The bio-oils (BO) are a promising renewable feedstock for the production of fuels with a lower environmental impact (CO2 neutral) compared to fossil fuels, and their characterization studies have increased in number in the last decades. BO contains inorganic species with elements such as Na, K, Ca, P, Fe, Si, etc., which can cause problems in processes like catalytic upgrading, and storage stability. The total analysis in BO is often performed with inductively coupled plasma optical spectrometry (ICP-OES), and other analytical techniques. From the speciation approach, the hyphenation of gel permeation chromatography (GPC) to inductively coupled plasma high-resolution mass spectrometry (ICP-HRMS) can be used as a tool to monitor the evolution of the hydrodynamic volume of the species containing the elements of interest in the BO. The present work aims for the inorganic speciation analysis of pine pyrolysis products by GPC-ICP-HRMS in order to link their composition to their respective production process. This valuable information regarding the hydrodynamic volumes of the observed species in the bio-oils could then be used in order to optimize the processes linked to the further removal of these problematic species. To this extent, a Thermo Scientific Element XR double-focusing sector field ICP-MS (Thermo Fisher, Germany) has been hyphenated to a Dionex high-performance liquid chromatography (HPLC) system. Three Waters (Waters Corporation, USA) styrene-divinylbenzene gel permeation columns were connected in series with a Styragel guard column. Three pine pyrolysis samples (biochar, BO, and vacuum distillation residue of BO) have been selected and were 5-fold diluted in THF, then 20 μL were injected and eluted isocratically at a flow rate of 1 mL/min of THF for about 80 min before detection using both UV and ICP-HRMS system. The obtained molecular weight distribution of the inorganic species studied shown slight differences between each sample because of their nature. The biochar showed high content of salt species, whereas in the pyrolysis BO a more dispersed distribution of species is observed because of the formation of possible aggregates between lignocellulosic fragments.

Inorganic speciation of pine pyrolysis bio-oils using gel permeation chromatography - inductively coupled plasma high-resolution mass spectrometry (GPC-ICP-HRMS)

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.