磁性四氧化三铁海藻酸钠复合物吸附剂去除水溶液中的Cr(Ⅵ)

The Removal of Cr(Ⅵ) from Aqueous Solution by Magnetic Ferroferric Oxide@ Sodium Alginate Composite Adsorbent

制备了磁性Fe3O4@海藻酸钠(Fe3O4@SA)复合物吸附剂,并对其进行了FTIR、XRD表征。将该吸附剂用于去除水溶液中的Cr(Ⅵ)离子,考察了溶液pH、吸附剂用量、吸附时间对吸附过程的影响。结果表明,Fe3O4@SA吸附Cr(Ⅵ)很大程度上依赖于溶液的pH。在溶液pH值为2,初始浓度为50 mg/L,吸附时间为120 min达到吸附平衡,Cr(Ⅵ)的去除率达到98.0%。吸附等温线拟合结果表明,Langmuir等温吸附方程更适合描述Fe3O4@SA对Cr(Ⅵ)的吸附行为,最大吸附量可达到147.06 mg/g。伪一阶和伪二阶动力学模型研究表明,该吸附过程更符合伪二阶动力学模型。

The magnetic ferriferrous oxide@ sodium alginate( Fe3O4@ SA) composite was prepared and characterized by Fourier transform infrared( FTIR) spectroscopy and X-ray diffraction( XRD). The Fe3O4@ SA composite was used as an adsorbent for the removal of Cr( Ⅵ) from aqueous solution. The effects of solution pH value,adsorbent dosage and contact time on the adsorption of Cr( Ⅵ) from aqueous solution were investigated. The experiments reveal that the adsorption of Cr( Ⅵ) onto the Fe3O4@ SA composite is highly pH dependent. The adsorption equilibrium is reached at about 120 min and the removal percent of Cr( Ⅵ) attains to 98. 0% at solution pH value of 2,initial Cr( Ⅵ) concentration of 50 mg/L,and adsorbent dosage of 0. 08 g. The linear regression analysis from Langmuir and Freundlich model shows that the Langmuir isotherm equation is better at describing the adsorption process of Cr( Ⅵ) onto the Fe3O4@ SA composite,and the maximum adsorption capacity is 147. 06 mg/g. By pseudo-first order and pseudo-second order kinetic model study,it is found that the adsorption process fits well with the pseudosecond order kinetics model.