Sustainable fabrication of a novel ZIF-67 modified with Atriplex halimus-mediated MoO3/GO-NH2 for expeditious removal of nitrophenol

Abstract

Herein, a novel, green, and sustainable MoO3/ZIF-67/AmGO composite has been fabricated for the removal of notorious o-nitrophenols (o-NPs) from wastewater. Atriplex halimus L. (saltbush) served a dual function where the plant extract was used for the synthesis of molybdenum trioxide (MoO3) NPs, while the spent biomass-derived biochar was utilized as feedstock to produce green graphene oxide (GO). Ultimately, the MoO3/ZIF-67/AmGO composite was in situ fabricated by mixing MoO3 and AmGO with ZIF-67 during its preparation by the self-templating approach. Remarkably, the adsorption of o-NP onto MoO3/ZIF-67/AmGO attained equilibrium in just less than 10 min. The kinetics and isotherms analyses verified that the o-NP adsorption onto MoO3/ZIF-67/AmGO adhered to the Pseudo-2nd-order and Freundlich models, with a consistent qmax value of 500 mg/g. A conceivable adsorption mechanism was investigated in detail. Moreover, the ionic strength test implied the impact of the salting-out phenomenon in boosting o-NP adsorption. The eco-friendly MoO3/ZIF-67/AmGO proves to be a sustainable adsorbent, displaying excellent recyclability in consistently removing o-NP across multiple cycles.