• Thermogravimetric Analysis
    (TGA) of Biochar
    At Celignis Biomass Lab

Background to TGA

Thermogravimetric analysis (TGA) is a useful means of evaluating the thermal behaviour of a material over a wide temperature range. This method of analysis is widely used to evaluate the stability, purity, and thermal tolerance of a range of materials such as polymers, fuels, and fibres.

As a result, TGA is particularly useful for examining new biobased materials and products and in comparing them against the alternatives (biobased and non-biobased) that currently exist in the marketplace.

Thermogravimetric analysis involves the weight of a sample being recorded as the temperature it is exposed to increases. TGA produces a curve, that shows the effect of temperature (or time), presented on the x axis, on the weight of the sample (the y axis). The weight is usually expressed in terms of the percentage of the sample that remains, versus the weight at the start of the experiment, at a given temperature/time.

We can undertake this analysis in a range of different atmospheres, with nitrogen and air being the most commonly used. At Celignis we would normally recommend using nitrogen as the enivronmental gas as this allows you to evalaute the volatility of the sample at different temperatures without the interference of combustion on the results.

Thermogravimetric Analysis of Biochar

TGA is a powerful analytical technique for the study of biochars because it allows researchers to examine the thermal stability of the material as a function of temperature. The thermal stability of biochars is an important factor to consider when evaluating their potential use as a soil amendment or for carbon sequestration. In particular, the temperature at which the biochar begins to decompose is important because it determines the maximum temperature to which the material can be exposed before it starts to degrade. If the temperature at which decomposition begins is too low, the biochar may not be stable enough for certain applications, such as those that involve exposure to high temperatures, such as those found in some industrial processes.

TGA can also be used to study the effect of upgrading (e.g. chemical and physical treatments) on the thermal stability of biochars. For example, one study investigated the effect of acid treatment on the thermal stability of biochar produced from sugarcane bagasse. The study found that the acid-treated biochar exhibited a higher thermal stability than the untreated biochar, indicating that the acid treatment improved the thermal stability of the material.

TGA can also be used to study the kinetics of thermal degradation. The kinetics of thermal degradation provide information on the rate at which the material decomposes as a function of temperature. This information can be used to determine the activation energy of thermal degradation, which is an important parameter for further understanding thermal stability.

TGA can also be used to study the chemical composition of biochar. As the sample is heated, different components of the biochar will degrade at different temperatures, resulting in different rates and extents of weight loss. By analyzing the weight loss curve, it is possible to determine the composition of the biochar. For example, TGA can be used to measure the amount of volatile matter in the sample, which is an important factor in determining its suitability for use as a fuel. Comparing the TGA curve of the biochar versus the TGA curve of the original pyrolysis feedstock can be particularly important in this regard.

TGA of Biochars at Celignis

We can undertake TGA analysis using just small amounts of sample (e.g 10 mg) whilst still providing accurate mass data for the experiment. We use a TA Instruments Q500 TGA system which, due to its precise control of temperature and gases, along with its highly sensitive weighing scales, is considered to be on the leading edge for scientific research.

We can employ various different programs for the TGA analysis, according to your particular preference, or we can recommend a suitable program based on our experience with the thermogravimetric analysis of a wide range of materials. Such properties that can be changed include:

- The temperature range over which the experiment is conducted.
- The rate of change of the temperature (for example an increase of 5 degrees Celcius per minute).
- Whether there are periods during which the temperature is held constant for a set period of time.
- Combinations of the above temperature treatments, for example periods during the program where the temperature is maintained coupled with phase(s) where one or more temperature gradients are applied.
- Different environmental gases used at different stages of the program. For example, we can run under a nitrogen atmosphere until the final stage of the program where air is then introduced, allowing the sample to be incinerated with only the ash remaining.
- Whether the data are reported as a function of time or temperature. We normally report results with temperature on the x axis but can change this according to your preference. We can also present the DTG curve in various forms.

Celignis Analysis Packages for Thermogravimetric Analysis of Biochar

Additional Information on TGA in Biochar

Feel free to get in touch with us if you have any questions about our TGA services, relevant members of the Celignis biochar team will be happy to assist. Those team members with the most experience with undertaking these tests and interpreting the resulting data are listed below. Also, click here to read more about our TGA methods.

Sajna KV

Bioanalysis Developer


Our Biomass Detective! Designs, tests, optimizes and validates robust analytical methods for properties of relevance to the various biochar market applications.

Dan Hayes

Celignis CEO And Founder

PhD (Analytical Chemistry)

Dreamer and achiever. Took Celignis from a concept in a research project to being the bioeconomy's premier provider of analytical and bioprocessing expertise.

Lalitha Gottumukkala

Chief Innovation Officer


A serial innovator managing multiple projects. Has particular expertise related to the upgrading of biochar and on the assessment of its impact on plant productivity and soil health.

Other Celignis Tests and Services for Biochar

Global Recognition as Biomass and Biochar Experts

Celignis provides valued services to over 1000 clients. We understand how the focus of biochar projects can differ between countries and have advised a global network of clients. We also have customs-exemptions for samples sent to us allowing us to quickly get to work no matter where our clients are based.

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Feedstock Evaluation

Our analysis packages can screen biochar feedstocks. We can estimate biochar yield and quality using feedstock chemical composition and can estimate biochar composition using the ultimate and major/minor elements analyses of the feedstock. With TGA analysis we can also monitor feedstock behaviour under pyrolysis conditions.

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Biochar Production

We can produce biochar samples from your feedstocks using a wide range of temperatures, heating rates, and residence times. We can formulate a Design of Experiments (DoE) to study the effects of varying process parameters on biochar yield and quality and can optimise these outputs according to your desired biochar market applications.

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Biochar Analysis

We have an extensive array of analysis packages to evaluate the suitability of biochar for a range of applications. These analyses cover properties relevant to combustion, soil amendment, feed, and biomaterials. Our reports compare the results against internationally-recognised limits for using the biochar in specific end-products.

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Biochar Combustion Properties

Biochar can be a superior fuel versus virgin biomass due to its greater carbon content and energy density. We offer a wide array of analysis packages to fully evaluate biochar as a fuel. For example, we can determine both organic and inorganic carbon and can monitor the behaviour of the biochar ash over wide temperature ranges.

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Soil Amendment & Plant Growth Trials

We can test biochar for several properties (e.g. water holding capacity, electrical conductivity etc.) relevant to its use in soil amendment. We can also grow plants in biochar-amended soils and assess the impacts of this approach on germination, plant growth, plant health, and soil biology.

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Analysis of PAHs in Biochar

Polycyclic aromatic hydrocarbons can be formed during the pyrolysis of biomass and accumulate in biochar, leading to potential risks to the environment. We can accurately quantify a range of different PAHs and determine if their concentrations exceed regulatory limits. We can also develop strategies to reduce the amount of PAHs in biochar.

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Surface Area and Porosity of Biochar

The suitable markets for a biochar are often greatly dependent on its surface area and pore size-distrubtion. We provide detailed reports on biochar surface area and porosity and can provide guidance on the implications of the results. We can also work on strategies to increase the surface area and modify the pore-size distribution of biochar.

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Biochar Upgrading

There are several different methods (covering physical, chemical and biologial routes) by which we can upgrade your biochar in order to increase its value and make it more suitable for the desired market applications. We are able to fully characterise the changes in physicochemical properties associated with upgrading.

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Biochar for Carbon Sequestration

Biochar's efficacy as a means for sequestering carbon depends on a range of factors (e.g. feedstock and pyrolysis conditions). We can undertake a range of analytical tests to help you determine the stability of your biochar's carbon. We can also suggest alternative approaches to improve carbon sequestration potential.

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Technoeconomic Analyses of Biochar Projects

Our TEA experts work with you to evaluate the economic prospects of your biochar facility, considering various scale, technology, and feedstock options. We apply accurate costing models to determine CAPEX/OPEX of simulated and pilot scale processes which are then used to determine key economic indicators (e.g. IRR, NPV).

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Research Project Collaborations

Celignis is active in a number of important research projects focused on biomass valorisation. Biochar is a key component in some of these ongoing projects as well as in several prior projects. We are open to participating in future collaborative research projects where our extensive infrastructure and expertise in biochar can be leveraged.

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