Improvement of textile dye removal by electrocoagulation with low-cost steel wool cathode reactor

The removal of azo Acid Black 1, anthraquinone Reactive Blue 4, and xanthene Eosin Yellow using electrocoagulation with different types of cathodes was investigated. When a dye of 100 mg L−1, electric current of 0.3 A, and iron plate anode were used, dye removals using a steel wool cathode (591 cm2) were 1.8–4.4 times faster than those using an iron plate (28 cm2) or stainless steel plate cathode (28 cm2). Even though the total iron concentrations in the solutions for these two cathodes were close, the ferric concentration in the solution using a steel wool cathode was greater than that using a stainless steel cathode. An increase in electric current and mixing speed enhanced the dye removal using a steel wool cathode cell. Results of the Vibrio fischeri light inhibition test indicate that the decolorized solutions contained low toxicity of byproducts (23–35% light inhibition). When the steel wool cathode was washed with water for 30 s, the efficiency of the steel wool cathode reactor did not decrease during the first seven times of reuse.

► The low-cost steel wool cathode reactor effectively removed dyes.
► The Fe3+ was predominant in the solution of the steel wool cathode reactor.
► Its voltage and energy consumption were low.
► The toxicity of decolorized solutions was low.
► Its efficiencies did not obviously decrease during the seven cycles of reuse.