Removal of textile dyes from aqueous solution by babassu coconut epicarp (Orbignya speciosa)

Babassu coconut (Orbignya speciosa) epicarp (BCE) was used as biomass to remove textile dyes from aqueous solution. Physical characteristics of the BCE were investigated using infrared spectroscopy (IR), point of zero charge (pH(pzc)), surface area, pore volume and diameter. A batch system was applied to study the sorption of Blue Remazol R160 (BR 160), Rubi S2G (R S2G), Red Remazol 5R (RR 5). Violet Remazol 5R (VR 5) and Indanthrene Olive Green (IOG) dye solutions by BCE. The effects of contact time and concentration on the sorption of the textile dyes onto the BCE were investigated. The interactions were assayed with respect to the pseudo-first-order, pseudo-second-order and the Elovich kinetic models by linear and non-linear regression methods, and were found to follow closely the pseudo-second-order. The ability of babassu coconut epicarp to sorb dyes gave the ordered set BR 160>VR 5>RR 5>R S2G >IOG. Equilibrium data also were fitted by linear and non-linear regression methods through the Langmuir, the Freundlich, the Temkin and the Dubinin-Radushkevich isotherm models. The equilibrium data were best represented by the Dubinin-Radushkevich, showing physical interactions between the species. (C) 2011 Elsevier B.V. All rights reserved.