Synthesis of magnetically recyclable g-C3N4/Fe3O4/ZIF-8 nanocomposites for excellent adsorption of malachite green

Abstract We synthesized magnetically recyclable g-C3N4/Fe3O4/ZIF-8 nanocomposites as an emerging adsorbent for the malachite green (MG) removal in aqueous solution. Bath absorption experiments for MG were done to explore the influence (pH, adsorbent dosage and initial concentration) on its absorption process. The adsorption isotherm and kinetics followed Langmuir model and pseudo-second-order kinetic model, respectively. The thermodynamic datas (ΔG○ 0, ΔS○ > 0) showed that the adsorption process for MG was feasible, endothermic and spontaneous. The g-C3N4/Fe3O4/ZIF-8 nanocomposites showed excellent removal properties for MG. The maximum equilibrium adsorption capacity could reach as high as 3412 mg/g. The g-C3N4/Fe3O4/ZIF-8 nanocomposites could be easily separated using an external magnet, and the nanocomposites could be repeatedly utilized after five cycles. The ultra-high adsorption capacity, easy separation, and excellent recyclability enabled the obtained g-C3N4/Fe3O4/ZIF-8 nanocomposites a good adsorbent for the adsorption of MG.