Green technology in textile processing: Part III—Eco-friendly dyeing of cotton goods

Abstract

A novel eco-friendly dyeing process is described for the dyeing of cotton with reactive, sulphur and vat dyes. Significant reduction in pollution load in tenns of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) is achieved by modified processes (Eco-Process I and Eco-Process II) employing standing bath or by substituting the nonecofriendly chemicals with the eco-friendly ones. The reductions achieved in BOD and COD respectively are 7.65% and 17.27% for reactive dyeing, 2.10% and 5.78% for sulphur dyeing and 11.41% and 17.92% for vat dyeing. A considerable amount of saving in water consumption is also achieved while dyeing with Eco-Process I and Eco-Process II. Eco-Process II, in particular, results in 38.70%, 50% and 83.33% savings in water consumption during dyeing with reactive, sulphur and vat dyes respectively. This has also reduced the volume of effluent in a process house.