Silica Polyamine Composites: New Supramolecular Materials for Cation and Anion Recovery and Remediation

• Published in: Macromolecular symposia Vol. 235; no. 1; pp. 161 - 178
• Main Authors: Hughes, Mark, Miranda, Paul, Nielsen, Dan, Rosenberg, Edward, Gobetto, Roberto, Viale, Alessandra, Burton, Sarah
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2006; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Amines; Anchors; Applied sciences; Cations; Composites; Exact sciences and technology; Forms of application and semi-finished materials; metal polymer complexes; Nuclear magnetic resonance; Polyamines; Polymer industry, paints, wood; Polymers; Silicon dioxide; solid state NMR; Sulfates; supramolecular structures; Technology of polymers; Separation capacity; Branched polymer; Metal ion; Allylic amine polymer; Concentration; Experimental study; Modeling; Silica; Composite material; Binding capacity; Copper ion; Lanthanide ion; Selenium ion; Vinyl amine polymer; Molecular model; Arsenic ion; Sorbent; Conformation; Polyethylene imine; Graft polymers
• ISBN: 3527315187; 9783527315185
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200650320

The surface coverage of amorphous silica gels used in the synthesis of silica polyamine composites has been investigated by 29Si 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‐13C 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 13C 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.