Slow Pyrolysis of Corncobs for Biochar as a Possible Alternative to Graphene Oxide

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:

• [email protected]

• https://my.linkedin.com/in/alexjosephlau

Muhammad Azwan:

• [email protected]

• https://my.linkedin.com/in/azwanmohdali