Adsorption of Methylene Blue from Aqueous Media Using Carbon-Alginate Granules

In this study, the adsorption of methylene blue (MB) from an aqueous solution on copper-alginate (Cu(II)-A) granules containing activated carbon derived from polyethylene terephthalate (PEtAC) with different experimental conditions was investigated. The composition and structure of the granules were characterized by SEM and BET methods. The effect of various variables including dye concentration, pH, adsorbent amount, and contact time was investigated by batch method. Equilibrium data were evaluated using Langmuir, Freundlich, and Temkin isotherms. The adsorption isotherm fits well with the Langmuir model (0.9973), which shows that the MB dye adsorption on the granules is homogeneous. The maximum adsorption capacity under optimal conditions for the removal of MB was 86.96 mg/g. Kinetic data were analyzed using the first-order and second-order Lagergren equations. The quasi-second-order model showed the best fit for the synthetic studies (R2 = 0.9997). In addition, no obvious decrease was observed after up to five adsorption cycles, indicating that the PETAC/Cu (II) -A adsorbent has good stability and reusability. Overall, the results show that the prepared granules can be used an am efficient adsorbent for the treatment of colored effluents.