Reuse of waste charcoal mill to adsorption of metallic ions on wastewater

Abstract

The search for solutions to waste minimization by the industry has increased every year, either by optimizing their processes and reducing manufacturing costs or meeting the requirements of environmental agencies in the sustainable systems framework. The solid waste generated by the milling of vegetable charcoal, commonly discarded in landfills, has been characterized and showed thermal stability, porosity and surface area capable of adsorbing metal ions in an aqueous medium efficiently. The residue had a BET surface area of 330 m2/g, which corresponds to approximately 60% of the area of a commercial activated carbon used in water and wastewater treatment. The adsorption efficiency was investigated in different concentrations of Cu2+, Cr6+ and Al3+, temperatures and exposure times. The temperatures and times evaluated had no significant effect on the removal of ions. The initial concentration of ions in mixed solution was important and the ions Al3+ and Cr6+ were efficiently removed even at high concentrations. The use of residue allowed the removal of 70% of Cu2+, 98% of Cr6+ and 99% of Al3+ ions in a natural water doped sample.