Removal of Copper from Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD)

Agabu Shane,Sydney Chinyanta,Xinyang Xu,Brian Chirambo,John Siame,Jackson Kawala,Musango Lungu,Victor Mwango Bowa,Alick Nguvulu,Tewodros Mitiku Tena

doi:10.4236/jwarp.2021.137026

Abstract

Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.

Highlights

Acid mine drainage (AMD) is mine wastewater usually at low pH that has elevated levels of heavy metals and sulphides
This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l
This study has demonstrated that acid mine drainage and other forms of wastewater can well be treated using ion exchange resins optimum conditions, in terms of pH, flow rate and coper ion concentration

Summary

Introduction

Acid mine drainage (AMD) is mine wastewater usually at low pH that has elevated levels of heavy metals and sulphides. Drainage acidity arises from oxidation of pyrite, the crystalline form of iron sulphide and copper pyrite. The contaminated water is often reddish-brown in color, indicating high levels of oxidized iron. As a result, pyrite weathers and reacts with oxygen and water in the environment [1] [2]. Mine drainage is formed when pyrite, an iron sulfide, is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy metals such as copper, lead, mercury, lead, zinc, etc. The acid runoff further dissolves heavy metals such as copper, lead, mercury, lead, zinc, etc. into ground or surface water [3] [4]

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