| Summary: | 碩士 === 國立高雄科技大學 === 海洋環境工程系 === 107 === About 88% sulfur oxide (SOX) in the atmosphere releases from industry and power plants through burning fossil fuel. At present, domestic power plants have used seawater for desulfurization of flue gas, this method will indeed increase the amount of sulfate in seawater. Historically, the gravimetric measure is the main method for determining sulfate in seawater. Due to time consumption, this study hopes to establish a method for rapid determination of sulfate concentration in seawater, thereby assessing how much of sulfur oxides are absorbed by seawater.
Turbidimetric sulfate determination (NIEA W430.51C) was adopted by the Environmental Protection Administration, which is mainly applicable for fresh water and sulfate concentration below 40 mg/L. However, sulfate concentration in the seawater is 60 times higher than the detection limit of the NIEA W430.51C declared. In this study, the concentration of sulfate in seawater is determined by a modified turbidity method. Firstly, a certain amount of barium chloride is added to react with most of the sulfate ions in the sample, then the sample is filtered. Secondly, sulfate concentration in the filtered liquid is determined by the NIEA W430.51C turbidity method. Finally, the total sulfate concentration of the sample was estimated from these two reactions.
The results show that the linear range of the turbidity meter is 0 ~ 120 mg/L, which is higher than that the NIEA W430.51C standard method describes. In addition, sample matrix has no effect on the slope of the calibration curve. Furthermore, the optimal conditions for measurement are as following: minimum sample demand is 100 g; Arabic gum as dispersant is suggested; colloid forming time is at least 4 minutes and the sample storage time could be last to a month. Finally, the analysis time of this method is 14±1 minute, the precision is about 0.2% (n=10), the recovery of sulfate at different ionic strengths demonstrates a 0.1% decrease according to the salinity increase of 1 psu.
Samples from the hydrothermal vent of Kueishan Island were testified by this method. The preliminary results show that the sulfur of hydrothermal vent is mostly in the state of SO2 and H2S, therefore, the sulfate concentration and pH value are generally lower in the hydrothermal vent but higher in the surrounding area.
|
|---|
