Decolorizing Methyl Orange by Fe-Electrocoagulation Process – A Mechanistic Insight

The aim of this work is to study the removal of methyl orange (MO) using electrocoagulation (EC) process. An electrochemical cell consisting of two iron electrodes, with 22.5 cm2 as an active surface, is used. Operating conditions are optimized such as nature and concentration of the supporting electrolyte, current density, pH, inter-electrode distance, MO concentration, and the connection mode. The decolorization degree obtained after 15 min of EC reached 83% at pH 7.25 with a current density of 64 A/m2. Depending on pH, three EC process mechanisms are suggested and less or more significant removal performances are obtained in these tests. The Scanning Electron Microscopy (SEM) observations show that the flocs formed by the EC process have two distinct morphologies: a lumpy structure and an amorphous structure, formed by particles of various sizes. The Energy Disperses X-ray (EDX) analysis of the surface of the flocs formed by the EC process shows a spectrum with levels of major elements of iron, oxygen and chloride, as well as carbon, sodium and aluminum are detected as minor elements. As proved in terms of MO elimination through this research and due to its several advantageous, EC process would find its convenient place in wastewater treatment technology