Minimizing Freshwater Consumption in the Wash-Off Step in Textile Reactive Dyeing by Catalytic Ozonation with Carbon Aerogel Hosted Bimetallic Catalyst.

Enling Hu,Shouxiang Jiang,Songmin Shang,Ka-Lok Chiu,Xiaoming Tao

doi:10.3390/polym10020193

Abstract

In textile reactive dyeing, dyed fabrics have to be rinsed in the wash-off step 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-off step. 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-off step, 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-off step in textile reactive dyeing.

Highlights

High dependence on freshwater is an outstanding problem in textile manufacturing for the production of value-added final textile products [1]
The catalyst Ag–Fe2 O3 @carbon aerogel (CA) has been adopted in catalytic ozonation for reclamation of waste rinsing effluents, pursuing effluent recycling to reduce freshwater consumption
It was found that the participation of the catalyst significantly facilitated dye degradation in catalytic ozonation of waste effluents

Summary

Introduction

High dependence on freshwater is an outstanding problem in textile manufacturing for the production of value-added final textile products [1]. The textile industry generally consumes massive amounts of freshwater for processing raw textile substrates in wet conditions, such as dyeing, printing and finishing. No matter which wet processes are applied, they cannot make full use of dyes and/or auxiliaries. Some of these chemicals would remain in water baths and have to be disposed with the hosting baths, generating the highly-polluted wastewater. Textile dyeing houses have been thought to be the most polluting unit among all industries, if considering both the volume and pollution load of effluents discharged [2]

Methods

Results

Conclusion