Evolution of solid contents in vinasse waste during electrocoagulation process at various current densities: Experimental and kinetic analyses

Abstract

Vinasse waste contained high solid contents. The goal of this study was to examine the effect of current densities (3.93, 4.72, 5.50 A/dm2) on the evolution of solid contents during electrocoagulation (EC) through experimental and kinetic analyses. Therefore, a new mechanistic model was proposed in this study. The results showed that the profiles of total solids (TS) mass had an interesting correlation with the liquid pH, in which at pH of 4.4–6, the TS mass increased and at pH of 6–7.3, the TS mass decreased during the EC process. The increase in TS mass at the beginning of the process was caused by the accumulation of iron hydroxy complexes and iron hydroxides. Besides the TS and liquid pH, this study also measured the total dissolved solids (TDS), total suspended solids (TSS), colour (absorbance value), scum, sludge, liquid temperature, liquid volume, dissolved Fe, and electrical voltage. All measured data were successfully predicted using the proposed mechanistic model with high accuracy (R2 = 0.9900–0.9985). By modelling, 14 important kinetic constant values were found.