Polycyclic aromatic hydrocarbons (PAHs) in biochar – Their formation, occurrence and analysis: A review

Wang, Congying; Wang, Yingdi; Herath, H.M.S.K.

doi:10.1016/j.orggeochem.2017.09.001

Cited by 154 publications

(87 citation statements)

References 92 publications

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“…Thus, hemicellulose and cellulose decomposition led to the formation of relatively heavy molecules at low temperatures and an increase in PAHs content with increasing temperature. The reverse trend was reported by Wang et al [16], where relatively light PAHs were formed at low temperatures, whereas relatively heavy PAHs were formed at high temperatures. The diversification of the research results led researchers to the conclusion that temperature alone is not the main factor influencing PAHs formation [14,15,35]-their formation seems to be a result of the synergic influence of temperature and feedstock type.…”

Section: Resultsmentioning

confidence: 57%

“…During the torrefaction of biomass, organic compounds are partially cracked in unstable fragments, composed of highly reactive free radicals, which then react with surrounding compounds and form more stable PAHs [12]. They are formed directly via lignin, cellulose, and hemicellulose dehydrogenation, dealkylation and aromatization; the elimination of functionalities in the compounds such as H 2 O, CO 2 , CH 4 , and H 2 S, results in aromatized structures [16]. Table 3 shows the contents of 15 PAHs, determined for two samples-wheat-barley straw pellets torrefied at 320°C and Acenaphthene, fluorene, phenanthrene, anthracene, and fluoranthene were detected in the analyzed samples.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, some of the previous studies showed that lignin decomposition resulted in an increase in PAHs concentration [16]. Lignin degrades at temperatures in the range of 180-300°C [36] and is considered to be decomposed to a large extent at temperatures higher than 300°C [37].…”

Section: Resultsmentioning

confidence: 99%

“…Unfortunately, the available literature does not offer a tool for predicting PAHs content in biochar, as the data do not show an overall trend in the relationship between PAHs formation and process parameters. PAHs content is strongly related to the feedstock type and process temperature [15], but a consensus has not yet been reached on this relationship [16]. Therefore, the authors investigated the PAHs content in biochar torrefied at different temperatures to evaluate its possibility of being used as fertilizer.…”

Section: Introductionmentioning

confidence: 99%

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Torrefaction of Agricultural Residues: Effect of Temperature and Residence Time on the Process Products Properties

Jagodzińska

Czerep

Kudlek

et al. 2020

Journal of Energy Resources Technology

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To date, few studies on the potential utilization of agricultural residue torrefaction products have been performed. Thus, torrefaction product characterization aimed at its potential utilization was performed. Wheat-barley straw pellets and wheat-rye chaff were used in the study. The impact of the torrefaction temperature (280-320°C) on polycyclic aromatic hydrocarbons (PAHs) content in the biochar and noncondensable gas (noncondensables) composition was investigated. The impact of the torrefaction time (30-75 min) on the composition of the condensable volatiles (condensables) and their toxicity were also studied. The torrefaction process was performed in a batch-scale reactor. The PAH contents were measured using high-performance liquid chromatography (HPLC), and the noncondensables composition was measured online using a gas analyzer and then gas chromatograph with flame ionization detector (GC-FID). The condensables composition and main compound quantification were determined and quantified using gas chromatography-mass spectrometry (GC/MS). Three toxicity tests, for saltwater bacteria (Microtox ® bioassay), freshwater crustaceans (Daphtoxkit F magna ® ), and vascular plants (Lemna sp. growth inhibition test), were performed for the condensables. The PAHs content in the biochar, regardless of the torrefaction temperature, allows them to be used in agriculture. The produced torgas shall be co-combusted with full-caloric fuel because of its low calorific value. Toxic compounds (furans and phenols) were identified in the condensable samples, and regardless of the processing time, the condensables were classified as highly toxic. Therefore, they can be used either as pesticides or as an anaerobic digestion substrate after their detoxification.

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Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Torrefaction of Agricultural Residues: Effect of Temperature and Residence Time on the Process Products Properties

Jagodzińska

Czerep

Kudlek

et al. 2020

Journal of Energy Resources Technology

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“…Recently, a lot of attention has been focused on rich carbon material (ERCM) such as biochar. Biochar is a co-product of biomass pyrolysis that is targeted as a material with applications in environmental protection (e.g., soil remediation) and agricultural management as a source for carbon sequestration (Beesley et al 2011;Wang et al 2017). It also improves soil physicochemical and biological properties, including nutrient status, soil structure, and water holding capacity (Lehmann et al 2011;Herath et al 2013), as well as modifies microbial community abundance and soil enzyme activity (Gomez et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Dissipation and sorption processes of polycyclic aromatic hydrocarbons (PAHs) to organic matter in soils amended by exogenous rich-carbon material

2019

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Purpose The aim of the research was to assess the effect of biochar addition on aging, degradation, and sorption processes of polycyclic aromatic hydrocarbons (PAHs) to soil organic matter. The study was carried out as a sorption experiment in strictly controlled water and air conditions, which allowed for the accurate observation and prediction of PAH behavior in soils. Materials and methods Four soils were fortified with a PAH mixture (Fluorene-Flu, Anthracene-Ant, Phenanthrene-Phe, Pyrene-Pyr, Chrysene-Chry) at 20 mg kg −1 of single-compound concentration level. The experiment was carried out in two trials: soils + 5PAHs amended with biochar and soil + 5PAHs without biochar addition with incubation times of 0, 1, 3, 6, and 9 months. After each interval time, the extractable (E-SOM) and stable organic matter (S-SOM) were measured as well as PAHs determined in two forms: total concentration (PAH-tot) and residual concentration (PAH-rest) after E-SOM extraction. The PAH loss and halflife times were estimated according to pseudo first-order kinetics equation. Results and discussion The amounts of PAH-tot in the soils without biochar decreased by an average of 92%, while in soil with biochar, this was 41% after 9 months of aging. The amount of PAHs-rest bounded with S-SOM after 9 months of incubation varied from 0.9 to 3.5% and 0.2 to 1.3% of the initial PAH concentration, respectively, for soils non-induced and induced by biochar. In soils without biochar, Flu, Ant, Phe, and Pyr exhibited similar T 1/2 (43-59 days), but Chry was characterized by a much higher and broader T 1/2 than other hydrocarbons (67-280 days). Biochar addition to the soils significantly influenced the half-life changes for all PAHs. The highest changes were noted for Phe (14-fold increase), and the lowest was for Flu (7-fold increase). Conclusions The addition of exogenous-rich carbon material such as biochar to the soil significantly changes the behavior and sorption potential of PAHs in the soil. Soils enriched with biochar are characterized by a higher persistence of PAHs, longer aging time, and lower affinity for sorption by native organic matter structures. Soils freshly polluted by PAH are mainly sorbed by E-SOM, which significantly increases their accessibility and reduces formation of bound-residues in the soil.

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Fate, Transport, and Impact of Biochar in the Environment

Pan¹,

Sun

Tsang

2023

Biochar Applications for Wastewater Treatment

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Polycyclic aromatic hydrocarbons (PAHs) in biochar – Their formation, occurrence and analysis: A review

Cited by 154 publications

References 92 publications

Torrefaction of Agricultural Residues: Effect of Temperature and Residence Time on the Process Products Properties

Torrefaction of Agricultural Residues: Effect of Temperature and Residence Time on the Process Products Properties

Dissipation and sorption processes of polycyclic aromatic hydrocarbons (PAHs) to organic matter in soils amended by exogenous rich-carbon material

Fate, Transport, and Impact of Biochar in the Environment

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