| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 106 === Environmental pollution such as diesel spill or accidental leakage into soil and groundwater occurs frequently. In the remediation methods, biological remediation can save costs and be an environmentally friendly remediation technique. However, biological reactions are affected by many factors. For example, oxygen is an important reactant involved in aerobic degradation of diesel. In recent years, many metal peroxide compounds with the ability to carry oxygen have used in remediation. The purpose of this study is to prepare and to characterize nano-scale oxygen-releasing calcium peroxide particles by chemical precipitation and physical grinding methods. Furthermore, synthesized micro/nano bubbles pumping with oxygen and the calcium peroxide nanoparticles were sutdied on their effects of microbial diesel degradation. The calcium peroxide particles synthesized by the chemical precipitation method using hexadecyl trimethyl ammonium bromide, Triton X-100, and carboxymethyl cellulose (CMC) were measured by dynamic light scattering. The size of the first two particles was more than 6 μm; however, the size of the calcium nanoparticles synthesized by CMC using Takuchi method (CMC-CaO2) was around 190 nm. The size of calcium peroxide nanoparticles synthesized by physical wet grinding method (wet-ground CaO2) with the addition of dispersant was 110 nm. All particles showed the characteristic peaks with calcium peroxide by X-ray diffraction. The particle sizes of the CMC-CaO2 and wet-ground CaO2 were less than 100 nm by means of a transmission electron microscope. Fourier transform infrared spectroscopy showed that the surface of the wet-ground CaO2 had a functional group of dispersants. The results of Raman spectroscopy also showed characteristic peaks of O-O function group. By pumping CMC+AlCl3 and basic medium with oxygen, micro/nano bubbles were generated. The particle sizes were around 400 nm and the dissolved oxygen (DO) can rise to 30 mg/L at around neutral pH. However, the DO both went down to 0 mg/L after a day. The DO could rise to 10 mg/L by adding wet-ground CaO2 and CMC-CaO2 into basic medium and can maintain up to 4 mg/L until 2 days. The pH values for these two treatments were 10.82 and 9.36, respectively. Micro/nano bubbles synthesized by CMC+AlCl3 and basic medium could help microorganisms to degrade diesel from 200 ppm to 98 and 125 ppm, respectively. Wet-ground CaO2 and CMC-CaO2 could help microorganisms to degrade diesel from 200 ppm to 118 and 101 ppm, respectively. The results showed wet-ground CaO2, CMC-CaO2 nanoparticles, and micro/nano bubbles had an ability to promote diesel degradation by microbes.
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