The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.
The metal plating industry produces a large amount of wastewater generally containing heavy metals with various chemical compounds; as such, treating the wastewater is both an environmental and an economic challenge. A vacuum evaporation system has been developed to effectively reduce the volume of plating wastewater. However, the gas stream discharged from the distillation unit of the evaporator is often contaminated with high concentrations of odorous compounds such as ammonia and dimethyl disulfide (DMDS). In this study, a non-thermal plasma process operated in wet conditions was applied to remove the odorous compounds, and it showed high removal efficiencies of greater than 99% for ammonia and 95% for DMDS. However, the gas flowrate more substantially affected the efficiency of ammonia removal than the efficiency of DMDS removal, because the higher the gas flowrate, the shorter the contact time between the odorous compound and the mist particles in the wet plasma reactor. The analyses of the maximum removal capacity indicated that the wet non-thermal plasma system was effective for treating the odorous compounds at a loading rate of less than 20 mg/m3/min even though the lowest amount of electrical power was applied. Therefore, the wet-type non-thermal plasma system is expected alleviate to effectively abate the odor problem of the vacuum evaporator used in the treatment of plating wastewater.
Boron doped fullerene C60 (B:C60) films were prepared by the thermal evaporation of C60 powder using argon plasma treatment. The morphology and structural characteristics of the thin films were investigated by scanning electron microscope (SEM), Fourier transform infra-red spectroscopy (FTIR) and x-ray photo electron spectroscopy (XPS). The electrochemical application of the boron doped fullerene film as a coating layer for silicon anodes in lithium ion batteries was also investigated. Cyclic voltammetry (CV) measurements were applied to the B:C60 coated silicon electrodes at a scan rate of 0.05 mVs-1. The CV results show that the B:C60 coating layer act as a passivation layer with respect to the insertion and extraction of lithium ions into the silicon film electrode.
플라즈마 용사법을이용하여 AISI 316 스테인레스 금속모재에 0.1mm 두께의 NiCrAlCoY2O3금속 결합층과 0.3mm 두께의 ZrO2(8wt%Y2O3) 세라믹층으로 구성된 이층 단열코팅층을 제조하였다. 코팅층의 미세조직, 금속결합층의 산화를 고찰하였으며, 900˚C에서 등은 시험과 열반복시험 후, 접합강도시험을 통하여 코팅층의 단사정 상은 열처리시간이 길어질수록 약간 증가하였다. 또한 비변태성 t'의 c/a는 용사상태에서 1.0099이였으며, 100시간 열처리 후에는 1.0115로 약간 증가하였다. 그리고 용사층의 접합강도는 열처리 시간이 길어질수록 감소하였다. 등온열처리 후에는 1.0115로 약간 증가하였다. 그리고 용사층 의 접합강도는 열처리 시간이 길어질수록 감소하였다. 등온열처리 후, 파괴는 주로 세라믹층에서 일어났으며, 반복 열처리되 시편에서는 10회 이후 대부분 금속결합층/세라믹층의 계면에서 일어났다.