Silver Nanoparticles Incorporated on Natural Clay as an Inhibitor against the New ISO SS Bacteria Isolated from Sewage Sludge, Involved in Malachite Green Dye Oxidation

Abstract

A facile, ecofriendly, and cost-effective method was developed to prepare a microporous material based on natural chemically modified bentonite with silver ions (BN-Ag0). This material presents a good catalytic activity against Malachite Green (MG) dye and bacteriostatic activity against a newly isolated bacterium from sewage sludge named hereafter “ISO SS” and Escherichia coli (E. coli). BN-Ag0 was characterized by the following methods: energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), Fourier-transform infrared (FTIR) spectroscopy, temperature programmed desorption (TPD) and X-ray Diffraction (XRD). The new bacterium ISO SS, was isolated using the technique of isolating a pure culture of anaerobically stabilized sludge. A mandatory characterization of ISO SS isolated strains from anaerobic stabilized sludge was performed in the process of identifying bacterial species. The cationic clay-based nanomaterial showed appreciable antibacterial activity against ISO SS, a Gram-negative bacterium. It also showed good activity against E. coli bacteria. As a catalyst in the catalytic ozonation of MG dye, BN-Ag0 significantly improves the oxidation time of the dye, due to its good adsorption and catalytic properties. The catalytic and antibacterial activities of the natural bentonite (BN) and of BN-Ag0 were examined using performant characterization techniques. The lifetime of the BN-Ag0 catalyst was also evaluated. Results obtained are expected to provide valuable findings for the preparation of a good microporous material with multiple functionalities.

Antifungal Properties of Nanosilver Clay Composites Against Fungal Pathogens of Agaricus bisporus

“…The structural modification of montmorillonite after AgNP incorporation is revealed by the increase in the intensity of O−H stretching (3620 cm −1 ), 1628 cm −1 (O−H bending) in plane Si−O stretching (997 cm −1 ), Al−O stretching (914 cm −1 ) [45] associated with the aluminosilicate structure (Figure 2B). The alteration of the band intensity could be attributed to the presence of AgNPs on the defects on the octahedral sheets [28,43] .…”

“…A noticeable difference was the appearance of a peak at 1384 cm À 1 , which indicated the existence of Ag in the composite, and this result agreed with that reported by Zhang et al [44] The FT-IR spectra demonstrated the inflexibility of the silicate structure and the non-bond chemical interface between the silicate structure and AgNPs in the composite. [42] The structural modification of montmorillonite after AgNP incorporation is revealed by the increase in the intensity of OÀ H stretching (3620 cm À 1 ), 1628 cm À 1 (OÀ H bending) in plane SiÀ O stretching (997 cm À 1 ), AlÀ O stretching (914 cm À 1 ) [45] associated with the aluminosilicate structure (Figure 2B). The alteration of the band intensity could be attributed to the presence of AgNPs on the defects on the octahedral sheets.…”

“…The alteration of the band intensity could be attributed to the presence of AgNPs on the defects on the octahedral sheets. [28,43] The appearance of an additional band at 1334 cm À 1 and the downward shift in the characteristic vibrations, namely SiÀ O stretch (997 cm À 1 ), in comparison to the unmodified clay mineral, indicates a disturbance in the bonding in the structure of the aluminosilicate [40,44,45] and hence a more ordered structure due to the presence of AgNPs.…”

Enhanced properties of PVDF membranes using green Ag-nanoclay composite nanoarchitectonics

“…The silicate structure bands of Si-O-Si were located in the region of 1152 and 1083 cm −1 . The peak at 381 cm −1 is assigned to the symmetric vibration of Si-O; the observed peak shifts can be attributed to the presence of organic cations (trimethyl stearyl ammonium) within the nanoclay layers [59,60]. The bands at 2530 and 2357 cm −1 represent the symmetric and asymmetric stretching vibrations of -CH 3 and -CH 2 supporting the intercalation of organic molecules from the organic ammonium cations and organic molecules that stabilized the AgNPs.…”

“…The Ag-Nanoclay spectra contain characteristic peaks corresponding to the nanoclay with additional peaks at 449 and 471, confirming the incorporation of the AgNPs within the nanoclay layers. In addition, the enhancement of the OH stretching peaks (3489-3559 cm −1 ) is attributed to the presence of capping organic molecules at the surface of the AgNPs from the P Argenta plant extract [37,60]. The presence of peaks corresponding to silicates in nanoclay, organic molecules in the plant extract, and AgNPs together in the Ag-Nanoclay composite confirm its successful synthesis and confirm that the organic molecules in the plant extract were not only used as reducing agents for Ag ions to AgNPs, but they also became a constituent of the Ag-Nanoclay composite.…”