Adsorption capacity of phenanthrene and pyrene to engineered carbon-based adsorbents produced from sewage sludge or sewage sludge-biomass mixture in various gaseous conditions

Abstract

Adsorption of phenanthrene (PHE) and pyrene (PYR) by engineered carbon-based adsorbents produced from sewage sludge in an atmosphere of nitrogen (N2) or carbon dioxide (CO2) at temperatures of 500, 600, and 700 °C was investigated. The addition of willow to the SSL decreased the biochar adsorption capacity. However, there was an increase in the adsorption capacity after changing N2 to CO2. The addition of willow to SSL and the type of carrier gas affected the mechanism of adsorption. The adsorption of PHE and PYR on the SSL-derived adsorbents produced in N2 occurred through pore filling. The adsorption on the SSL-derived adsorbents with willow followed the mechanism of π-π electron-donor-acceptor (EDA) interactions and hydrophobic interactions. A similar mechanism was observed with regard to the biochars produced from SSL in atmosphere of CO2. For the SSL-derived adsorbents with willow in CO2, the adsorption mechanism was observed to vary between PHE and PYR.