Selective removal of cationic dye from aqueous solution by low-cost adsorbent using phytic acid modified wheat straw

In this paper, the wheat straw (WS) was modified using phytic acid (PA) to improve adsorption capacity for selective removal of methylene blue dye (MB, cationic dye). The morphology, structure and surface state of the modofied wheat straw using phytic acid (PA-WS) were characterized using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The effects of pH, MB concentration, different temperatures and contact time on adsorption experiments were investigated. The maximum adsorption quantity of PA-WS for MB was up to 205.4   mg   g −1 at 25   °C. Equilibrium adsorption isotherm data indicated a good fit to the Langmuir isotherm model and the adsorption kinetic was well-fitted by the pseudo-second-order model and the Elovich model. Regeneration study revealed that PA-WS can be reused effectively. These results indicated that PA-WS was a promising adsorbent for the removal of cationic dyes.