Removal of methylene blue by using recoverable zeolite/Fe3O4 in a continuous stirred tank reactor (CSTR)

Magnetite (Fe₃O₄) particles deposited with zeolite, which was made from sodium hydroxide (NaOH), sodium aluminate (NaAlO₂) and sodium trisilicate (Na₂O₇Si₃) using the hydrothermal process, were used in the adsorption of methylene blue (MB). A continuous stirred tank reactor (CSTR) system was used for the adsorption of MB using zeolite/Fe₃O₄. This study encircled the continuous reactor with a magnet to prevent the adsorbent from flowing to the output, thus producing clean water devoid of Fe₃O₄ particles. The performance of the adsorbent was assessed based on the effects of adsorbent mass, flow rate, pH and concentration. The adsorbent was able to remove approximately 90% of the 20 mg L⁻¹ methylene blue from a 500 mL solution in 2 h, with a maximum adsorption capacity of 30.8528 mg g⁻¹. This adsorption process also exhibited high removal efficiency even after 5 regeneration cycles and 55 h of operation, confirming the successful production of zeolite/Fe₃O₄ as an effective MB adsorbent.