Removal of small-ring polycyclic aromatic hydrocarbons using cow and goat milk iron oxide nanoparticles

This work reports an environmentally friendly method for removing small-ring polycyclic aromatic hydrocarbons (PAHs) using iron oxide nanoparticles (IONPs) synthesized from pasteurized cow and goat milk and iron salts. IONPs were prepared at room temperature using FeSO4 (2.0 g in 500 mL) and 10.0 mL of milk at pH 12. Results show that IONPs were formed with low crystallinity. The presence of Fe was confirmed through energy-dispersive X-ray spectroscopy results. Transmission electron microscopy and X-ray diffraction data show smaller semi-spherical nanometer-size particles in an aggregated state. The PAH removal process was monitored using a fluorescence spectrometer, and the results showed that the type of iron salt used (Fe2+/Fe3+) in the preparation of IONPs had no significant effect on the removal of model PAHs. However, the ring structure of the PAHs plays a role in the time taken for the removal process. All PAHs were removed from water efficiently with naphthalene, anthracene, and fluorene removal efficiencies of 75%, >90%, and 70%, respectively. The current study shows that IONPs formed using milk have the potential to be used to remove PAHs from water.本研究报道了一种环保型方法，用于去除小环多环芳烃（polycyclic aromatic hydrocarbons, PAHs），所使用的氧化铁纳米颗粒（iron oxide nanoparticles, IONPs）由巴氏杀菌牛乳、山羊乳与铁盐合成。本研究在室温条件下，以2.0 g硫酸亚铁（FeSO4）溶于500 mL溶剂中，搭配10.0 mL乳源原料，在pH=12的环境中制备得到IONPs。结果表明，所制备的IONPs结晶度较低。通过能量色散X射线光谱（energy-dispersive X-ray spectroscopy）分析结果证实了铁元素的存在。透射电子显微镜（Transmission electron microscopy, TEM）与X射线衍射（X-ray diffraction, XRD）数据显示，产物为聚集态的半球形纳米级颗粒，粒径尺寸较小。采用荧光光谱仪（fluorescence spectrometer）对PAHs去除过程进行监测，结果显示，制备IONPs时所用铁盐的种类（Fe2+/Fe3+）对模型PAHs的去除效果无显著影响。但PAHs的环结构会对去除过程的耗时产生影响。所有PAHs均可被高效从水体中去除：萘、蒽及芴的去除率分别为75%、>90%及70%。本研究表明，以乳源制备的IONPs具备用于去除水体中PAHs的应用潜力。