Utilization of Langsat Fruit Peel Waste to Adsorb Metal Contents from Acid Mine Drainage

Abstract

The feasibility of using agricultural wastes, specifically the langsat fruit peel (Lansium domesticum cortex) as a low-cost sorbent (activated carbon) to remove Cu and Mn from acid mine drainage was investigated to determine the adsorption of the isothermal model in this study. Activated carbon could be made from the langsat fruit peel with 20% H3PO4 and 20% NH4OH chemical activation. Before being activated, the langsat fruit peel was charred at 300°C for 2 hours to produce carbon. The SEM-EDX results showed that a high carbon value of 78.62% was obtained from the activation process carried out with H3PO4. The pore formation was also larger and cleaner in carbon activated with H3PO4 than NH4OH. A BET surface area of 1.4456 m2/g was obtained for the activated carbon produced from the langsat peel waste. In addition, a BJH adsorption cumulative volume of 0.000701cm³/g was recorded for pores. The BJH adsorption average pore diameter (4V/A) for the activated carbon was 31.31399 nm, indicating a mesoporous scale size. The best activated carbon in terms of metals adsorption in acid mine drainage was in a mass of 4 grams, with each percent removal of 91.42% for Mn metal and 15.74% for Cu metal. The Langmuir and Freundlich isotherm adsorption equations were used in the adsorption process. Based on the data obtained, the isotherm curve corresponded more to the Langmuir model, indicating absorption occurred in a monolayer, with a linear regression coefficient, which was relatively closer to 1.