Adsorption of 5.5’-Disulfonicindigotin (5.5’-DI) onto Green Coconut Fiber (<i>Cocos nucifera</i> L.): Kinetic and Isotherms

Abstract

Green coconut fiber ( Cocos nucifera L.) has been largely used in solid-phase extraction. The effect of the initial dye concentration (1.91, 3.02 and 4.02) × 10 - 5 mol&#183L - 1 and solid phase contact (SPE) time were evaluated at different temperatures (283, 298 and 313) K at pH 2. Kinetic experimental data were applied to three simplified kinetic models: pseudo-first order, pseudo-second order, and intraparticle diffusion. The adsorption of 5.5’-DI onto the solid phase showed excellent fit to the pseudo-second order model. At 283, 298 and 313 K the maximum sorption, q max,exp , for the lowest initial concentration (C o = 1.91 × 10 - 5 mol&#183 L - 1 ) of 5.5’-DI were (5.01, 5.24 and 6.14) × 10 - 4 g&#183g - 1 ; for C o = 3.02 × 10 - 5 mol&#183L - 1 (0.93, 1.01 and 1.03) × 10 - 3 g&#183g