Removal of non benzidine direct red dye from aqueous solution by using natural sorbents: Beech and Silver Fir

摘要

The capacity of natural sorbents to remove direct dye from synthetic wastewater has been investigated. Two wood samples (Beech and Silver fir) were chosen to be tested for the removal of a direct red dye (DR). The effects of the support nature, dose, the specific surface of natural fibres, as well as the dye concentration, temperature and the pH influence on the adsorption process were investigated. The results indicate that the percentage of the removed dye rises with reducing the temperature and increasing the dose of the natural fibre, by reducing the apparent area of the sorbent. The kinetics of adsorption obeys a pseudo-second-order rate equation, and Sips isotherm models were found to fit the experimental results the best. The thermodynamic analysis shows that adsorption of DR on the investigated wood fibres was favourable and spontaneous.