Optimal activated carbon production from corn pericarp: A life cycle assessment approach

Abstract

In this research, the production of activated carbon (AC) from an agroindustrial waste (corn pericarp) by chemical activation with potassium hydroxide was optimized by using a central composite design. The multiobjective optimization involved maximizing the yield and methyl orange (MO) adsorption capacity of AC while simultaneously minimizing the single score —as an indicator of environmental impact obtained according to the ReCiPe 2008 method, using a life cycle assessment (LCA) approach—. The results show that after the multiobjective optimization, the maximal yield and MO adsorption capacity and the lowest single score were obtained at an activation temperature of 627 °C, an activation time of 93 min, and without activating agent. At these conditions, the predicted values for MO adsorption capacity, yield, and single score were 124.92 mg/g, 40.9%, and 0.06 Pt/kg of AC, respectively; while the respective experimental responses, were 141.13 mg/g, 50%, and 0.06 Pt/kg of AC. Furthermore, characterization of adsorbent obtained at the optimal conditions shows a rough surface and a pH value in the point of zero charge of 11.18, indicative of its potential use to remove negatively charged species from water. This research demonstrates that multiobjective optimization techniques combined with LCA is a useful approach for the cleaner production of an effective adsorbent.