No.

Pretreatments

Effect of

pretreatments

References

Energy conservation requirement

Process &

remarks

1

(a) Ozone at a charge level of at least about 0.1 wt/wt%, based on the dry weight of the cellulosic material for generating free radicals in the slurry

(b) Cellulase enzyme at a concentration from about 0.1 to about 10 lbs/ton based on the dry weight of the cellulosic material

A combination of both (a) and (b) mentioned above

Partial depolymerization of cellulose

[28]

>2% energy conserved

Comminution processing

2

Organic (morpholine, piperidine or mixtures) or inorganic (inorganic halide, an inorganic hydroxide, or mixtures thereof) swelling agent or a mixture thereof

Swelling of cellulose

[29]

1400 kWh/t energy required

500 kWh/t energy required

Comminution processing

80% nanocellulose (defined as having an average diameter of less than 30 nm)

45% of the material having average diameters less than 30 nm

3

Carboxymethylation

Increases the anionic charges due to the formation of carboxyl groups in the surface

[30]

5500 kWh/t without pretreatment (per pass through)- Minimum of 4 passes

2200 kWh/t with pretreatment (per pass through)-4 passes

30000 kW/t (total) without pretreatment

Microfluidization process

Ultra-fine friction grinding

4

Carboxymethylation OR by irreversibly attaching CMC onto cellulose fibres

Increases the anionic charges due to the formation of carboxyl groups in the surface

[31]

500 - 2300 kWh/t

Microfluidization process

5

Acid like sulfur dioxide, sulfurous acid, sulfur trioxide, sulfuric acid, lignosulfonic acid & their combinations or enzyme

Hydrolysis

[32]

<1000 kWh/t

Mechanical treatment