【摘要】 采用共沉淀法制备了具有壳-核结构的磁性吸附剂Fe3O4/MnO2,对其性质进行了系统表征,并对其铅吸附行为进行了初步研究.透射电镜(TEM)结果表明,Fe3O4/MnO2为大小不规则的纳米级细小颗粒.X-射线衍射仪(XRD)表征结果表明,Fe3O4/MnO2具有尖晶石的结构.振动样品磁强计(VSM)测得比饱和磁化强度为54.7 A·m2·kg-1,吸附剂磁性较强,易于磁分离;BET比表面积为76.5 m2·g-1.吸附试验结果表明,Fe3O4/MnO2对铅具有良好的去除效果(特别是在低平衡浓度情况下),最大吸附量为142.0 mg·g-1(pH=5.0);Langmuir等温线能更好地拟合Fe3O4/MnO2对溶液中铅的吸附(R2=0.852);吸附速率较快,在初始30 min内可达到平衡吸附量的80%,准二级动力学模型(R2=0.959)能较好地描述吸附过程;溶液pH对Fe3O4/MnO2吸附铅的影响较为明显,随pH升高,吸附量增大,但离子强度变化对吸附影响不大.更多还原

【Abstract】 An adsorbent with Fe 3 O 4 as magnetic core and MnO 2 as shell was prepared by co-precipitation process.The adsorbent was characterized using multiple techniques and its performance for Pb(II) removal from aqueous solution was investigated.The TEM image indicated that the shape of nanosized Fe 3 O 4 / MnO 2 particles was irregular.X-ray powder diffraction(XRD) analysis showed that the magnetic phase in Fe 3 O 4 / MnO 2 was spinel magnetite.The adsorbent has a highly specific saturation magnetization of 54.7 A·m2·kg-1and a specific surface area of 76.5 m2·g-1.The results of batch sorption experiments suggested that the Fe 3 O 4 / MnO 2 magnetic adsorbent was effective for Pb(II) removal from water,particularly at low equilibrium concentration.The isotherm data was well fitted by Langmuir model(R2= 0.852) with a maximal Pb adsorption capacity of 142.0 mg·g-1at pH 5.0.The adsorption of Pb(II) was very fast and over 80% of the equilibrium sorption capacity was achieved within 30 min.The pseudo-second order model(R2= 0.959) was more suitable to describe adsorption kinetic data.The Pb(II) adsorption increased with increasing values of solution pH and was not significantly affected by the change of ionic strength.更多还原