Decolorization of a textile vat dye by adsorption on waste ash

Abstract

An adsorption process using cheap adsorbents could be described as a simple, selective and low cost alternative for the treatment of colored waste water compared to conventional physical and chemical processes. In this study the use of a natural waste adsorbent - ash was investigated for the removal of a textile vat dye Ostanthren Blue GCD remaining after the dyeing of cotton textile. The ash obtained as a waste material during the burning of brown coal in the heating station of Leskovac (Serbia) was used for the treatment of waste waters from the textile industry, i.e., waste water after the dyeing process. The effect of ash quantity, initial dye concentration, pH and agitation time on adsorption was studied. The Langmuir model was used to describe the adsorption isotherm. Based on the analytical expression of the Langmuir model, the adsorption constants, such as adsorption capacity and adsorption energy, were found. Pseudo first and second order kinetic models were studied to evaluate the kinetic data.