Degradation of Malachite Green using Green Synthesized Iron Nanoparticles by <em>Coffea arabica</em> Leaf Extracts and its Antibacterial Activity

Abstract

The synthesis of biocompatible nanomaterials using bio-renewable plant extract has emerged as a promising alternative to traditional methods in recent years due to its cost-effectiveness, eco-friendliness, non-toxicity, and biocompatibility. In this research paper, we demonstrate using Coffea arabica leaf extract to synthesize zero-valent iron nanoparticles (GC-FeNPs). This study suggests that this method is efficient and environmentally friendly, making it a promising approach for developing biocompatible nanomaterials. The synthesized GC-FeNPs were characterized using Fourier-Transform Infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), and UV–Vis spectroscopy techniques. According to the analysis of data, polyphenolic/caffeine compounds in the coffee leaf extract act as reducing/capping agents by converting the Fe2+ to Fe0, and minimizing the aggregation. The FT-IR and XRD data confirm the encapsulation of the GC-FeNPs by the polyphenolic/caffeine compounds in the coffee leaf extract. The GC-FeNPs have a quasi-spherical shape morphology with a particle size of about 80 – 100 nm. Further, dye degrading ability, and the antibacterial activity of the GC-FeNPs were investigated using malachite green (MG) and gram-negative and gram-positive pathogens. Experimental data revealed that GC-FeNPs (~ 20 ± 1 mg) showed degradation activity against MG up to 55 % upon the 120-minute incubation. Furthermore, the kinetic analysis of GC-FeNPs on MG degradation was in accordance with the pseudo-second-order kinetic model (R2 = 0.9922). In addition, GC-FeNPs showed an antibacterial activity against gram-negative (E. coli, and S. enterica), and gram-positive (S. aureus) pathogens. The E. coli growth was highly inhibited by the GC-FeNPs compared to other strains. Overall, GC-FeNPs facilitate an alternative approach to degrade MG from textile effluents and industrial wastewater and treat the pathogen-contaminated water.