Enhanced removal of Cd(II) by poly(acrylamide-co-sodium acrylate) water-retaining agent incorporated nano hydrous manganese oxide

Abstract

In this study, the hydrous manganese oxide (MO) nano-particles impregnated into a poly(acrylamide-co-sodium acrylate) (PP), was synthesized as PPM, and its characterization, adsorption properties and mechanism were investigated. The transmission electron microscopy (TEM) revealed the mostly MO with size of lower than 20nm were dispersed in polymer. The MO greatly improved the Cd(II) uptake for PP in aqueous solution, due to its high affinity. These adsorptive processes are corresponded to the Sips isotherm model. It was revealed that maximum adsorption capacity (qm) of PP loaded with MO (Mn wt%=1.05%, PPM-40) and PP for Cd(II) are 507 and 281mg/g in present of 0.1M NaCl. However, the qm of PPM-40 and PP are 698 and 771mg/g without any NaCl. The preferential adsorption of PPM-40 to Cd(II) was showed when inferenced with salt ion. The XPS exhibited the 67% Cd(II) was captured by MO and 33% was by PP, in present of 0.1M NaCl. The seed germination and leaching experiments demonstrated that the PPM-40 can be taken as a filter for Cd(II) and supplied “clean” water for plant roots in soil. It is a potential in-situ fixation agent for remediation of agricultural soil polluted with Cd(II).