Epicarp and mesocarp of babassu (Orbignya speciosa): characterization and application in copper phthalocyanine dye removal

The mesocarp and epicarp components of the babassu palm tree were applied as novel alternative biosorbents for copper phthalocyanine textile dye removal from aqueous solutions. The natural biopolymers were characterized by elemental analyses, solid state 13C NMR, infrared spectroscopy, thermogravimetric analysis and X-ray diffractometry. Results demonstrated that the compositions of the mesocarp and epicarp are similar to those of other lignocellulosic materials, and that they were very effective for removal of the textile dye Turquoise Remazol. A pseudo second-order kinetic model resulted in the best fit with experimental data for both epicarp and mesocarp (R2 = 0.999), providing rate constants of sorption, k2, of 0.31 and 1.43 g mg-1 min-1, respectively. The Langmuir and Freundlich isotherm models were employed for adsorption analysis of the experimental data in their linearized forms. The second model resulted in the better fit for Turquoise Remazol dye, which presented maximum adsorption of 1.44 and 2.38 mg g-1 at pH 6.0 for mesocarp and epicarp, respectively. (author)