Desorption of Mercury Complex from Fe-Modified Montmorillonite Adsorbent Membrane

Abstract

With the use of nanotechnology, clay minerals, specifically montmorillonites, have been reengineered to be used in environmental remediation, especially in the treatment of mining wastewater containing hazardous heavy metal ions. The objective of this study is to assess the practicality of using iron-modified montmorillonite (Fe-MMT) nanomembranes in the removal of mercury using the adsorption process. The nanomembranes, which were synthesized via electrospinning, were subjected to mercury cyanide solutions during the batch adsorption set ups to determine the adsorption efficiency. During the subsequent elution tests, three factors– eluent type (CH3COOH and C6H807), eluent concentration (0.01 M and 0.05 M) and contact time (3 and 5 hours) – were tested. SEM images of the mats were acquired to study the structure of the adsorbent. HD XRF analysis was done to identify the ions present in the membrane, as well as the initial Hg concentrations, amount of remaining Hg in the wastewater after batch adsorption and amount of desorbed metal. Results showed that using the Fe-MMT nanomembrane as adsorbent material resulted to 61.74% removal of Hg in the mercury cyanide solutions with initial concentrations of 13.87 to 38.9 mg L-1. Acetic acid exhibited better desorption results, with the highest efficiency of 31.36% (0.01 M, 5 h) compared to citric acid’s 7.40% (0.05M, 3 h).