This study investigates sorption of Cu and Zn using mixed mineral systems to treat natural mine wastewater obtained from disused mine workings at Parys Mountain and Cwmrheidol in Wales, United Kingdom. Mixed mineral systems of kaolinite/montmorillonite, kaolinite/goethite and montmorillonite/goethite were tested with the mine waste water for sorption of Cu and Zn at variable pH. In addition, levels of saturation of hydroxyl complexes were analyzed. Batch reactions conducted at room temperature (23±2oC) revealed significant behavioral differences in Cu and Zn sorption by mixed mineral systems compared to each other and compared to single mineral systems. All mixed mineral systems sorbed more Cu than Zn when tested with Parys Mountain mine wastewater. On the other hand, all mixed mineral systems sorbed more Zn than Cu when tested with Cwmrheidol mine wastewater. This study conducted using single mineral suspensions and 1:1 mixed mineral suspensions indicated progressive increase in saturation indices with increase in pH. There was no evidence of stable hydroxylation of Cu and Zn species that could significantly contribute to the sorption of these metals by mixed mineral systems.
