Adsorption capacity of superabsorbent resin composite enhanced by non-thermal plasma and its adsorption kinetics and isotherms to lead ion in water

The 2-acrylamido-2-methyl propanesulfonic acid (AMPS)/acrylamide (AM) superabsorbent was modified by non-thermal plasma (NTP) under ambient temperature and pressure conditions. The results showed that NTP treatment can improve the adsorption property of superabsorbent obviously. After superabsorbent resin composite treated by NTP, the ΔSθ increased from 25.18 J/mol K to 47.01 J/mol K, the Ea decreased from 18.56 kJ/mol to 13.96 kJ/mol and the ΔGθ (25 °C) decreased from −1.994 kJ/mol to −2.447 kJ/mol. It indicated that the adsorption properties were enhanced and activation energy decreased by NTP treatment, which was due to available adsorption sites increased. The kinetic data of adsorption were found to best fit to the pseudo-second-order, while the equilibrium data were found to be well described by Freundlich model.