Minimizing freshwater consumption in the wash-offstep in textile reactive dyeing by catalytic ozonation with carbon aerogel hosted bimetallic catalyst

Abstract

In textile reactive dyeing, dyed fabrics have to be rinsed in the wash-offstep several times to improve colorfastness. Thus, the multiple rinsing processes drastically increase the freshwater consumption and meanwhile generate massive waste rinsing effluents. This paper addresses an innovative alternative to recycle the waste effluents to minimize freshwater consumption in the wash-offstep. Accordingly, catalytic ozonation with a highly effective catalyst has been applied to remedy the waste rinsing effluents for recycling. The carbon aerogel (CA) hosted bimetallic hybrid material (Ag-Fe2O3@CA) was fabricated and used as the catalyst in the degradation of residual dyes in the waste rinsing effluents by ozonation treatments. The results indicate the participation of Ag- Fe2O3@CA had strikingly enhanced the removal percentage of chemical oxidation demand by 30%. In addition, it has been validated that waste effluents had been successfully reclaimed after catalytic ozonation with Ag-Fe2O3@CA. They could be additionally reused to reduce freshwater consumption in the wash-offstep, but without sacrificing the color quality of corresponding fabrics in terms of color difference and colorfastness. This study may be the first to report the feasibility of catalytic ozonation in minimization of freshwater consumption in the wash-offstep in textile reactive dyeing.