Modification of Radiation Grafted Banana Trunk Fibers for Adsorption of Anionic Dyes

Pre-treated banana fiber were successfully grafted with glycidyl methacrylate (GMA) by employing preirradiation grafting technique with the aid of electron beam accelerator. GMA-grafted fibers were subsequently functionalized with trimethylamine (TMA). TMA functionalized fibers were subjected to elemental analysis to quantify the presence of nitrogen on the fibers. The adsorption of anionic dyes, acid blue (AB 80) and acid red (AR 86) in aqueous solution by TMA functionalized fibers were studied in this paper. The adsorption kinetics were evaluated with pseudo-first order and pseudo-second order. The kinetic adsorption data obtained follows the pseudo-second kinetic model which is supported by higher coefficient value, r(2) > 0.99, good agreement with q(e,cal) and q(e,exp) values and also represents chemisorption process control. The equilibrium adsorption data were also analyzed by Langmuir and Freundlich adsorption isotherm model. The adsorption of AB 80 dye obeys the Langmuir adsorption model whereas adsorption of AR 86 dye obeys the Freundlich adsorption isotherm model. Adsorption capacity of AR 86 dye is higher than AB 80 dye. The adsorption process was favorable as shown by the separation factor (RL) in the range of 0 < RL < 1. In desorption studies, high amount dyes was eluted with mixture of 50 % methanol + 30 % NaCl (0.5N) + 20% NaClO (1.0N).