| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系碩士班 === 91 === Industries which produce a lot of wastes are more and more interested in problems dealing with the environment. Among the waste sludges coming from industrial activity, toxicants such as heavy metals are often present insignificant concentration. Today under the pressure of a severe legislation, it is well known that industries must find a treatment for their wastes before putting them either in a landfill or in rivers for waste waters.
Recycling of heavy metals by inorganic acids and complexing agents has severe drawbacks. Organic acids could be an attractive leaching agent because the leaching behavior can be performed at mildly acidic conditions and they are biological degradable. This study would focus on the recycling heavy metals Cu and Zn from printed circuit board industry process sludge by using organic acids. On the other hand, heavy metals Cu and Zn in the leachate gained from the acid leaching process would be separated by using D2EHPA immobilized Amberlite XAD-4 resin.
The results of the experiments in the study were that Cu and Zn both showed the better dissolution efficiency in organic acids than in inorganic acids, and citric acid showed the best recycling result. When the reacting conditions were set on the proper condition, including the reacting temperature were raised to 65℃ and liquid to solid ratio (L/S) were about 15, Cu and Zn could be recycled about 95% and 98%, respectively. Particle size of sludge showed the relative low effect on the acid leaching process. Further more, Cu and Zn in the leachate could be separated effectively by using D2EHPA immobilized Amberlite XAD-4 resin, and citrate showed no effect under the leaching process.
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