Neutralizing Acid Rain With Foamed Cement Plate Made From Oyster Shell

• Main Authors: Hsien-Yun Hu, 胡嫻筠
• Other Authors: Ing-Jia Chiou
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/58951537079644947813

碩士 === 南亞技術學院 === 材料應用科技研究所 === 99 === In recent ten years, the incidence of acid rain in Taiwan is high up to 76.49%. The rainwater acidification problem is serious. The annual production of oyster shell waste is up to one hundred and sixty thousand metric tons which derives problems of odor and the lack of landfill site. Therefore, this study develops the foamed oyster shell cement plates through calcining the wasted oyster shells, hydration, foaming behavior at room temperature, and acid-alkali neutralization mechanism to improve the oyster shell recycling and rainwater reuse. The weight ratio of cement and oyster shells and the amount of the foaming agent are used as material design variables to study the water quality changes of artificial rainwater and recycled rainwater through the assessment of static and dynamic water flow. In addition, the optimal proportion and the applicable strategy will be suggested. The results show that non-calcined oyster shells contain weak alkaline calcium carbonate (CaCO3). After calcined under 650 ~ 1050 º C, the calcined oyster shell (OS) contains rich alkaline calcium oxide (CaO) and calcium hydroxide (Ca(OH)2). The pH value of oyster shells is positively correlated with the calcining temperature. In the recycled rainwater static conditioning experiment, if the volume ratio of rainwater to foamed oyster shell cement plates can be higher than 500, it is achievable to neutralize rainwater in 2 to 3 hours by using the foamed oyster shell cement plates of OS135, OS155, OS138, OS158. If the conditioning time is allowed to be more than 5 hours, it is suggested to adopt the volume ratio higher than 2000. In the recycled rainwater dynamic conditioning experiment, when the volume ratio is 1000 and the flow rate is 80mL/min, the plate of OS155 is the most efficient (48.65%) in neutralization and that of OS138 is the least efficient (27.63%). After 8 days (192 hours) of dynamic conditioning, the amount of released chloride of plate OS135 is higher than that of OS138. The weight loss rate of foamed oyster shell cement plates in order is OS158> OS138> OS155> OS135. The weight loss rate and the volume ratio are negatively correlated.