Immobilization of a polyionene complex on a silica gel surface immediately after polymer formation (in situ immobilization) and the covalent anchorage of polyhexamethylene guanidine hydrochloride onto an amino-containing silica surface have been performed. The adsorption properties of the modified silica adsorbents with respect to Cr(IV), Mo(VI), W(VI), As(V), P(V) and V(V) anions were studied. Silica gels with chemically-bound polyhexamethylene guanidine hydrochloride effected the quantitative removal of V(V), W(VI), Mo(VI) and As(V) anions from their acidic (pH = 2–4) and neutral solutions, although their kinetic characteristics were closer to those of polymeric sorbents. Silicas with in situ immobilized polyionene complexes quantitatively extracted As(V), W(VI) and Mo(VI) anions, and exhibited a high adsorption activity towards Cr(IV), P(V) and V(V) anions from acidic (pH = 1–4) media with adsorption equilibrium being attained at a high rate. The adsorbents synthesized exhibited high adsorption capacities towards the anions investigated.
Covalent bonding of polyhexamethyleneguanidine amides of maleic and o phthalic acids to the aminated silica surface was performed. The complexing properties of the obtained composite adsorbents with respect to Zn(II), Cu(II), Fe(III), Co(II), Pb(II), Ni(II), Mn(II), Mo(VI), and Cr(VI) ions were studied. The Mo(VI) and Cr(VI) reduction was detected on the modified silica surface bearing polyhexamethyle neguanidine amide with o phthalic acid. The formation of different ligand complexes with transition metal cations adsorbed on the synthesized composite surface was studied.
The pre-concentration of metal ions such as Pb(II), Cd(II), Zn(II), Hg(II) and Mo(VI) on silicas with covalently bound 8-hydroxyquinoline, 1-(2-pyridylazo)-2-naphthol or 4-(2-pyridylazo)resorcinol has been studied. The structures of metal-ion complexes with grafted phenolic-type analytical reagents were investigated by IR, ESR and electronic diffuse reflectance spectroscopies.
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