This (montmorillonite) where the nanomaterials have been fused

This section will be focusing on the metal
(Au, Ag, Pd, Ni) and also mineral (montmorillonite) where the nanomaterials
have been fused with the Nano-cellulose substrates 44. The nanocomposite
shows great results in electrical, optical and catalytic properties.

 

Nano-cellulose have different name which is
micro fibrillated cellulose (MFC) or Nano fibrillated cellulose (NFC),
nanocrystalline cellulose (NCC) or cellulose nanocrystal (CNC); and bacterial
cellulose (BC) 45.

 

The characteristics of the Nano-cellulose are high
specific surface area, mechanical strength and high porous structure. It is the
perfect platform to house the guest nanomaterial. Combining both Nano-cellulose-based
nanocomposites and guest nanomaterial will usually power up the properties. The
fusion between the guest nanomaterial and Nano-cellulose substrate can be done
in three different ways:

·      
formation
of the guest nanomaterial in a Nano-cellulose dispersion

·       formation of the guest nanomaterial in the
bulk structure of Nano-cellulose-based materials such as BC membranes

·      
direct
coating of the guest nanomaterial onto the Nano-cellulose surface as a
nano-sized layer

 

The application of Nano-cellulose-based Nanocomposites
can be done in several ways:

1.    
Antimicrobial filters

2.    
Catalysis

3.     Pollutant sensors

 

3.1      
Antimicrobial filters

 

Antimicrobial materials can prevent the
biofilm growth and increase the filter life. A research was conducted where Chitosan-based
antimicrobial materials was used in the purification of drinking water 46.

 

High number of AgNPs can be sustained in a
homogenous state due to the higher surface to volume ratio characteristic of
the Nano-cellulose. Thus, it can provide superior antimicrobial properties 47.

 

Further study has been done where the Nano-cellulose
surface has been modified which it can reduces the risk of AgNP leakage by
enhancing the capacity to restraining it 48.

 

3.2      
Catalysis

 

Nano-cellulose-based nanocomposites can act as the
catalytic decomposition of organic pollutants in the water.

Guest nanoparticle (NP) that are used for catalytic
application are mainly

·      
photocatalysts
like TiO2

·      
precious
metals (Au, Ag, Pt)

 

Nano-cellulose usually will act as a catalyst support
to slow down the nanoparticle accumulation. A research was conducted where a Nano-cellulose
aerogel was coated with a 7 nm wide TiO2 layer using the chemical
vapour deposition technique. It was proved that under the observation of UV
illumination, methylene blue on the nanocomposite was decomposed which shows
its potential in water treatment application. 49. Other than this,
research found out that TiO2 and Nano-cellulose nanocomposite showed
fascination results of photoswitchable water super absorption.

 

Precious metals (Au, AG, PT and Pd) are typical
material used for catalysts. With the presence of Nano-cellulose, reducing metal
salts will be able to create Metal-NP and Nano-cellulose nanocomposites. Some of the reduction agents used is H2, NaBH4
and Na3Citrate.

 

3.3      
Pollutant sensors

 

The applications not only cover the antimicrobial
filters and catalyst but can also be employed as biosensors. The study has been
done by many researchers with the AuNP and Nano-cellulose nanocomposites 50, 51.

 

There are some research done about the conductivity of
AuNP and BC by incorporate the nanocomposite in the electrode to identify
chemicals electrochemically 52. Zhang et al.
created the AuNP and BC nanocomposites and used them as sensors for H2O2
and glucose detection 50.

 

AuNP can also be function as different goal.
Researcher has found a method to vary the thickness of the SiO2 shell
on the AuNPs from 15 to 100 nm which is done by generating a specific
separation between AuNPs and the homogenous coating of SiO2. On the
AuNPs was produced. Thus, the thickness can be perceived by using the
transmission electron microscopy (TEM) images 53.