## 1 Introduction  
The current global energy and climate crisis demands an increased share of renewable sources. Biomass materials, which account for about 15% of the world's energy supply, are widespread in most countries, are low in cost and reduce greenhouse gas emissions, in line with the European Union directives for decarbonized energy by 2050. Furthermore, the European Union's Waste Framework Directive has set the management hierarchy for the recycling and reuse of waste, such as municipal waste, due to environmental restrictions, limited landfill sites and high cost [1]. Among thermochemical processes, pyrolysis is a promising solution for the reduction of the volume of waste material, destroying its hazardous constituents and allowing the recovery of energy and added-value products [2]. Biochar, the solid pyrolysis product, can be used not only for soil amelioration, improving its physicochemical and biological properties while sequestrating carbon and restoring contaminated soil and water, but also for heat and power generation, or tar-free fuel gas production [3; 4; 5; 6]. The liquid pyrolysis product, bio-oil, can be utilized as a source of special chemicals, or in energy appliances such as boilers, engines or turbines [7; 8]. The gaseous pyrolysis product, consisting of H\({}_{2}\), CO, CO\({}_{2}\) and light hydrocarbons, can be used to dry the biomass feedstock and supply the heat for the pyrolysis process [4; 8]. Many studies have been carried out to assess the properties of various biochars for soil amendment and active carbon applications [4; 5; 9; 10; 11; 12]. The properties of biochars are directly affected by the type of feedstock used and the pyrolysis operating conditions, especially temperature. The majority of previous studies focused on biochars derived from agricultural waste, such as rice straw, sugarcane bagasse, empty fruit bunches, corn residues, etc. [4; 13; 14; 15; 16], and only a few focused on forest waste [17; 18]. The characterization of biochars for their evaluation as energy sources was conducted by proximate and ultimate analyses, calorific value, specific surface area and pore volume, Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. Many different chromatographic and spectroscopic techniques have also been used to characterize bio- oils from a variety of species [4; 8; 17; 19; 20]. Gas chromatography-mass spectrometry (GC/MS) analysis was carried out to identify the individual chemical compounds in bio- oils produced from fast pyrolysis of woody biomasses at 500 \({}^{\circ}\)C. Several carbohydrates were detected [17]. A FTIR spectrometer was used to characterize various functional groups found in the bio-oil produced from the pyrolysis of date palm stones at 500 \({}^{\circ}\)C. The FTIR spectrum showed that the obtained bio-oil was composed of several functional groups belonging to various families of organic groups, namely aliphatic groups, oxygenated fractions and aromatic groups. The chemical composition of the bio-oil was determined by liquid column chromatography fractionation. [19]. The characterization of sugarcane bagasse bio-oil produced from semi-batch pyrolysis experiments at 500 \({}^{\circ}\)C was performed by FTIR, GC/MS and nuclear magnetic resonance (NMR) spectroscopy. It was found to consist of a complex mixture of chemical compounds, including acids, alcohols, aldehydes, furfural, furan, phenols and some aromatics [4; 20]. Meanwhile, the characterization of bio-oil produced from the pyrolysis of sawdust at 500 \({}^{\circ}\)C was performed using \({}^{1}\)H and \({}^{13}\)CNMR, FTIR and GC/MS analysis techniques. These analyses showed that the bio-oil was a reservoir of oxygenated and highly functionalized chemical compounds, such as phenols, ketones, alcohols, nitrogen-containing compounds, cyclic ethers, aromatic compounds, acids, halides, aldehydes, hydrocarbons, furan and esters [8].