Treating contaminated soil by conversion into carbonaceous adsorbents: an investigation of activation procedures

Abstract

The well established activated carbon manufacturing process has been investigated as a novel treatment for contaminated soil from gaswork sites by converting it into a porous carbonaceous solid with adsorbent properties. Several activation methodologies were evaluated: CO 2 , air, ZnCl 2 , H 2 SO 4 , H 3 PO 4 , FeSO 4 and HNO 3 . Thermal analysis of the soil provided information regarding appropriate carbonisation and activation conditions. Bulk samples were prepared using contaminated soil samples, with ZnCl 2 being found to be the most effective agent for the process, producing an adsorbent which possessed a BET surface area of 131m 2 g À1 . The aqueous adsorption ability of the soil carbons was studied using phenol and 4-nitrophenol as representative micropollutant organic molecules. The Langmuir monolayer capacity of the ZnCl 2 -activated soil was found to be 0.12 mmg À1for phenol and 0.23 mmg À1 for 4-nitrophenol.