焙烧对赤泥比表面积及孔隙结构影响的研究

采用焙烧方法对赤泥进行改性,通过氮吸附、扫描电镜(SEM)、红外光谱(IR)和X射线衍射(XRD)技术分析焙烧条件对赤泥微观结构的影响,例如焙烧温度和时间,并通过铜离子吸附实验对改性赤泥(R-RM)的吸附性能做出评价.结果表明,R-RM的比表面积和平均孔容积随焙烧温度升高和时间的延长都是先增大后减小,在387 ℃/2 h条件下分别达到最大值15.7303 m2/g和0.007946 cm3/g.焙烧能够使赤泥中的碳酸盐化合物分解,提高颗粒孔隙率;使结合水蒸发,从而疏通内部孔道,降低水膜对吸附质的传质阻力.在室温下,R-RM对20 mg/L铜离子的最大吸附容量为1.89 mg/g,去除率达94.5%.

Effect of Roasting on the Specific Surface Area and Pore Structure of Red Mud

The red mud was modified by roasting.The effect of roasting conditions on the micro-structure of red mud was analyzed by N2 adsorption, scanning electron microscopy (SEM), infrared spectrum (IR) and X-ray diffraction (XRD) technologies, such as roasting temperature and time.And the copper ion adsorption property of the modified red mud (R-RM) was also investigated.The results show that, the specific surface area (BET) and average pore volume (Pv) of R-RM firstly increase with the rising of roasting temperature and prolonging of time, then decrease.And under the optimal conditions of 387 ℃ and 2 h, they reach up to 15.7303 m2/g and 0.007946 cm3/g, respectively.The porosity is improved by decomposing the carbonate compounds, and the channels of particles are cleared by evaporating the combined water, thus lowing the mass transfer resistance of water-film upon adsorbate.Under room temperature, the maximum adsorption capacity of R-RM to 20 mg/L copper ion aqueous solution is 1.89 mg/g, and the removal is 94.5%.