Amino-functionalized cotton fiber for enhanced adsorption of active brilliant red X-3B from aqueous solution.

An amino-functionalized sorbent (ACF) was prepared by grafting amine group onto cotton fiber (CF) using tetraethylenepentamine (TEPA). The resulting composite was characterized using various instrumental techniques such as scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and pHpzc analysis. FTIR spectrum and pHpzc analysis illustrated the involvement of amine groups in the X-3B sorption process. ACF sorbent was tested for its ability to remove X-3B from an aqueous solution in batch experiments. The adsorption efficiency of ACF was 100% in comparison with 5.52% of raw cotton fiber when initial concentration of active brilliant red X-3B was 30 mg/l. Results suggested that solution pH hardly affected the removal of X-3B, and ACF remained stable sorption efficiency in the pH range of 3.0-12.0. High values of correlation coefficients indicated the adsorption kinetics could best described by the pseudo-second-order kinetic equation. The sorption isotherm of ACF fitted the Langmuir equilibrium model, with the maximum adsorption capacity of 270.27 mg/g at 293K. The obtained thermodynamic parameters showed that the adsorption of X-3B onto the adsorbent was spontaneous and exothermic. The excellent regeneration performance provided strong evidence of the potential of ACF for technological applications of dye removal.