Contaminants in biochar and suggested mitigation measures – a review

Han, Huawen; Buss, Wolfram; Zheng, Yubin; Song, Peizhi; Rafiq, Muhammad; Liu, Pu; Mašek, Ondřej; Li, Xiangkai

doi:10.1016/j.cej.2021.132287

Cited by 57 publications

(11 citation statements)

References 162 publications

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“…137 High pyrolysis temperatures (>700 °C) are favorable for biochar with low persistent free radicals (PFRs). 137,145,146 2.3. Biochar Properties and Methods for Characterization.…”

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

“…During biochar activations, it is also possible for the production of contaminants such as polyaromatic hydrocarbons (PAHs) . Volatile PAHs can be generated at temperatures over 600 °C in the vapor phase or can be released by the oxidation of bridges between large biochar polyaromatic ring systems. − Fast pyrolysis and gasification showed higher productions of PAHs in comparison to slow pyrolysis .…”

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

“…Volatile PAHs can be generated at temperatures over 600 °C in the vapor phase or can be released by the oxidation of bridges between large biochar polyaromatic ring systems. − Fast pyrolysis and gasification showed higher productions of PAHs in comparison to slow pyrolysis . Increasing carrier gas flow and thermal post-treatment can reduce the PAHs in biochar. − The type of biomass used for biochar production is an important factor to avoid biochar with a high content of potentially toxic elements (PTEs) . High pyrolysis temperatures (>700 °C) are favorable for biochar with low persistent free radicals (PFRs). ,, …”

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

“…Increasing carrier gas flow and thermal post-treatment can reduce the PAHs in biochar. − The type of biomass used for biochar production is an important factor to avoid biochar with a high content of potentially toxic elements (PTEs) . High pyrolysis temperatures (>700 °C) are favorable for biochar with low persistent free radicals (PFRs). ,, …”

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

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Perspectives of Engineered Biochar for Environmental Applications: A Review

2022

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Research on using biochar for environmental applications has witnessed unprecedented advances in the past decade. Biochar is universally considered one of the best alternatives to store carbon to fight global warming. Thus, the sequential use of biochar in environmental remediation compatible with carbon sequestration is receiving growing attention. One of the reasons for such huge interest is the possibility to engineer biochar with targeted properties (e.g., surface area and chemistry) relevant to existing environmental issues. These properties can be achieved by selecting appropriate raw materials, processing conditions, carbonization technology, and the possibility of selecting postproduction modification approaches. The objective of this review is to summarize strategies to enhance biochar properties relevant to its use in environmental services (e.g., water purification, air/gas cleaning, construction materials, soil amendments) and the corresponding results on the use of this material for these applications. The main methods for enhancing biochar properties for environmental applications reviewed include activation (physical and chemical), oxidation, metal and metal oxide modification, metal-free heteroatom doping, and biological modification. Both modified and unmodified biochars have been used for soil amendments as adsorbents of pollutants in the aqueous phase (e.g., removal of P and N, heavy metals, and organic pollutants), adsorbents of pollutants in the gas phase (e.g., biogas cleaning), as a catalyst, as an additive for improving anaerobic digestion, and as an admixture to cementitious/construction materials, with promising results in all cases. New opportunities for using biochar are being reported as the science of biochar production, modification, and use advances.

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“…137 High pyrolysis temperatures (>700 °C) are favorable for biochar with low persistent free radicals (PFRs). 137,145,146 2.3. Biochar Properties and Methods for Characterization.…”

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

Section: Biochar Production Formation Characterization and Modificationmentioning

confidence: 99%

See 2 more Smart Citations

Perspectives of Engineered Biochar for Environmental Applications: A Review

2022

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“…As a result, more consideration should be given to the pollutants produced by biochar. Traditional pollutants including VOCs, PAHs, dioxins, and heavy metals, as well as new contaminants like nanoparticles and PFRs, can all be generated during biochar synthesis, according to the existing literature (Han et al, 2022;Zheng et al, 2018). There is currently inadequate evidence in the literature to draw inferences on pollutants in biochar, thus further research is needed to fill in the gaps.…”

Section: Knowledge Gaps and Perspectivesmentioning

confidence: 99%