Ag-Modified ZnO for Degradation of Oxytetracycline Antibiotic and Reactive Red Azo Dye

Enhanced photocatalytic degradation of norfloxacin and amido black 10B using bael gum-infused ZnO/Ag₂CO₃ nanocomposites for sustainable approach to environmental remediation and antimicrobial activity

The presence of antibiotics and dyes as organic contaminants has caused severe wastewater pollution, posing a significant environmental concern globally. To address this issue, this study highlights the green synthesis of ZnO/Ag₂CO₃ nanocomposites using bael gum (BG) for the photocatalytic degradation of norfloxacin (NOF) and Amido Black 10B (AB 10B), along with their antimicrobial activity. The synthesized BG-ZnO/Ag₂CO₃ nanocomposites were extensively characterized for their optical, structural, morphological, chemical purity, crystal structure, and surface area properties using XPS, XRD, FT-IR, FESEM, EDS, photoluminescence (PL) spectra, Raman analysis, HR-TEM, BET, and LC-MS. The nanocomposites materials exhibited excellent photocatalytic performance under visible light irradiation, achieving the degradation efficiencies of 91.03 % for AB 10B and 81.5 % for NOF,with corresponding rate constants of 0.017 min-1 and 0.0028 min-1. The study further evaluated the influence of catalyst dosage, effect of pH, radical scavengers, reusability, and the stability. Kinetic analysis revealed that the bio-nanocomposite follows first-order kinetics for both pollutants. Scavenger studies identified hydroxyl radicals (•OH) as the primary active species in the degradation process. LC-MS analysis confirmed the formation of degradation intermediates for NOF and AB 10B. Additionally, the bio-nanocomposite demonstrated significant antibacterial activity against various bacterial strains using the agar well diffusion method, exhibiting strong bactericidal effects against pathogenic bacteria. This study emphasizes the potential of bael gum-based bio-nanocomposites for improved photocatalytic degradation and antibacterial activity in wastewater treatment across various industries.

Rapid and convenient synthesis of "green" ammonium-modified chitosan composite sponge with the existence of ascorbic acid for highly efficient removal of Congo red (CR)

In this study, a new green composite sponge made of chitosan and modified with ammonium ascorbate (ACS-CIT) was synthesized in just 10 min. Compared with CS-CIT (sponge prepared from acetic acid), ACS-CIT exhibits significantly enhanced adsorption performance for CR, with the saturated adsorption capacities increased from 353.667 to 1261.639 mg·g-1. The adsorption mechanism can be summarized as the generation of more hydrogen bonds, electrostatic attraction, and intra particle diffusion, revealing the addition of ascorbic acid introduced more hydroxyl groups, thereby enhancing the hydrogen bonding force, and the ammonium modification of chitosan improved the electrostatic attraction of the material, resulting in a significant increase in its adsorption capacity. Additionally, the prepared ACS-CIT showed excellent CR removal performance even in the presence of multiple interfering factors coexisting in the simulated wastewater, and the adsorption capacity remained stable after at least five cycles. Furthermore, the maximum bed capacity of ACS-CIT for CR is 1152.829 mg·g-1 under the given conditions of a flow rate of 1 mL·min-1, inlet concentration of 150 mg·L-1, a bed height of 1 cm respectively, and the breakthrough curve followed the Thomas model. The results indicated the eco-friendly and recyclable ACS-CIT is a promising adsorbent for CR dye removal in water.

Facile synthesis of water-soluble silver nanoclusters for the photocatalytic degradation of dyes by multivariate optimization approach

In this study, silver nanoclusters protected by the natural tripeptide ligand (GSH@Ag NCs) were constructed for photocatalytic dye degradation. The ultrasmall GSH@Ag NCs were found to exhibit a remarkably high degradation capability. Aqueous solutions of the hazardous organic dye Erythrosine B (Ery. B) and Rhodamine B (Rh. B) were subjected to degradation in the presence of Ag NCs under solar light and white-light LED irradiation. The degradation efficiency of GSH@Ag NCs was evaluated using UV-vis spectroscopy, where Erythrosine B showed considerably high degradation of 94.6% compared to Rhodamine B, which was degraded by 85.1%, corresponding to a 20 mg L^-1 degradation capacity in 30 min respectively under solar exposure. Moreover, the degradation efficacy for the above-mentioned dyes demonstrated a dwindling trend under white-light LED irradiation, attaining 78.57 and 67.923% degradation under the same experimental conditions. The astoundingly high degradation efficiency of GSH@Ag NCs under solar-light irradiation was due to the high I of 1370 W for solar light versus 0.07 W for LED light, along with the formation of hydroxyl radicals HO˙ on the catalyst surface initiating degradation due to oxidation.