Adsorption characteristics of anionic nutrients onto the PP-g-AA-Am non-woven fabric prepared by photoinduced graft and subsequent chemical modification

摘要

PP-g-AA-Am non-woven fabric, which possesses anionic exchangeable function, was prepared by chemical modification of carboxyl group in PP-g-AA non-woven fabric to amine group using diethylene triamine. Its sorption characteristics for anionic nutrients including isotherm, kinetics, effects of pH and co-anions, and regeneration efficiency were studied by batch sorption experiments. Sorption equilibriums of PO4-P on PP-g-AA-Am fabric were well described by the Langmuir isotherm model, and their sorption energies were ranged between 9.94 and 15.96 kJ/mol indicating an ion exchange process as primary sorption mechanism. Sorption kinetic data fitted with pseudo-second-order kinetic model and indicated that both external and intraparticle diffusion took part in sorption processes. The uptake of PO4-P by PP-g-AA-Am fabric increased with increasing pH of solution and its optimum pH region was in pH ≥4, whereas the uptake of NO_3-N and NO_2-N was higher in weak and strong acidic pH region, respectively. The sorption selectivity for anions by PP-g-AA-Am fabric was increased in the order: SO_4 ≥ PO_4 > NO_3 > Cl. The PP-g-AA-Am fabric could be regenerated by a simple acid washing process without lowering the sorption capacity or physical durability.