Adsorption-desorption of picric acid by weaky basic resin
弱碱性树脂吸附-解吸苦味酸

The adsorption and desorption of aqueous picric acid solution onto D301R weaky basic anion exchange resin were investigated. The kinetics, thermodynamics and adsorption mechanism were also studied. The results showed that the maximum adsorption ability of resin occured at pH = 2.7 ~ 10.2. The adsorption of picric acid on the resin obeyed Freundlich isotherm and was a spontaneous, endothermal and entropy increasing process. Kinetic analysis shows that the adsorption reaction could be approximated by a Lagergren pseudo-second-order-rate equation for which the intraparticle diffusion is the rate-controlling process with an adsorption rate constant of 7.23×10-5 ~ 1.20×10-4 g/(mg·min) and activity energy of 19.4 kJ/mol. Washout rate of 99% of the picric acid adsorbed on the resin can be eluted with a HNO3 + acetone solution quantitatively. The comparison of static adsorption and desorption confirmed the presence of irreversible chemical adsorption in the adsorption process. The synergistic interactions by the electrostatic, acid-base complex and hydrogen bonding were the main driving forces of picric acid adsorption on the weaky basic resin.