Modified bentonite as adsorbent material for the removal of the basic dye methylene blue from aqueous solutions

Methylene blue is an organic pollutant found in industrial effluents that is very toxic to humans and the environment. This study used 8-hydroxyquinoline-modified bentonite adsorbent to remove methylene blue from aqueous solutions. In the present work, different doses of modified bentonite were used as a new adsorbent for the removal of methylene blue. The effects of contact time, pH, adsorbent dose, and initial methylene blue concentration were recorded. Then, the adsorption data were described with Langmuir and Freundlich adsorption isotherms. The highest percentage of methylene blue adsorption was observed at pH = 7.5. The optimum amount of adsorbent was 0.1 g.L-1 and after 120 minutes, the process reached an equilibrium state. The adsorption of methylene blue increased following an increase in the pH of the solution. It was also observed that the contact time significantly affected the rate of methylene blue adsorption. The experimental data fit much better in the Freundlich (R2 = 0.999) model than the Langmuir (R2 = 0.992) model. So, 8-hydroxyquinoline-modified bentonite has the potential to be utilized for the cost-effective removal of methylene blue from aqueous solutions.