Sorption Purification of Model Solutions from Iron and Silicon Ions Using Aluminum Oxyhydroxide

Abstract

The sorption processes of iron(III) and silicon ions from a model solution have been investi-gated using nanofibrous aluminum oxyhydroxide as a sorbent, obtained by oxidizing aluminum powder with water at a constant temperature in the range from 60 to 75 °C; its surface area is 196.16 m2/g, the pore diameters are from 2 to 15 nm, and the lengths are up to 1 μm. Aluminum powder was obtained by electric explosion of a conductor in argon. The adsorption processes have been studied for iron and silicon ions on aluminum oxyhydroxide and activated carbon from a model solution containing iron(III) ions, silicon, and organic substances of humic origin. The degrees of extraction of iron and silicon ions have been 82% and 41%, respectively, for the aluminum oxyhydroxide sorbent, at the initial concentration of iron 6.7 mg/L and 25.6 mg/L of silicon. For activated carbon, these have been 25% and 9% at the same weight of the sorbent sample. The sorption time is 4 hours. The value of the maximum sorption capacity of aluminum oxyhydroxide with respect to iron ions is 10 mg/g, and 38 mg/g for silicon ions from the model solution. The nanofibrous aluminum oxyhydroxide can be used at the post-treatment stage to remove iron associated with organosilicon compounds from groundwater, where iron substances are present in the colloid form and their concentration does not exceed 2 mg/L and the concentration of silicon does not exceed 12.4 mg/L, with organic substances up to 6.2 mg/L.