Transcript Carbon Capture From Air - NDsciencefair

Megan Logue
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Is a .1 M or a 1 M solution of sodium
hydroxide more effective at extracting and
absorbing carbon dioxide from air?
Will carbon dioxide be absorbed more
efficiently by sodium hydroxide at 16°C or
32°C?
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The increasing amount of CO2 in the Earth’s atmosphere has the potential to
severely harm the environment and affect society.
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The purpose of carbon capture is to remove CO2 that would otherwise build
up in the atmosphere.
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One method of carbon capture is the implementation of artificial trees in the
environment.
◦ An artificial tree operates by enabling air to filter through its structure and removing
the air’s CO2 with a sorbent material, such as sodium hydroxide, or NaOH.
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The initial pH value of a solution of NaOH will decrease as it captures CO2
from air.
This change in pH can be used to determine the exactly how many molecules
of CO2 are extracted from air over a period of time.
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A solution of NaOH and water can be used to extract
CO2 from air. The reaction between a solution of
NaOH and CO2 is as follows:
◦ CO2 + H2O = H2CO3
◦ NaOH + H2CO3 = NaHCO3 + H2O
◦ NaHCO3 + NaOH = Na2CO3 + H2O
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Overall reaction:
◦ CO2 + 2 NaOH = Na2CO3 + H2O
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This indicates that for every two moles of NaOH, one
mole of CO2 is extracted from air.
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As the concentration of the NaOH solution
increases, the amount of CO2 absorbed will
increase as well.
Also, as the temperature of the system
increases, the amount of CO2 extracted from
the air will also increase.
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2 L of 1 M solution of NaOH
2 250 mL Erlenmeyer flasks
2 100 mL graduated
cylinders
2 aquarium pumps
2 stirring rods
Small weights
Water bath
Incubator
2 Vernier pH probes
2 Vernier temperature probes
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Logger Pro Date Logger
Computer
Water
Paper towels
Safety gloves
Safety goggles
Safety apron
Calculator
Sink
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A .1 M solution of NaOH and a 1 M solution of NaOH were prepared in separate Erlenmeyer flasks. Both flasks
were placed in the water bath set at 20°C.
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Separate tubes connected to aquarium pumps, a Vernier temperature probe, and a Vernier pH probe were placed
in each flask.
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The probes were set to collect samples at increments of 10 minutes over a time period of 24 hours with Logger
Pro Data Logger.
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After 24 hours, the collected data was recorded. The procedure at 20°C was repeated twice to perform a total of
three trials.
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Next, an incubator was set at 40°C. The .1 M and 1 M solutions of NaOH were placed in the incubator. An
aquarium pump, a Vernier temperature probe, and a Vernier pH probe, were placed in each flask.
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Once the temperature of each flask was stable at 40°C, the data collection was promptly started on Logger Pro
Data Logger. After 24 hours, the collected data was recorded. The procedure at 40°C was repeated twice to
perform a total of three trials.
After each trial was successfully completed, the changes in the pH of the solutions over time were calculated.
Mathematical models were used to determine the amount of CO2 molecules extracted from the air and removed
by each solution.
The final results of the experiment were compared and analyzed.
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Independent Variable
◦ Temperature
◦ Concentration of NaOH solution
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Dependent Variable
◦ Amount of CO2 removed
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Constants
◦ Erlenmeyer flasks, aquarium pumps, Vernier
temperature probes, Vernier pH probes, stirring
rods, small weights, Logger Pro Data Logger,
computer
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Stabilizing temperature
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Limited materials
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Evaporation of the NaOH solutions over the
24-hour time period
Time restrictions
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At 16°C, the .1 M NaOH solutions were more effective than the 1 M solutions.
At 32°C, the .1 M solutions produced similar results, but the 1 M solutions
removed more molecules of CO2. The final results suggested that the 1 M
solutions were more effective at 32°C.
This refutes the hypothesis that the CO2 extracted would increase as the
concentration of the NaOH solution increased.
It was also hypothesized that the CO2 extracted would increase as the temperature
of the system increased. This was rejected for the .1 M solutions but accepted for
the 1 M solutions.
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Lower concentrations of NaOH are likely to be more effective at cooler
temperatures, and greater concentrations of NaOH at warmer temperatures.
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Further Research
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Cost-effectiveness, carbon disposal and storage, different concentrations of NaOH solutions
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