Removal of inorganic compounds from acidic solutions by sorption

Abstract

Manufacturing processes, primarily mining activities, often result in the production of effluents containing high amounts of inorganic pollutants e.g. heavy metals or sulphates. This category includes also low value pH waters with high content of heavy metals, known as acid mine drainage (AMD). Low value of pH of these waters is a result of hydrogen cations release into aqueous environment during the process of pyrite oxidation. Together with heaps and ponds belongs to the negative effects of mining activities in the form of environmental burdens. According to Directive 2000/60/EC of the European Parliament it is necessary to ensure adequate water quality and protection of all water sources. In Slovak Republic, as the country with long mining traditions, now exist a few localities with existing AMD generation conditions (either in form of direct outflow from mine or leachate from tailing ponds). Finding of the new and cheap options for treatment of these waters can increase the quality of the environment in these localities and thus prevent adverse effects on fauna, flora or human beings. A cost effective methods also include sorption techniques. Their main positives are high efficiency, low cost and high degree of modifiability and regenerability of the used sorbents. This paper is focused on the utilization of natural sorbent for heavy metals removal from model sulphuric acid solutions (pH approx. 4). The adsorption properties of non-modified peat has been studied in order to determine its applicability for copper and zinc removal in treatment process of acid mine drainage (AMD). For purpose of the determination of the removal efficiencies of metals the experiments were performed under batch conditions using single and dual-component solutions under acidic conditions. The objectives of this work were to evaluate the effects of different parameters such as initial ion concentration, pH change or amount of the used sorbent on the sorption efficiency as an input data for further research of acid mine drainage treatment.