Air Stabilized Nano Zero Valent Iron (NZVI) - Synthesis and Application for Waste Water Treatment
Nano Zero Valent Iron (NZVI) particles were synthesized using the sodium borohydride reduction method (B-NZVI) and the Ethylene Di-amine Tetra Acetate (EDTA) supported method (E-NZVI). The synthesized particles were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). B-NZVI particles were aggregated and formed chain like structures in comparison to E-NZVI particles which looked spherical. The synthesized B-NZVI and E-NZVI particles were used for the removal of Methyl Orange (MO), a model contaminant in wastewater. Comparison was made between B-NZVI and E-NZVI particles in terms of stability and efficiency in dye removal. Various parameters affecting the removal of MO were investigated such as – the effect of nitrogen purging, particle concentration, initial solution concentration, pH of the solution, aging of the particles etc. The minimum particle concentration required to completely (100%) remove MO from 100 ppm solution was 10 mg E-NZVI, where 100% degradation efficiency was achieved at natural pH of 5.82 and at the end of 180 min. Only 30% MO removal efficiency was achieved using B-NZVI under the same set of experimental conditions. The decreased MO degradation in case of B-NZVI could be related to the agglomeration of the particles, resulting in a significant loss in reactivity. E-NZVI particles on the other hand were air stable and resulted in better degradation efficiencies than B-NZVI. The findings of this present study are significant for the degradation of various organic contaminants in wastewater.
Keywords - Nano Zero Valent Iron, stabilizing agent of NZVI, purification of water