Decolourization of Reactive Dye from Aqueous Solution using Electrocoagulation: Kinetics and Isothermal Study

Abstract

Abstract Reactive dyes are essential materials for the modern lifestyle due to rapid industrialization and urbanization, but they cause adverse effects on the environment. This research work aimed to decolourize the synthetic aqueous solution containing Reactive Black B (RBB) dye using electrocoagulation (EC) process with iron electrodes in batch reactor. The effect of operational parameters such as initial pH (3–9), the distance between electrodes (0.5–2 cm), current density (1.1–8.4 mA/cm2) and initial dye concentration (100–400 mg/L), was investigated in the presence of sodium chloride to maintain the conductivity of electrolytes. Under optimal value of process parameters, high decolourization (99.6%) was obtained at 25 min. The experimental data showed that pseudo-second order kinetics with a correlation coefficient (R 2 = 0.97) and Sips isotherm with a correlation coefficient (R 2 = 0.98) were found to be well fitted for kinetic and adsorption equilibrium models, respectively. The economic efficiency was also calculated on the basis of electrical energy consumption (EEC), specific electrical energy consumption (SEEC), and current efficiency, respectively. Moreover, characterization of EC generated sludge was also carried out by proximate analysis, IR spectra and XRD analysis. The results revealed that EC process using Fe electrode is quite efficient and clean process for decolourization of reactive dye from aqueous solution.