Characterization of Philippine Natural Zeolite and its Application for Heavy Metal Removal from Acid Mine Drainage (AMD)

Abstract

In this study, the adsorption efficiency of Philippine natural zeolite for treating acid mine drainage is investigated. The metal ions considered were Cu2+, Ni2+, and Pb2+ ions. The natural zeolite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDX). The XRD result revealed that the natural zeolite is mainly composed of heulandite (Ca,Na)2-3Al3(Al,Si)2Si13O36 • 12H2O. Plate-like structures having rough surface and micro-pores were observed. The natural zeolite exhibited adsorption efficiencies of 99.03%, 35.88% and 35.36% for Pb2+, Cu2+, and Ni2+ ions, respectively, which are higher than those of alumina adsorbent for the same ions. Based on these results, the Philippine natural zeolite has a great potential for removing cationic heavy metal species from acid mine drainage (AMD).