| Summary: | 碩士 === 明志科技大學 === 生化工程研究所 === 99 === The removal of antibiotics amoxicillin (AMO) using manganese oxide was investigated in this study. Amoxicillin, one kind of β-lactam and semi-synthesis of penicillin, is used to cure streptococcus, staphylococcus, pneumococcus, meningococcal, and others that are infected by bacteria. The antibiotics is manufactured and widely used in great amount that affect the environment and ecosystem directly and indirectly. Many antibiotics are metabolized by organisms and then excreted through fecal matter to natural water body. The concentration of antibiotics in the environment is low; however, it is the emerging pollutant today because its high impact on ecosystems and human beings. Therefore, this study adopted manganese oxide, which is abundant in nature, to adsorb and/or to oxidize the target pollutant. The control factor includes reaction time (0 to 48 hours), AMO concentrations (1× 10^-4 to 1× 10^-3 mole), pH (2 to 9), and temperatures (15, 25 and 35℃).
The pH zero point of charge of pyrolusite manganese oxide before is 5.2. The reaction between AMO and manganese oxide almost approaches pseudo-equilibrium at 36 hr, and the reaction kinetics obeys pseudo-second-order equation. The nitrogen purged before and during reaction did not significantly influences the AMO removal. At near neutral pH (6 ~ 7), the maximun removal of AMO approximate 90 % was obtained. The removal of AMO decreased with both pH increasing and decreasing. At acidic pH, that appeared to be only 40 % removal of AMO. Besides, at acidic condition AMO significantly enhances the dissolution of manganese oxide compared to that at alkalinity condition. AMO removal slightly increases with the temperature elevating. The prevalent buffer solution of sodium phosphate could successfully maintain the desired pH, but significantly influences the AMO removal. However, the buffer solution of sodium bicarbonate is vice versa, especially at acidic conditions the pH varies during the reaction. The results of LC-MS analysis displays that the, AMO could be hydrolyzed to amoxicillin penicilloic acid (m/z=383) and amoxicillin penilloic acid (m/z=339). Moreover, at alkaline condition, the new product with m/z 160 is yield and the concentration of amoxicillin penicilloic acid increases with reaction progressing; at acidic condition, the concentration of amoxicillin penilloic acid increases. Pyrolusite manganese oxides amoxicillin could plays the role of catalyst. Furthermore, FTIR-ATR analysis indicated that amoxicillin could be adsorbed by manganese oxides.
|
|---|
