A review on nitrogen transformation in hydrochar during hydrothermal carbonization of biomass containing nitrogen

Leng, Lijian; Yang, Lihong; Leng, Songqi; Zhang, Weijin; Zhou, Yaoyu; Peng, Haoyi; Li, Hui; Hu, Yingchao; Jiang, Shaojian; Li, Hailong

doi:10.1016/j.scitotenv.2020.143679

Cited by 140 publications

(37 citation statements)

References 103 publications

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“…This result is in accordance with other studies that showed that the availability of the carbon network is the key for N recovery to the HC during HTC. 42,43 The results show that the N-HC yield could be influenced by adjusting the concentration of the N precursor, the available carbon network, and the pH value of the reaction medium. Other reaction parameters could also influence the N content in the HC such as the reaction temperature or the retention time.…”

Section: The Influence Of N Precursor On the Hc Formation And Its N C...mentioning

confidence: 99%

Thermal treatment versus hydrothermal carbonization: How to synthesize nitrogen‐enriched carbon materials for energy storage applications?

Alhnidi

Straten

Nicolae

et al. 2021

Intl J of Energy Research

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The thermal treatment of an activated carbon/chars with a nitrogen precursor is not a sustainable nor an efficient method for the incorporation of N into the carbon structure. This study proposes the use of hydrothermal carbonization (HTC) as an environmentally friendly method for the incorporation of N into the bulk of carbon materials. The authors propose the following sequence for the synthesis of Nenriched carbon materials (NCM) for energy storage applications: HTC of the N precursor and biomass ! activation of N-hydrochar (N-HC). To investigate the proposed method, HTCs of spent coffee grounds (SCG) with N precursors (urea and alanine) were conducted at 220 C for 5 hours. The resulted N-HCs were subjected to a mild thermal activation via pyrolysis at 600 C for 2 hours. The results showed that HTC enhances the incorporation of N into the carbon matrix via many reactions, for example, the Maillard reaction (MR) or the Mannich reaction, which may accompany the formation of HC via the solved-intermediate pathway or the solid-to-solid pathway, respectively. However, adjusting some parameters before HTC, for example, the concentration of the N precursor and the pH value of the slurry is important to avoid a significant reduction in the N-HC yield. The proposed method led to the synthesis of NCM with a N content of 10.3wt% The X-ray photoelectron spectroscopy (XPS) confirmed the incorporation of N into the bulk of NCM and showed a significant increase in the content of heterocyclic N compounds (pyridinic N, pyrrolic N, and graphitic N) in the NCM. The incorporation of N via the proposed method significantly improved the electrochemical properties of NCM as the values of the specific capacitance and the electrical conductivity in the NCM increased by five times and four times, respectively.

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Section: The Influence Of N Precursor On the Hc Formation And Its N C...mentioning

confidence: 99%

Thermal treatment versus hydrothermal carbonization: How to synthesize nitrogen‐enriched carbon materials for energy storage applications?

Alhnidi

Straten

Nicolae

et al. 2021

Intl J of Energy Research

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“…The enrichment of the N, especially during hydrochar production, may be due to the intensive hydrolysis of the protein-rich food waste mixture to nucleic acids [24]. In the literature, it has recently been pointed out that the relatively high percentage of N in protein-rich food waste-derived hydrochar has continued to be a major challenge hindering its commercialization [25] or possible use as solid fuel. For MW of the food waste mixture, elemental N decreased slightly from 3.89 to 3.84%.…”

Section: Resultsmentioning

confidence: 99%

Comparative Investigation of the Physicochemical Properties of Chars Produced by Hydrothermal Carbonization, Pyrolysis, and Microwave-Induced Pyrolysis of Food Waste

et al. 2022

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This work presents a comparative study of the physicochemical properties of chars derived by three thermochemical pathways, namely: hydrothermal carbonization, HTC (at 180, 200 and 220 °C), pyrolysis, PY, (at 500, 600 and 700 °C) and microwave assisted pyrolysis, MW (at 300, 450 and 600 W). The mass yield of HTC samples showed a decrease (78.7 to 26.7%) as the HTC temperature increased from 180 to 220 °C. A similar decreasing trend in the mass yield was also observed after PY (28.45 to 26.67%) and MW (56.45 to 22.44%) of the food waste mixture from 500 to 700 °C and 300 to 600 W, respectively. The calorific value analysis shows that the best among the chars prepared by three different heating methods may be ranked according to the decreasing value of the heating value as: PY500, MW300, and HTC180. Similarly, a decreasing trend in H/C values was observed as: PY500 (0.887), MW300 (0.306), and HTC180 (0.013). The scanning electron microscope (SEM) analyses revealed that the structure of the three chars was distinct due to the different temperature gradients provided by the thermochemical processes. The results clearly show that the suitable temperature for the HTC and PY of food waste was 180 °C and 500 °C, respectively, while the suitable power for the MW of food waste was 300 W.

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“…During Stage III, weight loss varied from 41.48 to 59.78%. Knowing that the ɑ-cellulose content was found to be 46.09%, and that Yang et al [42] observed a low residual cellulose residue of 6.5% at 900 °C, the weight loss observed during Stage III probably included subsequent degradation of hemicelluloses and lignin besides cellulose. The decomposition of lignin was not evident from the observation of the curves since it was spread on a large temperature range (from 160 to 900 °C [37]) with a low mass-loss rate.…”

Section: Thermogravimetric Analysis Of Hemp Stalk During Thermochemical Conversionmentioning

confidence: 95%

“…In fact, the nature of the feedstock was the main factor affecting nitrogen evolution during the pyrolysis process. Due to the varied biochemical composition of each biomass, even within the same type of biomass, the trends of the N transformation according to pyrolysis severity is not obvious [42]. In general, lipid and protein-rich biomasses produce biochar with low yield, resulting in less retention of N in biochar.…”

Section: Evolution Of the Elemental Composition Through Carbonization Processmentioning

confidence: 99%

Valorization of Hemp Stalk Waste Through Thermochemical Conversion for Energy and Electrical Applications

Marrot

Candelier

Valette

et al. 2021

Waste Biomass Valor

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The presented research aimed at finding new ways to value hemp by-products (stalks) from the cannabidiol industry through thermochemical conversion. Chemical and elemental composition of hemp biomass was investigated by successive chemical extractions and Scanning Electron Microscopy along with Energy-dispersive X-ray Spectroscopy. Proximate and elemental analyses completed the chemical characterization of the hemp biomass and its biochar. Thermogravimetric analysis of the hemp biomass allowed to understand its kinetic of decomposition during thermal conversion. The carbon structure and porosity of the biochar were assessed by Raman spectroscopy and CO2 gas adsorption. Properties of interest were the energy production measured through calorific values, and the electrical conductivity. Two ways of valorisation of the hemp biomass were clearly identified, depending mainly on the chosen pyrolysis temperature. Hemp biochar carbonized at 400–600°C were classified as lignocellulosic materials with a good potential for solid biofuel applications. Specifically, the resulting carbonized biochar presented low moisture content (below 2.50%) favourable for high fuel quality, low volatile matter (27.1–10.4%) likely to show lower particle matter emissions, limited ash content (6.8–9.8%) resulting in low risk of fouling issues during the combustion, high carbon content (73.8–86.8%) suggesting strong energy density, associated with high higher heating values (28.45–30.95 MJ kg−1). Hemp biochar carbonized at 800–1000 °C displayed interesting electrical conductivity, opening opportunities for its use in electrical purposes. The electrical conductivity was related to the evolution of the biochar microstructure (development of graphite-like structure and changes in microporosity) in regard with the thermochemical conversion process parameters. Graphical abstract

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A review on nitrogen transformation in hydrochar during hydrothermal carbonization of biomass containing nitrogen

Cited by 140 publications

References 103 publications

Thermal treatment versus hydrothermal carbonization: How to synthesize nitrogen‐enriched carbon materials for energy storage applications?

Thermal treatment versus hydrothermal carbonization: How to synthesize nitrogen‐enriched carbon materials for energy storage applications?

Comparative Investigation of the Physicochemical Properties of Chars Produced by Hydrothermal Carbonization, Pyrolysis, and Microwave-Induced Pyrolysis of Food Waste

Valorization of Hemp Stalk Waste Through Thermochemical Conversion for Energy and Electrical Applications

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