Carbon Dioxide Absorption by Humic Substances: Mechanism and Optimal Parameters
Abstract
Humic acids, intricate organic polymers derived from sources such as coal, peat, and soil, possess a complex and uncertain structure characterized by acidic carboxylic and phenolic groups. This study delves into the absorption capacity of humic substances, specifically potassium humate, renowned for its extensive existence in nature. The focus of the experiment was the absorption of carbon dioxide (CO2) by potassium humate at temperatures of 10, 23, and 40 °C. Comparative calculations revealed consistent absorption rates of 33.87, 33.61, and 30.13 g CO2/kg over a four-day period. This stability in absorption capacity underscores the effectiveness of humic substances in capturing CO2. Titrimetric analysis was employed to determine the functional groups of potassium humate, with carboxylic and phenolic groups identified as the primary contributors to reactivity and activity. Barite and Ca-acetate methods were utilized to ascertain the total content of acid groups and carboxyl groups, respectively. The results, presented in tables and figures, provide valuable insights into the intricate molecular structure of humic substances and their potential applications in environmental remediation. The study enhances our understanding of CO2 sequestration mechanisms and highlights the significance of specific functional groups in humic substances for effective absorption processes.