Analysis of PAH in Biochar
PAHs are considered a carcinogen, meaning they have the potential to cause cancer in humans. They are also mutagenic, meaning that they can cause mutations in DNA, which can lead to genetic disorders.
In the environment, PAHs can be toxic to aquatic organisms, including fish and amphibians, and can also have negative effects on soil microbial communities. They are also persistent in the environment, which means they can remain in soil, water, and air for long periods of time.
Polycyclic Aromatic Hydrocarbons in Biochar
PAHs can be released from biochar into the environment through several pathways, including leaching, volatilization, and erosion. Leaching occurs when water percolates through the soil and carries PAHs with it. Volatilization occurs when PAHs evaporate from the surface of biochar and are released into the air. Erosion occurs when biochar is transported by wind or water and is deposited in other areas.
To minimize the release of PAHs from biochar, several strategies have been proposed. One strategy is to use low-temperature pyrolysis, which has been shown to reduce the formation of PAHs. Another strategy is to use feedstocks that result in lower levels of PAHs production, such as hardwoods. In addition, post-processing techniques, such as washing and air-drying, can be used to remove PAHs from biochar before it is applied to the soil.
Effect of Feedstock on PAHs in Biochar
With regards to feedstock, their differences in chemical compositions and structures can influence the formation and distribution of PAHs during the pyrolysis process. For example, biochar produced from wood feedstocks is often found to contain high levels of Benzo[a]pyrene, a highly toxic and carcinogenic PAH. This is because wood contains high levels of lignin, a complex polymer that can break down during pyrolysis to form PAHs such as Benzo[a]pyrene. Additionally, wood feedstocks tend to have a higher carbon content than other feedstocks, which can result in higher temperatures during pyrolysis and greater production of PAHs.In addition to the formation of PAHs during pyrolysis, the presence of PAHs in the original feedstock can also influence their presence in the resulting biochar. For example, feedstocks that have been contaminated with PAHs from sources such as air pollution, waste disposal, or industrial activities may contain higher levels of these compounds, which can be transferred to the biochar during pyrolysis.
Effect of Pyrolysis Conditions on PAH Levels
Temperature is one of the most important factors in determining the types and amount of PAHs in biochar. Generally, higher pyrolysis temperatures lead to greater production of PAHs, including more toxic and carcinogenic forms such as benzo[a]pyrene and indeno[1,2,3-cd]pyrene. This is because high temperatures can break down complex organic molecules into simpler ones, including PAHs, and can promote reactions that favour their formation.However, there is a limit to the amount of PAHs that can be formed at high temperatures, as excessive heating can cause the PAHs to decompose into simpler compounds.
With regards to residence time, longer residence times typically lead to increased formation of PAHs, as they provide more time for reactions to occur.
Main PAHs in Biochar
Some of the main PAHs found in biochar include:- Benzo[a]pyrene - a PAH consisting of five fused benzene rings. It is a highly toxic and carcinogenic polycyclic aromatic hydrocarbon that is commonly found in biochar produced from wood feedstocks. It is formed during high-temperature pyrolysis and can remain in the environment for long periods of time.
- Indeno[1,2,3-cd]pyrene - a polycyclic aromatic hydrocarbon that consists of six fused benzene rings and a five-membered ring. It is another highly toxic and carcinogenic PAH that is commonly found in biochar.
- Phenanthrene - a PAH that consists of three fused benzene rings. It is commonly found in biochar produced from agricultural waste feedstocks.
- Fluoranthene - consists of four fused benzene rings and is commonly found in biochar produced from wood feedstocks.
- Pyrene - also consists of four fused benzene rings and is also commonly found in biochar produced from wood feedstocks.
Types of PAHs Determined
- Napthalene - a polycyclic aromatic hydrocarbon that consists of two fused benzene rings.
- 2-Methylnaphthalene - consists of a naphthalene ring with a methyl group attached at the second position.
- 1-Methylnaphthalene - consists of a naphthalene ring with a methyl group attached at the first position.
- Acenaphthylene - consists of two fused benzene rings with a triple bond between them.
- Benzo[j]fluoranthene - a polycyclic aromatic hydrocarbon that contains five fused benzene rings. It is a member of the fluorene family of PAHs
- Anthracene - consists of three fused benzene rings. It has a blue fluorescence and is primarily used in the production of dyes, plastics, and other industrial chemicals
- Benzo[a]anthracene - a polycyclic aromatic hydrocarbon that consists of four fused benzene rings and a five-membered ring.
- Dibenzo[a,h]anthracene - a PAH that consists of five fused benzene rings.
- Chrysene - a PAH consisting of four fused benzene rings.
- Benzo[b]fluoranthene - consists of five fused benzene rings.
- Benzo[k]fluoranthene – a PAH that also consists of five fused benzene rings.
- Benzo[ghi]perylene - a polycyclic aromatic hydrocarbon consisting of six fused benzene rings.
- Benzo[e]pyrene- a PAH consisting of five fused benzene rings.
Electrical Conductivity, Water Holding Capacity, pH, Liming, Germination Inhibition, Acenaphthene, Acenaphthylene, Anthracene, Benz[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[ghi]perylene, Benzo[a]pyrene, Chrysene, Dibenz[a,h]anthracene, Fluoranthene, Fluorene, Indeno[1,2,3-cd]pyrene, 1-Methylnaphthalene, 2-Methylnaphthalene, Naphthalene, Phenanthrene, Pyrene
Electrical Conductivity, Water Holding Capacity, pH, Liming, Germination Inhibition, Cation Exchange Capacity, Scanning Electron Microscopy (SEM) Image, Time to Germination, Mean Shoot Length (Week 1), Mean Shoot Length (Week 2), Mean Shoot Length (Week 3), Mean Shoot Length (Week 4), Shoot Weight (Week 4), Mean Root Length (Week 4), Root Weight (Week 4), Acenaphthene, Acenaphthylene, Anthracene, Benz[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[ghi]perylene, Benzo[a]pyrene, Chrysene, Dibenz[a,h]anthracene, Fluoranthene, Fluorene, Indeno[1,2,3-cd]pyrene, 1-Methylnaphthalene, 2-Methylnaphthalene
Thernogram - Under Nitrogen, Thermogram - Under Air, Moisture, Inherent Moisture, Ash Content (815C), Carbon, Hydrogen, Nitrogen, Sulphur, Oxygen, Organic Carbon, Inorganic Carbon, Chlorine, Volatile Matter, Fixed Carbon, Specific Surface Area (Nitrogen Gas Adsorption), Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium, Gross Calorific Value, Net Calorific Value, Ash Shrinkage Starting Temperature (Reducing), Ash Deformation Temperature (Reducing), Ash Hemisphere Temperature (Reducing), Ash Flow Temperature (Reducing)
Checking PAH Levels Against Threshold Values
In the European Union, PAHs are regulated under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation. The regulation sets limits on the amount of PAHs allowed in consumer products and the EU also sets limits on PAHs in ambient air, surface water, and sediments.
The European Biochar Certificate (EBC) is an organisation set up to ensure the quality and safety of biochar produced in Europe. It was established in 2012 by a group of experts from different European countries and is now supported by various research institutions, companies, and associations.
The EBC is based on a set of criteria that cover the production, properties, and use of biochar. The EBC includes guidelines for polycyclic aromatic hydrocarbons in biochar to ensure that the biochar produced meets strict safety and quality standards. Two different threshold values (16 EPA PAH and 8 EFSA PAH) are provided, as described below:
8 EFSA PAH - These are eight Polycyclic Aromatic Hydrocarbons that the European Food Safety Authority (EFSA) identified as being of priority concern for human health. These eight PAHs are classified as priority pollutants due to their persistence in the environment, bioaccumulation potential, and toxicity to human health. The EFSA has set maximum limits for these PAHs in food and feed products, and they are also included in the European Union's REACH regulation. The EBC guidelines provided different threshold values for the total of these 8 PAHs according to the planned application market for the biochar. For example, a threshold value of 1 g per tonne of biochar is set for most applications with the exception of biochar used in basic materials, where the threshold value is 6 grams per tonne. The 8 PAHs covered by the EFSA are: Benzo[a]anthracene, Benzo[a]pyrene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Chrysene, Dibenzo[a,h]anthracene, Indeno[1,2,3-cd]pyrene, Phenanthrene.
These tables are provided in our pdf reports. An example table is provided here.
Understanding Links Between Process, Feedstock and PAH Levels
If you are currently producing a range of different from biochars covering different feedstocks and/or process conditions then we can help in screening these biochar samples for their PAH contents and compositions. We can then use data analysis tools to look for trends and correlations across the dataset. This can lead to greater understanding on what factors are most important, according to your particular conditions, with regards to PAH levels in biochar. From this we can provide guidance on how conditions can be optimised for reduced PAH concentrations, whilst also considering other factors such as target biochar yields and composition. Such data can feed into our technoecomomic analyses of biochar production scenarios.Additionally, at Celignis we can also produce biochar samples from your feedstock(s), with factors such as pyrolysis temperature, residence time, and heating rate being varied in order to see the effects on the yield and quality of biochar. We can formulate a design of experiments (DoE) for exploring the relationships between these factors and responses, also taking into account the production and distribution of PAHs. We can also potentially explore the use of certain additives during the pyrolysis process (e.g. potassium hydroxide) that may help to can reduce the formation of PAHs during pyrolysis. These additives can help break down PAHs into simpler compounds, which are less harmful to human and environmental health.
Exploring Strategies to Reduce PAH Levels in Biochar
There are a number of different strategies that we at Celignis can test to reduce the levels of PAHs in your biochar samples. For example, we can wash or leach the biochar (using water or other solvents). This treatment can potentially remove any remaining ash or soluble organic compounds that may contain PAHs.If we are also involved in the production of biochar samples from your feedstock(s) then we can also undertake feedstock pre-treatment experiments. These may include washing or soaking the biochar samples in water, which can help remove any contaminants or impurities that may contribute to the formation of PAHs during pyrolysis.
Sajna KV
Bioanalysis Developer
PhD
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.
Global Recognition as Biomass and Biochar Experts
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Lignin (Klason), Lignin (Acid Soluble), Acid Insoluble Residue, Ash (Acid Insoluble),
As P10 plus protein-corrected lignin, water-soluble sugars, uronic acids, acetyl content and starch.
Glucuronic Acid, Galacturonic Acid, Mannuronic Acid, Guluronic Acid, 4-O-Methyl-D-Glucuronic Acid, Iduronic Acid,
Total Sugars in Enzyme Hydrolysate, Glucose in Enzyme Hydrolysate, Xylose in Enzyme Hydrolysate, Arabinose in Enzyme Hydrolysate, Mannose in Enzyme Hydrolysate, Galactose in Enzyme Hydrolysate, Rhamnose in Enzyme Hydrolysate, Cellobiose in Enzyme Hydrolysate, Enzymatic Hydrolysis Kinetics, Cellulose Conversion Yield, Xylan Conversion Yield, Combined Sugar Yield, Cellulose Conversion Rate, Xylan Conversion Rate,
As P121 plus comparisons with data from the non-pretreated original sample, including: Increase in Cellulose Accessibility after Pre-Treatment, Percent Increase in Cellulose Conversion Efficiency, Percent Increase in Cellulose Conversion Rate.
As P9 but on the solid residue after enzymatic hydrolysis.
Formic Acid, Acetic Acid, Levulinic Acid, Furfural, Hydroxymethylfurfural,
Includes all hydrolysate sugars and kinetics in P121 and: Cellulose Conversion Yield, Cellulose Conversion Rate
Includes all hydrolysate sugars and kinetics in P121 and: Xylan Conversion Yield, Xylan Conversion Rate
Total Sugars in Enzyme Hydrolysate, Glucose in Enzyme Hydrolysate, Maltose in Enzyme Hydrolysate, a-Amylase Hydrolysis Kinetics, Glucoamylase Hydrolysis Kinetics,
Glucose, Xylose, Fructose, Sucrose, Mannose, Arabinose, Galactose, Rhamnose, Xylitol, Sorbitol, Trehalose, Mannitol, Arabinitol, Glycerol, Raffinose,
Levulinic Acid, Formic Acid, Hydroxymethylfurfural, Furfural, Acetic Acid, gamma-Valerolactone,
Xylobiose, Xylotriose, Arabinobiose, Arabinotriose,
Maltose, Maltotriose, Maltotetraose, Maltopentaose, Maltohexaose, Maltoheptaose, Maltooctaose,
Glucuronic Acid, Galacturonic Acid, Mannuronic Acid, Guluronic Acid, 4-O-Methyl-D-Glucuronic Acid, Iduronic Acid,
Gibberellic Acid, Indole-3-acetic acid, Indole-2-acetic acid, Indole-3-propionic acid, Indole-3-butyric acid, 6-Benzylaminopurine, Kinetin riboside, Abscisic acid, Salicylic acid,
beta-Carotene, Ergocalciferol (Vitamin D2), Alpha-tocopherol (vitamin E), Phylloquinone (Vitamin K1),
Thiamine (Vitamin B1), Riboflavin (Vitamin B2), Niacin (Vitamin B3), Niacinamide (vitamin B3), Pantothenic Acid (Vitamin B5), Pyridoxine (Vitamin B6), Folate (Vitamin B9), Cobalamin (Vitamin B12), Ascorbic Acid (Vitamin C),
Fucose, Mannitol, Glucose, Xylose, Mannose, Arabinose, Galactose, Rhamnose, Total Sugars, Glucuronic Acid, Galacturonic Acid, Mannuronic Acid, Guluronic Acid, Iduronic Acid,
Alanine, Arginine, Aspartic Acid, Asparagine, Cystine, Glutamic Acid, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine, Valine,
Aluminium, Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium,
Arachidic Acid, Behenic Acid, Decanoic Acid, Erucic Acid, Lauric Acid, Linoleic Acid, Linolenic Acid, Myristic Acid, Caprylic Acid, Oleic Acid, Palmitic Acid, Palmitoleic Acid, Stearic Acid, Lignoceric Acid,
Fucoxanthin, Astaxanthin, Chlorophyll-c, Chlorophyll-a, Chlorophyll-b, Lutein, beta-Carotene, Neoxanthin, Antheraxanthin, Violaxanthin,
Gibberellic Acid, Indole-3-acetic acid, Indole-2-acetic acid, Indole-3-propionic acid, Indole-3-butyric acid, 6-Benzylaminopurine, Kinetin riboside, Abscisic acid, Salicylic acid,
beta-Carotene, Ergocalciferol (Vitamin D2), Alpha-tocopherol (vitamin E), Phylloquinone (Vitamin K1),
Thiamine (Vitamin B1), Riboflavin (Vitamin B2), Niacin (Vitamin B3), Niacinamide (vitamin B3), Pantothenic Acid (Vitamin B5), Pyridoxine (Vitamin B6), Folate (Vitamin B9), Cobalamin (Vitamin B12), Ascorbic Acid (Vitamin C),
Chlorophyll-a, Chlorophyll-b, Lutein, beta-Carotene, Neoxanthin, Astaxanthin, Zeaxanthin, Antheraxanthin, Violaxanthin,
Biomethane Potential (BMP), Total Biogas Volume, Total Solids, Volatile Solids, pH, Biogas Methane Content, Biogas Carbon Dioxide Content, Biogas Oxygen Content, Biogas Hydrogen Sulphide Content, Biogas Ammonia Content,
Total Solids, Volatile Solids, pH, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Phosphorus, Potassium, Ammonia, Carbon, Hydrogen, Nitrogen, Sulphur,
Residual Biogas Potential (RBP), Total Biogas Volume, Total Solids, Volatile Solids, pH, Biogas Methane Content, Biogas Carbon Dioxide Content, Biogas Oxygen Content, Biogas Hydrogen Sulphide Content, Biogas Ammonia Content,
Acetic Acid, Lactic Acid, Propionic Acid, Butyric Acid, Isobutyric Acid, Valeric Acid, Isovaleric Acid,
Levoglucosan, Cellobiosan, Mannosan, Galactosan, Glucose, Xylose, Mannose, Arabinose, Galactose, Rhamnose, Fucose, Sucrose, Cellobiose, Total Sugars,
31 constituents including Phenol, Furfural, Syringol, and Vanillin
Specific Surface Area (Nitrogen Gas Adsorption), BET Isotherm (5 Point Using Nitrogen),
Specific Surface Area (Nitrogen Gas Adsorption), BET Isotherm (20 Point Using Nitrogen), Pore Volume (Using Nitrogen), Pore Size Distribution (Using Nitrogen), Average Pore Width (Using Nitrogen),
Specific Surface Area (Nitrogen Gas Adsorption), BET Isotherm (40 Point Using Nitrogen), Pore Volume (Using Nitrogen), Pore Size Distribution (Using Nitrogen), Average Pore Width (Using Nitrogen),
Gross Calorific Value, Net Calorific Value, Ash, Carbon, Hydrogen, Nitrogen, Sulphur, Oxygen,
Aluminium, Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium,
Antimony, Arsenic, Cadmium, Chromium, Cobalt, Copper, Lead, Manganese, Mercury, Molybdenum, Nickel, Vanadium, Zinc,
Ash Shrinkage Starting Temperature (Reducing), Ash Deformation Temperature (Reducing), Ash Hemisphere Temperature (Reducing), Ash Flow Temperature (Reducing),
Moisture, Ash Content (815C), Carbon, Hydrogen, Nitrogen, Sulphur, Oxygen, Chlorine, Volatile Matter, Fixed Carbon, Aluminium, Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium, Gross Calorific Value, Net Calorific Value, Ash Shrinkage Starting Temperature (Reducing), Ash Deformation Temperature (Reducing), Ash Hemisphere Temperature (Reducing), Ash Flow Temperature (Reducing),
As P393 plus inorganic carbon, organic carbon, TGA (under nitrogen and air), and inherent moisture
Aluminium, Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium,
Antimony, Arsenic, Cadmium, Chromium, Cobalt, Copper, Lead, Manganese, Mercury, Molybdenum, Nickel, Vanadium, Zinc,
Acenaphthene, Acenaphthylene, Anthracene, Benz[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[ghi]perylene, Benzo[a]pyrene, Chrysene, Dibenz[a,h]anthracene, Fluoranthene, Fluorene, Indeno[1,2,3-cd]pyrene, 1-Methylnaphthalene, 2-Methylnaphthalene, Naphthalene, Phenanthrene, Pyrene,
Time to Germination, Mean Shoot Length (Week 1), Mean Shoot Length (Week 2), Mean Shoot Length (Week 3), Mean Shoot Length (Week 4), Shoot Weight (Week 4), Mean Root Length (Week 4), Root Weight (Week 4),
As Deluxe package plus P383, SEM Imaging (P387) and Plant Growth Trials (P388)
Includes everything from P391 (Physical Properties Ultimate), P394 (Thermal Properties Ultimate), and P397 (Soil Amendment Ultimate)
Gross Calorific Value, Net Calorific Value, Ash, Carbon, Hydrogen, Nitrogen, Sulphur, Oxygen,
Aluminium, Calcium, Iron, Magnesium, Phosphorus, Potassium, Silicon, Sodium, Titanium,
Antimony, Arsenic, Cadmium, Chromium, Cobalt, Copper, Lead, Manganese, Mercury, Molybdenum, Nickel, Vanadium, Zinc,
Volatile Matter, Fixed Carbon, Moisture, Ash, Carbon, Hydrogen, Nitrogen, Sulphur, Oxygen, Gross Calorific Value, Net Calorific Value, Chlorine,
Ash Shrinkage Starting Temperature (Oxidising), Ash Deformation Temperature (Oxidising), Ash Hemisphere Temperature (Oxidising), Ash Flow Temperature (Oxidising),
Celignis is a Partner in 3 Successful Proposals for EU Funding
We are pleased to announce that three of the proposals involving Celignis, submitted to the CBE-JU programme for funding collaborative biomass research in Europe, were successful. These projects will provide an additional funding of €1.5m to Celignis and build on our achievements in other CBE and EU projects. In particular, the projects are all at enhanced TRLs (6/7) and will use our existing Celignis Bioprocess infrastructure and will also fund further development of our bioprocessing capacities and the Bioprocess Development Services we offer our clients.
Details on the funded projects are provided below:
BIONEER - This project was funded under CBE-JU topic IA-06 and focuses on the TRL 6/7 production of biobased platform chemicals. Celignis's activities in the project focus on scaling up the work undertaken in our ongoing
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The 2024 North American Biochar Conference will take place in Sacramento, California, on Feb 12-15
On Feb 12-15 we'll be exhibiting at the 2024 North American Biochar Conference, taking place at the SAFE Credit Union Convention Centre in Sacramento, California.
We're looking forward to interacting with the 1000+ expected attendees, outlining our extensive range of analytical and application testing services for biochar.
Celignis CIO Lalitha Gottumukkala will also be a member of the expert panel focused on developing improved laboratory methods for biochar characterisation.
Click here to register for the event.
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This Networking Event Will Involve Discussions on Collaborations for Proposals to the 2024 CBE-JU Topics
The Circular Bioeconomy Europe Joint Undertaking (CBE-JU) is an organisation that funds biomass research in Europe at various Technology Readiness Levels (TRLs). Since 2016 Celignis has been an active participant in a number of projects funded by the CBE-JU.
The Biobased Industries Consortium (BIC) is the steering committee that helps to steer the focus of research for the CBE-JU programme. In 2023 Celignis joined the BIC as a Full Industry Member and participated in several proposals submitted for different research topics in the CBE-JU's 2023 Work Programme.
On Feb 8th Celignis's Dan Hayes, Lalitha Gottumukkala, and Oscar Bedzo will be attending a BIC networking event in Brussels where we will discuss potential collaborations in the research programme topics recently announced for 2024.
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This position will involve working closely with senior management, fostering existing and new client relationships.
Situated in Limerick, Ireland, Celignis currently operates at two centres, Celignis Analytical and Celignis Bioprocess, actively engaging in a variety of private and public bioeconomy projects. As we continue to expand, we're looking to strengthen our team of 14 with a Business Administration and Client Relationship Manager who can bring a blend of enthusiasm and expertise.
This position will involve working closely with senior management, fostering existing and new client relationships, and ensuring successful delivery of our services, playing a key role in our ongoing growth and success.
Click here for more details about the position.
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The event takes place on May 3rd at Carrick-on-Shannon
We are pleased to announce that, on May 3rd, Celignis will be presenting and exhibiting at the National Biochar and Carbon Products Conference 2023, which is taking place in Carrick-on-Shannon in County Leitrm, Ireland.
This conference is being organised under the auspices of the Interreg Northwest Europe-funded THREE C Project, entitled 'Creating and sustaining Charcoal value chains to promote a Circular Carbon economy in NWE Europe'.
The conference will highlight both Irish stakeholders who are currently working in the biochar and carbon products sector, but also partners from the THREE C project (covering Netherlands, Luxembourg, Germany, Belgium, France and Wales, as well as Ireland) who have interesting stories and products to share.
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