Process optimization for green synthesis of iron nanoparticles by extract of fenugreek (Trigonella foenum-graecum L.) seeds

Background: The green synthesis of nanoparticles using plants presents important advantages over other biological systems. Natural compounds present in plant extracts can reduce metal ions to nanoparticles in a single-step green synthesis process. Seeds of fenugreek with various compounds and antioxidant activity are suitable for green synthesis. Objective: In this study, the performance of fenugreek seeds extract was evaluated for iron nanoparticles production. Methods: The fenugreek (Trigonella foenum-graecum L.) seeds were extracted with a distilled water solution at environmental temperature and this aqueous extract was used for the iron nanoparticles synthesis. Response surface methodology was applied to optimize nanoparticle production by considering three independent variables: the extract to metal ion ratio (1.5-6.5), incubation time (30-90 min), and temperature (35-65 °C). Results: Mixing the fenugreek seeds extract and iron salt solution with a volume ratio of 1.5 at 36.5 °C for 90 min led to the optimization of iron nanoparticle production with the narrowest size distribution. At the optimized condition, the nanoparticle size was in the range of 20-40 nm. Conclusion: Iron nanoparticles were successfully synthesized with fenugreek seed extract. Physical parameters such as time, temperature, and mixing volume ratio of the extract to metal ions can control the average size of the synthesized green iron nanoparticles.