Degradation of methylene blue with iron recovered from acid mine drainage by applying the homogenous fenton like process

Abstract

In this investigation the degradation of a methylene blue sample was evaluated using the principle of the homogeneous Fenton Like process where iron as a catalyst was recovered from a synthetic sample of acid mine drainage by selective precipitation. Globally, acid mine drainage is considered an important residue of extractive mining and its uncontrolled dumping has negative effects on the ecosystem. Recovering a waste and using it as input to treat another is a relevant opportunity. Selective precipitation of iron was performed using a saturated solution of calcium hydroxide. The precipitated iron (III) hydroxide was solubilized with sulfuric acid to obtain iron (III) sulfate and then was used as a catalyst in the tests of degradation of methylene blue having as variables the amount of iron (III) sulfate, hydrogen peroxide, pH and time. All tests determined a degradation percentage above 95%, which demonstrated the recovery of iron from the acid mine drainage. The analysis of the results shows us in an initial model that the pH in the experiment was not a significant variable. The adjusted linear model excluding pH showed that hydrogen peroxide is the main variable that has a significant effect on the degradation of methylene blue followed by iron sulfate recovered from acid mine drainage.