聚乳酸包覆零价铁钝化剂的制备及性能研究

Preparation and Performance of Passivant Polylactic Acid-Coated Zero Valent Iron

以可降解聚乳酸(PLA)为稳定剂,采用二次反相微乳法包覆零价铁(ZVI)制备PLA包覆ZVI钝化剂(PLAZVI),通过粒度分析、微观形貌分析、Fe元素分布分析、红外光谱分析、X-射线光电子能谱分析对钝化剂进行表征,结果显示:ZVI在PLA基质中分散良好,PLA包覆增大了ZVI颗粒间距,提升了ZVI钝化剂的稳定性;PLA-ZVI为表面光滑、界面清晰的微球结构,粒径范围为0.1~2.0μm,可在有氧环境中保持稳定。同时,从垃圾填埋场土壤中筛选得到一株PLA降解菌株1601#,鉴定其为节杆菌属菌株,该菌株可增强PLA-ZVI的重金属钝化能力,在Cr(Ⅵ)污染土壤中,加入菌株1601#的Cr(Ⅵ)清除率较未加的提高了7.82%。

Using biodegradable polylactic acid（PLA）as a stabilizer,we prepared a passivant,namely,PLAcoated zero valent iron（PLA-ZVI）by a secondary reverse microemulsion method.We characterized the passivant by the analyses of grain size,micromorphology,Fe element distribution,Fourier transform infrared spectrum,and X-ray photoelectron spectroscopy.The results showed that ZVI particles were homogeneously distributed in PLA matrix,PLA coating increased the distance of ZVI particles and improved the stability.PLA-ZVI particles had smooth surface and clear interface microsphere structure with the particle size of 0.1-2.0μm.Meanwhile,they had good stability in aerobic environment.We screened a PLA-degrading strain from soil of landfill site,which was identified as Arthrobacter sp.and named 1601~#.The strain 1601~#could enhance the passivation capability with heavy metal of PLA-ZVI.In Cr（Ⅵ）contaminated soil passivation test,the Cr（Ⅵ）removal rate of PLA-ZVI in the presence of strain 1601~#was 7.82% more than that in the absence of strain 1601~#.