The Study of Sorption of Toxic Basic Dyes from Aqueous Solutions on H2O 2 Treated Recycled Wool-based Nonwoven Material and Related Toxicity Analysis

Abstract

The aim of this study was to investigate the potential use of recycled wool-based nonwoven material for removal of basic dyes C.I. Basic Yellow 28 and C.I. Basic Red 46 from aqueous solutions. To improve the sorption properties, the recycled wool-based nonwoven material was treated with hydrogen peroxide. The sorption capacity, the sorption kinetics, and the influence of initial dye concentration and pH on the sorption were studied. The acute toxicity of dyes was evaluated using a ToxAlert® 100 biological test, which is based on inhibition of the bioluminescence of Vibrio fischeri . The percent of inhibition ( %I) before and after the sorption, 50 % effective concentration ( EC50) and toxicity units ( TU) were determined. The results indicated that recycled wool-based nonwoven material can be used as an efficient sorbent for removal of investigated basic dyes. Hydrogen peroxide treatment considerably improved the sorption properties of the material for both dyes. The sorption kinetics of dyes on the hydrogen peroxide treated material obeyed pseudo-second order kinetic model. The Freundlich sorption isotherm was found to represent well the experimental sorption data. The increase of initial dye concentration and pH positively affected the sorption of basic dyes. An ion exchange mechanism of dye sorption was confirmed by desorption studies. The toxicity decreased after the sorption of both dyes.