Adsorption of organic dyes on metallurgical slag of Fe-Ni alloy production

Abstract

The optimal parameters of organic dyes adsorption on the metallurgical slag of the Fe-Ni alloy production of the Pobuzhsky Ferronickel Plant, Ukraine: pH, the mass ratio "dye: slag ad-sorbent", the type of chemical activation depending on the mode of the adsorption process were determined. Sorption of organic dyes (methylene blue MB, Congo red and methyl violet MV) by slag was studied spectrophotometrically. It is shown that after acid and alkaline activation the surface adsorption centers are formed on the surface of the slag: hydroxyl and silanol groups, whose dissociation causes a negative charge of the particles surface. The most appropriate ratio is "MB: slag" = 1 mg/g, at which the adsorption value a=0.92 mg/g is recorded at a treatment effi-ciency of 92 %. The maximum efficiency of MB adsorption by slag based on diopside was record-ed in the pH range of 4.8-10.4. The dependence of the type of chemical activation of slag with basic mineral-diopside on the sorption mode of organic dyes was determined. Slag acid activa-tion is advisable in the static mode of MV sorption; alkaline-under conditions of MV dynamic sorption with a low rate of solution passage through the sorbent layer. Diopside-based slag is ex-pedient to use as an adsorbent of organic dyes at the level of their low concentrations at the local treatment of wastewater generated during the certain technological operations.