Experimental study on the treatment of Fe2+ and Mn2+ in mine waste water by biofortified medical stone

For the Acid mine drainage to deal with difficult，high processing costs and other issues.Maifan stone from three different producing areas，Liaoning (No.1 maifan stone)，Shandong (No.2 maifan stone) and Heilongjiang (No.3 maifan stone)，were used as raw materials to treat acid mine drainage (AMD) with Sulfate Reducing Bacteria (SRB). The single factor experiment was used to investigate the effect of medical stone from different areas on SRB activity and the effect of biological medical stone on AMD repair. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize biological maifan stone，and the removal mechanism of pollutants in AMD was elucidated. The results show that：① The single factor experiment of the effect of maifan stone from different producing areas on SRB activity found that the logarithmic growth period of SRB was prolonged by three kinds of maifan stone from different producing areas. The pH of the medium increased from 6.86 to 8.36，8.33 and 8.24，respectively，which were all higher than 0.698 in the control group. The effect of three kinds of maifan stone from different producing areas on SRB activity was：No.2 maifan stone > No.1 maifan stone > No.3 maifan stone. ② In the single factor experiment of biological medical stone treatment of AMD，No.2 maifan stone treatment effect of AMD is the best. After treatment，pH value increases to 7.43，Eh decreases to -192 mV，the maximum OD600 is 0.586，and the highest removal rates of SO2-4，Fe2+ and Mn2+ are 93.89%，94.45% and 80.44%，respectively. ③ All the three maifan stone are lamellar structure with gullies on the surface and internal pores. No.2 maifan stone has more pores and larger specific surface area than the other two kinds of maifan stone. SEM and XRD results show that SRB is loaded on the surface of maifan stone，and some of the original peaks such as kaolin peak in maifan stone are changed，and new FeS peak，MnS peak and Mn(OH)2 peak appear.