CuO‐SiO₂ based nanocomposites: Synthesis, characterization, photocatalytic, antileishmanial, and antioxidant studies

Abstract

The abatement of toxic pollutants and drug-resistant pathogens from water is one of the major environmental issues. In this work, we are reporting the preparation, detailed characterization and photocatalytic degradation, and biological activities of bimetallic oxides (CuO-SiO 2 ) nanocomposite. For this purpose, CuO, SiO 2 nanoparticles, and CuO-SiO 2 nanocomposites were successfully synthesized through sol-gel process. The nanoparticles and nanocomposite were prepared by taking the Cu(NO 3 ) 2 .3H 2 O as copper oxide precursor and TEOS as silica precursor using absolute ethanol and water as solvents The molar ratio of TEOS: Glycerol: H 2 O used was 1.5:1:6.6 respectively. The synthesized nanoparticles and nanocomposites were characterized by using Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The nanocomposites and individual nanoparticles were then applied as catalysts for their activities toward catalytic/ photocatalytic degradation of crystal violet (CV) dye in an aqueous medium.The degradation progress was monitored by UV-Visible spectroscopic analysis. It was found that CuO-SiO 2 nanocomposite shows good photocatalytic activities toward the removal of crystal violet dye as compared to the catalytic activities of its individual constitutes. The antileishmanial and antioxidant activities results indicate that synthesized materials have promising biological attributes.

Facile Synthesis of Fe3O4−SiO2 Nanocomposites for Wastewater Treatment

“…In this case, DMSO was used as a negative control and Miltefosine as a reference drug. The previous literature [ 41 ] indicates that the antileishmanial activity increases with the increase in concentration, that is, at a higher concentration, the antileishmanial activity is greater, and vice versa. Figure 13b reveals that as the concentration of the solution increases, the antileishmanial activity of the nanocomposite enhances.…”

“…The antileishmanial activity of the synthesized Fe 3 O 4 ‐SiO 2 nanocomposite was also carried out via the previously established method in ref. [41]. In this method, the nanocomposite of Fe 3 O 4 ‐SiO 4 was subjected to screen its leishmanicidal potential while using 10% Fetal Bovine Serum (FBS), 1% Miltefosine (antibiotic), and 1% Hepes ( N ‐hydroxyethylpiperazine‐ N '‐ethane sulfonic acid) buffered RPMI‐1640 medium for Leishmania tropical promastigotes.…”

“…Notably, as the concentration increases, the antioxidant activity also enhances. [41,42] Figure 13a shows that at various concentrations of solution, the antioxidant activity is different for the respective nanocomposite. The antioxidant activity of the nanocomposite for various concentrations of the solution is in the order of 1000 > 500 > 250 μg mL −1 .…”

“…Antioxidant Activity of Fe 3 O 4 -SiO 2 Nanocomposite: For Fe 3 O 4 -SiO 2 nanocomposite, a previously developed method (1,1-diphenyl-2-picrylhydrazyl [DPPH] assay) had been used to induce antioxidant activity. [41] The Fe 3 O 4 -SiO 2 nanocomposite with different concentrations (such as 250, 500, and 1000 μg mL −1 ) was prepared and ascorbic acid served as a reference point for quality control. About 1 mL of each Fe 3 O 4 -SiO 2 nanocomposite (250, 500, and 1000 μg mL −1 ) was mixed with 1 mL of the DPPH solution (0.12 mm) prepared in methanol and an additional 4 mL methanol was added to it and kept in the dark for 40 min.…”

“…Silica (SiO 2 ), an inert coating material, is also used to reduce toxicity, promote stability, biodegradability, and biocompatibility, and to prevent nanoparticle aggregation. [ 12 ] Based on the literature, some of the silica‐based nanocomposites such as Ag/SiO 2, [ 13 ] PdNi/C, [ 14 ] Au@SiO 2 , and SiO 2 @Au core–shell, [ 15 ] SiO 2 @Au@GO, [ 16 ] Zr‐SiO 2 , [ 17 ] NiO/SiO 2 , [ 18 ] CuO‐SiO 2 , [ 19 ] Al 2 O 3 ‐SiO 2 , [ 20 ] TiO 2 ‐SiO 2 ‐S, [ 21 ] Al 2 O 3 ‐SiO 2 ‐MgO, [ 22 ] CoFe 2 O 4 /SiO 2 , [ 23 ] and Fe 3 O 4 ‐SiO 2 , [ 24 ] etc., have been reported and gained interest due to the low refractive index and higher thermal and mechanical stability of SiO 2 . [ 25 ] However, iron‐based composites such as Fe 3 O 4 ‐SiO 2 are known for their potential applications in drug delivery, biocatalysis, heavy metals removal, photocatalysis, MRI contrast agents, biomolecular separations, biomarker immobilization, etc.…”