黏质沙雷氏菌对稀土废水中Dy(Ⅲ)的生物吸附性能及吸附机理分析

Biosorption characteristics and mechanism of Dy(Ⅲ)in rare earth wastewater by Serratia marcescens

以从稀土矿区分离筛选的黏质沙雷氏菌为生物吸附剂,吸附回收低浓度稀土废水中Dy(Ⅲ),借助Zeta电位、场扫描电子显微镜(SEM)、X射线能谱仪(EDS)、傅立叶红外光谱(FTIR)和X射线光电子能谱(XPS)等手段对吸附机制进行分析。结果表明,黏质沙雷氏菌对Dy(Ⅲ)具有较好的吸附性能,当Dy(Ⅲ)溶液pH为5.00、吸附时间为120 min、Dy(Ⅲ)初始质量浓度为30 mg/L、黏质沙雷氏菌用量为0.4 g/L时,Dy(Ⅲ)的吸附量和去除率可分别达到95.81 mg/g和95.86%。黏质沙雷氏菌对Dy(Ⅲ)的吸附过程遵循Langmuir吸附等温线和准二级吸附动力学模型,属于单层化学吸附。黏质沙雷氏菌对Dy(Ⅲ)的吸附机制有静电吸引作用、离子交换作用以及与—NH_(2)和—COOH等含N、O活性官能基团的配位作用。研究结果有助于筛选、开发新型生物吸附试剂,促进生物吸附法在稀土元素回收中的应用。

Serratia marcescens isolated from rare earth mining area was used as biosorbent to adsorb the Dy(Ⅲ)in rare earth wastewater.Zeta potential,scanning electron microscope(SEM),energy dispersive spectrometer(EDS),Fourie transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)were used to analyze and explore the adsorption mechanism.The results showed that Serratia marcescens had exellent adsorption performance for Dy(Ⅲ).Under the optimum conditions of solution pH of 5.00,adsorption time of 120 min,initial Dy(Ⅲ)mass concentration of 30 mg/L and adsorbent dosage of 0.4 g/L,the adsorption capacity and removal rate of Serratia marcescens for Dy(Ⅲ)could reach 95.81 mg/g and 95.86%respectively.The adsorption process of Dy(Ⅲ)by Serratia marcescens follows Langmuir adsorption isotherm and quasi second-order adsorption kinetic model,indicating that the adsorption process was a monolayer chemical adsorption.The adsorption mechanism of Serratia marcescens for Dy(Ⅲ)was mainly manifested in electrostatic attraction,ion exchange and coordination with O and N containing functional groups such as—NH_(2) and—COOH.The results of this study were helpful to screen and develop new biosorbents and promote the application of biosorption in the recovery of rare earth elements.