Electrocoagulation in textile wastewater treatment: Amaranth azo dye removal

Releasing dye-contaminated textile wastewater into water bodies without proper treatment has adverse effects on the environment and poses serious health risks to living beings. Amaranth is one of the widely used textile red azo dyes in Sri Lanka, and it is discharged improperly because traditional water treatment methods often fall short of effectively removing the dyes due their diverse and persistent nature. Electrocoagulation (EC) provides a promising alternative. Although EC has been widely investigated, no studies has examined the application of carbon-based materials as electrodes. This study aimed to evaluate the application of a carbon felt cathode combined with an aluminium anode for removing the Amaranth azo dye from synthetic textile wastewater. The effect of initial pH, applied potential, stirring speed, and electrolysis time on EC performance were studied to identify the optimal condition, and the results revealed 100% efficiency to remove 20 mg/L dye solution in 30 minutes of electrolysis at 6.4 V, pH 2, and 1000 rpm without any additional electrolytes. The study confirmed successful application of carbon felt as a cathode material and highlights that pH is a crucial factor in generating the types of coagulant species, and the system is self-pH neutralizing with treatment time.