The Different Faces of Biochar: Contamination Risk Versus Remediation Tool

Hilber, Isabel; Bastos, Ana Catarina; Loureiro, Susana; Soja, Gerhard; Marsz, Aleksandra; Cornelissen, Gerard; Bucheli, Thomas D.

doi:10.3846/16486897.2016.1254089

Cited by 79 publications

(39 citation statements)

References 158 publications

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“…1 Since biochar has a high sorption potential for a large range of contaminants its use has also been proposed for the remediation of soils and sediments. 2,3 The properties of biochar are known to change following its application to soil, as a result of ageing processes. 1,4 Ageing can, for instance, modify the bulk elemental composition and porosity of biochar, 4 as well as the composition and bioaccessibility of intrinsic organic compounds such as polycyclic aromatic hydrocarbons (PAHs).…”

Section: Introductionmentioning

confidence: 99%

Effect of ageing on the properties and polycyclic aromatic hydrocarbon composition of biochar

Sigmund

Bucheli²,

Hilber³

et al. 2017

Environ. Sci.: Processes Impacts

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The influence of ageing on biochar properties has been investigated by comparing three fresh biochars with biochars artificially aged by either HO thermal oxidation or horseradish peroxidase enzymatic oxidation. In addition, a field-aged counterpart for one of the biochars was recovered from an agricultural field site, four years after application. Biochar properties, including surface areas and pore volumes (derived by N and CO physisorption) and elemental compositions, showed only minor changes following both artificial and field ageing, indicating high biochar stability. Concentrations of the 16 US EPA PAHs were measured in all of the biochars and a contaminant trap was used to investigate the effect of ageing on their bioaccessibility. The concentrations of total and bioaccessible PAHs ranged from 4.4 to 22.6 mg kg and 0.0 to 9.7 mg kg, respectively. Concentrations of the 16 US EPA PAHs decreased following field ageing, but the proportion of low molecular weight PAHs increased. The observed changes in PAH composition with field ageing can be explained by uptake from the surrounding soil and intra-biochar transfer processes. To better understand changes in PAH composition with ageing, an additional broad range of alkylated PAHs was also analyzed in selected samples. Our results show that the tested artificial ageing protocols are unable to approximate the changes in PAH composition resulting from field ageing. Nevertheless, total and bioaccessible PAH concentrations decreased for both artificially and field-aged biochars, indicating that biochars release PAHs when they are freshly produced and that the risk of PAH release decreases with ageing.

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Section: Introductionmentioning

confidence: 99%

Effect of ageing on the properties and polycyclic aromatic hydrocarbon composition of biochar

Sigmund

Bucheli²,

Hilber³

et al. 2017

Environ. Sci.: Processes Impacts

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“…This significantly lower number of field studies may be attributed to some environmental constraints (changing temperatures, rainfall, microbial activity and soil pH) impeding the application of biochar in the field. The analysis of publications on field work suggest that significant work is required to assess the efficiency of biochar in the field and to translate laboratory or greenhouse results to field realities, consistent with the conclusions of Hilber et al (2017a). The number of publications between 2009 and 2017 grouped according to publication type (i.e.…”

mentioning

confidence: 56%

“…Several studies notably Hale et al (2012), Han et al (2016), Hilber et al (2012) and Yavari et al (2015), have all discussed the possibility of biochar being a source of contaminant itself in soil. During pyrolysis, compounds such as PAHs, dioxins and PCBs may develop in biochar together with some heavy metals like Pb, Cd, Cu, Zn, and Al from the original biomass material (Hilber et al 2017a). These compounds are often not available for microbial breakdown as they remain tightly bound to biochar matrices through π-π interactions (Yavari et al 2015).…”

Section: Challenges In Field Application Of Biocharmentioning

confidence: 99%

Advances in research on the use of biochar in soil for remediation: a review

et al. 2018

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Purpose Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a low-cost material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants. Materials and methods Bibliometric analysis were carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e. As and Pb), and three organic classes (i.e. sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively) while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides and hydrocarbons, respectively. Results and discussion The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanolwater partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar's suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield and mine soils) at different pH levels (4-5.5) and contaminant concentrations (< 50 and > 50 mg kg-1). Conclusions Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar's ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist.

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“…These include the potential provision of refuge for microbial communities, shifts in available nutrients and nutrient ratios (Gundale, DeLuca 2006;Prendergast-Miller et al 2014), bioavailable contaminants (e.g. Elad et al 2012;Graber, Elad 2013;Denyes et al 2012;Hilber et al, this issue), enhanced plant root development and systemic defence against biotic or abiotic stress (Elad et al 2010;Jaiswal et al 2014) as well as microbial or plant-symbiont molecular signalling dynamics (Spokas et al 2010;Masiello et al 2013;Graber et al 2015).…”

Section: Soil Biodiversity and Ecotoxicologymentioning

confidence: 99%

Biochars in Soils: Towards the Required Level of Scientific Understanding

Tammeorg

Bastos

Jeffery

et al. 2016

Journal of Environmental Engineering and Landscape Management

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Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar’s effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar’s contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil ph buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.

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The Different Faces of Biochar: Contamination Risk Versus Remediation Tool

Cited by 79 publications

References 158 publications

Effect of ageing on the properties and polycyclic aromatic hydrocarbon composition of biochar

Effect of ageing on the properties and polycyclic aromatic hydrocarbon composition of biochar

Advances in research on the use of biochar in soil for remediation: a review

Biochars in Soils: Towards the Required Level of Scientific Understanding

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