Optimization of parameters for effective removal of Cr(VI) species by burnt brick clay

Abstract

The extent of removal of Cr(VI) species from aqueous solution by brick particles is highly dependent on the firing temperature of brick clay used for removal of Cr(VI) species, since many physical and chemical changes occur during firing. The highest removal of Cr(VI) species by brick clay is obtained with clay fired at 200 °C. The amount of suspended matter is low with brick clay fired at temperatures ranging from 200 °C to 600 &°C as seen with turbidity measurements. Optimization of parameters, such as duration of stirring (10 minutes) and settling time period (2 hours), leads to 60% removal of Cr(VI) by brick particles fired at 200 °C in batch experiments, without pH control, despite the negative charge of the source of Cr(VI). Dynamic experiments conducted in packed columns also effectively remove Cr(VI). The extent of removal does not significantly depend on solution pH up to 11 and on common interferents.