الفهرس | Only 14 pages are availabe for public view |
Abstract Various characterizations such as X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy were performed on the synthesized catalysts to evaluate their morphology, chemical structure, and chemical composition. Furthermore, an innovative photoreactor was designed and fabricated. The optimization of operating parameters (e.g., pH, light intensity, flow rate, catalyst dose and initial pollutant concentration) was carried out. The optimum values of pH, light intensity and catalyst dose were 3, 153 W/m2 and 0.25 g/L in the case of sulfamethazine using CNTs/LaVO4 nanocomposite, whereas pH of 4.0, flow rate of 5.5 mL/min and initial chlorpyrifos concentration of 44.9 mg/L were the favorable conditions for achieving the highest degradation efficiency of chlorpyrifos using GNPs/ZrV2O7. The degradation rates of various pollutants decreased with the increase of initial pollutant concentration. The reaction rates were 0.0135, 0.0109 and 0.0032 min-1 at initial trimethoprim concentrations of 5.0 mg/L, 10.0 mg/L and 15.0 mg/L, respectively at pH of 7, flow rate of 5 mL/min and reaction time of 240 min using MIL-53(Al)/ZnO. The reusability performance of various catalysts for the decomposition of various pollutants was evaluated in coated mode for five repetitive runs. The degradation efficiencies of carbamazepine (CBZ) were 91.6%, 87.7%, 86.8%, 84% and 83.1% in five consecutive runs after a reaction time of 90 min, whereas the removal rates of diazinon were 99.7%, 96.3%, 94.8%, 93.5% and 92.1% after a reaction time of 60 min using CNTs/MOF-808. The explanation of degradation mechanism and the specification of major reactive species responsible for photodegradation using various catalysts were attained using trapping experiments. The identification of transformation products generated during the photodegradation process of various pollutants was conducted and the degradation pathways were proposed. Regarding the real wastewater degradation, the TOC removal efficiency of pharmaceutical wastewater was 89.5%, 84%, 74%, 69.8% and 60.5% in the five consecutive cycles, whereas it was 94.3%, 93.1%, 85.8%, 76.2% and 73.2% in the case of agrochemical wastewater using CNTs/LaVO4. The reasonable cost employing catalyst coated plates into the constructed reactor as well as the high stability of catalyst coated plates confirmed the applicability of photocatalysis process. |