Magnetic nanocellulose-based adsorbent for highly selective removal of malachite green from mixed dye solution

Herein, a novel magnetic adsorbent (BC/AA/MN@Fe₃O₄) was successfully prepared from waste bamboo fiber tissue and montmorillonite, and subsequently applied for the highly selective removal of malachite green (MG, removal efficiency = 97.3 %) from the mixed dye solution of MG with methyl orange (MO, removal efficiency = 4.5 %). The magnetic adsorbent has a high porosity with abundant mesopores. In the single dye MG solution, the adsorbent could effectively remove MG over a wide pH range from 4 to 10, and the maximum adsorption capacity (q_max) was 2282.3 mg/g. Moreover, the magnetic adsorbent could remove MG from various solutions including mixed dye solution, high salinity solution, and real river water dye solution. The thermodynamic results proved that the adsorption process of MG was spontaneous and endothermic. The adsorption of MG was due to the comprehensive effects of electrostatic attraction, hydrogen bonding interactions and ions exchange, between the adsorbent and MG. Furthermore, the BC/AA/MN@Fe₃O₄ exhibited an excellent reusability with adsorption efficiency above 53.4 % after five consecutive cycles. Therefore, the prepared magnetic nanocellulose-based adsorbent was expected to be a promising material for highly selective adsorption and separation of MG from mixed dye solution.