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

The well established activated carbon manufacturing process has been invest igated as a novel treatment for contaminated soil from gaswork sites by con verting it into a porous carbonaceous solid with adsorbent properties. Seve ral activation methodologies were evaluated: CO2, air, ZnCl2, H2SO4, H3PO4, FeSO4 and HNO3. Thermal analysis of the soil provided information regardin g appropriate carbonisation and activation conditions. Bulk samples were pr epared using contaminated soil samples, with ZnCl2 being found to be the mo st effective agent for the process, producing an adsorbent which possessed a BET surface area of 131 m(2) g(-1). 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 Zn Cl2-activated soil was found to be 0.12 mmg(-1) for phenol and 0.23 mmg(-1) for 4-nitrophenol. (C) 2000 Society of Chemical Industry.