Characterization and utilization of coconut coir and bentonite-based adsorbents for removal of lead metal ion from hazardous liquid waste

Abstract

Adsorbent is one of the most commonly used materials because of its high adsorption effectiveness. However, adsorption with one type of adsorbent causes a lower adsorption efficiency. This study aims to determine the characterization of adsorbents from coconut coir and bentonite-based adsorbents and the combined adsorbent from coconut coir charcoal and bentonite and to examine the adsorption capacity of lead metal ion on these adsorbents. The types of adsorbents used in this study were coconut coir charcoal without activation, coconut coir charcoal with activation, pure bentonite, bentonite with activation, and combination of activated coconut coir charcoal: activated bentonite with mass ratio of 70:30. The research was initiated with pyrolysis of coconut coir at temperature of 400°C, then activated chemically with 0.3 M HCl solution. The resulting adsorbents were characterized using Scanning Electron Microscopy (SEM) to determine the morphological structure, Fourier Transform Infra-Red Spectrophotometer (FTIR) to determine the functional groups, X-Ray Diffraction (XRD) to determine the crystalline structure. Then the adsorption of lead metal ions was carried out by using these adsorbents. The results showed that the best adsorption efficiency is by adsorbent combination of activated coconut coir charcoal: activated bentonite with mass ratio of 70:30. The adsorption efficiency of lead metal ions using activated coir adsorbents: activated bentonite (70:30) is 35.0%. The activated coconut coir charcoal: activated bentonite with mass ratio of 70:30 has the largest adsorption capacity of lead metal ions which is 182.71 mg/gr.