Synthesis of Green Iron Nanoparticles using Laterite and their application as a Fenton-like catalyst for the degradation of herbicide Ametryn in water

- Laterite based iron nanoparticles were synthesized using eucalyptus leaf extracts.
- Synthesized iron nanoparticles were applied as a heterogeneous Fenton's catalyst.
- Response surface methodology was proposed for the design of experiments.
- Reaction kinetics indicate that the oxidative degradation of ametryn is very fast.

The Fe nanoparticles were synthesized using eucalyptus leaf extracts. The low cost and locally available laterite was used as a source of iron rather than using iron salts (Ferrous sulfate, Ferric chloride etc.). The raw laterite particles (RLPs) and synthesized green iron nanoparticles (LGFeNPs) were characterized using FESEM-EDX, XRD, FTIR and BET techniques. The obtained results confirm that 20-70 nm of spherical iron particles were formed with surface area of 36.62m2∕g. Later, the LGFeNPs were applied as a Fenton-like catalyst for the degradation ametryn in aqueous medium. The effect of variables (H2O2∕COD (1-3.25), H2O2∕Fe (2-10), pH (2-5) and reaction time (30-240)) involved in the treatment process was studied on two responses (COD and ametryn removal efficiency) using the response surface methodology. The optimum values were found to be 2.125, 6, 3.5 and 135 min for H2O2∕COD, H2O2∕Fe, pH and reaction time respectively with H2O2 dosage of 17 mg/L and 2.83 mg/L of LGFeNPs. The analysis of variance (ANOVA) results proved that, the obtained results were satisfactory with predicted values. Compared with chemical (NaBH4 reduction) and green synthesis using iron salts as a precursor, the laterite based green synthesis proved to be more effective in degradation of ametryn with faster reaction kinetics.

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