Removal of Reactive Red 120 dye from wastewater using electrocoagulation: optimization using multivariate approach, economic analysis, and sludge characterization

A multivariate approach, response surface methodology with Central Composite Design is employed to optimize the electrocoagulation process to eliminate color and COD from wastewater containing Reactive Red 120. The five input variables are optimized as pH?=?6.8, initial dye concentration?=?1299.8 mgL(?1), current density?=?13.45 mAcm(?2), process time?=?69.62?mins., and electrode gap?=?1.77 cm to maximize color and COD removal as 93.47% and 81.31%, respectively. Operating cost at optimum conditions is determined and found to be Rs 152.61 m(?3). Physicochemical characterizations of sludge and electrode are carried out using FTIR, FESEM, XRD, and SEM.