My idea took a lot of revising, but in the end, the element I chose was a better cathode based on facts. One of the strengths in my work was the research it took to find a better cathode. It took me a while to find a better cathode/oxidizers, but praseodymium was a better oxidizer and it fit the purpose. If I had more time to improve, I would probably have found a cathode of the same standards as praseodymium, but be a lot less expensive. I was going through so many different cathodes that were sub-par to the original until I finally found praseodymium.
Throughout the process of creating this letter and this idea, I learned more about the subject of reduction potential and started to understand the process of trial and error. As I said in the previous paragraph, I went through a lot of different oxidizers to come to praseodymium. A lot of the oxidizers I found were either too weak in charge capacity or a gas which would not be usable because the cathode needed to be either a liquid or a solid. One example was fluorine. Fluorine had a very high reduction potential (not as much as praseodymium), but when at room temperature, the solid dissolves into a gas, making it useless for the battery.
2) The concept of the mole is very important in the measurement of all things involving chemistry. In chemistry, atoms are very small and there are a massive amount of atoms and molecules in everything that exists. Moles make measuring atoms and other particles easy instead of saying some incredibly long number. Moles also help us determine how many particles are in something. The idea of moles is a key concept that makes everything involving chemistry easier.
Figure 1
Table 1: Average Reduction in Samples’ Mass Over Time
Figure 2 and Table 2 depict the average water lost each day in mass for each sample.
Figure 2
Table 3
Figure 3
A comparative
study to determine biochars’ ability to retain water in acid mine
impacted soils
Bryan Bauer*, Zack Dowd*
*Animas High School, Durango, Colorado 81301, United States
________________________________________________________________________
ARTICLE INFO ________________________________________________________________________
Keywords:
Biochar
Acid mine impacted soils
Pyrolysis
Water retention
________________________________________________________________________
Bryan Bauer*, Zack Dowd*
*Animas High School, Durango, Colorado 81301, United States
________________________________________________________________________
ARTICLE INFO ________________________________________________________________________
Keywords:
Biochar
Acid mine impacted soils
Pyrolysis
Water retention
________________________________________________________________________
ABSTRACT
________________________________________________________________________
This paper examines biochar’s effect on the water retention of soils that have been contaminated with acid mine waste and acid mine drainage. It further focuses on the specific percentage by mass of biochar that is most effective at retaining water, as leachate has been known to cause water and soil pollution. A popular remedy for this is by revegetation, and as such, soils that have unfit levels of water retention it becomes difficult for flora to grow. Thus it is imperative to remediate contaminated soils through revegetation and the soils ability to retain water. In order to determine the percentage of biochar that is most efficient at retaining water, the mass of each sample was taken each day to give a range of data that shows the loss in mass over five days. Our research concluded in a twenty percent biochar producing the most effective percentage in retaining water, due to it losing the least amount of water per day. As our results have concluded 0% biochar is the most effective at maintaining water within the soil.
________________________________________________________________________
________________________________________________________________________
This paper examines biochar’s effect on the water retention of soils that have been contaminated with acid mine waste and acid mine drainage. It further focuses on the specific percentage by mass of biochar that is most effective at retaining water, as leachate has been known to cause water and soil pollution. A popular remedy for this is by revegetation, and as such, soils that have unfit levels of water retention it becomes difficult for flora to grow. Thus it is imperative to remediate contaminated soils through revegetation and the soils ability to retain water. In order to determine the percentage of biochar that is most efficient at retaining water, the mass of each sample was taken each day to give a range of data that shows the loss in mass over five days. Our research concluded in a twenty percent biochar producing the most effective percentage in retaining water, due to it losing the least amount of water per day. As our results have concluded 0% biochar is the most effective at maintaining water within the soil.
________________________________________________________________________
1. Introduction
Acid
mine drainage is leaching metals into the Silverton water supply as well as the
surrounding unaffected soils. Acid mine impacted soils are often mine
tailings that are the leftover soil, rock and debris that was dumped after it
was mined. Rain and snow seep through these contaminated soils which
washed out metals and contaminants, creating a leachate. These
contaminants are leached into the surrounding unaffected soils, possibly
contaminating other water supplies such as rivers, lakes, and streams.
This soil contamination has a harmful effect on the region’s biota.
This can change the pH of the water in lakes and streams, affects the
hardness of the water, and can introduce harmful metals into the water
supplies, such as As, Hg, Zn, Cu, and Pb. These metals may cause harm to
humans as well as native organisms. It is therefore necessary to stop
these acid mine drainages as quickly and effectively as possible. One way
to do this is through the application of biochar. Biochar is a form of
charcoal that is created from a carbon-based biomass, such as lodge pole pine
and ponderosa wood that has undergone pyrolysis (process in which materials are
superheated with the absence of oxygen). Biochar is a porous substance,
created to provide an amendment to act as a carbon sink in agricultural soils,
or in our case, mine impacted soils while at the same time, improving soil
fertility (Chan et al. 2007;Ogawa et al. 2006). Biochar has a high
surface area, so when biochar is applied at high rates, it can also increase
soil water retention. However, biochars can contain other compounds such as
phenolic compounds, crystalline silica, dioxin, and heavy metals that are
harmful to plants, microbes and humans (Cao et al. 2009; Thies and Rillig 2009)
as well as to essential nutrients (Gaskin et al. 2008). These harmful chemicals
and compounds can be introduced to the biochar during the process of creating
the biochar, therefore, biochar can either inhibit or benefit the seedling
growth and germination.
Biochar can also alter organic matter materialization,
which is connected to the dispersion of necessary nutrients such as nitrogen
and other gases. The change in the nutrient status of the soil can affect both
the seed germination and plant growth. The application of biochar to acidic
soils (i.e our contaminated soils) can increase the soil pH levels to alkaline
levels (the soil is becoming more basic). The diversity in characteristics of
biochar indicate that biochar responses will differentiate based on the type
and rate of biochar applied to soil and the soil characteristics as well such as
soil carbon levels, soil pH, and other components of soil fertility.
Normally, the contaminated soils would affect the plant and
harm it, causing slower plant growth or deterioration of the plant, but if the
biochar absorbs and retains contaminated water from the mine drainage, then it
could reduce the effects of the contaminated soils, protecting the plants while
reducing the contamination of the surrounding water supplies at the same time.
2. Materials and Methods
2.1 Experimental Design:
This laboratory experiment took place at Animas High School
2.2. Experiment Setup:
We used an electronic scale in order to measure the mass of
each sample, a 100mL graduated cylinder to measure out the amount of water we
put into each sample each day. A heat lamp was used to grow the plants
underneath a tarp. To begin our procedure we selected a contaminated mine
site that contained the tailings from the site. We then applied biochar in
varying amounts; 0% composition biochar, 10% composition biochar, 20%
composition biochar, and 30% composition biochar, to form three samples that
replicate of each level of treatment by volume. Creating three duplicate
samples of each treatment
2.3. Procedure:
Every week we massed each sample, added 100mL of water and
massed the sample again. In addition to the main test, we conducted a trial of five days in order
to determine how much water the soil would retain over the course of the trial,
depending on its treatment. After massing each sample at the first day of
the week, before and after watering, we massed them every day for the rest of
the week not adding any more water throughout this process. This gave us
the water retention over the course of the week in mass. This would give
us a sample of how much water each treatment would hold for a week. The
decrease in mass over time gave us the amount of water the soil samples held.
The difference in mass from each measurement is the mass of the water
content. There are several possible ways that water can be lost within
the soil including: evaporation, absorption by plants, and draining out the
bottom.
2.4. Example Experiment:
For example: a sample of 10% biochar by mass, was
massed with an electronic scale. It was massed at 300g, adding 100mL of
water increased the mass to 356g, this was taken on Monday. On Tuesday it
was massed with the same electronic scale and massed at 345g, on Wednesday:
337g, Thursday: 323g, and Friday: 311g. The sample’s decrease in mass is
the amount of water it held over the sample week, every day it lost 10g of
water.
3. Results
During our investigation of biochar’s retention of water,
we collected data independent of the weekly collection. We used the data
from the site, Across From Bonner (AFB), for our experiment to get a pinpoint
area that we could use. This proved to be more efficient for our experiment.
For this data, we collected the mass of the samples each day in order to
determine the amount of water that each treatment held for five days. As
is expected, when watering the samples, there were increases in the mass. The
original gain in mass for the samples with 0% treatment was +57.01g (for sample
one), +34.28g (for sample two), and +50.97g ( for sample three). The original
gain in mass for the samples with 10% treatment was +48.03g (for sample one),
+47.45g (for sample two), and +50.06g (for sample three). The original gain in
mass for the samples with 20% treatment was +40.2g (for sample one),
+39.68g (for sample two), and +42.12g (for sample three). The original gain in
mass for the samples with 30% treatment was +42.04g (for sample one), +48.51g
(for sample two), and +53.88g (for sample three). This data was not inserted
into our current data because of accuracy purposes. As shown in Figure 1, we
analyzed the decrease in mass, in grams, for each treatment’s biochar
percentage over the course of the five days. This data shows how our
samples mass decreases as the water content within evaporates or is absorbed by
plant growth.
Table 1 states the exact data associated with Figure 1.
Shown in Figure 3 is the trend line of each data point we collected for
Figure 1. In order to determine which sample was most efficient at
holding water, we created a trend line for each treatment as well as and R2
value. Table 3 is the total mass lost by each treatment over the course
of the entire experiment, in other words the water lost over five days
Figure 1Table 1: Average Reduction in Samples’ Mass Over Time
|
Date
|
Avg. Mass (g)
|
Date
|
Avg. Mass (g)
|
Date
|
Avg. Mass (g)
|
Date
|
Avg. Mass (g)
|
|
Treatment 0%
|
|
Treatment 10%
|
|
Treatment 20%
|
|
Treatment 30%
|
|
|
3/5/2012
|
334.33
|
3/5/2012
|
350.6
|
3/5/2012
|
361.61
|
3/5/2012
|
385.43
|
|
3/6/2012
|
329.23
|
3/6/2012
|
341.61
|
3/6/2012
|
353
|
3/6/2012
|
375.22
|
|
3/7/2012
|
|
3/7/2012
|
333.19
|
3/7/2012
|
346
|
3/7/2012
|
365.5
|
|
3/8/2012
|
312.57
|
3/8/2012
|
323.9
|
3/8/2012
|
338
|
3/8/2012
|
354.7
|
|
3/9/2012
|
304.47
|
3/9/2012
|
315.42
|
3/9/2012
|
329.29
|
3/9/2012
|
344.6
|
Figure 2 and Table 2 depict the average water lost each day in mass for each sample.
Figure 2
Table 2: Average Water Loss
Each Day
|
Date
|
Water Loss (g)
|
Date
|
Water Loss (g)
|
Date
|
Water Loss (g)
|
Date
|
Water Loss (g)
|
|
Treatment 0%
|
|
Treatment 10%
|
|
Treatment 20%
|
|
Treatment 30%
|
|
|
3/6/2012
|
-15.13
|
3/6/2012
|
-9
|
3/6/2012
|
-8.65
|
3/6/2012
|
-10.21
|
|
3/7/2012
|
|
3/7/2012
|
-8.42
|
3/7/2012
|
-7
|
3/7/2012
|
-9.72
|
|
3/8/2012
|
-16.66
|
3/8/2012
|
-9.29
|
3/8/2012
|
-8.04
|
3/8/2012
|
-10.78
|
|
3/9/2012
|
-8.1
|
3/9/2012
|
-8.48
|
3/9/2012
|
-2.9
|
3/9/2012
|
-10.12
|
Table 3
|
Biochar Treatment
|
Starting Mass
|
Final Mass
|
Total Mass Lost (g)
|
Total Mass Lost
(% of Starting Mass) |
|
0%
|
334.33
|
304.47
|
29.86
|
8.93
|
|
10%
|
350.6
|
315.42
|
35.18
|
10.03
|
|
20%
|
361.61
|
329.29
|
32.32
|
8.93
|
|
30%
|
385.43
|
344.6
|
40.83
|
10.59
|
Figure 3
4. Discussion
In conclusion, the soil samples with 10% biochar and 30%
biochar treatment stood out to us the most. As both treatments have and R2
value of 0.9998, they were both promising. However the 30% treatment has
a steeper decline in mass over the duration of the experiment according to the
slope equation in Figure 3. These treatments also had the most total
water loss in a percent of the starting mass; according to table 3, 30% being
the most. Since the 30% treatment had the most water lost and the
steepest slope, the 30% treatment lost the most amount of water the fastest.
Therefore with this evidence treatments 10% and 30% biochar, though have
the best R2 value, seem to lose more water, specifically 30% bichar.
0% and 20% biochars seem to have a very similar slope according to Figure
3 as well as fairly good R2 values at a little less than the R2
values of 10% and 30% treatments. 0% biochar treatment has the lowest R2
value and that may be explained by the presence of a null value that was not plotted.
This may have skewed the R2 value some. They do
however have the most gradual slope and the least amount of total water lost.
As a matter of fact these treatments had almost the exact same percentage
of total water lost, this would make the 20% treatment the same as the 0%. Our
results have yielded in 0% and 20% to be the most effective at retaining water,
due to that they have virtually the same data associated with them the more
effective one out of the two is 0% as it is more cost effective. Our
results show 0% biochar by mass treatment is the most effective at retaining
water in acid mine impacted soils.
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Xinde, Pullammanappallil Pratap, and Yang Liuyan (2011) Biochar Derived from Anaerobically Digested
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Janice Thies, Caroline A. Masiello,William C. Hockaday, and David Crowley.
Biochar effects on soil biota.
- J. W. Gaskin, C. Steiner, K. Harris, K. C.
Das, B. Bibens. Effect of Low-Temperature Pyrolysis On Biochar for
Agricultural Use.
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