Assessment of sorbent materials for treatment of hydrocarbon contaminated ground water in cold regions

In this investigation different sorbent materials (MYCELX coated sand, granular activated carbon (GAC) and surfactant-modifed zeolite (SMZ)) were tested for their suitability for capture of sparingly soluble hydrocarbons in soil water. These materials were assessed for their potential use in permeable reactive barriers in cold regions. Batch sorption tests at 20 °C and 4 °C were performed along with a number of surface characterization techniques, including thermogravimetric analysis, nitrogen adsorption and Fourier transform infrared analysis (FTIR). ionic strength and pH tests were also conducted to determine their impact on hydrocarbon sorption.The results of the surface characterization tests showed that the quality of the MYCELX coating on the sand was highly variable, thus leading to unreliable adsorption results. GAC proved to be the best sorbent material at high and low temperatures on a mass basis. However, on a surface area basis, SMZ performed better than GAC. High ionic strength and high and low pH had little effect for hydrocarbon sorption onto GAC and SMZ. Both GAC and SMZ exhibited reduced adsorption efficiency at 4 °C compared to 20 °C. The extent of the reduced adsorption efficiency varied depending on the hydrocarbon.