Production Temperature Effects on the Structure of Hydrochar-Derived Dissolved Organic Matter and Associated Toxicity

Hao, Shilai; Zhu, Xiangdong; Liu, Yuchen; Qian, Feng; Fang, Zhi; Shi, Quan; Zhang, Shicheng; Chen, Jianmin; Ren, Zhiyong Jason

doi:10.1021/acs.est.7b04983

Cited by 99 publications

(32 citation statements)

References 55 publications

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“…Previous research has pointed to the potential presence of some problematic substances including polycyclic aromatic hydrocarbons (PAHs) (Keiluweit et al, 2012;Zhao et al, 2020), heavy metals and other elements (such as Cd, Pb, Cu, Zn, and As) (Freddo et al, 2012;Stefaniuk et al, 2016), water dissolved organic matters (WDOMs) (Smith et al, 2016;Ghidotti et al, 2017) and persistent free radicals (Liao et al, 2014;Lieke et al, 2018). Consequently, a series of studies have been performed on the effects of such hazardous chemicals since they can induce biotoxicity inhibiting germination, causing tissue damage and cytotoxicity (Oleszczuk et al, 2013;Sigmund et al, 2017;Hao et al, 2018;Zhang et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy

Luo

Lin

Liu

et al. 2020

Journal of Hazardous Materials

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With the aim to develop optimized biochar with minimal contaminants, it is important significance to broaden the understanding of biochar. Here, we disclose for the first time, a highly toxic substance (metal cyanide, MCN, such as KCN or NaCN) in biochar. The cyanide ion (CN -) content in biochar can be up to 85870 mg/kg, which is determined by the inherent metal content and type in the biomass with K and Na increasing and Ca, Mg and Fe decreasing its formation. Density functional theory (DFT) analysis shows that unstable alkali oxygen-containing metal salts such as K2CO3 can induce an N rearrangement reaction to produce for example, KOCN. The strong reducing character of the carbon matrix further converts KOCN to KCN, thus resulting biochar with high risk.However, the stable Mg, Ca and Fe salts in biomass cannot induce an N rearrangement reaction due to their high binding energies. We therefore propose that high valent metal chloride salts such as FeCl3 and MgCl2 could be used to inhibit the production of cyanide via metal interactive reaction. These findings open a new point of view on the potential risk of biochar and provide a mitigation solution for biochar's sustainable application.

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Section: Introductionmentioning

confidence: 99%

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy

Luo

Lin

Liu

et al. 2020

Journal of Hazardous Materials

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“…On the other hand, pyrolysis above 700°C induces a drastic decline of biomethane promotion. These ndings may be explained by changes of molecular structure with temperature (Hao et al, 2018). Indeed, Keiluweit et al (2010) observed a gradual change in the molecular structure of plant biomass-derived biochar with temperature.…”

Section: Effect Of Pyrolysis Temperaturementioning

confidence: 99%

Biochar promotes methane production during anaerobic digestion of organic waste

et al. 2021

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Climate change and energy demand are calling more sustainable fuels such as biomethane produced by anaerobic digestion of organic waste. Biochar addition to waste is presumed to enhance the e ciency of methane production, yet individual reports disclose contradictory results. Therefore, we performed a meta-analysis of 27 selected publications containing 156 paired measurements of control and biocharamended treatments to assess the impact of biochar on methanogenic performance. Results show that biochar promotes biomethane production substantially with a high Hedge's d value of 5.7 ± 1.04, yet sporadic publications report a methane decline. Methanogenic performance is statistically controlled by feedstock type, pyrolysis temperature and biochar concentration, but not controlled by pH, size, surface area and methanogen species. Our ndings should help to tune the parameters of anaerobic digestion with biochar to optimize biomethane productions.

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“…A study by Bargmann et al (2014b) showed that the addition of HC initially inhibited seed germination of barley, but this effect was diminished after nine weeks, likely due to microbial decomposition. It was suggested that this decomposition was indirectly facilitated by the dissolved organic carbon (DOC) content of the HC, which stimulated microbial growth (Gronwald et al 2015;Hao et al 2018). The transient nature of this effect was also evinced by and Mukherjee et al (2016).…”

Section: Introductionmentioning

confidence: 99%

The influence of hydrochar from biogas digestate on soil improvement and plant growth aspects

Jager

Röhrdanz

Giani

2020

Biochar

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Hydrochar (HC), produced by hydrothermal carbonization, offers technical advantages over biochar (BC) produced by pyrolysis, and is suitable for soil amelioration, carbon sequestration, and enhanced plant growth. BC grain size has been shown to influence nutrient retention, microbial colonization and aggregate formation; however, similar research for HC is lacking. Pot trials were conducted to investigate the influence of HC grain size [coarse (6.3-2 mm), medium (2-0.63 mm) and fine (< 0.63 mm)], produced from biogas digestate, for soil improvement in three soils: loamy Chernozem, sandy Podzol, and clayey Gleysol, at a 5% HC application rate (w/w). All soils including two controls (with and without plants) were analysed for water holding capacity (WHC), cation exchange capacity (CEC), wet aggregate stability, pH, plant available nutrients (PO 4 -P, K and N min ) and germination and biomass success using standard laboratory and statistical methods. Soil pH showed a compensatory shift toward the HC pH (7.2) in all soils over the course of the study. For example, the pH of the medium grained HC treatment for the Chernozem decreased from 7.9 to 7.2 and increased in the Podzol and Gleysol from 5.9 to 6.1 and 4.9 to 5.5, respectively. The nutrient-rich HC (2034 ± 38.3 mg kg −1 PO 4 -P and 2612.5 ± 268.7 mg kg −1 K content) provided only a short-term supply of nutrients, due to the relatively easily mineralized fraction of HC, which allowed for quick nutrient release. The pH and PO 4 -P effects were most pronounced in the fine grained HC treatments, with a ~ 87%, ~ 308% and ~ 2500% increase in PO 4 -P content in the Chernozem, Podzol and Gleysol, respectively, compared to the controls at the beginning of the study. The same trend was observed for the K and NH 4 + content in the fine and medium grained HC treatments in all soils. No seed germination inhibition of Chinese cabbage was observed, with average germination rates > 50% in all soils. An effect on NO 3 − content was indeterminable, while there was little to no effect on biomass production, WHC, CEC and aggregate stability. In conclusion, the application of 5% fine grained HC significantly influenced the nutrient content over a short-term. However, the application rate was insufficient to substantially improve plant growth, nor to sustain a longer-term nutrients supply, regardless of grain size.

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Production Temperature Effects on the Structure of Hydrochar-Derived Dissolved Organic Matter and Associated Toxicity

Cited by 99 publications

References 55 publications

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy

Reveal a hidden highly toxic substance in biochar to support its effective elimination strategy

Biochar promotes methane production during anaerobic digestion of organic waste

The influence of hydrochar from biogas digestate on soil improvement and plant growth aspects

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