Removal of ciprofloxacin (CIP) pollutant from wastewater using conventional process is particularly challenging due to poor removal efficiency. In this work, CIP was photocatalytically degraded using a porous ZnO/SnS2 photocatalyst prepared via microwaves. The influence of process parameters (e.g., pH, catalyst mass and initial CIP concentration) and radical scavengers on visible-light induced degradation of CIP on the catalyst was investigated. From the study, it was found that visible-light induced degradation of CIP on ZnO/SnS2 is a surface-mediated process and the reaction kinetics followed the Langmuir-Hinshelwood first-order kinetics. It was found that the optimum condition for CIP degradation was at pH of 6.1 and catalyst dosage of 500 mg L-1. Higher catalyst dosage however led to a decline in reaction rate due to light scattering effect and reduction in light penetration.
Chitosan possesses electron-rich amino (-NH2) and hydroxyl (-OH) moieties which can anchor with transition metal ions during synthesis. Herein, chitosan was employed as an additive to prepare bismuth ferrite (BFO) via hydrothermal approach. The characterization studies revealed that adding chitosan during BFO synthesis leads to the creation of more oxygen vacancies. The performance of chitosan modified BFO (CMB) was evaluated as peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) removal. Apparently, the addition of 10 wt% chitosan during BFO synthesis (CMB-10) resulted in 1.7 times increase of performance compared to the pristine BFO. Increasing the catalyst loading and PMS dosage resulted in positive effect with 5.7 and 1.9 times rate enhancement, respectively. The CMB-10 exhibited tolerance against pH variation, water matrix, and interfering species. The scavenging experiments indicated that singlet oxygen (1O2), superoxide radicals (O2•-) and sulfate radicals (SO4•-) played a major role in CIP degradation. These reactive oxygen species were generated from PMS activation via Fe3+/Fe2+ and Bi5+/Bi3+ coupling, and oxygen vacancies on the catalyst surface. The CIP degradation pathways were also elucidated based on the detected CIP intermediates. Overall, this study provides insights into the use of chitosan to prepare sustainable materials for pollutants removal via PMS activation.
The fluoroquinolone antibacterial drug ciprofloxacin (cip) has been used to cap metallic (silver and gold) nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH₄ as a mild reducing agent. Metallic nanoparticles (MNPs) showed constancy against variations in pH, table salt (NaCl) solution, and heat. Capping with metal ions (Ag/Au-cip) has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL). MNPs also exhibited significant antibacterial activity against selected bacterial strains.
In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.