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Silica Polyamine Composites: New Supramolecular Materials for Cation and Anion Recovery and Remediation
Author(s) -
Hughes Mark,
Miranda Paul,
Nielsen Dan,
Rosenberg Edward,
Gobetto Roberto,
Viale Alessandra,
Burton Sarah
Publication year - 2006
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200650320
Subject(s) - trichlorosilane , materials science , polymer chemistry , polymer , silane , adsorption , chemical engineering , hybrid material , chemistry , organic chemistry , composite material , silicon , nanotechnology , engineering
Summary: The surface coverage of amorphous silica gels used in the synthesis of silica polyamine composites has been investigated by 29 Si NMR. By diluting the polyamine anchor silane, chloropropyl trichlorosilane, with methyl trichlorosilane it was found that surface coverage could be markedly improved for a range of amine polymers after grafting to the silica surface. The commensurate decrease in the number of anchor points and increase in the number of free amines results in an increase in metal capacity and/or an improvement in capture kinetics. Solid state CPMAS‐ 13 C NMR has been employed to investigate the structure and metal ion binding of a series of these composite materials. It is reported that the highly branched polymer, poly(ethyleneimine) (PEI) exhibits much broader 13 C NMR resonances than the linear polymers poly(allylamine) (PAA) and poly(vinylamine) (PVA). These results are understood in terms of the low energy conformations calculated from molecular modeling studies. Three new applications of the technology are also presented: 1) separation of lanthanides as a group from ferric ion and all other divalent ions; 2) a multi step process for recovering and concentrating the valuable metals in acid mine drainage; 3) a process for removing low level arsenic and selenium in the presence of sulfate using immobilized cations on the composite materials.