Abstract

A temperature controlled carbonization process (5-800 °C for 1-4 h) of metal forms of different kinds of partially or totally saturated sulphonated styrene-divinylbenzene copolymer based ion-exchangers loaded with various valence state metal ions has been evaluated. The effect of temperature, nature and valence of metal ions, crosslinking and other parameters on the composition and properties of the formed composites have been evaluated. Depending on the ionic form and the saturation degree of the ion exchangers the sulphur content of the ion-exchangers can partially transform into metal sulphides, SO3 or SO2. Ni(II), Mn(II) and Zn(II) forms of the ion-exchangers resulted the appropriate MIIS type metal sulphides (NiS, MnS or ZnS), while copper(II) resulted metallic copper formation at 500 °C in 2 h. Both iron(II) and iron(III) forms of sulphonated styrene-divinylbenzene copolymers resulted Fe0.95S and -Fe formation at 800 °C for 2 h, however, the ratio of these compounds depended on the valence state of iron and were found to be 8:1 and 7:2 in the case of Fe(III) and Fe(II)-forms, respectively. The shape of the formed carbon particles are bead-like and the hardness of the formed carbon beads proportional
with the divinylbenzene content of the starting polymer. The higher divinylbenzene content the harder beads of carbon forms. All the beads have a leak due to evolution of gases which emitted at the weakest part of ball-like bead. The ball like metal-containing activated carbon
beads have low hydrodynamic resistance towards fluid streams and this carbonisation method can be used as an environmentally friendly way for processing of waste ion-exchangers into industrially usable carbon based metallic containing composites.

Key words: metal-containing activated carbons; waste ion-exchangers; carbonization; metal/metal compound-carbon composites; sulphonated styrene-divinylbenzene copolymers