Materials from wooden biomass Pyrolytic conversion of structured - - PowerPoint PPT Presentation

Materials from wooden biomass Pyrolytic conversion of structured alkaline lignins to porous carbonized materials

FINNISH–JAPANESE WORKSHOP ON FUNCTIONAL MATERIALS May25－26， 2009 （ Espoo and Helsinki, Finland）

Masashi KIJIMA Institute of Materials Science Graduate School of Pure and Applied Sciences University of Tsukuba, Japan

H2O, ….N,P,S

hν

CO2 Cellulose & Lignin Functional Materials (high-value added)

Conversion Combustion extraction

CO2 + H2O

Nutrition intake

CO2 recovery system in nature

Cellulose & Lignin Wood

Main component

Constructional material, Furniture, paper, etc Fuel (wood), charcoal Bio- and semisynthetic polymers (structured fiber, film, powder) Structured carbonized and carbon materials (activated carbon, carbon fiber etc.) (Carbon-rich materials) Refined raw material Unrefined raw material

Organic materials (extracts, derivatives). Direct usage Of structured materials Chemical approach Thermal conversion

Purpose of our research

Synthesis of functional carbon-rich materials from wooden biomass

Organic materials Semiconducting materials Conducting carbonized materials Carbon materials

∆ ∆ ∆

300ºC 800ºC 1500ºC Cellulose & Lignin

Low content of C Various functional groups in the material Possible to restructurize Structured C-rich Materials High-C content: uniform & homogeneous composition Application: thermoelectric-conversion, Photovoltaic & sollar cells, electrodes for batteries, fuel cell, EDLC, Stable porous Energy-source (H2 etc) storage material etc.

OH OH OH OH OCH3 OH H3CO OCH3 OH

(a) p-coumaryl alcohol (b) coniferyl alcohol (c) sinapyl alcohol

(a) (b) (c)

Advantage of lignin to convert into carbon materials: Lignin has the phenolic components: high C fixation ability on anaerobic pyrolysis

＜aromatic structural unit＞ ＜a possible structure＞

Lignin

There has been reported several results on carbonization of lignin and preparation of activated carbon

Activated carbon and the pore structure

＜characteristics＞ Surface area : ～1000 m2/g ＜preparation＞ Activated carbon:Physical and chemical activation macropore 50 nm < W mesopore 2 nm < W < 50 nm micropore W < 2 nm ＜applications＞ Adsorbent & gas sotrage molecular sieve electrodes micropore Surface area (adsorption site) Meso,macropore pore volume (diffusion of material)

Preparation methods of porous carbon

Without activation process

＜Activated method＞ conventional

activation H2O, CO2, or KOH etc 800 ºC ~ 1000 ºC Carbonized material Activated C Raw materials （ from wood） carbonization

＜Pyrolytic method＞

carbonization pyrolysis Raw materials Porous C

① Pyrolysis of alkaline lignin

SBET (500 ～ 3000 m2/g)

Porosity is largely dependent

• n the hardening and

elimination temperatures of raw mateials

20 40 60 80 100

TG [% ]

200 400 600 800

Temperature[℃] DTA[a.u.] 東京化成 ナカライテスク

Alkaline Lignin

Elemental analysis C: 51.72 %， H: 5.12 %, N: 0.13 % (Nacalai), C: 51.83 %, H: 4.78 %, N: 0.11 % (Tokyo Kasei) Reagent grade(available) Black powder， Water soluble

Tokyo Kasei Nakalai exo

CL1： r.t ~ 900 ºC 10 ºC/min CL2： r.t ~ 900 ºC 4 ºC/min CL3： r.t ~ 900 ºC 2 ºC/min CL4： r.t ~ 900 ºC 1 ºC/min CL5： r.t ~ 300 ºC 10 ºC/min 300 ºC (1) 300 ºC ~ 900 ºC 10 ºC/min CL6： r.t ~ 350 ºC 10 ºC/min 350 ºC (1) 350 ºC ~ 900 ºC 10 ºC/min CL7： r.t ~ 350 ºC 10 ºC/min 350 ºC (2) 350 ºC ~ 900 ºC 10 ºC/min CL8： r.t ~ 350 ºC 10 ºC/min 350 ºC (3) 350 ºC ~ 900 ºC 10 ºC/min

Carbonization conditions

(annealing time)

① Carbonization of alkaline lignin

Furnace r.t ~ 900 ºC

Argon gas inlet

Sample

Alkaline lignin CL4 CLW

10μm 10μm 10μm

CL4 ： deposition on the surface was a Na salt confirmed by XPS CLW ： After washing CL4 with water, the deposition was cleaned off

27 0.19 0.69 0.65 0.17 1031 899 ― CLW

Vmeso/ Vtotal (%) Vtotal (ml/g)

0.55 664

SBET (m2/g)

46

Yield (%) Vmeso (ml/g) Wmicro (nm) Vmicro (ml/g) Stotal (m2/g)

0.15

DH

655

αs

28 0.90 0.09 CL4

sample

Carbonization results and N2 adsorption data

SEM

Control of structure and morphology of carbonized materials

benzene water SDBS carbonization

Particles in nano-micron scale

② Preparation of micellar lignins and the carbonization Reverse micelle

Microporous C-particles Aims: 1) Increase of effective surface area. 2) Generation of new pore space between the particles

Benzene (ml) SDBS (mg) Water (ml) 45 50 5 ML3

SO3

• Na+

Sodium Dodecylbenzenesulfonate(SDBS)

Typical conditions

Particle samples could not be obtained in this case. In order to obtain particle lignins, (3) rigid lignin gels are synthesized

CML3

10μm

(in solution) (freeze-dried)

carbonization Freeze-dried

Preparation of micellar lignins （ ML) and their carbonization

ML3

Fine-structured ML

39 0.45 1.16 1.14 0.19 928 1340 17 CML3

Vmeso/ Vtotal (%) Vtotal (ml/g)

0.55 664

SBET (m2/g)

46

Yield (%) Vmeso (ml/g) Wmicro (nm) Vmicro (ml/g) Stotal (m2/g)

0.15

DH

655

αs

28 0.90 0.09 CL4

sample 2 4 6 8 1 1 2 1 4 1 6 1 8 C L 4 C M L 3 S a m p l e Surface area [m

2/g]

. 2 . 4 . 6 . 8 1 1 . 2 1 . 4 Pore volume [ml/g S B E T S αs V t

• t

a l

CL4 CML3

Comparison of N2 adsorption results of CL and CML

Under basic aqueous conditions, alkaline lignin was reacted with formaldehyde to give a swelled polymer gel, which was carbonized after freeze drying.

∆

Swollen lignin gel Carbon particles

Freeze-dried Lignin+HCHO+NaOH

④ Preparation of lignin-gel particles and their carbonization ③ Preparation of alkaline lignin gel and the carbonization

Toward synthesis of carbonized lignin particles

L L L HCHO L L L Freeze-dried, carbonization Swollen polymer gel carbonized

SEM Images of lignin deriv. before and after carbonization

LG CLG CMLG2 CMLG1 MLG1 MLG2

10μm 10μm 10μm 10μm 10μm 10μm

200 400 600 800 1000 1200 1400 1600 1800 CL4 CML3 CLG CMLG1

Sample

Surface area [m

2/g]

0.2 0.4 0.6 0.8 1 1.2 P

• r

e v

• l

u m e [ m l / g ]

SBET Sαs Vtotal

CL4 CML3 CLG CMLG 39 0.45 1.16 1.14 0.19 928 1340 17 CML3 30 0.23 0.78 0.70 0.17 1029 915 42 CLG 26 0.30 1.14 0.78 0.28 1528 1423 29 CMLG

Vmeso/ Vtotal (%) Vtotal (ml/g)

0.50 738

SBET (m2/g)

45

Yield (%) Vmeso (ml/g) Wmicro (nm) Vmicro (ml/g) Stotal (m2/g)

0.06

DH

920

αs

11 0.70 0.26 CL4

sample

Carbonization and N2 adsorption results

Electrical double layer capacitor (EDLC) characteristics

• f the carbonized lignins

0.5M Et4NBF4/ PC

55 85 CML 23 41 CLG 53 60 CMLG1 7 Cation (F/g) 0 ~ -1.5V 11 Anion (F/g) 0 ~ + 1.5V CL Sample

at 0.05 A/g

Et4N+ ： 0.68nm BF4

• ：

0.44nm

1M H2SO4

0.05 0.1 0.5 100 200 300 current density [A/g] capacitance [F/g] CL CML CLG CMLG1

0.2 0.4 0.6 0.8 1 200 400 600 800 Relative Pressure P/P0 Vads [cc/g(STP)] CL4 CLG CMLG1 HTCL HTCLG HTCMLG

Effect of heat-treatment (1500℃) on porosity

• f the carbonized lignins

26 0.30 1.14 0.78 0.28 1528 1423 CMLG1 30 0.23 0.78 0.70 0.17 1029 915 CLG 39 0.45 1.16 1.14 0.19 928 1340 CML3 28 0.15 0.55 0.90 0.09 655 664 CL4 63 0.20 0.20 0.32 0.32

• 187

187 HTCMLG 55 0.22 0.22 0.40 0.40

• 176

176 HTCLG

• HTCML

45 0.18 0.18 0.40 0.40

• 213

213 HTCL Vmeso/Vtotal (%) Vmeso (ml/g) Wmicr

• (nm)

Vmicro (ml/g) Stotal (m2/g) DH Vtotal (ml/g) αs SBET (m2/g) Sample

Summary & Conclusions

Porous carbons are obtained from alkaline lignin (L) and their structured derivatives (ML, LG, MLG) by pyrolytic method. Surface area and microporosity of CL can be increased by the structuration

• f the starting materials (ML, LG, MLG). Meso to macroporous spaces (pore

volume) can be enlarged by the structuration. Microporosity can be eliminated from the carbonized lignins by 1500ºC heat- treatment. During the carbonization and heat-treatment processes, these materials almost retain their surface morphology. These thermal conversion reactions are going to be applied to other lignin and cellulose derivatives in various forms (particle, film and fiber). Aims and key words of this research : Conversions of wooden biomass to semiconductive and conductive carbon-rich materials; Addition of high carbon fixation ability; Regulation of nano-structures (porosity etc); Applications Acknowledgement: Thanks to T. Hirukawa (Univ Tsukuba) & T. Hata (Kyoto Univ)