Gold deposition on magnetic porous composites synthesized from modified wood sawdust at different temperatures

In this work, porous magnetic carbonic composites with a surface area of 1000–1350 m²/g were prepared during carbonization of wood sawdust modified by chlorides of iron and zinc at temperatures of 400 and 800 °C. It was shown that capacity of the samples with respect to gold deposited from HAuCl₄ solution is 0.3–0.5 g/g and depends on the carbonization temperature of the synthesized composite. Moreover, amount of gold deposited on the composite correlates with the magnetite content. It is assumed that one reason for the high capacity of composite with respect to gold is interaction of chloroaurate ions with magnetite phase contained in composite. It was noted that morphology of gold on the sample surface depends on synthesis temperature of composite: Gold deposited on porous composite obtained at a temperature of 400 °C is in the form of radiant-needle particles, and spherical particles of gold are formed at the composite surface obtained at the temperature of 800 °C.