Biogas trace compound removal with ashes using proton transfer reaction time-of-flight mass spectrometry as innovative detection tool

The feasibility of reusing waste materials as an inexpensive sorbent to remove volatile organic compounds from gaseous waste streams has been demonstrated. Ashes from wood-chips were tested as sorbent materials for VOCs removal with a PTR-ToF-MS instrument. Both scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and BET analysis were used to identify the structural characteristics, elemental composition and surface area of the tested ashes respectively. Most of the tentatively identified compounds were less strongly adsorbed by wet ash: thiols, siloxanes, carbonyl compounds and terpenes. Hydrogen sulfide and alcohols show improving removal performance in wet conditions. These results are related to the water solubility properties. Siloxanes were tentatively identified and monitored with PTR-ToF-MS. This demonstrates how this instrument is a suitable tool for simultaneously providing a multitude of analysis for rapid in situ monitoring of fuel contaminants. Considering the low cost, and the recycling of environmental pollutants, wood ashes are a possible choice for VOCs removal from biogas