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

Abstract

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.