研究目的
Investigating the photocatalytic degradation of pharmaceutical micro-pollutants (progesterone, ibuprofen, and naproxen) using ZnO as a photocatalyst under UV light irradiation, and evaluating the effects of operating parameters and reactor types on degradation efficiency.
研究成果
ZnO photocatalyst is highly efficient for degrading progesterone, ibuprofen, and naproxen under UV light, with degradation efficiencies up to 92.3%, 94.5%, and 98.7% respectively. The kinetics follow pseudo-first-order behavior, and degradation rates increase with initial contaminant concentration but decrease above optimal catalyst loading due to factors like light scattering. The membrane reactor shows promise for large-scale applications, with performance improving with oscillation frequency. This photocatalysis method is a viable advanced oxidation process for wastewater treatment.
研究不足
The study was conducted at specific initial concentrations and catalyst loadings; results may not extrapolate to higher concentrations where kinetics could shift to zero-order. The experiments were done at neutral pH, and effects of other pH levels or environmental conditions were not explored. The membrane reactor's performance is dependent on oscillation frequency, and catalyst recovery or long-term stability was not fully addressed.
1：Experimental Design and Method Selection:
The study used batch stirred and submerged membrane photocatalytic reactors to investigate the degradation of contaminants. Photocatalysis with ZnO under UV light was employed based on its efficiency and advantages over other catalysts.
2：Sample Selection and Data Sources:
Stock solutions of progesterone (PGS), ibuprofen (IBU), and naproxen (NAP) were prepared in methanol and diluted to specific concentrations (e.g., 20, 40, 80 ppm) using deionized water. Experiments were conducted at natural pH.
3：List of Experimental Equipment and Materials:
Equipment included a 100-mL glass reactor (Pyrex), magnetic stirrer/heater, UV lamp, oscillatory membrane reactor with a 0.2-μm hydrophilic PVDF membrane (Microdyn Nadir GmbH), peristaltic vacuum pump, McMillan flowmeter (model S112), and syringe filters. Materials included ZnO photocatalyst, methanol, and deionized water.
4：2-μm hydrophilic PVDF membrane (Microdyn Nadir GmbH), peristaltic vacuum pump, McMillan flowmeter (model S112), and syringe filters. Materials included ZnO photocatalyst, methanol, and deionized water.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: For batch experiments, catalyst was added to contaminant solutions, stirred in darkness for 30 min to achieve adsorption equilibrium, then exposed to UV light for 120 min with samples taken at intervals. For membrane reactor experiments, similar setup was used with oscillatory motion and permeate flow measurement.
5：Data Analysis Methods:
Photodegradation efficiency was calculated using concentration changes. Kinetics were analyzed using pseudo-first-order model with rate constants determined from linear regression of ln(c0/c) vs. time.
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