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Washing biochar modifies its properties for use as a soil amendment. The important biochar properties for use as a soil amendment are hydrophilicity, adsorption, and stability. Biochar was obtained with intermediate pyrolysis at 400°C of three different feedstocks: woodchips, Bayview Flowers Digestate, and Storm Fisher Digestate biomass. A simple wash with an aqueous surfactant solution improved the properties of the biochar for soil amendment, with a non‐ionic surfactant combined with oxidizing hydrogen peroxide being the most effective. The improved properties included the removal of tars and possible modification of surface properties that increased hydrophilicity and adsorption and decreased leaching of any hydrocarbons that could negatively impact the surroundings. As a result, the washed biochar will exhibit better water retention and a more hospitable environment for the growth of beneficial microorganisms. In addition, by making the biochar more hydrophilic, a wash will make its granulation easier, reducing dust emissions during its application and allowing its formulation with enhancement additives. Although many post‐pyrolysis treatments of biochars have been investigated, the proposed wash is simple and effective, with beneficial advantages for downstream processing and application as a soil amendment. [ABSTRACT FROM AUTHOR]

A challenge in recent years has been the rational use of forest and agriculture residues for the production of bio-fuel, biochemical, and other bioproducts. In this study, potentially useful compounds frompyrolytic ligninswere identified byHPLC-MS/MS and untargetedmetabolomics. The metabolites identified were 2-(4-allyl-2-methoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)-1-propanol, benzyl benzoate, fisetinidol, phenyllactic acid, 2-phenylpropionic acid, 6,3'-dimethoxyflavone, and vanillin. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), trolox equivalent antioxidant capacity (TEAC), and total phenolics content (TPC) per gram of pyrolytic lignin ranged from 14 to 503 mg ascorbic acid equivalents, 35 to 277 mg trolox equivalents, and 0.42 to 50 mg gallic acid equivalents, respectively. A very significant correlation was observed between the DPPH and TPC (r = 0.8663, p ≤ 0.0001), TEAC and TPC (r = 0.8044, p ≤ 0.0001), and DPPH and TEAC (r = 0.8851, p ≤ 0.0001). The polyphenolic compounds in the pyrolytic lignins which are responsible for radical scavenging activity and antioxidant properties can be readily profiled with HPLC-MS/MS combined with untargeted metabolomics. The results also suggest that DPPH, TEAC, and TPC assays are suitable methods for the measurement of antioxidant activity in a variety of pyrolytic lignins. These data show that the pyrolytic lignins can be considered as promising sources of natural antioxidants and value-added chemicals. [ABSTRACT FROM AUTHOR]

Wood pellets were pyrolyzed using a microwave oven and different microwave power, apparatus set-up and microwave absorbers (none, Fe, and carbon). Pyrolysis was realized in a short time in the presence of Fe or carbon while it was incomplete if the absorber was not present. Furthermore when the absorber was present the shape of the pellets remained unaltered while if the absorber was not employed pellets were disaggregated. Three fractions were collected from each pyrolysis: a gas, a liquid also called bio-oil and a solid called bio-char. The bio-oil contained two phases and they were quantitatively characterized through a GC/MS-FID procedure using an internal standard according to a previously reported method. HPLC/MS, FTIR and 1 H NMR spectroscopy were also employed for characterization of these liquids. Cellulose pyrolysis products were present in the upper phase such as water, acetic acid, furans (such as furfural), carbohydrates and their derivatives. Compounds from pyrolysis of lignin such as phenols and veratric acid were present in the bottom phase. The microwave assisted pyrolysis showed the possibility to efficiently convert wood pellets in different products. The main economical important components may be separated and used as chemicals, natural drugs or pesticides, while the remaining components, the solid and the gas may be used for energy production (solid and bio-oil). Solid may be also used for carbon sequestration. [ABSTRACT FROM AUTHOR]

A simple procedure was suggested for the chromatographic analyses of bio-oils from pyrolysis of various feedstock employing different technologies. An acetonitrile solution of each bio-oil was prepared without any extraction or other sample pretreatments. Preliminary thin layer chromatography showed a large number of compounds having a broad range of retention factors (Rfs) among 0–1. Products having a retention factor over 0.9 were mainly detected by GC while some other compounds were only identified by HPLC. GC/MS-FID analysis was used to identify and quantify compounds using peak areas and relative response factors (RRFs). A new equation was proposed to estimate RRFs of compounds identified via their MS spectra when experimental RRFs were not readily available. The novel procedure was employed to characterize bio-oils from pyrolysis of wood of different source or obtained using different pyrolysis procedure. Using this RRF method guaiacol, furfural, butan-2-one, levoglucosan, acetic acid and many other compounds were quantified in bio-oil samples. Different amount of them were found as a function of the type of wood, and pyrolysis conditions adopted. For instance levoglucosan was the main compound using carbon as MW absorber however acetic acid was prevalent when a MW absorber was not employed and both of them were absent in bio-oils from classical heating. The HPLC/MS of bio-oils showed cyclohexancarboxylic acid, 1,2,4-trimethoxybenzene and 2,6-dimethylphenol among the main products present in all bio-oils. On the contrary 4-hydroxyacetophenone and (3,4,5-trimethoxy) acetophenone were present in bio-oil from pyrolysis of wood using MW oven and 2,5-furandiylmethanol when a MW oven without any absorber was employed. Cyclohexanone was present in bio-oils obtained with a thermal heating or a MW oven without any absorber. [ABSTRACT FROM AUTHOR]