Highly efficient removal of metallic ions by using a linde type-A zeolite obtained from a hazardous waste

Coal acid mine drainage (AMD) contaminates natural water to form mine-impacted water (MIW), which is characterized by high levels of acidity, sulfate, and metallic ions. This study investigates the use of a Linde Type-A (LTA) zeolite obtained from a hazardous industrial waste for Al3+, Fe2+, and Mn2+ removal from synthetic aqueous solutions. The aim of this study is to stablish a basis for the subsequent treatment of MIW in order to obtain reuse water. In a central composite rotatable design (CCRD) study, 8.25 g L¿1 zeolite and 147 rpm were the optimal conditions for treating the multicomponent solution, yielding 99.9, 99.9 and 99.3% removal for Al3+, Fe2+, and Mn2+, respectively. Isothermal studies showed that the affinity of the ions by the zeolite were ranked as Al3+>Mn2+>Fe2+. The best fitting isothermal models for monocomponent solutions were Tóth, Freundlich, and Sips for Al3+, Fe2+, and Mn2+, respectively. In the multicomponent solution, Sips and Freundlich were the better fitting models for Al3+ and Mn2+, respectively, indicating a weakness of the sorbate-sorbent interactions. Kinetic studies revealed that the quantitative removal of Al3+ was achieved in 5 min. The multicomponent solution was transformed into water that was suitable for non-potable use after an optimal time of 60 min. The results demonstrate that LTA zeolite synthetized from hazardous waste has a high potential for remediating contaminated water by metallic ions at low dosages and short times. Using LTA zeolite for remediating contaminated water could make a positive contribution to the circular economy and environmental sustainability.

This research was financed by the Brazilian National Council of Scientific and Technologic Development (CNPq), Coordination for the Improvement of the Higher-Level Personnel (CAPES)-finance code 001, and Spanish Ministry of Economy and Competitiveness (Project CTM2012-34449).