Pretreatment of different materials:
An international perspective
Mohammad J. Taherzadeh
School of Engineering
University of Borås
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
A variety of lignocelluloses are attractive in different reagions!
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Complex plants cell walls
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
A challenge by lignin and hemicellulose!
Hemicellulose
Lignin
Cellulose chains
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Challenge of crystallinity!
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Alternative patterns of aggregation
Helical form of a 6 by 6 nm nanofibrils
is compared with that of nine 2 by 2
helical nanofibrils packed as close as
possible, with the same period.
A. The fibrils were twisted individually and
then the assembly also twisted.
B. The individual fibrils were twisted of
90°over 300 nm and then packed as
closely as possible
C. The fibrils were collectively subjected to
twist.
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Alternative patterns of aggregation
Cellulose is deposited alone
The most efficient load-bearing structure
Would not be
mechanically
stable
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Changes during Isolation
•
Two stages in isolation will influence the
final pattern of aggregation:
1. Elevation of temperature
2. Effect of drying
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Effects of elevated temperature

Cellulose is hydrated in its native state at
the level of elementary nanofibril
Temperature elevation changes the state
of aggregation of native cellulose.
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Drying?
Drying results in distortion of nanofibrils
by:
Removing too much of the water needed to
lubricate the motion of the nanofibrils
relative to each other.
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Changes during Isolation

Linear parallel segments, which are
artifacts of isolation processes are easily
mistaken for naturally accuring
crystalline domains.
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Pretreatment in order to:

Release cellulose from the structure:
 Remove or hydrolyze hemicelluloses
 Remove lignin




Reduce cellulose crystallinity
Provide enough accessible surface area to absorb
the enzymes
Adsorption/desorption rates of the enzymes
Remove inhibitory compounds following the
substrate
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Pretreatment methods
(various efficiency on different factors)
Physical methods
Chemical & Physicochemicals
Biological
milling:
- Ball milling
- Two-roll milling
- Hammer milling
- Colloid milling
- Vibro energy milling
irradiation:
- Gamma-ray irradiation
- Electron-beam irradiation
- Microwave irradiation
Others:
- Hydrothermal
- High pressure steaming
- Expansion
- Extrusion
- Pyrolysis
Explosion:
- Steam, Ammonia, CO2, SO2 , Acids
Alkali:
- NaOH, NH3, (NH4)2SO3
Acid:
- Sulfuric, Hydrochloric & Phosphoric
acids
Gas:
- ClO2, NO2, SO2
Oxidizing agents:
- Hydrogen peroxide
- Wet oxidation
- Ozone
Solvent extraction of lignin:
- Ethanol-water extraction
- Benzene-water extraction
- Ethylene glycol extraction
- Butanol-water extraction
- Swelling agents
Organosolvs/ Ionic liquids
Fungi and actinomycetes
(lignin peroxidase, manganese
peroxidase, laccase…)
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Cellulose solvents effective for crystallinity
Component type
Transition metal complexes with
amines or NH3
Transition metal complexes with
tartaric acid
Ammonium hydroxides
Alkali hydroxides
Acids
School of Engineering
Sovent
Active component
Cadoxen
Cdtren
Cooxen
Cupren
Cuam
Cuen
Nioxam
Nioxen
Nitren
Pden
Zincoxen
[Cd(H2 N-(CH2)2 -NH2)3 ](OH)2
[Cd(NH2 CH2 CH2)3 N](OH)2
[Co(H2 N-(CH2)2 -NH2)2 ](OH)2
[Cu(H2 N-(CH2)3 -NH2)2 ](OH)2
[Cu(NH3)4 ](OH)2
[Cu(H2 N-(CH2)2 -NH2)2 ](OH)2
[Ni(NH3)6 ](OH)2
[Ni(H2 N-(CH2)2 -NH2)3 ](OH)2
[Ni(NH2 CH2 CH2)3 N](OH)2
[Pd(H2 N-(CH2)2 -NH2 ](OH)2
[Zn(H2 N-(CH2)2 -NH2)2 ](OH)2
FeTNa
Triton B
TEOH
Triton F
GuOH
Na6 [Fe(C4H3O6)3]
Trimethylbenzyl ammonium hydroxide
Tetraethylammonium hydroxide
Dimethyldibenzyl ammonium hydroxide
Guanidinium hydroxide
NaOH
LiOH
H3PO4
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Possible non-aqueuous cellulose solvents
Component type
Sovent name
Unicomponent
N-Alkylpyridinium halogenides
Oxides of tertiary amines
Bi-component
Tri-component
Active component
N-Ethylpyridinium chloride
N-Methylmorpholine-N-oxide
Triethylamine-N-oxide
N-Methylpiperidine-N-oxide
Dimethyl sulfoxide (DMSO) containing solvents DMSO/methylamine
DMSO/KSCN
DMSO/CaCl2
DMSO/TBAF
Liquid ammonia/sodium or ammonium salts
NH3 /NaI (NH4 I)
NH3 /NaSCN (NH4 SCN)
Dipolar aprotic solvents/LiCl
N,N-Dimethylacetamide/LiCl
N-Methylpyrrolidone/LiCl
Pyridine or quinoline containing systems
Pyridine/resorcinol
Quinoline/Ca(SCN)2
NH3 or amine/salt/polar solvent
NH3 /NaCl/DMSO
Ethylenediamine/NaI/N,NDimethylformamide
NH3 or amine/SO2 or SOCl2 /polar solvent
Diethylamine/SO2 /DMSO
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Low-temperature Ionic Liquids (80-130 C)
1-Ethyl-3-methylimidazolium acetate [EMIM]OAc
1-Ethyl-3-methylimidazolium chloride [EMIM]Cl
1-Allyl-3-methylimidazolium chloride [AMIM]Cl
1-Butyl-3-methylimidazolium chloride [BMIM]Cl
1-Butyl-3-methylimidazolium bromide [BMIM]Br
1-Butyl-3-methylimidazolium acetate [BMIM]OAc
1-Butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF4
1-Butyl-3-methylimidazolium hexafluorophophate
[BMIM]PF6
1-Butyl-3-methylimidazolium methylsulfate [BMIM]MeSO4
Imidazole salts
1-Octyl-3-methylimidazolium chloride [OMIM]Cl
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Milling: Usually part of the process!

Milling:






Ball milling
Two-roll milling
Hammer milling
Colloid milling
Vibro energy milling
Functions:
 Size reduction
 Degree of crystallinity

High energy costs!
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Irradiations

Irradiation:
– Gamma-ray irradiation
– Electron-beam irradiation
– Microwave irradiation



Usually good results
Expensive!
Ultrasound might have a good
a chance for commercialization
(already in the market)
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Hydrothermal process


Cooking in liquid hot water generally at 150-210 °C
Water under high pressure can:
–
–
–
–


Autohydrolysis occur due to releasing some carboxylic acids such as
acetic acid,
Advantages:
–
–
–
–

Penetrate into the biomass,
Hydrate cellulose,
Remove hemicellulose (a major function),
Remove part of lignin (but not so effective),
No addition of chemicals,
No neutralization afterward,
No corrosion-resistant materials for reactor,
Could be combined with e.g. a delignification process
Industrial application such as by Danish Inbicon
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
High-pressure steaming (+explosion)

Cooking with steam generally at 150-220 °C & 0.5-20 min
If followed by explosive releasing of the pressure = Steam explosion
Steam explosion is one of the most popular pretreatments
Explosion has important function
pH reduces due to autohydrolysis

Industrtial applications by e.g.




– Cambi (Norway)
– Chemtex (Italy)
– Greenfield (Canada)
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Dilute-acid processes!



Similar methods in pulp industries
Similar temperature/Pressure as steam explosion!
Improvement by addition of:
–
–
–
–

Dilute-acid (0.1-1% acids: H2SO4, HCl, etc.)
Carboxylic acids (e.g. acetic acid)
1-4% SO2
CO2
Functions:
– Open up the polymers
– Hydrolysis of hemicellulose

Potential commercialization by e.g :
– POET (USA)
– SEKAB (Sweden)
– ABENGOA (USA)
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Alkaline cooking!

Treatment with alkaline solutions:
– NaOH,
– Ca(OH)2 (lime) or
– Ammonia (AFEX)







Popular in pulp industries (kraft process)
To remove lignin effectively (+ sometimes a part of
the hemicellulose)
To reduce crystallinity of cellulose
Generally at about 90-130 C for a few minutes to
hours
High pH (e.g. 11-12) or alkali concentrations 1-20%
High amount of NH3 is needed (e.g. 1:1 kg/kg
NH3/biomass)
Can also be used with explosion
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Oxygen treatments (wet oxidation)!







Wet oxidation = treatment with water and air or O2 at
140-200 C for e.g. 30 min.
It is exothermic process (because of oxidations)
It is a combination of solubilization and degradation
reactions
Hydrolytic reactions  organic acids
The hemicelluloses are extensively cleaved to
monomeric sugars;
The lignins undergo both cleavage and oxidation;
Cellulose is partly degraded.
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Organosolves/Ionic liquids!

Lignocelluloses are mixed with organic liquid (and
water?) and heated to dissolve:
– Ligning
– And/or cellulose

Temperatures of 80-200 °C can be used:
– Depends on the solvent used!


Simple solvents such as ethanol or acetone can be used!
Low Temperature Ionic Liquids are hot research topic
today!
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Our latest results for high
crystalline cellulose!





N-Methylmorpholine-N-oxide (NMO or NMMO)
No toxicity
Solvent of cellulose
Industrial solvent
80-130 C
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Conclusion

Lignocelluloses are diffent:
 Type,
 Age,
 Crystallinity
 Dryness,
 Type of the cell wall
 ….


Pretreatments have different effectivities on various
lignocelluloses,
Great developments in pretreatments, but still long
way to go…
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery
Thank you!
Question?
School of Engineering
Mohammad.Taherzadeh@hb.se
Tel: +46-70-7171032
www.hb.se/ih/resourcerecovery