Fruit extract capped colloidal silver nanoparticles and their application in reduction of methylene blue dye

Ultrasonic-assisted sustainable extraction and dyeing of organic cotton fabric using natural dyes from Dillenia indica leaf

As a means of preventing environmental damage caused by synthetic dyes, eco-friendly textile dyeing with natural dyes is gaining popularity worldwide. This study focused on the extraction of dyes from the leaf of Dillenia indica (D. indica) tree using an ultrasonic extraction technique and applied on the organic cotton fabrics. The ultrasonic method was used for both extractions of D. indica dyes and dyeing of organic cotton fabrics. Here, the amount of D. indica powder used were 5% and 6.67% for producing light and dark shade, respectively. The investigation of the color fastness to washing, rubbing, and light for the dyed organic cotton fabrics indicated an excellent rating. The spectrophotometric analysis revealed the L* (lightness or darkness), a* (redness or greenness), b* (yellowness or blueness), C* (chroma), h* (hue), R% (reflectance), and K/S (color strength) values, which accurately represented the shade of the dyed organic cotton fabric. To understand the interaction between D. indica dye and organic cotton fabrics, different characterization including, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were performed. The characterization outcomes confirmed the successful deposition of D. indica dyes on the organic cotton fabrics. The other comparable testing results such as bursting strength, air permeability, and thermogravimetric analysis (TGA) of dyed and undyed organic cotton fabrics were in the acceptable range. One of the important findings of this research was no chemicals were utilized during the extraction and dyeing of organic cotton fabrics. This process can be referred to as completely chemical-free and advantageous for the environment because no chemicals were needed during extraction or dyeing. Therefore, the natural dye extracted from D. indica is extremely promising and could be a viable option for the sustainable dyeing of cotton fabrics in the textile dyeing industry.

Chitosan Nanocomposite Coatings Containing Chemically Resistant ZnO-SnOx Core-shell Nanoparticles for Photocatalytic Antifouling

Functional nanocomposites with biopolymers and zinc oxide (ZnO) nanoparticles is an emerging application of photocatalysis in antifouling coatings. The reduced chemical stability of ZnO in the acidic media in which chitosan is soluble affects the performance of chitosan nanocomposites in antifouling applications. In this study, a thin shell of amorphous tin dioxide (SnO_x) was grown on the surface of ZnO to form ZnO–SnO_x core–shell nanoparticles that improved the chemical stability of the photocatalyst nanoparticles, as examined at pH 3 and 6. The photocatalytic activity of ZnO–SnO_x in the degradation of methylene blue (MB) dye under visible light showed a higher efficiency than that of ZnO nanoparticles due to the passivation of electronic defects. Chitosan-based antifouling coatings with varying percentages of ZnO or ZnO–SnO_x nanoparticles, with or without the glutaraldehyde (GA) crosslinking of chitosan, were developed and studied. The incorporation of photocatalysts into the chitosan matrix enhanced the thermal stability of the coatings. Through a mesocosm study using running natural seawater, it was found that chitosan/ZnO–SnO_x/GA coatings enabled better inhibition of bacterial growth compared to chitosan coatings alone. This study demonstrates the antifouling potential of chitosan nanocomposite coatings containing core–shell nanoparticles as an effective solution for the prevention of biofouling.

Strong and nonspecific synergistic antibacterial/antibiofilm impact of nano-silver biosynthesized and decorated with active ingredients of Oscimum basilicum L

In this study, Ocimum basilicum (a proven broad spectrum medicinal plant for broad-spectrum pharmacological activities) leaf extract was used as conjugates for the fabrication of silver nanoparticles (AgNP). Color change of the reaction mixture and UV-Visible spectrophotometry indicated the fabrication of silver nanoparticles, further X-ray diffraction (XRD) crystallography, scanning electron microscopy (SEM), transmission electron microscopic images (TEM), and Selected area electron diffraction (SAED) confirms the purity, monodispersity, and morphology including size (22.4 nm) and conjugated functional group of Ocimum basilicum. The conjugation of functional OH, N-O, and C=O groups was confirmed by Fourier-transform infrared spectroscopy (FT-IR). The engineered AgNP have shown significantly efficient antibacterial and antibiofilm activities (92.7% biofilm inhibition) on diverse clinical strains and thus showed its potential for use in clinical applications.

Valorisation of Fruits, their Juices and Residues into Valuable (Nano)materials for Applications in Chemical Catalysis and Environment

One of the most abundant wastes from all around the world is nutrient resources. Among them, fruits, their extracts, and residues comprise a major portion, which contain many valuable components that get lost during disposal or become burden on the shrinking landfills. These concerns are addressed by seeking sustainable processing methods that would have a minimal environmental impact. The crops contain renewable chemicals which are useful for catalysis, wastewater treatment, or preparation of nanomaterials; there has been an upsurge for the industrial applications of (nano)materials as their environmental and catalytic appliances is a fascinating subject to design cheaper and safer catalytic systems. Due to the excellent chemical properties of the fruit extracts, they have garnered attention as cost-effective catalysts and support materials. This review focuses on the preparation of (nano)materials and their catalytic and environmental applications and highlights the potential appliances and industrial benefits derived from these low-cost renewable and sustainable greener sources thus essentially converting waste into wealth.

Green synthesis of silver nanoparticles using methanolic fruit extract of Aegle marmelos and their antimicrobial potential against human bacterial pathogens

Plant-based synthesis of nanoparticles has generated worldwide interest because of cost-effectiveness, eco-friendly nature and plethora of applications. In the present investigation, antimicrobial potential of silver nanoparticles (AgNPs) of methanolic extract of Aegle marmelos fruit has been investigated. Agar well diffusion method was used for determining antimicrobial activity of solvent extracts (viz., petroleum ether, chloroform, acetone, methanol and aqueous), and AgNPs. Among these, methanolic extract of A. marmelos showed highest inhibitory activity against B. cereus (16.17 ± 0.50 mm) followed by P. aeruginosa (13.33 ± 0.62 mm) and E. coli. Phytochemical analysis of methanolic extract of A. marmelos revealed the presence of tannins, saponins, steroids, alkaloids, flavonoids, and glycosides. AgNPs synthesized using A. marmelos methanolic extract, characterized by UV-Visible spectroscopy, atomic force microscopy, dynamic light scattering, and X-ray diffraction showed a peak at 436 nm and size ranged between 159 and 181 nm. Evaluation of the antimicrobial potential of green synthesized AgNPs recorded the highest inhibitory activity against B. cereus (19.25 ± 0.19 mm) followed by P. aeruginosa (16.50 ± 0.30 mm) and S. dysentriae. The minimum inhibitory concentration (MIC) of synthesized AgNPs was found to be in the range of 0.009875-0.0395 mg/100 μl which was quite lower than the MIC of crude extract i.e. 0.0781-0.3125 mg/100 μl. The results obtained indicated that the different crude extracts of A. marmelos plant as well as AgNPs have a strong and effective antimicrobial potential that provide a marvelous source for the development of new drug molecules of herbal origin which may be used for the welfare of humanity.