slow pyrolysis of corncobs for biochar as a possible alternative to graphene oxide
TRANSCRIPT
Slow Pyrolysis of Corncobs for Biochar
as a Possible Alternative to Graphene
Oxide
by
Alexander Lau
Muhammad Azwan Mohd Ali
Why Graphene?
Graphene, which is known as an allotrope of carbon in the
form of a two dimensional, atomic-scale, honey-comb lattice
is highly demanded in the market these days.
Graphene
Supercapacitor
Reducing food waste
Wearable technology
Graphene for Sports
Graphene filtration
Biomedical applications
Problem with existing
method of graphene
production
1. The mining process of
graphite is costly and highly
polluting.
2. Side products of Chemical
Vapor Deposition method is
highly toxic.
Solution
Studies on the bio-char of corn cobs for the similarities in
the properties (optical) of the bio-char and graphene
Drying of
feedstock
Slow Pyrolysis
Analyses
Sample chosen for thin
film fabrication (Scotch
tape method)
UV-Vis Absorption
Spectroscopy test
Sample pH Temperature /◦C
Feedstock (corn cobs) 4.11 27.7
200 DCPT bio-char 5.03 32.4
300 DCPT bio-char 8.06 28.0
400 DCPT bio-char 8.55 29.0
500 DCPT bio-char 8.64 33.7
600 DCPT bio-char 8.99 29.9
DCPT – degree Celsius pyrolysis temperature
General Results: Moisture Content
Bio-char
temperature
Analysis
/◦C Moisture / % Ash / % Volatile / % Fixed carbon /
%
600 3.46 7.23 12.46 80.31
500 3.31 6.68 17.27 76.05
400 1.28 3.46 32.98 63.56
300 1.34 3.04 40.00 56.96
200 3.13 1.05 72.56 26.39
Purpose: To increase porosity.
Types: Physical and chemical activation
Steps:
1. Immerse in nitric acid, HNO3 for 24
hours.
2. Dry and extract the biochar
Basic structure of lignin Nanostructure similar to graphene.
Activated Biochar Structure Graphene Structure
Our FESEM findings on activated and non-activated biochar with 5000x
magnification
Activated carbon
Carbon activation
Non-activated carbon
Scotch Tape Method on glass substrate
Ultraviolet-visible spectroscopy
Studies optical properties of thin films and material surfaces
1. Absorbance spectrum
2. Transmission spectrum
Moisture content:
More analysis should be taken for statistical confidence to properly
determine the moisture content of biochar. It seems that pyrolysis
temperature at 300oC and 400oC are similar. On the other hand, 200oC,
500oC and 600oC themselves are also similar with one another.
Ash content:
Ash content of biochar shows a linear trend. It would be more likely that the
linearity of this trend would stop at a certain point as pyrolysis temperature
increases. Pyrolysis at higher temperature should be done to find if there is
a maximum ash content.
Thin film fabrication:
Chemical Vapour Deposition (CVD) or Spin Coating techniques. Time
constraints would be a factor in manufacturing such thin films and would not
be recommended for a part-time research project and only for a full time
effort.
Further investigations should be made.
1. High quantity of biochar and oil are produced at 300oC.
2. Carbon content reaches a maximum percentage of about 80% at 600oC.
3. The fact that carbon activation changes shape of pores could be used in
electrochemical reactions
4. Biochar thin films can mimic graphene oxide thin films.
Alexander Lau:
• https://my.linkedin.com/in/alexjosephlau
Muhammad Azwan:
• https://my.linkedin.com/in/azwanmohdali