Investigation of effective parameters on synthesis of Goethite with solution oxidation method in the laboratory scale

Research subject: 

The pure Goethite nanoparticles were synthesized successfully with solution oxidation method and by using raw materials Iron (II) sulfate heptahydrate (FeSO4.7H2O) and sodium hydroxide (NaOH).

Research approach: 

In this study, the simulation of experiment was implemented by Minitab software, with complete factorial method, at 40°C, the variation of two parameters including the flow rate of entered gas in the solution reaction (Q) and mass percent ratio of raw materials (R) (mass percent of iron (II) sulphate to mass percent of sodium hydroxide), in two levels (Q=2 and 13.3 Lit/min) and (R=1 and 3) were evaluated. The qualitative analysis of results was performed by X-ray diffraction (XRD), synthesis of Goethite phase (α-FeOOH) confirmed Iron oxyhydroxide and the Energy-dispersive X-ray spectroscopy (EDX), illustrated that the synthesized Goethite has high purity percentage (≥99.8%). The field emission scanning electron microscopy (FESEM) for Goethite reported a bar-shaped crystal structure, with an average particle Cluster size between (23-43nm), based on R and Q and by analyzing the oxidation-reduction potential(ORP) results, it was seen that the reaction time of Goethite formation is between 635-2210s.

The statistical analysis of results with Minitab software can create Correlation relations for Goethite, between two parameters(Q and R) and two response (reaction time(t) and average particle Cluster size(d)) at the temperature of reaction solution 40°C. regarding the relations, it was seen that at the temperature of reaction solution 40°C, with an increase in air flow rate(Q) and decrease of the mass percent ratio of raw materials(R), the reaction time and average particles Cluster size of Goethite decrease generally and vice versatile. Also, the percentage change (R) has a higher impact on average particles Cluster size and reaction time than changes (Q).