Electrochemical decolorization of acid dye baths and their reuse potential in subsequent textile dyeing processes

Abstract This study investigates the electrochemical decolorization of waste acid dye baths and evaluates their potential reuse in subsequent textile dyeing processes. Four different anode materials (iron, aluminum, stainless steel and graphite) were examined to optimize color removal efficiency and assess the influence of electrochemically generated by‐products on dyeing performance. Under optimized operating conditions, aluminum anodes achieved over 90% color removal without generating harmful chlorinated species. However, fabrics dyed in these treated baths exhibited noticeable color differences (ΔE >1), attributed to aluminum's mordanting effect, which enhanced dye uptake particularly for blue dyes. Conversely, iron anodes led to residual metal contamination, while steel and graphite promoted hypochlorite formation, causing dye degradation in subsequent acid dyeing cycles. To mitigate these limitations, iron‐treated baths were alkalized with Na ₂ CO ₃ and successfully reused in reactive dyeing. Additionally, a membrane‐separated electrochemical system effectively eliminated iron and hypochlorite, enabling the reuse of treated baths in vat dyeing applications. These findings highlight that electrochemical treatment not only facilitates substantial color removal but also supports sustainable water and chemical resource management in textile manufacturing.