Unveiling the dye adsorption capability of Moringa oleifera functionalized hybrid porous MOF–GO composites: in vitro and in silico ecotoxicity assessment via antibacterial and molecular docking studies†

Abstract

The present study demonstrated the synthesis of sustainable and eco-friendly composites composed of Fe & Al metal–organic frameworks (Fe-MOF and Al-MOF) and their graphene oxide composites (AlGC and FeGC). Post-synthetic surface functionalization of developed composites was done with Moringa oleifera leaves powder extract. The synthesized MOFs and composites were characterized using standard techniques. The ability of synthesized MOFs and composites to remove methyl orange (MO) and methylene blue (MB) dyes from wastewater was evaluated. Based on the higher dye removal ability, detailed dye adsorption studies were performed with functionalized composites (AlGC and FeGC). Taguchi optimization design was utilized to optimize the four testing factors, viz. contact time, initial dye concentration, composite dosage, and temperature, along with five levels for each factor to achieve the highest capacity for dye adsorption. The composites exhibited outstanding equilibrium adsorption capacities for MO (AlGC: 577 ± 37 and FeGC: 631 ± 42 mg g⁻¹) and MB (AlGC: 336 ± 13 and FeGC: 387 ± 7 mg g⁻¹) dyes, which are found to be the highest among the reported composites so far. Applying isotherms, kinetics, and thermodynamic models confirmed the spontaneous, endothermic reactions for the physisorption of both dyes. The regeneration studies showed more than ∼65% dye removal efficiency of both the composites up to three adsorption–desorption cycles, which confirms their reusability at the industrial scale. The environmental toxicity of developed composites was analyzed by antibacterial studies against selected ecologically important soil bacteria as well as by molecular docking studies against protein targets of selected microorganisms.