Used Filter Cartridges as Potential Adsorbents of Organic Pollutants

Abstract

The main objective of this study was to assess the usefulness of exhausted activated carbon-based filter cartridges for the removal of organic pollutants from aqueous solutions using the example of two model pollutants: synthetic dyes with different particle sizes, i.e., methylene blue (MB) and malachite green (MG). In order to determine the organic dyes’ adsorption mechanism, the effects of phase contact time, initial dye concentration, pH, and temperature of the system were investigated. Langmuir and Freundlich isotherm models were employed to analyze the experimental data. Additionally, all adsorbents were characterized in terms of the ash content, type of porous structure, presence of surface functional groups, pH value, and iodine adsorption number—which is one of the quality control parameters of activated carbons. Adsorption tests have shown that carbonaceous materials from bottle filters and filter jugs can be successfully used for the removal of organic dyes from the liquid phase. The maximum sorption capacity of this type of adsorbent towards methylene blue was 333.06 mg/g, while in the case of malachite green it was 308.75 mg/g. For all carbonaceous materials, a better fit to the experimental data was achieved with a Langmuir isotherm than a Freundlich one. It has also been shown that the efficiency of MB and MG adsorption from aqueous solutions decreases with increasing temperature of the system—the best results were obtained at 25 °C. A better fit of the kinetics data was achieved using the pseudo-second order model.