Electrochemical wastewater treatment with simultaneous hydrogen production in textile industry

Abstract

The textile industry is a major contributor to water consumption and greenhouse gas emissions, ranking 4th and 5th respectively in terms of impact in the EU. The process of major concern are the finishing operations, such as brightening, dyeing, printing and mercerizing, which require water at high temperatures. These processes result in effluents with high levels of alkalinity and conductivity, making their wastewater ideal for electrochemical treatment. The industry has used various strategies to treat these wastewaters, but has not considered using electrochemical processes in conjunction with hydrogen co-generation, which could help decarbonize the textile finishing industry. The study evaluates the use of mercerizing and dyeing effluents as electrolytes for hydrogen production, coupled with color removal in the latter. The hydrogen flow rate depends solely on the effluent conductivity, with no detected effect from the present contaminants. Both effluents achieve hydrogen generation efficiencies of over 70%. The electrochemical treatment of dyeing effluent achieves 97-99% color removal and generates hydrogen equivalent to 19,5% of the electric energy consumed during treatment.