Green Rust I (Cl-) (GRI(Cl-)) was prepared from ferrous and ferric chloride solution. The effect of phosphate on GRI(C l-) and final products was studied by adding Na2HPO 4 to GRI(Cl-) suspensions prior to oxidation according to Fe/P molar ratio of 10.5, 55 and 137, and water blank without containing any phosphate. Analysis of supernatant solution of intermediate and final product by inductively couple plasma spectrometer (ICP) showed complete adsorption and retention of phosphate in GRI(Cl-) and final product respectively. The X-ray diffraction (XRD) patterns of intermediate and final products revealed that phosphate stabilizes GRI(Cl-) and the effect is more pronounced for highest phosphate concentration (Fe/P of 10.5). The substantial broad XRD peaks of lepidocrocite in the case of Fe/P molar ratio of 10.5 indicated the effect of phosphate in reducing crystallite size. The dramatically reduction in particle size was noticed from the TEM observation with the addition of phosphate species. The presence of phosphate species in rust may be beneficial in terms of improved corrosion resistance for stabilization of GRI(C l-) and smaller particle size of final products.
- Green rust i(C)
- Marine environment