Study of hexamine removal by activated carbon modified with magnetic iron oxide nanoparticles for application in treatment of hexamine industrial wastewater

The industrial wastewater produced by hexamine plants is considered as a major environmental polluting factor, and hence its treatment is required. The adsorption of hexamine from aqueous solutions onto activated carbon modified with magnetic iron oxide nanoparticles (AC-MIONs) was studied in a batch process. Langmuir, Freundlich, and Toth isotherm models were used to fit the experimental data and then isotherm parameters were determined. The effects of activated carbon and AC-MIONs amounts, solution pH, contact time, temperature, and electrolyte concentration on the adsorption capacity were studied. The results indicate that AC-MIONs were a more efficient adsorbent for hexamine than activated carbon and have potential for the adsorption of hexamine from industrial hexamine wastewater. Pseudo-first order rate equation was able to provide realistic description of adsorption kinetics. The rate of adsorption process on AC-MIONs is higher than that on AC. Desorption of hexamine from AC-MIONs is easier than AC. Therefore, the AC-MIONs can be a good reusable and economical sorbent.