The existence of dissolved organic matter (DOM) in aquatic environments presents significant challenges to both the environment and public health. This study examines the adsorption efficacy of six organic adsorbents, such as three commercial (coconut shells CS, palm kernel shells PKS, and graphite GR) and three waste-based materials (plantain peels PP, water hyacinth leaves WHL, and corn cobs CC) for DOM removal. The waste-derived adsorbents were prepared using thermal and chemical activation techniques, while the commercial adsorbents were used in their standard forms. Adsorption experiments were conducted and analyzed using both kinetic and isotherm models to evaluate removal efficiency and underlying mechanisms. Kinetic modeling revealed that CS, PP, CC, and GR followed pseudo-second-order kinetics, PKS conformed to pseudo-first-order kinetics, and WHL exhibited intra-particle diffusion dominance. The Freundlich isotherm model effectively characterizes the adsorption equilibrium for every material, indicating the multilayer adsorption and heterogeneity of the adsorbent surfaces. Among all tested materials, GR showed the highest DOM removal efficiency (up to 96%) and excellent thermal stability, making it the most effective adsorbent overall. WHL also showed competitive performance, while CS emerged as the most economically viable option despite having slightly lower removal efficiency. Surface area alone does not guarantee adsorption efficiency. Pore accessibility (governed by size/distribution) and surface chemistry (functional group diversity) are equally critical. The findings suggest that both commercial and waste-derived adsorbents hold promise for sustainable and cost-effective water treatment applications. Integrating such materials could enhance the circular economy and offer scalable solutions for addressing water quality issues in developing regions.
Kusumadewi et al. (Sun,) studied this question.