In this study, the effects of number of washes, oxidation degree, carboxylation, and hydrothermal reduction temperature on the antibacterial activity of graphene oxide (GO) and reduced graphene oxide (rGO) nanomaterials were investigated. GO derivatives with different numbers of washes (1-5W) and oxidation levels (3X, 6X, and 9X), carboxylated GO (GO-COOH), and rGO samples obtained at different hydrothermal reduction temperatures (100, 140, and 180 degrees C) were characterized by X-ray diffraction, field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, zeta potential analysis, and Raman spectroscopy, and were subsequently evaluated for antibacterial activity against gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli). The washing experiments showed that, in the presence of residual acids (1W), a 5-log reduction was achieved for S. aureus at 600 & micro;g/ mL, whereas after acid removal (5W), purified GO produced a 2-log reduction at the same concentration. In contrast, no meaningful change in activity was observed for E. coli as a function of number of washes (similar to 1 log). In the oxidation optimization experiments, the 6X oxidation level yielded the highest antibacterial efficacy against S. aureus, producing a 5-log reduction at 800 & micro;g/mL, while excessive oxidation (9X) led to a plateau in activity because of structural defects. Carboxylation decreased activity against S. aureus by 40% at 800 & micro;g/mL (from 5 log to 3 log) because of electrostatic repulsion, while leaving the already low activity against E. coli (similar to 1 log) unchanged. In the hydrothermal reduction experiments, partial reduction at 100 degrees C produced the optimal hydrophilic-hydrophobic balance for S. aureus (3-log reduction at 240 & micro;g/mL), whereas the higher hydrophobicity at 180 degrees C enabled effective inhibition of E. coli (2-to 3-log reduction at 180-240 & micro;g/mL). These findings show that antibacterial efficacy depends on the compatibility between surface chemical properties and bacterial cell-wall structure.
A [H]-accelerated catalytic Fenton system was developed using Pd/UiO-66(Zr)-F4 as the catalyst. This system enabled the regeneration of Fe2+and facilitated the continuous generation of both & centerdot;OH and 1O2 through [H]-mediated electron transfer at ambient temperature and pressure. Under the conditions of 0.2 g L-1 catalyst (Pd loading 0.516 wt%), 25 mu M Fe2+, 60 mL min-1 H2 flow (as the [H] source), 20 mM H2O2, and pH 3, approximately 89% of carbamazepine (initial concentration 20 mg L-1) was degraded within 3 h using trace iron. However, the catalytic activity of Pd/UiO-66(Zr)-F4 gradually declined from 89% to 53% over six reaction cycles. This decrease was likely due to loss of specific surface area caused by microstructural degradation associated with hydrogen spillover effects.
In the present work, a facile hydrothermal route was employed to synthesize the nanocomposite MgFe2O4/MoS2, which acted as a heterogeneous photo-Fenton catalyst for the degradation of a synthetic diazo dye, Acid Blue 113 (AB113). The nanocatalyst produced underwent analysis using multiple characterization techniques. The parameters influencing the oxidative reaction were statistically modeled and optimized using response surface methodology. Optimal degradation efficiency for AB113 (94.92%) was attained at pH 8.79 using 10 mg of MgFe2O4/MoS2 nanocatalyst, 1.6 mL of H2O2, and a reaction duration of 27 min. The synergistic effect resulting from the formation of electron-hole pairs renders the combined photocatalysis and Fenton process a more efficient treatment approach. The kinetic study data indicate that the photo-Fenton process follows the pseudo-first-order model. The nanocatalyst fabricated demonstrated exceptional stability, maintaining a high degradation performance after seven consecutive photo-Fenton cycles. The results obtained indicate that the MgFe2O4.MoS2/H2O2/Vis system is an effective method for treating wastewaters containing organic contaminants.
In this study, a series of water-soluble ruthenium(II) p-cymene complexes bearing carboxylic acid-functionalized ligands (Ru1-Ru3) were synthesized, fully characterized (1H NMR,13C NMR, and FT-IR), and evaluated in two distinct catalytic transformations: tandem nitroarene reduction/N-methylation and transfer hydrogenation. Of the catalysts tested, Ru1 exhibited superior catalytic activity in both systems. Under optimized conditions (1 mol% Ru1, 8 mmol NaBH4, 110 degrees C, 2 h in methanol), Ru1 promoted the one-pot tandem transformation of nitrobenzene to N-methylaniline with up to 93% conversion using methanol as a sustainable C1 and H2 source. Furthermore, Ru1 proved highly effective in the transfer hydrogenation of acetophenone and various structurally diverse ketones using isopropanol as the hydrogen donor (0.5 mol% catalyst, 0.5 mmol KOH, 82 degrees C, 1.5 h), delivering the corresponding secondary alcohols in moderate to excellent yields (51%-98%). These protocols offer atom-economical, sustainable, and versatile catalytic routes for both amine functionalization and carbonyl reduction.
Functionalized p-conjugated polymers have emerged as promising electrochromic materials due to theirwell-defined molecular structures, facile synthesis, and ability to form smooth and homogeneous thin films. Furthermore, surface cross-linking enhances the mechanical and environmental stability of these films while improving their durability during electrochemical operation. In this study, a unique band gap-tunable pentamer (FBP) was developed featuring a D-A-D-A-D configuration, which includes thiophene, coumarin, and fluorene. Cross-linked films (FBPX) were obtained using both spray and electrospray methods in the presence of tetrathiol-based crosslinkers and 366 nm light, thanks to the functionalizable allyl groups present in the FBP structure. UV-Vis analysis revealed absorption maxima at 410 nm and 330 nm for FBP and FBPX films, respectively, with corresponding optical band gap (Eg,opt) values of 2.88 and 3.30 eV. Moreover, electrochemical measurements indicated HOMO-LUMO energy levels of eV for FBP and eV for FBPX, demonstrating the influence of cross-linking on the electronic structure of the films. Atomic force microscopy analysis revealed that the electrospray deposition method significantly increased the surface roughness, with RMS values rising from 6.2 nm for the spin-coated film to 84.6 nm for the electrospray-coated film, resulting in a highly textured and porous morphology. Furthermore, electrochromic devices based on FBPX films were fabricated using different coating and surface cross-linking techniques. These results demonstrate that surface cross-linking and coating methodology significantly influence the electrochromic performance, enabling enhanced color modulation, durability, and response characteristics of FBPX-based electrochromic devices.
