Removal of rhodamine B and methylene blue using waste fibers from Inga edulis Mart as bioadsorbent: kinetics and thermodynamic parameters

In the present work, the modification, characterization, and application of the adsorption tests of the Ingá edulis Mart peels were carried out in the adsorption in natura and modified form in basic medium (NaOH 3 mol L-1) to perform the adsorption of methylene blue dyes and rhodamine b. This material was applied for the study of adsorption in aqueous medium where the best conditions of the main parameters were found. The influence of several factors, such as solution pH, contact time, adsorbent mass, and dye concentration, was studied by batch experiments. The optimum contact time to reach equilibrium was 20 min for Ingá edulis Mart in natura and modified in methylene blue and 40 min for Ingá edulis Mart in natura and modified in rhodamine b. The optimal adsorbent dose was 200 mg for both dyes. The study of the adsorption kinetics revealed that the adsorption process was better adjusted to the pseudo-first order kinetic model and the Langmuir isotherm in all configurations of the studied systems. The results obtained show that the biosorbents from the bark of Ingá edulis Mart can be applied as a low-cost adsorbent for removing methylene blue and rhodamine b from effluents, since it showed good adsorption capacity with the maximum adsorption value Qm of 25,62 mg g-1 for Rb and 30,47 mg g-1 for MB for adsorption after modification. Thermodynamic studies in this research showed a spontaneous, favorable, and endothermic adsorption.