is physisorption and that it operates according to endothermic, spontaneous, and PFO model processes. While, PFO, endothermic, and non-spontaneous processes are satisfied by the catalytic decomposition of SO. After five application cycles, MKCO demonstrated good catalyst reusability with a 3.4% decrease in degrading efficiency. For lower contaminant concentrations and shorter application times, Photo-Fenton catalytic degradation of organic pollutants is more effective than adsorption.

Graphical abstract

Fenton and Photo-Fenton degradation of Safranin-O

Ultrasound-assisted biosynthesis of CuO-NPs using brown alga Cystoseira trinodis: Characterization, photocatalytic AOP, DPPH scavenging and antibacterial investigations

This contribution reports the biosynthesis of CuO NPs via ultrasound method using the Cystoseira trinodis extracts as an eco friendly and time saving process. The characterization of cupric oxide NPs was performed using XRD, FE-SEM, EDX, TEM, AFM, photoluminescence, UV-Vis, Raman and FT-IR spectroscopy investigations. SEM images show the spherical structure with the average crystallite size 6nm to 7.8nm of CuO. XRD analysis approved the formation of pure monoclinic crystallite structures of CuO NPs. These observations were confirmed by TEM analysis. The photocatalytic studies reveal the activity of the prepared CuO NPs as an efficient catalyst for the degradation of methylene blue (MB) in the presence of UV and Sunlight. CuO NPs under varying experimental parameters such as dye concentration, catalytic load, pH. The results of the in vitro biological screening effect of CuO NPs (zone of growth inhibition and minimal inhibitory concentrations) in comparison with cephalexin (as a standard compound) using the disc diffusion method was demonstrated the significant bactericidal activity against some bacteria strain including Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), and Streptococcus faecalis (S. faecalis). Furthermore, the Nps found to inhibit the activity of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals effectively. This study introduces a facile, green and low coast method for the synthesis of monoclinic CuO NPs with catalytic, antioxidant and antibacterial properties.

Synthesis of hierarchical three-dimensional copper oxide nanostructures through a biomineralization-inspired approach

Three-dimensional (3D) copper oxide (CuO) nanostructures were synthesized in a regenerated Bombyx mori silk fibroin aqueous solution at room temperature. In the synthesis process, silk fibroin served as the template and helped to form the hierarchical CuO nanostructures by self-assembly. Cu(OH)2 nanowires were formed initially, and then they transformed into almond-like CuO nanostructures with branched edges and a compact middle. The size of the final CuO nanostructures can be tuned by varying the concentration of silk fibroin in the reaction system. A possible mechanism has been proposed based on various characterization techniques, such as scanning and transmission electron microscopy, X-ray diffraction, and thermogravimetric analysis. The synthesized CuO nanostructured material has been evaluated as an anode material for lithium ion batteries, and the result showed that they had a good electrochemical performance. The straightforward energy-saving method developed in this research may provide a useful preparation strategy for other functional inorganic materials through an environmentally friendly process.

Room temperature synthesis of 2D CuO nanoleaves in aqueous solution

A simple room temperature method was reported for the synthesis of CuO nanocrystals in aqueous solution through the sequence of Cu(2+) → Cu(OA)2 → Cu(OH)2 → Cu(OH)(2-)4 → CuO. Sodium oleate (SOA) was used as the surfactant and shape controller. The as-prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy (UV-vis) and differential thermal analysis (DTA). It can be seen that 1D Cu(OH)(2) nanowires were first obtained from Cu(OA)(2) and, at room temperature, converted into 2D CuO nanoleaves (CuO NLs) in a short time under a weakly basic environment. On prolonging the reaction time, the top part of these 2D nanoleaves branched and separated along the long axis to form 1D rod-like nano-CuO because of the assistance of SOA. A possible transformation mechanism of Cu(OH)(2) to CuO nanostructures at room temperature in aqueous solution is discussed. The transformation velocity can be controlled by changing the pH value of the system. The prepared CuO NLs were used to construct an enzyme-free glucose sensor. The detecting results showed that the designed sensor exhibited good amperometric responses towards glucose with good anti-interferent ability.