RAPID DEGRADATION OF AZO DYES USING NANO-SCALE ZERO VALENT IRON

Abstract

In the present study, nano-scale Zero Valent Iron (NZVI) was synthesized in ethanol medium by the method of ferric iron reduction using sodium borohydride as a reducing agent under atmospheric conditions. The obtained iron nanoparticles are mainly in zero valent oxidation state and remain without significant oxidation for hours. A systematic characterization of NZVI was performed using XRD, SEM and TEM studies. The obtained iron nanoparticles consist of a zero valent core surrounding a rest oxide shell. The diameter of iron nanoparticles was predominantly within the range 20-110 nm. Refractory azo-dye compounds used in the textile industry are commonly detected in many industrial waste water. In this study the removal efficiency of three azo dyes, namely, methyl orange, sunset yellow and acid blue a, with laboratory synthesized NZVI particles in relation to the NZVI dosage, dye concentration and pH was determined. Increasing the dose of NZVI particles enhanced the decolonization of the dyes. The degradation decreased with increasing solution pH and concentration of dyes. These findings demonstrated the fast removal of azo dye compounds with NZVI and the advantage of the synthesized NZVI particles to treat azo dye contaminated wastewater.