Comparative adsorption of glyphosate from aqueous solution by 2-aminopyridine modified polystyrene resin, D301 resin and 330 resin: Influencing factors, salinity resistance and mechanism

摘要

Comparative adsorption of glyphosate from aqueous solution by 2-aminopyridine modified polystyrene resin (denoted GQ-08 resin), D301 resin and 330 resin was investigated with respect to influencing factors, salinity resistance and mechanism. Results showed the maximum adsorption capacity of glyphosate onto the three resins was observed at pH of 2.51, and glyphosate was adsorbed in the form of HO-PO2--CH2-NH2+-CH2-COOH and HO-PO2--CH2-NH2+-CH2-COO-. The adsorption capacity of glyphosate onto the three resins followed the order 330 resin > D301 resin > GQ-08 resin, consistent with their total exchange capability order. GQ-08 resin exhibited excellent salinity resistance. Salinity resistance of GQ-08 resin resulted from the hydrogen bonding for the adsorption of glyphosate, while 330 resin and D301 resin exhibited the single adsorption mechanism of anion exchange. (C) 2015 Elsevier B.V. All rights reserved.