Use of Activated Carbon from the Seed of Persea Americana (var Hass) in the Removal of Mercury (Hg2+) from Wastewater

Abstract

This work aimed to study the removal of mercury from industrial wastewater, using activated carbon from Hass avocado seed. The seed was carbonized to obtain activated carbon. Orthophosphoric acid at 21% w/v was used as an activating agent. The Hg²⁺ concentration was determined by atomic absorption spectroscopy. The chemical surface of the material was performed by Fourier transform infrared spectroscopy. The carbons were morphologically characterized using a scanning electron microscope. The conditions of the experiments were 50 mL of industrial wastewater at room temperature, pH 6.0, initial concentration of mercury 0.036 mgL^-1 and 0.2 gL^-1 of adsorbent material. The average removal efficiency of activated carbon (CA) for Hg²⁺ was 84% and an equilibrium concentration of 0.006 mgL^-1 after 60 minutes. Two kinetic models and one diffusion model were applied. The model that best describes the adsorption process was the Elovich model with an R² of 0.9897. Results show that the seed of Persea americana is useful for obtaining carbon and becomes a good alternative to use in industrial wastewater treatments for the removal of Hg²⁺, turbidity, color, and total solids.