(186o) Bulk Synthesis of Quasi-Carbon Dot Via Two Step-Method from Rice Husk

Bulk
synthesis of quasi-carbon dot via two step-method from Rice Husk

Prashant
Kumar, Sudipto Chakraborty

Department
of Chemical Engineering, IIT Kharagpur

E-mail: prashantkumar.ch@iitkgp.ac.in, sc@che.iitkgp.ernet.in

Abstract

Carbon
dot (CD) – A newbie from the carbon nanomaterial family is gaining utmost
attention, due to attractive property such as non-toxicity, solubility,
stability[1].
Additionally, the oxygenous functional group on the surface imparts them reducibility
property thereby ease of functionalization[2],
so it can reduce metal precursors and forms compound with metals possessing high
thermal conductivity[3].
Due to these properties, it is getting due relevance in heat transfer
application, in particular, nanohybrid kind of nanofluid synthesis[3].
Therefore, the need for bulk CD for nanofluid synthesis arises. Herein, we propose
a method of carbon dot synthesis using the two-step method for the bulk CD requirement,
a method derived from CD synthesis from rice husk that finds application in other
areas [4].
The proposed method involves carbonization followed by nitric acid oxidation,
followed by a copious amount of distilled water wash leads to the formation of purified
quasi-carbon dot from rice husk (CD-RH/CD). The synthesized CD was characterized
using various characterization techniques. FTIR analysis was done to check the
formation of associated functional groups of the CD. In figure 1, FTIR plot
shows that oxidation of carbonized rice husk (C-RH) with nitric acid causes the
introduction of carboxyl functional group at 1720 cm^-1, as well as
enhancement in intensity of functional groups such as hydroxyl, aldehyde at their
respective peak positions in CD, which confirms the formation of various oxygen-containing
the functional group. CHNS analysis was done to check the changes in the
elemental composition due to CD formation, which is compared with carbonized
rice husk as shown in table 1. The increase in oxygen content in case of CD
indicates the formation of the oxygen-containing functional group in species. Zeta
potential was done to check to dispersion stability of C-RH and CD-RH in water
and is tabulated in table 2. Increase in the zeta potential value can be
attributed to the increase in oxygen functional group on carbon surface which
imparts higher stability than carbonized rice husk. DLS was performed for size
determination of the prepared nanoparticles. XRD was done to check the presence
of the amorphous and graphitic structure in the sample. FESEM was done to study
their morphology. Finally, EDAX was done to check the surface composition of
different elemental species of the sample. Due to brevity, only few
characterization results are included with this abstract. Above mentioned
analysis is in concurrence with the one available in the literature for CD. The
synthesized CDs have potential application in metal-based nanohybrid
preparation, which can be used in heat transfer enhancement where water is present
as the base fluid.

Figure
1. FTIR plot of carbonized rice husk (C-RH) and carbon dot derived from rice
husk (CD-RH)

Table
1. Elemental composition of carbonized rice husk (C-RH) and carbon dot from
rice husk (CD-RH)

Table 2. Zeta potential
of carbonized rice husk (C-RH) and carbon dot from rice husk (CD-RH)

References:

[1]      A.
L. Himaja, P. S. Karthik, and S. P. Singh, “Carbon Dots: The Newest Member of
the Carbon Nanomaterials Family,” Chem. Rec., vol. 15, no. 3, pp.
595–615, 2015.

[2]      R. Das, R. Bandyopadhyay, and P.
Pramanik, “Carbon quantum dots from natural resource: A review,” Mater.
Today Chem., vol. 8, pp. 96–109, 2018.

[3]      Z. Azizi, A. Alamdari, and M.
Mohammad, Doroodmand, “Highly stable copper/carbon dot nanofluid Preparation
and characterization,” J. Therm. Anal. Calorim., 2018.

[4]      P. Zhen et al., “Synthesis
of carbon nanoparticles from waste rice husk used for the optical sensing of
metal ions,” New Carbon Mater., vol. 31, no. 2, pp. 135–143, 2016.