Effects of Different Nitrogen Sources on the Formation of Biogenic Jarosite

Abstract

The effects of nitrogen sources on the biosynthesis of jarosite were investigated by analyzing the changes in pH, Fe2+, total Fe (TFe), and jarosite production in a 9K culture medium containing different nitrogen sources. Three nitrogen sources, namely (NH4)2SO4, carbamide (CO(NH2)2), and NH4NO3, were used in this study. The solution’s pH and Fe2+ concentrations were set to 2.5 and 160 mmol/L, respectively. The results demonstrated that the three different nitrogen sources could be used by Acidithiobacillus ferrooxidans (A. ferrooxidans) LX5, but the degree of utilization differed. The addition of (NH4)2SO4 facilitated the growth of A. ferrooxidans LX5 compared with the other two nitrogen sources, while the bacterial activity in the CO(NH2)2 set was minimum. The pH of the solution had an inverse correlation with bacterial activity. The mineralization rate using (NH4)2SO4 as the nitrogen source was 42.48%, which was slightly higher than the rates obtained with CO(NH2)2 and NH4NO3 (31.67% and 35.35%, respectively). The resulting minerals showed a different appearance and chemical composition. However, the XRD spectra showed similar chemical structure. The jarosites were identified as a mixture of jarosite, ammonioiarosite, and carphosiderite.