Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites

The overall goal of the following experiment is to characterize the physical, chemical, and biological properties of six bio chars to be used as soil amendments for the remediation of contaminated sites in basic biochar utility properties, percent moisture and organic matter. Proximate and ultimate analysis, pH and particle size distribution are determined. Toxicant reporting analysis includes seed germination and earthworm avoidance testing, as well as contaminant testing for polycyclic aromatic hydrocarbons, polychlorinated, bio fennels and metals, including mercury in biochar advanced analysis and soil enhancement properties.

The bio chars are tested for nutrients including ammonia, nitrate, nitrite, and phosphorus, as well as their ability to absorb or immobilize contaminants via evaluation of their specific surface area and cation exchange capacity. The results of these methods detailed the physical, chemical, and biological characteristics of biochar and determine their eligibility to be used as soil amendments for the remediation of contaminated sites. The main advantage of using these methods is that they're the same as those outlined by the International Biochar Initiative or IBI and their standardized protocol, and we have shown them to be accurate and effective at analyzing multiple Bio chars.

Many of these methods will be familiar to scientists specializing in soil research, provided that the correct quality assurance and quality control measures are followed. These methods are reliable and easily applied to both biochar and their feedstocks. In our previous work, we emphasized the importance of careful characterization of biochar prior to field scale implementation.

When we learned that the IBI was developing a standardized protocol, we had already begun this project, and so we were able to accommodate many aspects of the IBI protocols into our work. My PhD student, Mackenzie Deez, and my master student Michelle Parisian, and a certified laboratory technician will be demonstrating these procedures Prior to starting this procedure. Calibrate the pH probe before use with calibration standards.

Following this add point 25 grams of biochar to 25 milliliters of distilled deionized water in a centrifuge tube. Shake the solution manually for two minutes, then centrifuge a solution for 3000 Gs for five minutes. When finished, collect the supinate into a glass test tube and measure the pH for particle size distribution via progressive dry cing.

Record the weight of seven US standard sieves following this place, 60 grams of biochar in the 4.7 millimeter sieve. Then place the lid on the top and secure the stack of sieves on the shaker. After shaking the sample for 10 minutes, record the weight of each sieve.

Report the data in an Excel file as percent remaining in each sieve. For germination tests, ensure that the respective amounts of each treatment are three grams of biochar, 10 grams of potting soil, and one piece of filter paper. Then place the treatments into the respective Petri dishes.

Next place five pumpkin seeds and 50 alfalfa seeds into the Petri dishes. For each treatment using a graduated cylinder, add 15 milliliters of water to all Petri dishes and cover them with the respective lids. Place the Petri dishes for germination under 14, 10 hour fluorescent photo period.

Maintaining the temperature at 27 plus or minus six degrees Celsius to simulate a summer day and night cycle. After seven days, record the number of seeds germinated and report the results as percent germinated per Petri dish. Measure the root length of germinated seeds using a ruler.

Then report the root lengths as a sum of each Petri dish. Mix bio chars using a spade and bucket with potting soil at a rate of 2.8%by weight. Following this, fill each of the compartments.

Have an earthworm avoidance wheel with 120 grams of potting soil as a control or potting soil biochar mixture with every other compartment serving as an unamended control. At this point, remove isea petito from a healthy soil mixture of peat moss maintained at 30%moisture, choosing worms ranging from 0.3 to 0.6 grams in size. Add 10 worms to the round middle compartment and cover the avoidance wheel with aluminum foil.

After 48 hours, remove the worms and record their location in the avoidance wheel to determine the polychlorinated bio fennel or PCB concentration. Dry 10 gram soil samples overnight at 25 degrees Celsius for 18 to 24 hours. When finished, grind the samples to a fine powder with 10 grams of sodium sulfate and 10 grams of ottawa sand.

Next place, two grams of sample into a soli thimble and add 100 microliters of deco chloro bienal as an internal surrogate standard. Extract the samples in a oxit apparatus for four hours at four to six cycles per hour in 250 milliliters of di chloro methane following extraction. Transfer each sample extract to a tube and concentrate to one milliliter using a vacuum, using a gas chromatograph equipped with an electron capture detector, a fused silica capillary column and appropriate software analyzed biochar extracts for total a clause reporting values as microgram per gram dry weight.

The results of this table outline the physical, chemical, and biological properties required to completely characterize biochar and its feed stocks. The protocols outlined in this manuscript and required to obtain these results are consistent with those outlined in the IBI standardized protocol. Biological testing of biochar is important to assess its toxicity.

Exposure to contaminants may inhibit the earthworms ability to perform essential soil functions such as decomposition, nutrient mineralization, and soil structure improvements. The testing yielded significant differences among bio chars. New biochar showed no detrimental effects on the earthworm isia feta as assessed by earthworm avoidance.

However, worms significantly avoided old biochar, pumpkin and alfalfa seeds germinated well with 67%and 81%germination respectively. Roots also proliferated well with average lengths after seven days being 14 centimeters and 55 centimeters for pumpkin and alfalfa seeds respectively. Old biochar showed toxicity to plants and all other bio chars evaluated showed no detrimental effects to seed germination as measured by percent's, germination, and root length after seven days.

All methods are required to effectively characterize biochar prior to field scale application. However, many of these methods can be performed at the same time, and this minimizes the amount of time required for biochar characterization. When carrying out any of these methods, it is essential to ensure that the biochar is properly homogenized and that a representative sample is taken.

There are many aspects of quality assurance and quality control that are integral to each method and critical to producing reliable data. Following thorough biochar characterization, field scale application of biochar may begin. The objective of these studies may be to minimize contaminant bioavailability via absorption, improve crop yields via increased cat exchange capacity in nutrient additions, or to evaluate the carbon sequestration potential of biochar by determining its stability and soils over time.

After watching this video, you should have a good understanding of the chemical, physical, and biological methods required to completely characterize biochar. The biochar can then be used as a soil amendment for the init remediation of contaminated sites.