Thermal depolymerization of lignocellulosic biomass at 400-600 oC in the absence of oxygen yields liquid, char, and gas. The presence of high oxygenates (40 wt.%) in the liquid fraction contributes to deleterious properties such as low heating value, high viscosity, corrosiveness, and low thermal stability. The present study investigates an upgrading strategy for crude biogenic pyrolysis oil using various adsorbents (calcium hydroxide, red mud, bentonite, dolomite, used silica, and new silica) with petroleum ether as a diluent. The textural and microstructural features of the adsorbents are analysed using various characterization techniques - a scanning electron microscopy (SEM) and a Brunauer–Emmett–Teller (BET) specific surface area analyser. The objective of the study was to induce a separation of soluble and insoluble phases in petroleum ether (upper homogeneous fraction and lower non-homogeneous fraction with adsorbents) using various cheap adsorbents, and to find the best adsorbent for the refining process. The original crude oil and the refined oil from the upgradation strategy were extensively characterized using multiple analytical techniques to understand the chemical, thermal, and stability characteristics. The results showed that calcium hydroxide is more effective in the removal of oxygenates in comparison with other adsorbents due to variations in surface area.

The upgrading of crude biogenic pyrolysis oil (CO) was carried out using a simple scalable, inexpensive upgrading strategy based on the use of various adsorbents. The upgraded oil and the efficiency of the process were extensively characterized using various analytical techniques. The preliminary objective of the study was to identify the best adsorbent for refining CO. The adsorbents were characterized using scanning electron microscopy (SEM) and a Micromeritics 3Flex Instrument to determine the morphology and surface area of the adsorbents used. Crude and upgraded oil were extensively characterized to understand chemical composition, stability, and thermal properties. The importance of the study is to remove oxygenated compounds in CO using industrial waste adsorbents and solvent. The present upgrading strategy separates CO into an upper homogeneous soluble phase in petroleum ether and a lower non-homogeneous insoluble phase in petroleum ether. Oxygenates are reduced from 40.13 wt.% to 0.14 wt.% with the use of calcium hydroxide as an adsorbent and petroleum ether as a solvent. Finally, a discussion on the overview of the upgradation strategy is briefly summarized at the end of the manuscript