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This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).

The pervaporation separation of organic compounds from acetone-butanol-ethanol (ABE) fermentation model solutions was studied using activated carbon (AC) nanoparticle-poly (dimethylsiloxane) (PDMS) mixed matrix membranes (MMM). The effects of the operating conditions and nanoparticle loading content on the membrane performance have been investigated. While the separation factor increased continuously, with an increase in the concentration of nanoparticles, the total flux reached a maximum in the MMM with 8 wt % nanoparticle loading in PDMS. Both the separation factor for ABE and the total permeation flux more than doubled for the MMM in comparison to those of neat PDMS membranes prepared in this study.

In recent years, bio-lubricants have received a growing interest for industrial applications. Still, a full-scale implementation in machinery lubrication requires a thorough evaluation of their performance through tribological and operational tests to stand upon their performance. Additionally, the promising outcomes achieved by nanoadditives in improving the performance of synthetic lubricants have prompted research efforts to identify suitable nanoadditives for bio-grease. This paper introduces a bio-grease from a hybrid vegetable oil and glycerol monostearate as a thickener for the lubrication of rolling bearings. Activated carbon nanoparticles (ACNPs) as nanoadditives were synthesized, characterized, and incorporated into the bio-grease at concentrations of 0.5, 1, and 2% by weight. Tribo-tests were conducted on these bio-grease blends, and running tests were carried out using 6006 ball bearings on a custom test rig. Throughout a 30-min test run under a radial load of 10% of the bearing’s dynamic load rating, mechanical vibrations and power consumption were measured and analyzed for each bearing. The bio-grease with ACNPs exhibited a substantial reduction in wear scar diameter (WSD) and coefficient of friction (COF), achieving improvements of up to 73.6 and 65%, respectively, in comparison to lithium grease. Furthermore, the load carrying capacity was enhanced by 200%. The study revealed a strong correlation between measured vibration amplitudes and the viscosity of the bio-grease. The absence of high frequency resonant bands in vibration spectra indicated that the test grease samples satisfied the conditions of elastohydrodynamic lubrication, and these findings were corroborated through calculations of the minimum oil film thickness.

Membrane technologies have developed as one of the main contributors to the resolution of water-related problems. This study seeks to examine the impact of active carbon nanoparticles (ACNPs) on the characterization and mechanical properties of polyethersulfone (PES) ultrafiltration membranes. The PES-AC composites were prepared using the phase inversion technique with a doctor blade by including ACNPs at varied weight percentages (0.01, 0.02, 0.03, 0.04 wt%). Produced membranes were characterized using FTIR, TGA, SEM, and XRD techniques, and the mechanical properties were evaluated using a tensile test, following the guidelines of the ASTM 638M-3 standard, utilizing a uniaxial universal testing machine. SEM images reveal that PES pure membranes consist of a porous bulk layer and dense skin layer. The addition of ACNPs decreased the pore size of the membranes with total thickness varying from 140 to 150 μm. Fourier-transform infrared spectroscopy (FTIR) indicated that with increasing ACNPs concentration, the peak intensities are related to C–C stretching bonds and acidic C–O groups. The XRD analysis showed that with higher ACNPs loading, there are a decrease in the amorphous phase of mixed matrix membranes (MMMs) and the highest intensity (2 θ  = 12.99°) at 2% ACNPs concentration. The tensile strength of the MMMs increased and reached an ideal value of 3.386 MPa when loaded with 2% ACNPs. Also, the optimum rate of tensile strain with 40% enhancement was achieved with 2% ACNPs compared with the pristine PES membrane.

Harsh acid oxidation of activated charcoal transforms an insoluble carbon-rich source into water-soluble, disc structures of graphene decorated with multiple oxygen-containing functionalities. We term these pleiotropic nano-enzymes as “pleozymes”. A broad redox potential spans many crucial redox reactions including the oxidation of hydrogen sulfide (H2S) to polysulfides and thiosulfate, dismutation of the superoxide radical (O2−*), and oxidation of NADH to NAD+. The oxidation of H2S is predicted to enhance protein persulfidation—the attachment of sulfur to cysteine residues. Persulfidated proteins act as redox intermediates, and persulfidation protects proteins from irreversible oxidation and ubiquitination, providing an important means of signaling. Protein persulfidation is believed to decline in several neurological disorders and aging. Importantly, and consistent with the role of persulfidation in signaling, the master antioxidant transcription factor Nrf2 is regulated by Keap1’s persulfidation. Here, we demonstrate that pleozymes increased overall protein persulfidation in cells from apparently healthy individuals and from individuals with the mitochondrial protein mutation responsible for Friedreich’s ataxia. We further find that pleozymes specifically enhanced Keap1 persulfidation, with subsequent increased accumulation of Nrf2 and Nrf2’s antioxidant targets.

The widespread use of mineral cutting fluids in metalworking poses challenges due to their poor wettability, toxicity, and non-biodegradability. This study explores cactus oil-based nanofluids as sustainable alternatives for metal cutting applications. Samples of cactus oil are prepared in plain form and with 0.025 wt.%, 0.05 wt.%, and 0.1 wt.% activated carbon nanoparticles (ACNPs) from recycled plastic waste. Plain cactus oil exhibited a 34% improvement in wettability over commercial soluble oil, further enhanced by 60% with 0.05 wt.% ACNPs. Cactus oil displayed consistent Newtonian behavior with a high viscosity index (283), outperforming mineral-based cutting fluid in thermal stability. The addition of ACNPs enhanced the dynamic viscosity by 108–130% across the temperature range of 40–100 °C. The presence of nano-additives reduced the friction coefficient in the boundary lubrication zone by a maximum reduction of 32% for CO2 compared to plain cactus oil. The physical and rheological results translated directly to the observed improvements in surface finish and tool wear during machining operations on H13 steel. Cactus oil with 0.05 wt.% ACNP outperformed conventional fluids, reducing surface roughness by 35% and flank wear by 57% compared to dry. This work establishes cactus oil-based nanofluids as a sustainable alternative, combining recycled waste-derived additives and non-edible feedstock for greener manufacturing.

Our group has synthesized a pleiotropic synthetic nanozyme redox mediator we term a “pleozyme” that displays multiple enzymatic characteristics, including acting as a superoxide dismutase mimetic, oxidizing NADH to NAD+, and oxidizing H2S to polysulfides and thiosulfate. Benefits have been seen in acute and chronic neurological disease models. The molecule is sourced from coconut-derived activated charcoal that has undergone harsh oxidization with fuming nitric acid, which alters the structure and chemical characteristics, yielding 3–8 nm discs with broad redox potential. Prior work showed pleozymes localize to mitochondria and increase oxidative phosphorylation and glycolysis. Here, we measured cellular NAD+ and NADH levels after pleozyme treatment and observed increased total cellular NADH levels but not total NAD+ levels. A 13C-glucose metabolic flux analysis suggested pleozymes stimulate the generation of pyruvate and lactate glycolytically and from the tricarboxylic acid (TCA) cycle, pointing to malate decarboxylation. Analysis of intracellular fatty acid abundances suggests pleozymes increased fatty acid β-oxidation, with a concomitant increase in succinyl- and acetyl-CoA. Pleozymes increased total ATP, potentially via flexible enhancement of NAD+-dependent catabolic pathways such as glycolysis, fatty acid β-oxidation, and metabolic flux through the TCA cycle. These effects may be favorable for pathologies that compromise metabolism such as brain injury.

Polyvinylchloride (PVC) based heterogeneous cation exchange membranes were prepared by the solution casting technique. The effect of super activated carbon nanoparticles concentration as filler additive in membrane matrix on ionic transfer behaviors of the membrane was studied. SOM images showed uniform particles distribution and relatively uniform surfaces for the membranes. The membrane water content was improved initially by using of super activated carbon nanoparticles up to 0.5 %wt in the casting solution and then began to decrease by more increase of nanoparticles content ratios from 0.5 to 4 %wt. Utilizing of activated carbon nanoparticles in the casting solution also led to increase of water contact angle, membrane ion exchange capacity, fixed ionic concentration, membrane potential, transport number and membrane selectivity obviously.An Opposite trend was observed for the membrane electrical resistance. The sodium flux/permeability was also enhanced initially by increase of nanoparticles concentration up to 0.5 %wt and then decreased slightly by more increase of nanoparticles loading ratios from 0.5 to 1 %wt. The sodium flux was sharply enhanced again by more increase of nanoparticles concentration form 1 to 4 %wt. The membrane transport number and selectivity were increased initially by increase of electrolyte concentration and then showed decreasing trend. The membranes showed higher transport number and selectivity at neutral pH compared to other pH values. The ED results showed that dialytic rate of lead ions was increased by utilizing of super activated carbon nanoparticles in the membrane matrix.