- 期刊
奈米零價鐵微粒復育受鉻污染水體之研究
Decontamination of Cr-Species in Groundwater by Adsorptive Reduction onto Fe(0) Nanopowders
摘要
國內地下水體受鉻重金屬污染十分嚴重，易造成人體健康危害及生態環境之衝擊。本研究之主要目的是探討奈米零價鐵微粒吸附鉻離子污染物之效率與結構分析，並分析吸附反應前後鉻之微細結構。奈米零價鐵粉是由化學還原法製備，粒徑大小約30-50 nm。奈米零價鐵微粒對Cr之吸附去除效率非常高，平均可達99%以上；而且對高濃度鉻離子，仍具有相當高的吸附去除效率。FE-SEM顯示吸附鉻之奈米零價鐵微粒結構成不規則鬆散狀，可能部分奈米零價鐵微粒被氧化生成氧化鐵（Fe2O3）非結晶型粉末。XANES光譜也指出吸附鉻之奈米零價鐵微粒中鉻以Cr（III）為主，並參雜少量Cr（0）之成份；EXAFS 光譜更明確提出Cr（VI）還原成Cr2O3，同時Fe（0）氧化為Fe2O3。本研究也是一典型應用同步輻射光源及精細光譜研究奈米微粒吸附毒性金屬及其在表面之氧化還原反應之實例。由於奈米零價鐵微粒具有高吸附去除效率，因此，奈米零價鐵微粒相當適合應用於重金屬污染場址之活性反應穿透牆（reactive permeable barrier）現址復育技術。
並列摘要
Remediation of groundwater contaminated with Cr species by zero-valent iron nanoparticles has received considerable attention in recent years. Therefore, the main objectives of the present study were to investigate the destruction and removal efficiency (DRE) and the adsorption kinetics of Cr aqueous solutions on the nanophase zero-valance iron. Experimentally, nanoscale zero-valent iron particles of this study were prepared by borohydride reduction method at room temperature and ambient pressure. The DRE of Cr species on Fe(0) nanoparticles was ＞99% of average in the range of 1000-15000 ppm. The Cr-adsorbed Fe(0) nanoparticles measured by FE-SEM were abnormally incompact, it was possible that Fe(0) nanoparticles were, to some extent, oxidized in the adsorption process. The existence of Cr species on the Fe(0) nanoparticles was also confirmed by XANES. It was found that mainly Cr(III) with a small amount of Cr(0) was adsorbed onto the Fe(0) nanoparticles. EXAFS spectra showed Cr species all reduce to Cr2O3 while oxidizing the Fe(0) to Fe2O3. It is also very clear that decontamination of Cr species in groundwater via the in-situ remediation with nanophase Fe(0) permeable reactive barriers would be environmentally attractive in the future.