Conversion of foliar residues of Sansevieria trifasciata into adsorbents: dye adsorption in continuous and discontinuous systems.

The study analyzed the potential of leaf powder prepared from the residual leaves of the species Sansevieria trifasciata, as a potential adsorbent for methylene blue (MB) removal. The equilibrium was reached fast for almost all concentrations after 60 min, obtaining the maximum capacity of 139.98 mg g for 200 mg L. The increase in temperature disfavored the dye adsorption, with the maximum adsorption capacity of 225.8 mg g, observed for 298 K. The thermodynamic parameters confirmed that the adsorption process is spontaneous and exothermic. A direct sloping curve was established for the fixed bed, with breakthrough time (t), column stoichiometric capacities (q), and the mass transfer zone lengths (Z) were 1430, 1130, and 525 min; 60.48, 187.01, and 322.65 mg g; and 8.81, 11.28, and 10.71 cm, for 100, 200, and 500 mg L, respectively. Furthermore, in a mixture of several dyes, the adsorbent obtained the removal of 51% of the color.