赤泥-黄土协同净化含Cd(Ⅱ)酸性矿井废水

为改善固体废弃物赤泥(red mud, RM)对含Cd(Ⅱ)酸性矿井废水(acid mine drainage, AMD)的净化能力，采用RM和天然黄土(loess, L)协同处理含Cd(Ⅱ)-AMD。通过批试验探究了RM和L的质量比、初始pH、接触时间、投加量和颗粒粒径对RM和L混合材料(RM-L)处理AMD效果的影响。结果表明：L显著改善了RM-L对酸性溶液的pH缓冲能力，降低碳酸盐结合态Cd(Ⅱ)的占比。RM-L协同处理含Cd(Ⅱ)-AMD的最优质量比为7∶3。增加最优质量比下RM-L(RM-L₇₃)的投加量和减小RM-L₇₃的颗粒粒径均能够提高Cd(Ⅱ)的去除效率。对于初始浓度为100 mg/L和初始pH=3的AMD,8 g/L的RM-L₇₃对Cd(Ⅱ)的去除率可达99.2%,并能够将AMD的pH提高至8.0。通过扫描电镜(scanning electron microscope,SEM)和X射线衍射(X-ray diffraction,XRD)发现RM和L混合后的RM-L₇₃颗粒具有良好的...

Synergistic Purification of Acid Mine Drainage Containing Cd(II) by Red Mud and Loess

To enhance the purification capacity of solid waste red mud (RM) for acid mine drainage (AMD) containing Cd(II), RM and loess (L) were used for synergistic treatment Cd(II)-AMD in this study. The effects of RM and L mass ratio, initial pH value, contact time, dosage, and particle size on the treatment of AMD by RM and L mixture(RM-L) were investigated through batch experiments. The results indicate that L significantly improves the buffering capacity of the RM-L to AMD and reduces the proportion of carbonate speciation of Cd(II). The optimum mass ratio of RM and L for co-treatment of Cd(II)-AMD is 7:3. The increase in dosage and decrease in particle size of RM-L under optimum mass ratio(RM-L73) benefit the removal efficiency of Cd(II). The RM-L73 at 8 g/L can be removed 99.2% of Cd(II) and increased the pH value of AMD to 8.0 when the initial concentration of AMD is 100 mg/L and the initial pH is 3. It is found that particles of RM-L73 has great dispersibility after mixing RM and L, calcite and aluminosilicate minerals in RM-L73 play a significant role in neutralization and Cd(II) removal by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis.