| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 106 === Due to the recent attention of Emerging Contaminants (ECs), this study focuses on the environmental impact of Pharmaceuticals and Personal Care Products (PPCPs). Because of the low metabolic rate of PPCPs in living organisms, most of the drugs are directly discharged into the environment, with the highest concentration of Acetaminophen (APAP). Photocatalytic treatment, one of Advanced Oxidation Processes (AOPs), is considered to be a non-toxic, chemically stable and effective in degradation, simple in operation, and inexpensive, that is an ideal method for treating PPCPs. However, it has recently been discovered that nanomaterials have an impact on the environment and return to the human body for health concerns.
In this study, ferric oxide (Fe3O4) was used as the carrier of titanium dioxide (TiO2). 20 mg/L APAP was placed in a 500 mL beaker, and the reaction parameters such as addition dose and pH value, recovery and reuse level were measured by photocatalytic reaction at an ultraviolet wavelength of 365 nm. Finally, the reaction kinetics was investigated.
The results showed that the dose of TiO2 and Fe3O4 affects the photocatalytic degradation and recovery efficiency. At the same reaction time, 10-F/T(20) has a better degradation rate of 75% and recovery rate of 103% compared to other catalysts. The degradation rate increases with the addition dose, but the excess dose may cause shadowing effect, which reduces the degradation rate. Therefore the optimum addition dose is 100 mg/500 mL. In the batch experiments with various pH values, the degradation rates of the pH values adjusted by the buffer solution were neutral (54%) > alkaline (32%) > acidic (20%), but all were inferior to that of pH without addition of buffer solution. In the case where no buffer solution was added, the degradation rate reached 100% in the same reaction time, so the subsequent recovery and reuse tests did not control the pH value with any buffer solution. When the 10-F/T (20) recovery and reuse experiment was carried out, it was found that the first recovery rate was only 60% (60 mg) of the original test (100 mg). The presumed reasons may be that the reactor volume is too large, Fe3O4 itself possesses insufficiently magnetism, and the size of magnetic rod and its magnetism are too small, or the precipitation time is insufficient to affect the recovery rate of the catalysts, which in turn affects the reuse rate. If the effect of the first recovery rate is excluded, further calculation will multiply the first recovery amount and degradation rate by 1.6 times. The recovery amount (96 mg) is closer to the originally added dose of 100 mg, and the degradation rate (81.6%) is similar to the original one (91%). After adjustment, the recovery amount is about 87.7-96 mg and degradation rate is around 81.6-96%. It can be seen that even if the catalysts are recovered after the photocatalytic reaction and reused four times, they still possess a good degradation effect. This study found that APAP degraded by TiO2/Fe3O4 particles (10-F/T(20)) is a pseudo first-order reaction.
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