Use of Nanoclay as an Adsorbent to Remove Cu(ii) from Acid Mine Drainage (amd)

Abstract

In this research, the adsorption of copper ions from acid mine drainage (AMD) using nanoclay as an adsorbent, was studied. To obtain the nanoclay, a montmorillonite (MMT) was modified with hexadecyltrimethyl ammonium (HDTMA) bromide. It was characterized by XRD and BET by adsorption of N2 to 77K. The AMD was taken from an abandoned mine located in Jauja, Peru, which was analyzed by ICP-MS and gave a copper concentration of 38 mg/L. To determine the appropriate dosage, the nanoclay mass required for adsorption was determined, being 0.07 g/mL. The adsorption experiments were performed in batch system, at pH from 3 to 8 and contact times from 30 to 90 minutes, at room temperature, in aqueous solutions of 50 mg/L of Cu(II). The highest percentage of Cu(II) removal was given at pH 8 and 30 minutes of contact time, with 96% of removal. The mechanism of adsorption was studied at several initial concentrations of copper, using the models of Langmuir and Freundlich, finding that the one that best suited this process was the Langmuir isotherm. The adsorption capacity of the nanoclay, calculated by the Langmuir isotherm for Cu(II) was 7.53 mg/g. Finally, this procedure was applied to samples of AMD, obtaining a final concentration of 0.4 mg/L for Cu(II) after the treatment.