比較微米級和奈米級零價鐵對水中五氯酚之去氯處理

Dechlorination of Pentachlorophenol by Nanoscale and Microscale Zero-Valent Iron

本研究係以批次試驗探討商用微米級之Fe^0粉（100及325 mesh）及自製奈米級（Fe^0、Fe^0／Ni^0）粉末對水中五氯酚（PCP）之去氯還原處理之效果及動力研究。結果顯示，奈米級之Fe^0／Ni^0粉末對PCP之去氯還原效果明顯比奈米級Fe^0粉和兩種商用微米級Fe0粉好很多，PCP減少速率也加快。去氯反應也可由動力試驗結果看出其依序去氯之反應途徑：PCP→TeCP→TCP→DCP。吸附在商用微米級之Fe^0粉表面上之PCP比在水溶液中容易被去氯還原且其被去氯還原之效率也較高，但也需相當長時間（120 hrs）反應後。商用微米級之Fe0粉與PCP溶液反應時，在液相中氯酚類化合物大約佔總氯酚類化合物的70%；固相中氯酚類化合物大約都佔總氯酚類化合物的30%。若是自製奈米級Fe^0，氯酚類化合物在液相大約佔總氯酚類化合物88%；固相中氯酚類化合物大約佔總氯酚類化合物的12%。此外，若是自製奈米級（Fe^0／Ni^0）則於整個試程中只有極微量氯酚類化合物吸附在金屬粉末上。

The aim of this study is to explore both effect and kinetics of dechlorination of pentachlorophenol （PCP） by commercial microscale iron powder （100 and 325 mesh） and nanoscale iron （Fe^0 and bimetallic Fe^0／Ni^0）. Nanoscale bimetallic Fe^0／Ni^0 had more significant effect on the dechlorination of PCP than other irons and the decrease of PCP. The reaction pathway of PCP dechlorination could be revealed as follows: PCP→TeCP→TCP→DCP. Smaller part of PCP was adsorbed on the surface of commercial microscale iron powder （100 and 325 mesh）, but could be dechlorinated easier than the larger part of PCP in the bulk solution. About 70% of total chlorophenols existed in liquid phase after the reactions of commercial microscale iron powder （100 and 325 mesh） with PCP whereas about 30% of total chlorophenols in solid phase. About 88% of total chlorophenols existed in liquid phase after the reactions of nanoscale iron with PCP whereas about 12% of total chlorophenols in solid phase. However, there were trace chlorophenols found in solid phase after the reactions of nanoscale bimetallic Fe^0／Ni^0