Biochar - Science topic

I'm guiding an undergraduate bioengineering student's research, making biochar from algae. Preliminary results show that besides being able to store carbon, it also produces nitrogen, phosphate and potassium elements. But it has not yet been applied in the field. It is planned that next year it will be continued by other students.

Potential Risks:

Regulatory Challenges:

The application of biochar and sewage sludge can significantly influence soil physical, chemical, and biological properties in both beneficial and potentially adverse ways. Here’s a breakdown:

Greeting

Iwould like to be as a team in some work

Biochar and sewage sludge are both valuable soil amendments that can significantly influence nutrient availability, soil organic carbon (SOC) sequestration, and microbial activity, though their effects differ based on their properties and interactions with soil and cropping systems. Biochar, a carbon-rich product derived from pyrolysis of organic materials, enhances nutrient retention by reducing leaching and improving cation exchange capacity (CEC), particularly in sandy or degraded soils. It also promotes SOC sequestration due to its recalcitrant nature, contributing to long-term carbon storage. Sewage sludge, on the other hand, is rich in organic matter and nutrients like nitrogen and phosphorus, which can immediately boost soil fertility. However, its application requires careful management to avoid heavy metal contamination and nutrient imbalances. Both amendments stimulate microbial activity, but biochar tends to create a more stable habitat for beneficial microbes due to its porous structure, while sewage sludge provides readily available organic substrates that can temporarily increase microbial biomass and activity.

In my research experience, I observed how beneficial microbes like Rhizobium and Bacillus significantly enhanced the growth and production of Capsicum (bell peppers) when combined with these amendments. Rhizobium, known for its nitrogen-fixing capabilities, improved nitrogen availability in the soil, leading to healthier plant growth and higher yields. Bacillus species, which promote phosphorus solubilization and produce growth hormones, further enhanced root development and nutrient uptake. When biochar was applied, the porous structure provided a favorable environment for these microbes to colonize and thrive, leading to sustained microbial activity and nutrient cycling. Sewage sludge, while providing immediate nutrients, also supported microbial proliferation, but its effects were more pronounced in the short term. Over time, the combination of biochar and beneficial microbes proved more effective in improving soil health and crop productivity, as it balanced nutrient availability, enhanced SOC sequestration, and maintained a robust microbial community. These findings highlight the importance of integrating biochar and microbial inoculants in cropping systems to achieve sustainable soil health and long-term agricultural productivity.

You need not to measure adsorption isotherm again, it is suffucien to treat the measured adsorption data by t-plot method

Yes, pyrolysis can be done in two steps instead of one. This approach is often referred to as “two-step pyrolysis” or “catalytic pyrolysis.” In the first step, the biomass or organic material is heated in laboratory devices (special ovens) in order to break down the large molecules into smaller granules, resulting in bio-oil and char. Further heating or catalytic treatment of the bio-oil is carried out to improve the yield or quality of the product.

The temperature must be regular because it has a significant effect on the material to be heated inside the oven, which leads to improved efficiency and product properties. It can also facilitate the use of specific catalysts that may be more effective under certain conditions.

Dileep Singh , the question is if these experimental runs are independent. If these runs share something that serves as a source of relevant common variance, then they should not be considered intependent. Such a thing could be a lot of a chemical or compound that may vary considerably in some relevant property.

You must ask yourself if the variability between these experimental runs may be expected to be as large as the variability beteen runs performed in different labs (that do not share the lots you used). If yes, then they can be considered independent. If not, and if the lot was the critical component, then your data allows inference about the properties of that lot you used, and it may not generalize to other lots.

Natural organic matter (NOM) can be effectively removed from surface water using methods such as coagulation with coagulants like poly aluminum chloride, adsorption with activated carbon, and advanced oxidation processes. Combining these techniques, such as integrating coagulation with ozonation, can enhance removal efficiency and improve overall water quality.

Biochar is a carbon-rich material produced through the pyrolysis of organic matter in low-oxygen conditions. Its application to sandy soils significantly impacts their chemical properties, improving fertility, nutrient dynamics, and overall soil health. Here are the detailed effects of biochar on the chemical properties of sandy soil:

1. Increased Cation Exchange Capacity (CEC):

Sandy soils typically have low CEC, meaning they cannot retain nutrients effectively. Biochar has a high surface area and is rich in functional groups, which increase the soil's ability to hold and exchange essential nutrients like calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺), and ammonium (NH₄⁺). This prevents nutrients from being washed away by water, making them more available to plants.

2. Improved Nutrient Retention:

The porous structure of biochar acts as a sponge, adsorbing nutrients and water. This reduces nutrient leaching—a common issue in sandy soils due to their large particle size and low organic matter content. As a result, biochar helps maintain soil fertility over time.

3. pH Regulation:

Sandy soils are often acidic, which can limit the availability of certain nutrients. Biochar typically has an alkaline nature, which helps neutralize soil acidity and create a more favorable environment for nutrient uptake and microbial activity. This is especially beneficial for crops sensitive to low ph.

4. Enhanced Soil Organic Carbon (SOC):

Biochar is a stable form of carbon that remains in the soil for long periods. Its addition increases the soil's organic carbon content, which improves nutrient cycling and long-term soil fertility. Biochar also interacts with native organic matter, further enhancing soil chemistry.

5. Improved Microbial Activity:

The chemical composition of biochar supports the growth of beneficial soil microorganisms by providing a habitat and releasing small amounts of nutrients. These microbes play a critical role in nutrient mineralization and improving soil structure.

6. Reduction of Toxic Elements:

Biochar can adsorb toxic elements like heavy metals (e.g., lead, cadmium) and limit their availability in the soil. This property protects plants from toxicity and enhances overall soil health.

7. Greater Efficiency of Fertilizers:

By retaining nutrients and reducing leaching, biochar increases the efficiency of applied fertilizers. This reduces the need for frequent fertilizer applications, making agricultural practices more sustainable.

In conclusion, biochar addresses many of the chemical limitations of sandy soils by improving nutrient retention, increasing pH and CEC, and enhancing soil organic matter. These changes make sandy soils more productive and sustainable for agriculture and plant growth.

Biochar plays a significant role in improving the chemical properties of sandy soil by increasing its cation exchange capacity (CEC). This enhancement allows the soil to retain essential nutrients, such as potassium, calcium, and magnesium, which would otherwise leach away quickly due to the low nutrient-holding capacity of sandy soil. Biochar also helps to raise the pH of acidic sandy soils, making them more suitable for plant growth. Additionally, it can improve soil microbial activity by providing a habitat for beneficial microorganisms. Overall, biochar contributes to soil fertility, reduces nutrient loss, and supports sustainable agricultural practices in sandy soils.

Biochar improves all soil properties, especially the physical ones, as it improves soil aeration, which enhances and activates microbial activity. In addition, it has a large surface area that improves the composition and porosity of the soil. All of these properties improve soil moisture content and the ability of the soil to retain moisture, which is positively reflected in plant growth.

@dragan ugrinov with very low carbon content won't it be affect the reduction and thereby overall productivity of blast furnace? Can you please share the %ge of carbon in biochar and the reduction reactions involving biochar?

Actually, is there any other method other than physical and mechanical methods that can be used to obtain nanobiochar from biochar?

if you activate you biochar, what does happen to the surface?

This is the question. you should 1st understand, and then you can work with your adsorpitons hypothesis

Dear Doctor

Go To

[Abstract

The term “biomass” encompasses all substances found in the natural world that were once alive or derived from living organisms or their byproducts. These substances consist of organic molecules containing hydrogen, typically oxygen, frequently nitrogen, and small amounts of heavy, alkaline earth and alkali metals. Magnetic biochar refers to a type of material derived from biomass that has been magnetized typically by adding magnetic components such as magnetic iron oxides to display magnetic properties. These materials are extensively applicable in widespread areas like environmental remediation and catalysis. The magnetic properties of these compounds made them ideal for practical applications through their easy separation from a reaction mixture or environmental sample by applying a magnetic field. With the evolving global strategy focused on protecting the planet and moving towards a circular, cost-effective economy, natural compounds, and biomass have become particularly important in the field of biochemistry.

Conclusion

This review focuses on magnetic adsorbents prepared from agricultural waste biomass to remove different dyes from textile wastewater. Adsorption is a desired process for eliminating pollutants thanks to its ease of use, efficacy, energy efficiency, cheapness, lack of harmful by-products, simple design, and magnetic separation capabilities. Recently, magnetic adsorbents have been widely used for dye removal because of their unique surface chemistry containing ketones, aldehydes, carboxylic...]

Estimating soil organic carbon (SOC) formation and loss when using organic amendments like biochar, manure, and compost involves several steps and can be approached through different methods, including field experiments, modeling, and laboratory analysis. Here's a general outline of how you can estimate SOC dynamics with these amendments: 1. Field Experiments and Sampling 2. Modeling SOC Dynamics 3. Laboratory Incubation Studies 4. Isotopic Tracing (if applicable) 5. Data Analysis and Interpretation 6. Long-Term Monitoring ,, Tools and Resources: Case Studies and Literature

These steps will help you estimate how much SOC is formed or lost due to the application of organic amendments, and allow you to assess the long-term sustainability and carbon sequestration potential of these practices.

Himanshu Tiwari Here's a distinction between the carbon sequestration potential of biochar and other negative emission technologies:

Biochar:

1. Long-term storage: Biochar can store carbon for centuries to millennia.

2. Soil-based: Biochar is applied to soils, enhancing fertility and structure.

3. Carbon sink: Biochar acts as a carbon sink, reducing atmospheric CO2.

4. Scalability: Biochar production can be scaled up or down depending on feedstock availability.

5. Co-benefits: Biochar improves soil health, increases crop yields, and reduces soil erosion.

Afforestation/Reforestation:

1. Short-term storage: Carbon is stored for decades to centuries.

2. Land-based: Requires large areas of land for planting trees.

3. Carbon sink: Trees absorb CO2 through photosynthesis.

4. Scalability: Limited by land availability and competition with agriculture.

5. Co-benefits: Enhances biodiversity, improves water cycles, and supports wildlife habitats.

Carbon Capture and Storage (CCS):

1. Short-term storage: Carbon is stored for decades to centuries.

2. Industrial-based: Captures CO2 from power plants and industrial processes.

3. Carbon sink: CO2 is injected into geological formations for storage.

4. Scalability: Limited by high costs, energy requirements, and infrastructure needs.

5. Co-benefits: Reduces emissions from industrial sources, supports clean energy transition.

Key differences:

1. Duration of carbon storage: Biochar offers longer-term storage than afforestation and CCS.

2. Land requirements: Afforestation requires large land areas, while biochar can be applied to existing soils.

3. Scalability: Biochar production can be scaled up or down, while CCS is limited by high costs and infrastructure needs.

4. Co-benefits: Biochar offers additional benefits like soil improvement and increased crop yields.

In summary, biochar offers a unique combination of long-term carbon storage, soil-based application, and co-benefits like improved soil health. While afforestation and CCS are important negative emission technologies, they have different characteristics and

Please take a look on it.

Add powder Sigma, St. Louis, MO to 30 mL H2O and adjust to pH 7.5 with HCl. The volume is adjusted and the solution is stored at 4°C for up to two weeks and then at room temp.

One of the main limitations of the COD test is its inability to differentiate between biodegradable and biologically inert organic matter on its own.it is the amount of oxidant consumed during oxidation of organic substances present in water samples. As per the standard methods of detecting COD, potassium dichromate (K2Cr2O7) or potassium permanganate (KMnO4) are generally used as oxidizing agents. It was found that for dosages of activated carbon in the range of 50–150 mg/l, the removal efficiencies for BOD increased from 27–70% to 76–94% while those for COD increased from 16–64% to 72–92.5% for inlet values of 45–95 mg/l and 110–200 mg/l for BOD and COD respectively. The activated carbon filter will need to be replaced as its ability to dechlorinate the water will slowly decline. Spent carbon can be re-activated; however, re-activated filters should only be used in waste-water treatment applications. In recent years, the COD has increasingly been replaced by the total organic carbon (TOC) parameter. Since the limit values of the pollution levels are usually given in terms of the COD, efforts are being made to find the correlation between these parameters.

Biochar (biological charcoal) draws carbon from the atmosphere, providing a carbon sink on agricultural lands. Its capacity for carbon sequestration, agricultural improvement, and waste utilization positions it as a key player in the transition towards a more sustainable and environmentally friendly future. Biochar improves soil, leading to better crop growth. Carbon farming captures carbon from the air, reducing pollution. Conservation ecology protects wildlife and natural habitats. Fair consumption means using resources wisely and reducing waste. The Carbon Loophole in Climate Policy assesses the embodied carbon associated with the production of goods that are ultimately traded across borders and therefore excluded from domestic climate policy.Increase productivity of grasslands and croplands, which adds carbon in roots and residues. Increase use of agroforestry, which builds above-ground carbon. Pursue efforts to build soil carbon, despite the challenges, in areas where soil fertility is critical for food security.

Bishal Dhungana

A well-structured agricultural marketing system and agribusinesses can help achieve net zero emissions by promoting sustainable practices. For example, better market access reduces food waste, which cuts emissions. Emerging scientists, leaders, and professionals can drive innovation in sustainable farming methods, like using renewable energy or improving soil health.

However, policy loopholes still allow high-polluting industries to emit large amounts of carbon despite sanctions. Stronger regulations and enforcement are needed. Consumers can help by eating less processed food and choosing more plant-based options, which lowers the carbon footprint of their diets.

Emerging concepts like carbon farming, biochar, and agroforestry have great potential. Carbon farming can capture carbon dioxide in soil, biochar improves soil health and locks in carbon, and agroforestry combines trees and crops, enhancing biodiversity and storing carbon. These practices can significantly contribute to agricultural sustainability.

Hi Paul, thanks very much for the thinking on this. The vexing thing is that we prepared 8 samples, all basically the same way (10g biochar with 20ml DI water, shaken overnight), the only difference being the source of biomass and the firing temp of the char. Only two samples had this milky white response to the reagent. I took the pH of all the samples, and the anomalous one was actually the lowest pH (range was 10 to 12), coming in at 10. It sure looks like a precipitate, but the confusing part is that none of the other samples behave like this, and I have done thousands of samples in my career and never seen this. I suppose I could acidify the sample, catch and dry the precipitate and run it on XRD.

There is no definitive answer to your question unless the nature of the incorporation is known. The usual approaches apply: fine grinding and your informed guesses with different degrees of intensity.

Thank you so much Prem Baboo

Thank you Mam for your reply.

You can act locally and a big effect can be through political pressure on developed countries

Post activation shows the better results, but then there is the activated char clean-up and neutralisation. There is also a significant mass loss of char in the process. There are lots of publications on this subject. The stronger the alkali, the higher the temperature, the more the mass loss and the higher the surface area.

Biochar's long-term effectiveness in soils is influenced by its original material and how it was made, along with the type of soil, climate, and how it's used in land management. Different combinations of these factors can affect how well biochar improves soil health, stores carbon, and supports plant growth over time.

You need to use whatever pore size/material that gives you clear solutions.

You may find that whatever colloids are present will pass different filter sizes to a variable degree. Under such circumstances, I suggest you be more specific in your description.

Hi, Sir Yuri Mirgorod ! Thank you very much!

Noted on this!

Ayushi Mishra

Your table apparently gives the specific surface area. As the pore radius decreases, the specific surface area should increase, but it decreases. It can not be so.

Bonsoir!

The use of biochar based N fertilizers has been considered among the most effective strategy for reducing nitrogen loss and improving nitrogen use efficiency (NUE). And slow release of nitrogen.BCU is manufactured by coating biochar outside urea with a coating machine. Te percent of biochar in BCU is about 22.56%.

The reduction of nitrogen loss and improvement of NUE could be attributed to the porosity, large specific surface area, surface charges, variety of surface functional groups and a small amount of active carbon present in Biochar. These properties of biochar could increase soil water holding capacity, adsorb inorganic nitrogen, influence nitrification and denitrification of nitrogen in soil, increase microbial biomass, and change soil structure of bacterial community .

Biochar used for BCU can be prepared based on pyrolysis of vinasse in a fixed-bed heating furnace. The pyrolysis temperature was 600 °C and the pyrolysis time is about 90 min. The pH, specific surface area, ash content, C content, H content, N content, O content, O/C molar ratio, and H/C molar ratio of biochar are 8.88, 172.48 g/m2, 29.89%, 61.32%, 1.62%, 2.79%, 1.66%, 0.02, 0.32, respectively.

Hello Ipah, I agree with what Dr. Ganachari explained, so much is that as it is a material that has already been transformed into graphene oxide, this material will no longer behave like a common carbonaceous material, as materials such as biomass or even Even carbon that has not been activated or transformed into some other material, can be treated at temperatures above 100 °C, the ideal for these materials (graphene oxides or activated carbon) is temperatures of 150 to 180 °C for 8 to 12 hours another detail that you have to keep an wacthful on is which analysis gas will be adopted and its purity, as these parameters also influence the analysis, a quantity of material that is used for analysis ~ 150 mg is already a quantity enough for BET analysis, of course depending on the sample holder, the good thing about this characterization is that you don't "lose the sample"

Thank you so much Sir

Check out the article below:

Materials | Free Full-Text | Magnetic Biochar Obtained by Chemical Coprecipitation and Pyrolysis of Corn Cob Residues: Characterization and Methylene Blue Adsorption (mdpi.com)

I've no experience, and guess that the answer depends on what you intend to use the biochar for and where the absorbance falls

The nature of biochar is to expand niches for biological microbial communities. The physical spaces are habitats for these organisms to fix and abide. The role in an acid soil includes a liming effect. The alkaline nature of many chars can immobilize micronutrients in alkaline soil conditions. The carbon in soil can increase dramatically will biochar as the stablized pyrolized carbon can take thousands of years to decay.

The ability to increase soil organic matter levels can depend more on the resistance of the materials to decay rather than just the quantity.

Because the char conversion can yield a renewable energy resource but also it has the significant ability to sequester in the soil carbon which otherwise would reside as atmospheric carbon dioxide.

The choice of method for calculating total organic carbon in biochar depends on your specific goals and the characteristics of your samples. While loss on ignition (LOI) can provide an estimate of total organic carbon, it may not be as accurate as other methods like combustion or wet oxidation. Consider the purpose of your analysis and the precision required for your results when deciding on the appropriate method.

Who ! good Question

Slightly Correction

In your question

Biochar Mass M in kg= (kg/m2) ×Depth (m)× Container area (m2) =Kg. m

Not Fit, you must be known Mass Kg=Density X Volume

Biochar amount m (kg)= m = density(ρ) X Volume (V)

Biochar application rate (kg/m3) X {(Depth (m)× Container area (m2)} =m (Kg)

=2 X (1/0.2) X 0.2 X 2.25

4.45 Kg

Wood Bio char is produced by pyrolysis, with Nitrogen Therefore, nitrogen is purged to remove any gases (O2 etc.) present in pyrolysis reactor and also, to provide inert atmosphere. The idea is to control the heating process such that carbon loss to carbon dioxide is minimized therefore minimizing loss of fixed carbon to environment, use of nitrogen helps to reduce the burning of the pyrolysis product thereby improving the yield.500℃ of pyrolysis temperature is used to make wood . The biochar fixed carbon contents increased with increasing feedstock treatment temperatures. Typical oxygen to carbon ratios (O:C) are between 0.2 and 0.6, which are called char or charcoal, depending on the position in the black carbon spectrum. If no oxygen is present combustion does not occur, rather the biomass thermally decomposes into combustible gases and bio-char

For XRD, the figure shows a remarkable and mysterious description of the x-y axes (cycle number - capacitance retention). Is it even a diffraction pattern? If so, the peak at diffraction angle 10o 2 theta may be a consequence of insufficient sample size. The irradiated area was probably significantly larger than the size of the sample.

It is better to increase the acquisition time, or energy, to improve the spectra quality. After you can deconvolute each spectrum using Gauss curve (centered around 1347 cm-1 for the D band and 1579 cm-1 for the G band). The graphitization index ID/IG can be computed as these to bands areas ratio.

This is quite interesting.

It is believed that the pyrolysis at an elevated temperature (≥700 °C) usually lead to higher porosities in the product derived from woody feedstocks. This could be due to the slow decomposition of lignin in woody feedstocks at lower temperature. Rate of decomposition increases at higher temperature (≥700 °C) leading to higher porosities in the pyrolyzed product. On the other hand, peat-based biomass is characterized with higher content of hemicellulose which easily gets decomposed relatively at lower temperatures and produced porous biochar.

May be after the degassing at 200 for 6 h, the content of residual hemicellulose in your biochar started degrading. There may be other reasons for that, but I think you need to check the composition of hemicellulose and lignin.

Washing biochar modified with minerals such as bentonite or diatomite can be a complex process, as it varies depending on the specific circumstances and desired outcome. However, certain general steps can be followed to ensure adequate washing of biochar and removal of minerals in the final step. These steps include preparation, initial rinse, decantation, filtration, and drying. It is important to note that the washing process may differ based on various factors, such as the type and amount of mineral used for modification, as well as the intended application of the modified biochar. Therefore, it is recommended to consult specific guidelines or protocols provided by experts or manufacturers for the best results.

I believe that the ideal values for ash content, volatile matter, and pH of biochar depend on the specific application, but some general guidelines can be followed:

The key difference is the presence of Fe3O4 or not in the prepared biochar. If it contains magnetic Fe3O4, we call the biochar magnetic biochar. If not, we call it biochar. If the size of the biochar is within nanometer, we call it nano biochar. The size reduction tech such as ball milling or in-situ synthesis can make it nano.

Pre-treatment: The preparation and pre-treatment of biochar can also impact its adsorption capabilities. Puffed rice biochar might not have undergone suitable activation or modification processes to enhance its adsorption properties.

Chemical Properties: The chemical composition of the biochar can influence its adsorption capacity. Some biochars may have functional groups on their surface that enhance their ability to adsorb certain pollutants. Puffed rice biochar may lack these functional groups or have an unfavorable chemical composition for dye removal.

Bonsoir!

Le biochar ou ce qui peut l’être améliore la dite production végétale.

For the classification of the various biochar production methods, I consider that the concepts of the combustion, pyrolysis and gasification operations involved must be taken into consideration, which in one way or another lead to the quantity and quality of the product obtained. In this, the stoichiometric equations until reaching the Boudouar equation 2CO → CO2 + C, is the main aspect. This is achieved by controlling the reactions that take place during the decomposition of biomass into liquid and gaseous compounds, the reactions that take place between the solid, liquid and gaseous phases, the control of the temperature and the configuration of the fluid displacement zone. . In general; Pyrolysis is the thermal degradation of biomass in the absence of an oxidizing agent, it is a thermal transformation process in which it is possible to obtain solid, liquid or gaseous products and, on the other hand, it is the first step in the processes of gasification and combustion. With the configuration of the fluid displacement zone, the time factor necessary for the stoichiometry of the reactions is regulated.

High pyrolysis temperature promotes the production of biochar with a strongly developed specific surface area, high porosity, pH as well as content of ash and carbon, but with low values of CEC and content of volatile matter. This is most likely due to significant degree of organic matter decomposition. I know smoke is hazardous but not at that level. But charcol is better than direct burning of coal.

I agree with Paul, If the soil was strongly acidic respiration might increase if the biochar increased the pH to a more favorable level. However, it's also likely that the act of incorporation may have caused a large C-loss through increased respiration. The question then relates to having a well-matched control treatment.

Can you test the respiration hypothesis? Paul.

No

yes

During absorption experiments, the sorption or leaching will depend on the concentration of the phosphate solution. Previous research work has revealed an increase in the concentration of phosphorus at equilibrium time after sorption experiments at lower phosphate solution concentrations, while at higher concentrations of phosphate solution, sorption was observed.

No, chemically engineered biochar and chemically modified biochar are not the same terms.

Chemically engineered biochar refers to biochar that has been intentionally modified through chemical processes to enhance its properties or functionality. This modification can involve the introduction of specific chemicals or additives to alter the biochar's surface chemistry, pore structure, or other characteristics. The goal of chemically engineering biochar is to tailor its properties for specific applications, such as environmental remediation or water treatment.

On the other hand, chemically modified biochar is a broader term that encompasses any form of biochar that has undergone chemical modifications. This includes both chemically engineered biochar and biochar that has been modified through other means, such as impregnation with chemicals or surface treatments.

In summary, chemically engineered biochar refers specifically to biochar that has been intentionally modified through chemical processes, while chemically modified biochar is a broader term that encompasses any form of biochar that has undergone chemical modifications, regardless of the specific method used.

Can you give more details and tell what you are trying to do or give any insights into the data which is available to you. ?

Hi Mary, You may need a combination of methods to identify such compounds, e.g., a chromatographic technique for separation followed by a variety of detectors. You will ultimately need samples of pure compounds to complete the study, Paul.

What is the purpose? Can you identify currently unused input sources?

Volume of water retained by biochar divided by volume of biochar, gives water holding capacity of biochar.

ِDear, Dr. Krishna Poudel. You are looking for a very good goal in action. In order to provide you with the right decision, you should first introduce the climatic components and the target soil environment in a table, and then we would give you a model based on the environmental data for soil health.

This paper might be helpful: Wathudura et al 2020.

A couple of points to add to Lamia Fatima 's answer:

Best of luck.

If the use is to correct acidity the more important long-term property may be 'lime equivalent' rather than CEC and lime equivalent is readily measured by titration.