The effect of calcination on natural calcareous bentonite for Mn and Fe adsorption in aqueous solution

Abstract

Abstract Mn and Fe are common metallic elements found in wastewater. In high concentration these elements can cause environmental and health risks. This study was conducted to examine the improvement of natural calcareous bentonite (NCB) adsorption capacity on Mn and Fe in aqueous solution after high-temperature calcination. The NCB sample was prepared in three conditions: untreated, calcined at 200 °C and 800 °C. The Mn adsorption test showed the calcined sample at 200 °C had no significant differences uptake to the untreated with an increase in pH from 3 to 7 in one hour and reached the equilibrium in 24 hours. Disparately, the calcined sample at 800 °C showed much higher Mn uptake, immediate equilibrium, and an extreme increase in pH from 3 to 11 just in one hour. The Fe adsorption test for three sample conditions exhibited immediate Fe uptake and equilibrium within just one hour, with no differences in Fe uptake. However, the pH in equlibrium time had different increase. The untreated and the calcined sampel at 200 °C had an increase pH from 3 to 7 while the calcined sample at 800 °C had an increase pH from 3 to 11.