A GENERAL SURVEY OF THE PROPERTIES OF A NEW CLASS OF FUNCTIONALISED MATERIALS WITH ORGANOPOLYSILOXANE STRUCTURE

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Abstract
The metal sorption properties of a series of 14 functionalised organopolysiloxanes are reported. Such materials have been synthesized at DEGUSSA by polycondensation of suitably bifunctional silane monomers. The corresponding functional groups or combination of functional groups are : -SH; -S-; -SH + -S-; -NH- + -S-; -NH-[CH2] 2-NH2; -N=CH-C5H4N; -N=CH-C8H4OH; -NH-C[=S]-NH-; -NH-C[=S]-N[-]-[CH2] 2-N[CH3] 2; -NH-C[=S]-N[-]-C[=O]-C8H5; -NH-C[=S]-S-; -P[C8H5]-; -P[C8H5] 2 and -SO3H. Such materials appear as spherical or egg-shaped solid particles with a grain size of about 0.1 to 1.5 mm and surface areas up to 700 m2 / g. They are composed of a siliceous core and contain a high concentration of functional groups which, moreover, are bound to the matrix via carbon-silicon bonds which are fairly stable towards hydrolysis. They can therefore be safely used over a large range of acidities : i.e. from [HCI] > 6 mol / L up to about pH 11 or 12. The main advantages of the new functionatised organopolysiloxanes lie in the absence of swelling or shrinking during sorption operations and in their high thermal stability (up to 200 °C). The ion sorption properties of these organopolysiloxanes have been investigated by studying the fixation of a series of metal species (Ag(I), As(III), Sb(III), Bi(III). Cu(II), Ni(II). Ga(III), Fe(III), Pd(II) and Pt(IV)) representing the main families of metal ions.