Removing selenite ions (SeO32−) from aqueous solutions by 4-vinyl pyridine monomer grafted poly(ethylene terephthalate) fibers and an estimation of its adsorption mechanism over pH dependency of the adsorption

In this research, 4-Vinyl pyridine grafted poly(ethylene terephthalate), (4VP-g-PET), fibers were synthesized using the radical polymerization method and used as a novel adsorbent for removing selenite (SeO 3 2− ) ions from aqueous solutions. SEM and FTIR spectroscopy were used to examine the structure of the synthesized fibers. Batch experiments were used to conducted the adsorption research. Parameters affecting the adsorption performance like pH, grafting yield, adsorption time, initial selenite concentration and temperature were investigated. The best removal of selenite ions was attained at pH 6. Interestingly, the fibers displayed significant adsorption potential at higher pHs even in highly alkaline environments. Within 3 h, adsorption equilibrium was established, and kinetically, the adsorption process was found to obey the pseudo-first-order kinetic model. Grafting yield increased the amount of selenium adsorption up to 47 percent. The synthesized fibers’ maximum selenite adsorption ability was found to be 26.91 mg g −1 . Thermodynamic parameters Δ H 0 , Δ S 0 and Δ G 0 of the adsorption were also calculated. The adsorption reaction was determined to be exothermic. The possible adsorption routes were proposed. The synthetic adsorbent, 4VP-g-PET fibers, may be a promising alternative adsorbent for removing selenite from aqueous media.