Bio-Remediation of Acid Mine Drainage in the Sarcheshmeh Porphyry Copper Mine by Fungi: Batch and Fixed Bed Process

Abstract

Acid mine drainage (AMD) containing high concentrations of iron and sulphate, low pH and variable<br />concentrations of heavy metals leads to many environmental problems. The concentrations of Cu and Mn<br />are high in the AMD of the Sarcheshmeh porphyry copper mine, Kerman province, south of Iran. In this<br />study, the bio-remediation of Cu and Mn ions from acid mine drainage was investigated using two native<br />fungi called Aspergillus niger and Phanerochaete chrysosporium which were extracted from the soil and<br />sediment samples of the Shour River at the Sarcheshmeh mine. The live fungi was first harvested and<br />then killed by boiling in 0.5 N NaOH solution. The biomass was finally dried at 60 C <br />for 24 h and<br />powdered. The optimum biosorption parameters including pH, temperature, the amount of biosorbent and<br />contact time were determined in a batch system. The optimum pH varied between 5 and 6. It was found<br />that the biosorption process increased with an increase in temperature and the amount of biosorbent.<br />Biosorption data were attempted by Langmuir and Freundlich isotherm models and showed a good match.<br />Kinetic studies were also carried out in the present study. The results show that the second-order kinetics<br />model fits well the experimental data. The biosorption experiments were further investigated with a<br />continuous system to compare the biosorption capacities of two systems. The results show that<br />biosorption process using a continuous system increases efficiency up to 99%. A desorption process was<br />eventually performed in order to recover Copper and Manganese ions. This process was successful and<br />fungi could be used again.