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

Abstract

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.

Possible Involvement of Permian Phosphoria Formation Oil as a Source of REE and Other Metals Associated with Complex U-V Mineralization in the Northern Bighorn Basin?

“…This separation required first the use of WP-4 followed by BPAP. The WP-4 removed the large excess of iron and BPAP selectively removed the entire family of lanthanides from mixtures of transition metals, alkali and alkaline earth metals at low pH [102]. This study demonstrates the feasibility to separate REE metals from a metal matrix like that of mine leachates.…”

“…Weld in Laverton, Australia. These studies separated Ce(III), La(III), Nd(III), Sm(III), and Pr(III) from the solution matrix that contained Fe(III), Mn(II), Ca(II), Mg(II), Al(III), Zn(II), Ti(IV), and other lower concentration trace metals [102]. This separation required first the use of WP-4 followed by BPAP.…”

Kinetic, equilibrium and thermodynamic modelling of the sorption of metals from aqueous solution by a silica polyamine composite

“…The elemental composition of the BPAP made from BP-1 is 14.20% C, 3.03% H, 3.36% N, 4.34% P (Kailasam et al, 2009;Hughes et al, 2006).…”

Metal coordination and selectivity with oxine ligands bound to silica polyamine composites

“…SPCs are composed of a silica gel support covalently bonded to linear or branched water soluble chelating polyamines. [5][6][7][8][9][10][11][12] The SPCs are synthesized via the following steps: acid washing of the silica gel surface, humidification, silanization with a mixture of methyltrichlorosilane (MTCS) and chloropropyltrichlorosilane (CPTCS), and finally addition of a polyamine and a modifying ligand ( Fig. 1).…”

“…1). 5 SPCs show no shrinking or swelling, they withstand operating temperatures of up to 110 C, and have anticipated stability to radiolytic decomposition. They also exhibit long usable lifetimes due to their rigid macrostructure and the multipoint anchoring of the polymer.…”