SUMMARY
The sawdust of ayous was used as an absorbent of the removal of purple of bromocrésol from aqueous solutions. The sawdust of ayous was treated by the sulphuric acid, the soda and the acetate of ethyl with an aim of stabilizing it and of increasing its capacity of adsorption; this enabled us to determine the pH of balance, and the pH of zero load. The biosorption was studied according to the time of contact, of the mass of biosorbant. The study of time of contact showed that balance is reached at the end of 10 min with a capacity of adsorption of 0.56 mg/g, that is to say a rate of elimination of 98.96 %. The kinetic study showed that the biosorption of purple of bromocresol follows better the model pseudo-second order with the coefficient of correlation of 0.999. The study of the isotherms of adsorption showed that the biosorption is described by the model of Langmuir with a coefficient of adsorption of 0.990.