Green synthesis of iron nanoparticles for malachite green removal

Green synthesis of iron nanoparticles (Fe NPs) using plant extract is a suitable alternative for chemically syn-thesised Fe NPs due to their low cost, high stability, high reactivity, and environmental compatibility. The objective of the present study is to synthesise Fe NPs from ethanolic seed coat extracts of Strychnos nux vomica (SN) and Abrus precatorius (AP) and to investigate the removal efficiency for malachite green dye (MG). The synthesised AP-Fe NPs exist in crystalline and amorphous forms with particle sizes ranging between 3 and 32 nm, whereas SN-Fe NPs are amorphous with particle sizes ranging between 2.1 and 5 nm. The removal efficiency of prepared Fe NPs for MG shows that the AP-Fe NPs were more effective than SN-Fe NPs. The malachite green removal efficiency increases with increasing nanoparticle dosage and contact time. Acidic pH and low initial concentration of the dye solution were the other favourable conditions for malachite green removal. [4-(dime-thylamino)phenyl]-phenylmethanone, benzoic acid and diphenylmethanone are the malachite green degradation products identified after treating with AP-Fe nanoparticles.