微藻矿化去除Pb^(2+)的研究

Study on the Removal of Pb(2+) by Biomineralization Media via Microalgae

藻类作为水体中的初级生产力,通过生物积累、生物矿化等生理功能与环境中的重金属相互作用、对重金属地球生物化学循环起到关键作用。为了探讨藻类生物矿化去除水体中重金属的现象,文中研究了淡水微藻FZUL-321对Pb^(2+)的去除及矿化。结果表明:微藻FZUL-321对Pb^(2+)有较强的去除能力,且是一个快速去除的过程。随着Pb2+浓度增大,该微藻对Pb^(2+)的去除效果也增大。在弱酸性条件下(p H5.0),其去除Pb^(2+)的效果较好。如在Pb^(2+)初始浓度为100 mg/L,p H 5.0,去除时间为40 min,此时Pb^(2+)的去除量为423.2×10^(-3)干重。原子力显微镜(AFM)对细胞表面的形貌进行观察,发现微藻FZUL-321与Pb(2+)作用后,细胞形貌和尺寸变化较大,如细胞褶皱并塌陷,细胞表面变得粗糙等。傅里叶红外光谱(FT-IR)结果表明藻细胞表面的羧基、氨基和磷酸基团等官能团参与前期Pb2+的吸附沉淀。最终,通过一系列生化作用,微藻FZUL-321将离子态的Pb^(2+)矿化,X射线衍射(XRD)分析显示,矿化产物为Pb_5(PO_4)_3OH。

As the contributor to the primary productivity, alga plays an important role in biogeochemical cycles throughbioaccumulation and biomineralization of heavy metals. In this paper, we studied the removal and mineralization of Pb^(2+) using themicroalgae. The results show that the microalgae had a strong removal capacity for Pb^(2+) and it was a fast process. With the increasingconcentration of Pb^(2+), the removal of Pb^(2+) also increases. In the condition of weak acid(p H = 5.0), the removal of Pb^(2+)was better. Theremoval amount was 423.2×10^(-3) with the initial Pb^(2+)concentration of 100 mg/L, p H 5.0, and the contact time of 40 min. Atomic ForceMicroscope(AFM) results showed that the shape and size of the cell had been changed after the interaction with Pb^(2+) and the cellsurface became rough. Fourier Transform Infrared(FT-IR) revealed that cell surface functional groups, such as carboxyl, amido, andphosphonates, were involved in the removal of Pb^(2+). X-ray diffraction(XRD) pattern shows that, under the effect of microalgae, lead ionswere mineralized as Pb_5(PO_4)_3OH.