Activated Carbon for Gas Purification: Alternative to Improve Air Quality in Cities

Carbón Activado para la Purificación de Gases: Alternativa para Mejorar la Calidad del Aire en las Ciudades

Abstract

Activated carbon is a versatile material due to its porosity and molecular adsorption capacity, characteristics that vary according to the activation method used; In the present investigation, active carbon was synthesized by impregnating coconut shells and orange peels with phosphoric acid (H3PO4) at 23.54% m/m, at a carbonization temperature of 450°C and 650°C, resulting in a material capable of adsorb carbon dioxide (CO2), a product of the afterburning of a car. In the first phase, a physicochemical analysis of the adsorbent was carried out; it was exposed to gaseous CO2 to determine its possible adsorption, through the displacement of a column of water; Furthermore, using the Langmuir isotherm, a specific surface area of 796 m2/g was found. The second stage was designed a system that integrated both alkaline solutions and active carbon to quantify the adsorption of CO2, coming from the post-combustion of the selected automobile; This system was evaluated in three different run times for a constant acceleration in which the quantities of CO2 emitted by the car and that adsorbed by the activated carbon were determined. Finally, the active carbon, saturated with CO2, was subjected to constant stirring in distilled water at a temperature between -5 and 5°C, in order to promote the solubility of said gas in the solution; This and the measurement of pH, allowed the quantification of the gas through the titration with sodium hydroxide of carbonic acid, a product of the chemical reaction between CO2 and water. Likewise, the percentage of CO2 removal in the gas streams studied was estimated, being approximately 90% in most cases.