生物铁锰氧化物的制备及其对Mn(Ⅱ)吸附特征研究

Preparation of Biological Fe-Mn Oxides and Its Adsorption Characteristics for Mn (Ⅱ)

利用驯化获得的铁锰氧化混合细菌制备生物铁锰氧化物(BFMO),采用比表面积测定仪(BET)、扫描电镜(SEM-EDS)和傅里叶红外变换光谱(FT-IR)对所生成的BFMO进行表征,通过考察投加量和pH值对Mn(Ⅱ)吸附性能的影响,探究了BFMO对Mn(Ⅱ)的吸附机理。结果表明:BFMO具有较大的比表面积(79.22 m^2/g),孔体积为0.15 cm^3/g,表面含有许多含氧官能团,有利于Mn(Ⅱ)的吸附。SEM-EDS进一步表明生物铁锰氧化物中既含有铁锰氧化物,也有微生物菌体生成的细胞类物质。BFMO对Mn(Ⅱ)的去除效果较好,在pH值为7.0、投加量为2 g/L、固液比为1 g∶500 mL时,吸附量为16.43 mg/g,吸附过程符合准二级动力学模型和Freundlich吸附等温模型,说明吸附过程主要由化学反应控制,属于多层吸附。

Biological iron and manganese oxide (BFMO) was generated by Leptothrix discophora.The BFMO was characterized by specific surface area analyzer (BET),scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR).The effects of dosage and pH value on the adsorption performance of Mn (Ⅱ) were investigated,and the adsorption mechanism of BFMO for Mn (Ⅱ) was explored.The results show that BFMO has a large specific surface area (79.22m^2/g),a pore volume of 0.15 cm^3/g,and many oxygen-containing functional groups on the surface,which is conducive to the adsorption of Mn (Ⅱ).SEM-EDS further show that there are not only iron and manganese oxides in biological iron and manganese oxides,but also cellular substances produced by microbial bacteria.The removal effect of BFMO on Mn (Ⅱ) is better.When pH value was 7.0,dosage was 2 g/L,solid-liquid ratio was 1 g:500 mL,the adsorption capacity was 16.43 mg/g,the adsorption process was in accordance with the pseudo second-order kinetic model and Freundlich adsorption isotherm model,indicating that the adsorption process was mainly controlled by chemical reaction and belonged to multilayer adsorption.