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

FINNISH–JAPANESE WORKSHOP ON FUNCTIONAL MATERIALS May25 － 26 ， 2009 （ Espoo and Helsinki, Finland ） Materials from wooden biomass Pyrolytic conversion of structured alkaline lignins to porous carbonized materials Masashi KIJIMA Institute of Materials Science Graduate School of Pure and Applied Sciences University of Tsukuba, Japan

CO 2 + H 2 O Combustion h ν Cellulose extraction & Lignin CO 2 Conversion H 2 O, ….N,P,S Functional Materials (high-value added) Nutrition intake CO 2 recovery system in nature

Unrefined raw material Constructional material, Direct usage Of structured Furniture, paper, etc materials Fuel (wood), charcoal Organic materials (extracts, derivatives). Chemical approach Wood Bio- and semisynthetic polymers (structured fiber, film, powder) Cellulose Thermal conversion & Lignin Structured carbonized and carbon materials (activated Main component carbon, carbon fiber etc.) (Carbon-rich materials) Refined raw material

Purpose of our research Synthesis of functional carbon-rich materials from wooden biomass ∆ ∆ ∆ Carbon Conducting Organic Semiconducting materials carbonized materials materials materials 300ºC 800ºC 1500ºC Cellulose Structured C-rich Materials & Lignin High-C content: uniform & homogeneous composition Low content of C Various functional Application: thermoelectric-conversion, groups in the material Photovoltaic & sollar cells, electrodes for batteries, fuel cell, EDLC, Stable porous Possible to restructurize Energy-source (H 2 etc) storage material etc.

Lignin ＜ a possible structure ＞ ＜ aromatic structural unit ＞ OH OH OH (a) (b) (c) OCH 3 OCH 3 H 3 CO OH OH OH (a) p -coumaryl alcohol (b) coniferyl alcohol (c) sinapyl alcohol Advantage of lignin to convert into carbon materials: Lignin has the phenolic components: high C fixation ability on anaerobic pyrolysis There has been reported several results on carbonization of lignin and preparation of activated carbon

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

Preparation methods of porous carbon ＜ Activated method ＞ conventional activation carbonization H 2 O, CO 2, or Activated C Raw materials KOH etc Carbonized （ from wood ） 800 ºC ~ 1000 ºC S BET material (500 ～ 3000 m 2 /g) ＜ Pyrolytic method ＞ Without activation process carbonization Porosity is largely dependent on the hardening and pyrolysis elimination temperatures of Raw materials Porous C raw mateials ① Pyrolysis of alkaline lignin

100 Alkaline 80 Lignin TG [% ] 60 Black powder ， 40 Water soluble Tokyo Kasei 東京化成 20 ナカライテスク Nakalai 0 Elemental analysis C: 51.72 % ， exo H: 5.12 %, DTA[a.u.] N: 0.13 % (Nacalai), C: 51.83 %, H: 4.78 %, N: 0.11 % (Tokyo Kasei) 0 200 400 600 800 Temperature[ ℃ ] Reagent grade(available)

① Carbonization of alkaline lignin Sample Furnace r.t ~ 900 ºC Argon gas inlet Carbonization conditions CL1 ： r.t ~ 900 ºC 10 ºC /min (annealing time) 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

SEM 10 μ m 10 μ m 10 μ m Alkaline lignin CL4 CLW CL4 ： deposition on the surface was a Na salt confirmed by XPS CLW ： After washing CL4 with water, the deposition was cleaned off Carbonization results and N 2 adsorption data α s DH S BET sample Yield V total (ml/g) V micro W micro S total V meso / V total (m 2 /g) V meso (ml/g) (%) (m 2 /g) (%) (ml/g) (nm) CL4 46 664 655 0.09 0.90 0.55 0.15 28 ― CLW 899 1031 0.17 0.65 0.69 0.19 27

Control of structure and morphology of carbonized materials Microporous C-particles Particles in nano-micron scale carbonization Aims: 1) Increase of effective surface area. 2) Generation of new pore space between the particles Typical conditions SDBS Water SDBS Benzene benzene (ml) (mg) (ml) ML3 5 50 45 water - Na + SO 3 Sodium Dodecylbenzenesulfonate(SDBS) ② Preparation of micellar lignins Reverse micelle and the carbonization

Preparation of micellar lignins （ ML) and their carbonization (in solution) (freeze-dried) 10 μ m CML3 ML3 Freeze-dried carbonization Fine-structured ML Particle samples could not be obtained in this case. In order to obtain particle lignins, (3) rigid lignin gels are synthesized

Comparison of N 2 adsorption results of CL and CML α s DH S BET V total sample Yield V micro W micro S total V meso V meso / V total (m 2 /g) (ml/g) (m 2 /g) (%) (ml/g) (%) (ml/g) (nm) CL4 46 664 655 0.09 0.90 0.55 0.15 28 CML3 17 1340 928 0.19 1.14 1.16 0.45 39 1 8 0 0 1 . 4 S B E T 1 6 0 0 1 . 2 S αs 1 4 0 0 2 /g] Pore volume [ml/g 1 V t o t a l 1 2 0 0 Surface area [m 0 . 8 1 0 0 0 8 0 0 0 . 6 6 0 0 0 . 4 4 0 0 0 . 2 2 0 0 0 0 CL4 CML3 C L 4 C M L 3 S a m p l e

Toward synthesis of carbonized lignin particles ③ Preparation of alkaline lignin gel and the carbonization Under basic aqueous conditions, alkaline lignin was reacted with formaldehyde to give a swelled polymer gel, which was carbonized after freeze drying. Freeze-dried, carbonization L L HCHO L L L L Swollen polymer gel ④ Preparation of lignin-gel particles and their carbonization ∆ Freeze-dried carbonized Swollen lignin gel Carbon particles Lignin+HCHO+NaOH

SEM Images of lignin deriv. before and after carbonization 10 μ m 10 μ m 10 μ m LG MLG1 MLG2 10 μ m 10 μ m 10 μ m CLG CMLG1 CMLG2

Carbonization and N 2 adsorption results α s DH S BET V total sample Yield V micro W micro V meso S total V meso / V total (m 2 /g) (ml/g) (%) (m 2 /g) (%) (ml/g) (nm) (ml/g) CL4 45 738 920 0.26 0.70 0.50 0.06 11 CML3 17 1340 928 0.19 1.14 1.16 0.45 39 CLG 42 915 1029 0.17 0.70 0.78 0.23 30 CMLG 29 1423 1528 0.28 0.78 1.14 0.30 26 1800 1.2 SBET 1600 ] 1 g 2 /g] 1400 S α s / l m Surface area [m 1200 0.8 [ Vtotal e 1000 m 0.6 u l 800 o v 600 0.4 e r o 400 P 0.2 200 0 0 CL4 CML3 CLG CMLG CL4 CML3 CLG CMLG1 Sample

Electrical double layer capacitor (EDLC) characteristics of the carbonized lignins 1M H 2 SO 4 0.5M Et 4 NBF 4 / PC 300 CL CML Anion (F/g) Cation (F/g) Sample CLG capacitance [F/g] 0 ~ + 1.5V 0 ~ -1.5V CMLG1 200 CL 11 7 CML 85 55 100 CLG 41 23 CMLG1 60 53 0 0.05 0.1 0.5 at 0.05 A/g current density [A/g] Et 4 N + ： 0.68nm - ： BF 4 0.44nm

Effect of heat-treatment (1500 ℃ ) on porosity of the carbonized lignins 800 CL4 CLG CMLG1 HTCL 600 Vads [cc/g(STP)] HTCLG HTCMLG 400 200 0 0 0.2 0.4 0.6 0.8 1 Relative Pressure P/P 0

α s Sample DH S BET V total S total V micro W micr V meso V meso /V total (m 2 /g) (ml/g) (m 2 /g) (ml/g) (ml/g) (%) o (nm) HTCL 213 213 - - - 0.40 0.40 0.18 0.18 45 HTCML - - - - - - - HTCLG 176 176 - - - 0.40 0.40 0.22 0.22 55 HTCMLG - - - 187 187 0.32 0.32 0.20 0.20 63 CL4 664 655 0.09 0.90 0.55 0.15 28 CML3 1340 928 0.19 1.14 1.16 0.45 39 CLG 915 1029 0.17 0.70 0.78 0.23 30 CMLG1 1423 1528 0.28 0.78 1.14 0.30 26

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 of 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 1500 º C 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)