Evaluation and implementation of methods for quantifying organic and inorganic components of biochar alkalinity

Fidel, Rivka B.

doi:10.31274/etd-180810-290

Cited by 11 publications

(12 citation statements)

References 53 publications

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“…Total biochar carbonates (CO3 2-+ HCO3 -) were quantified in triplicate using a modified NaOH trap method (Fidel, 2012). Briefly, 2 g of each biochar (or 1 g of HW5s and MW6g, see section The quantities of CO3 2and HCO3in the total biochar carbonates (determined above)…”

Section: Carbonate Alkalinitymentioning

confidence: 99%

Characterization and quantification of biochar alkalinity

et al. 2017

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Lack of knowledge regarding the nature of biochar alkalis has hindered understanding of pH-sensitive biochar-soil interactions. Here we investigate the nature of biochar alkalinity and present a cohesive suite of methods for its quantification. Biochars produced from cellulose, corn stover and wood feedstocks had significant low-pK organic structural (0.03-0.34 meq g), other organic (0-0.92 meq g), carbonate (0.02-1.5 meq g), and other inorganic (0-0.26 meq g) alkalinities. All four categories of biochar alkalinity contributed to total biochar alkalinity and are therefore relevant to pH-sensitive soil processes. Total biochar alkalinity was strongly correlated with base cation concentration, but biochar alkalinity was not a simple function of elemental composition, soluble ash, fixed carbon, or volatile matter content. More research is needed to characterize soluble biochar alkalis other than carbonates and to establish predictive relationships among biochar production parameters and the composition of biochar alkalis.

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Section: Carbonate Alkalinitymentioning

confidence: 99%

Characterization and quantification of biochar alkalinity

et al. 2017

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“…Linhares et al (2012) say that biochar interaction with the environment can form new compounds with carboxyl groups directly connected to the charcoal recalcitrant aromatic structures, contributing to the cation exchange capacity. These processes were conducted according to Fidel (2012) and Tsechansky & Graber (2014 , and P contents (Claessen, 1997) -are shown in Figure 2.…”

Section: Methodsmentioning

confidence: 99%

Biochar in substrate composition for production of teak seedlings

Rezende

Santos

Maia

et al. 2016

Pesq. agropec. bras.

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-The objective of this work was to evaluate the development and quality of clonal seedlings of teak (Tectona grandis) grown in substrate with two types of biochar. The assay was carried out in a randomized complete block design, with ten treatments and four replicates: CS, commercial substrate, composed of pine bark and vermiculite at a ratio of 4:1; NS, nursery substrate composed of carbonized rice husk and coconut fiber at 1:1; and the remaining treatments were composed of the inclusions of biochar (BC) or activated biochar (BCA) in the CS, at the proportions of 25, 50, 75, and 100%. The development and quality parameters of seedlings were evaluated 90 days after striking the minicuttings in the substrates. BCA substrate additions at 25, 50, and 100% allowed for a development of height and stem diameter comparable to that of the NS. Biochar without the activation procedure does not improve quality parameters of seedlings, in comparison with the commercial substrate. The use of 25% activated biochar added to the commercial substrate is enough to improve seedling growth performance to the same level as that provided by the already validated NS.Index terms: Tectona grandis, agroindustrial waste, biochar activity, pyrolysis, seedling quality. Biochar na composição de substratos para a produção de mudas de tecaResumo -O objetivo deste trabalho foi avaliar o desenvolvimento e a qualidade de mudas clonais de teca (Tectona grandis) cultivadas em substrato com dois tipos de biochar. O ensaio foi realizado em delineamento de blocos ao acaso, com dez tratamentos e quatro repetições: SC, substrato comercial, composto de casca de pinus e vermiculita à proporção de 4:1; SV, substrato do viveiro, composto de casca de arroz carbonizada e fibra de coco a 1:1; e o restante dos tratamentos foi composto de inclusões de biochar (B) e biochar ativado (BA), nas proporções de 25, 50, 75 e 100% do SC. Os parâmetros de desenvolvimento e qualidade das mudas foram avaliados 90 dias após o plantio das estacas nos substratos. A adição de 25, 50 e 100% de BA possibilitou o desenvolvimento em altura e diâmetro do coleto comparável ao proporcionado pelo SV. O biochar sem o procedimento de ativação não melhora os parâmetros de qualidade das mudas, em comparação ao substrato comercial. A adição de biochar ativado na proporção de 25% já é suficiente para melhorar o crescimento das mudas para o mesmo nível proporcionado pelo já validado SV.Termos para indexação: Tectona grandis, resíduo agroindustrial, atividade do biochar, pirólise, qualidade de mudas.

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“…If the ash fraction were to dissolve in the Boehm reactants, it would violate the assumption that the reactants only interact with organic surface functional groups (Cheng et al, 2006). Indeed, carbonates and other inorganic alkalis have been previously quantified in biochars and were found in sufficient concentrations to interfere with the Boehm titration (Fidel, 2012). Second, if organic biochar carbon were to partially dissolve in the reactants, it would violate the assumption that the carbon and reactant phases were fully separated before titration (Kim et al, 2012).…”

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confidence: 99%

Evaluation of Modified Boehm Titration Methods for Use with Biochars

2013

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The Boehm titration, originally developed to quantify organic functional groups of carbon blacks and activated carbons in discrete pK ranges, has received growing attention for analyzing biochar. However, properties that distinguish biochar from carbon black and activated carbon, including greater carbon solubility and higher ash content, may render the original Boehm titration method unreliable for use with biochars. Here we use seven biochars and one reference carbon black to evaluate three Boehm titration methods that use (i) acidification followed by sparging (sparge method), (ii) centrifugation after treatment with BaCl (barium method), and (iii) a solid-phase extraction cartridge followed by acidification and sparging (cartridge method) to remove carbonates and dissolved organic compounds (DOC) from the Boehm extracts before titration. Our results for the various combinations of Boehm reactants and methods indicate that no one method was free of bias for all three Boehm reactants and that the cartridge method showed evidence of bias for all pK ranges. By process of elimination, we found that a combination of the sparge method for quantifying functional groups in the lowest pK range (∼5 to 6.4), and the barium method for quantifying functional groups in the higher pK ranges (∼6.4 to 10.3 and ∼10.3 to 13) to be free of evidence for bias. We caution, however, that further testing is needed and that all Boehm titration results for biochars should be considered suspect unless efforts were undertaken to remove ash and prevent interference from DOC.

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Evaluation and implementation of methods for quantifying organic and inorganic components of biochar alkalinity

Cited by 11 publications

References 53 publications

Characterization and quantification of biochar alkalinity

Characterization and quantification of biochar alkalinity

Biochar in substrate composition for production of teak seedlings

Evaluation of Modified Boehm Titration Methods for Use with Biochars

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