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PublicationAnti-inflammatory, anti-bacterial, and anti-cancer activities of ag-nanoparticles generated by Plectranthus amboinicus(Elsevier, 2024-09)The present study aimed to synthesize and characterize silver nanoparticles using Plectranthus amboinicus leaf extract and investigated their cytotoxicity, anti-bacterial, anti-migratory, anti-inflammatory, and anti-cancer properties. Phytogenic AgNPs were characterized by UV–visible spectroscopy, Dynamic light scattering, XRD, Transmission electron microscopy, energy dispersive X-ray (EDX), and Fourier-transformed infrared spectroscopy. Anti-proliferative, anti-migratory, anti-inflammatory, and anti-bacterial activities were examined by MTT assay, scratch assay, human RBC membrane stabilization, and Kirby-Bauer disc diffusion assay. Green synthesized AgNPs showed a surface plasmon peak at 430 nm under a UV–visible spectroscope. Spherical morphology with a size distribution between 20 and 70 nm was observed by TEM. Various biomolecule functional groups capping AgNPs were found by FTIR spectroscope. The crystalline structure of synthesized AgNPs was confirmed through XRD. These green synthesized AgNPs exhibited less toxicity to NIH/3T3 mouse embryonic fibroblast cells and showed good anti-cancer activity with IC50 value of 2 µg/mL by inhibiting the proliferation and migration of melanoma cells. Heat-induced hemolysis of RBC was prevented significantly in a dose-dependent manner, indicating the anti-inflammatory activity of green synthesized AgNPs IC-50–35 µg/mL. The anti-bacterial activity against E. coli, K. pneumonia, and S. aureus results showed that the zone of inhibition was increased along with increased concentrations of AgNPs in all bacterial cultures.
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PublicationMetal-polymer-clay nanocomposites based electrochemical sensor for detecting hydrazine in water sources(Elsevier, 2024-12)AgNPs embedded polymer-clay (AgNPs@PEI-HNT) nanocomposites were successfully employed to sensitively detect hydrazine in water samples using differential pulse voltammetry (DPV) and amperometry methods. In-situ polymerization was utilized for assembling the polymer-clay composites, which were subsequently coated with AgNPs. PEI improves conductivity and absorbs AgNPs on the surface of HNTs, as evidenced with the help of UV-Visible, IR spectroscopy, XRD, XPS and morphological studies (FE-SEM and TEM). Nanocomposites were coated with GCE, which improved their electrocatalytic performance during hydrazine oxidation. The Tafel plot, Galus and Cottrell equations were used to compute the electron transfer coefficient (0.64), catalytic reaction rate constant (4.81 × 104 M−1s−1) and diffusion coefficient (2.56 × 10−5 cm2/s) of hydrazine at AgNPs@PEI-HNT/GCE. Amperometry technique was used to determine the LOD along with sensitivity of hydrazine, which were 0.22 nm and 116.76 µA µM−1 cm−2. Modified electrode offers enhanced properties for example strong anti-interference capability, good reproducibility, long-term stability, sensitivity, and so on. The designed sensor successfully detects hydrazine in water samples with high recovery rates (R.S.D. < 5 %).
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PublicationEffectiveness of direct sulfonated polysulfone in dual chamber microbial fuel cells based dewatered sludge for power generation(Springer, 2024-08)In the realm of bioprocess technology, microbial fuel cells (MFCs) are regarded as a noteworthy innovation that can simultaneously bioremediate wastewater and utilise as renewable energy applications. The investigation began with synthesizing composite proton exchange membrane (PEM) with sulfonated polysulfone (SPSF) and sulfonated chitosan (SCS) as a separator for MFCs. A composite membrane has been developed by crosslinking a microporous SPSF substrate with a thin layer of chitosan (CS). The membrane was then evaluated for its suitability in MFCs which employ dewatered sludge. The appearance and physico-mechanical properties of this composite were thoroughly examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), proton conductivity measurements, back-end titration tests, and water uptake studies. Attempts were made to enhance the connection between the duo polymers such as PSF and CS by providing surface changes with the incorporation of sulfonation properties. As a result, two novel types of composite materials were developed: (SPSF/CS) and (SPSF/SCS), which were made by altering a PSF membrane’s surface before adding a chitosan layer using the non-solvent phase inversion technique. The proton conductivity of SPSF/CS and SPSF/SCS composites was measured and contrasted with that of unmodified PSF. The composite, SPSF/SCS-1, 0.5 wt%, showed greater proton conductivity and ion exchange capacity (IEC) (1.7 meq/g, 0.061 S/cm) than the unaltered PSF (0.99 meq/g, 0.009 S/cm). According to the MFCs performance, the SPSF/SCS-1, 0.5 wt% membrane demonstrated a substantial electricity production compared to pristine PSF 38.57 mW/m2 and 0.449 mW/m2. These results vividly depicted that the composite SPSF/SCS PEM increases the productivity of dual-chamber MFCs.
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PublicationChitosan-mediated tailoring of cadmium sulphide nanoparticle: synthesis, properties, and interactive mechanisms(Elsevier, 2024-09)This study explores the synergistic effects of chitosan-coated cadmium sulphide (CdS) nanoparticles (NPs) at varying concentrations on their structural, optical, and photocatalytic properties. CdS NPs are known for their promising photocatalytic potential, but their practical application often requires stability enhancement and reduced toxicity. Chitosan, a natural biopolymer, offers unique advantages such as biocompatibility and heavy metal adsorption capabilities, making it an attractive candidate for surface modification of CdS NPs. Our investigation reveals that chitosan-coated CdS NPs exhibit concentration-dependent changes in their crystalline structure, bandgap energy, particle size, and vibrational characteristics. Notably, CdS NPs synthesized with 1.5 g chitosan concentration display the smallest bandgap and particle size, suggesting optimal photocatalytic activity. This research provides valuable insights into tailoring CdS NPs for efficient visible light photocatalysis, with implications in environmental remediation and energy conversion.
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PublicationSulphur/functionalized graphene composite as cathode for improved performance and life cycle of lithium-sulphur batteries(Elsevier, 2024)Over the past years, significant advantages have been introduced to upgrade the performance of lithium-sulfur battery (Li-S) batteries since their prototype in the 1960s. Due to high theoretical energy density and cost efficiency, Li-S batteries have obtained great attention and have made great progress in the last few years. In this work, we developed the sulfur-attached few-layer graphene composite (S/FLG), sulfur-attached functionalized few-layer graphene using acetic acid (S/FLG-COOH) and sulfur-attached functionalized few-layer graphene using strong acid H2SO4 and HNO3 (S/FLG-OH) as a cathode material with high sulfur loading. The material's structure is confirmed through XRD. The surface morphology is confirmed through SEM and elemental composition has been obtained through EDAX. The functional groups are confirmed through FTIR. The defect level and number of layers are confirmed through Raman characterization with an excitation laser wavelength of 532 nm. The electrochemical performance of three cathodes is also identified through EIS, CV, and GCD characterization. Meanwhile, highly developed defects and edges found in the functionalization of few-layer graphene using the strong acid (H2SO4 and HNO3) which consists of a hydroxyl functional group (FLG-OH) serve as polysulfide reservoirs to mitigate the shuttle effect. Among these cathodes, S/FLG-OH shows a high specific capacitance of 157.4 F g−1 and when applied as a cathode host on a coin cell it obtained a voltage of about 2.6 V. Well-performed S/FLG-OH cathode was used to fabricate the Coin Cell. The fabricated Coin Cell with S/FLG-OH as the cathode shows a stable potential over 50 cycles.