Use of red mud activated at different temperatures as a low cost adsorbent of reactive dye

Uso de lama vermelha ativada em diferentes temperaturas como um adsorvente de baixo custo de corante reativo

ABSTRACT

Red mud, a waste product generated during alumina extraction from bauxite, could be used as a low-cost adsorbent. Here, the effect of thermal treatment on the adsorption of Reactive Blue 19 (RB19) dye by red mud was compared with the adsorption capacity of untreated red mud. Thermal treatment of red mud at 500°C results in an increase in adsorption capacity from 357 mg g^-1 (untreated red mud) to 416 mg g^-1, under acidic conditions. Red mud samples thermally treated at 600°C and 800°C show a reduction in adsorption capacity, however, falling to 337 mg g^-1, in acid medium. The change in the maximum adsorption capacity of red mud to RB19 following thermal treatment is associated with specific surface area. Red mud subjected to 500°C can be used for the treatment of water and wastewaters with a higher efficiency than untreated red mud, thus finding possible application in the textile industry.

Keywords:
low-cost adsorbent; isotherms models; environmental management; cleaner production