Application of seed residues fromAnadenanthera macrocarpaandCedrela fissilisas alternative adsorbents for remarkable removal of methylene blue dye in aqueous solutions

Two novel ecological and low-cost adsorbents were prepared from seed residues of the tree speciesAnadenanthera macrocarpaandCedrela fissilisfor the removal of methylene blue dye in water. The materials were comminuted and characterized by different techniques. The particles of samples have a rough surface with cavities. The optimum dosage and pH for both materials were 1 g L(-1)and pH 8. The pseudo-second-order model was the most suitable for describing the adsorption kinetics for both systems. TheAnadenanthera macrocarpapresented a maximum experimental capacity of 228 mg g(-1), while theCedrela fissilis, a similar capacity of 230 mg g(-1)at 328 K. The Toth model was proper for describing the equilibrium curves for both systems. The thermodynamic indicators show that the adsorption process is spontaneous and endothermic for both materials. The application of materials for the simulated effluent treatment showed 74 and 78% of color removal usingAnadenanthera macrocarpaandCedrela fissilissamples, respectively. Overall, seed residues ofAnadenanthera macrocarpaandCedrela fissiliscould be potentially applied for adsorptive removal of colored contaminants in wastewater.