Removal of reactive dyes using a high throughput-hybrid separation process

Abstract

Toxic and carcinogenic reactive dyes are abundantly used in textile industries due to their wide variety of colour and texture. In this study, a hybrid separation process was used to remove four common reactive dyes (reactive yellow, red, black and brown) from aqueous solution. Synthetic solution of these dyes was subjected to adsorption by activated carbon followed by microfiltration (MF), using a ceramic membrane module. Dyes were completely removed by adsorption at pH 4.5 and the dye-loaded adsorbents were removed by cross-flow MF. Maximum Langmuir adsorption capacity of activated carbon for these four dyes was in the range of 88–106 mg/g. Effects of trans-membrane pressure drop and cross-flow rate on the throughput of the combined process was investigated. Membrane fouling was due to the cake type of layer formed by the activated carbon particles. Five different washing protocols were tested for their efficiency and the acid–alkali wash was found to be the most effective.