2012/12/18

活性炭を用いた水の浄化

第7講義
2012, Dec. 18

エネルギー・環境を支える
エネルギー・環境を支える
新規機能性活性炭（Novel Functional Activated Carbons for the Applications toEnergy and Environmental Devices）

尹 聖昊
九州大学 先導物質化学研究所
yoon@cm.kyushu-u.ac.jp
Contents:
1. 活性炭の構造、細孔分析及び応用
2. 繊維状ナノ炭素の調製、構造及び応用

Structure of PAN based carbon fiber

Control of structural units
fiber axis
Aromatic planar molecule
spinningLc(002)
Deformed micro-domain
Stacking unit of planar molecules(Molecular assemble unit)

Closely packed microdomains in mesophase
pitch

Aligned micro-domains in
the mesophase pitch fiberGraphitic unit
Micro-domain(Quasi-aligned molecular assemble unit)

DomainHeatTreatment

Pitch fiber

Pleat unit

Graphitized fiber

IAMS, Kyushu University “Axial nano-scale microstructure in the graphitized fiber inherited from liquid crystal mesophase pitch”
Carbon, 34, 83-88 (1996) S. H. Yoon, Y. Korai, K.Yokogawa, S. Fukuyama, M. Yoshimura, I. Mochida1

2012/12/18

Best carbon?

Carbon materials from the structural points

Carbon is an Indispensable Material for Energy related Devices
Best Structure for Best Performance
Best Selection
Best Selection
Scientific Cycle- Structural Understanding
Carbon- Structure Preparation- Working Mechanism
Molecular Level
Electrochemical
Catalytic / Kinetics
Molecular / Heat Transfer

Activation

How to prepare the activated carbons
Selection of Precursor- Pore Framework / Density- Properties of Pore Wall, Composition / Graphitic Extent- Reactivity at Activation- Non-graphitizable precursors like polymer, biomass and isotropic coke forusual AC or ACF- Graphitizable precursors like anisotropic cokes or mesophase pitch for EDLC
electrode materials
Activation Procedures- CO2, H2O- Alkali Hydroxides / Carbonates; More Research- Selective Catalytic Gasification ; Catalyst Control

CO2CO2C

CO2CCCO2CC2CO2COCO2C 2CO2COCCarbon materials

Very Large Surface Area > 3000 m2/g
Adequate Pore And Wall

Activation reagents• Air, CO2, Steam• KOH (NaOH), ZnCl2
72

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Chemical activation

Conventional concept of activated carbons

10STM images of ACFs

Structure of glassy carbon

123

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Novel concept of activated carbon

Pore nucleation in activated carbon

Surface Area, Pore：Depth & VolumeSurface Structure
Surface Chemistry
Based and Edge Plane, Substituents
Hetero Atoms in Hexagon
Carbon Structure of Wall
Micro, Nano, Macro Structure of Carbon Wall-Graphitization Extent-Domain Structure
Density, Reactivity (Activated Surface)Precursor : Structure and Reactivity

13

Novel concept of activation

14

Novel understanding of activation mechanism

Precursor of ACF has been composed of nanostructural primary units

Structural factor should be considered for the better
understanding of activated carbons and their applications.
Size and arrangement of BSU
Etching and diffusion of oxidative
agent against BSU

Pores from intraparticles (Slit shaped? Micropores lessthan 2 nm)
Pores from interparticles (Channeled shaped having
wider pore size distributions (0.2 ~ 50 nm)
151642012/12/18

Novel recognition of the structure of ACs

17

Pore size distribution （NLDFT））

Pore size distribution (Xe-NMR)

20※N.Shiratori, et al., Langmuir 2009, 25(13), 7631-7637.

5

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Adsorption of toluene by various ACs

Effect of functional groups (Xe(Xe-NMR)

21

22

Typical Hazard Gases in the Atmosphere

Ox
SO2

Removal of SOx and NOx Using ACFs
SPMCONONO2CO2

NVOCs: Dioxin, PCBBenzene
VOCs
Toluene etc.

Sick-house
gases

6

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DeSOx mechanism using ACF

ACF
SO42-SO2

SO2
SO225
20
15

SO2AfterACF
度ACF通
SO2濃通過後の
12:00

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5/1

5/2

5/3

5/4

5/5

5/6

5/7

5/8 5/9

Data from Dr. Shimohara
Of Fukuoka H & E Institute

Active Sites on Carbon Surface

12:00

12:00

4/234/23

2Lapse0 0 1年 of(1 7time
日間(day))2001

H2O
SO3(ad.)×H2O

H2SO4(ad.)

ACF surface

12:00

0O2SO2(ad.)

環境AmbientSO2 濃度 air

10518:00

SOSO2濃度(ppb)
2 (ppb)

セット
OG20A
ACF(0.100g)セ(0.100g)

aq. H2SO4

SO2+ad.→SO2ad.
SO2ad.+1/2O2→SO3ad.
SO3ad.+H2O→H2SO4ad.
H2SO4ad.+H2O→aq.H2SO4

Breakthrough of SO2 Removal
Optimum Post-Heat treatment with Reductive Oxygen Removal

Oxygen functional group

Acidic nature: Oxidative
Basic nature: Reductive

Free valence
Benzyne bonds on edge

Oxygen activation

Hetero-atoms in edge

Zigzag or Armchair

Hexagon stacking heightHydrophilic/Hydrophobic
Small surface energy
How to control ?

SO2 1000ppm,O2 5vol.% H2O 10vol.%,N2 balance, Flow rate: 100ml/min, Temperature: 50℃

7

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Effect of Heat Treatment

ＳＯ２Ｏ
ＨＨ Ｏ

ＳＯ２Ｈ
Ｏ Ｈ Heat treatment

Ｈ２ＳＯ４。
aqＡｒ

Ａｒ,CO,COＡｒ
2CarbonCH(wt.%, dry)
93.5
0.6
97.0
0.4
96.8
0.2

OG-15A
OG15A-H1100(0min)
OG-15A-H1100(1h)

NO

0.5
0.5
0.3

5.5
2.2
2.7

Ash（％）

SO2 removal at stationary state (%)

The Effect of Heat Treatment for SO2 RemovalRemoval of Functional Groups
with Least Changes of Carbon Structure
Surface Area and Hexagon Stacking

100

OG20A (2150m2/g)
OG15A (1360m2/g)
OG10A (1060m2/g)

80

OG8A (840m2/g)
OG7A (690m2/g)
OG5A (480m2/g)

60

40

20
SO2 1000 ppm, O2 5 vol%, H2O 10%
W/F= 2.5 ☓ 10-3 g.min.ml-1, Temperature 30 oC

0.00.00.1

As-received

600

700

800

900

1000 1100 1200

Heat Treatment Temp. (oC)DeSOx by ACF and CNF-ACF Composite

NO & NO2 Oxidation over ACF
NONO3DeSOx Properties of ACF and ACF-CNFIdentified reaction
PO-CNF 1%cat., 5mingrowing
PO-CNF 5% cat.,

NOO2NO2NO
HeatingNO2NO2(ad.)

NO3(ad.)5min growing
H11000NO(ad.)

O(ad.)

ACF surface

aq.HNO3Time (h)Strong Inhibition of H2O
DeSOx condition: SO2 1000ppm, O2 5vol%,H2O 10vol%,N2 balance、、Total flow rate: 100 ml/min
Reaction Temperature: 50 ℃

The oxidation of NO2 always produces NO
And NO3- through the disproportionation.
PDU for SOx Removal by ACF

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The Mechanism of NO Reductive Removal

NOx Reduction at Room Temperature

NOx + O2N2 +H2ONOO2NO(ad.)

O(ad.)

N2 + H2O

NH3(NH2)2CONO2(ad.) + NH3(ad.)

ACF

ACF surface• NOx oxidation• Urea Activation• NOx in Environment• Roles of ACF : More variety of ACF

The mechanism of NO removal consists of adsorption andoxidation of NO into NO2 which is reduced with NH3

Adsorption of NO2 in ACF

Scavenging activities against NO

Flow rate: 300ml / min

20ppm

ACF (0.100g)
NO2
Glass tube
NO22NONO
2NO2
Including of O2 (21%)

NO

Flow rate: 300ml / min

20ppm

10ppm

NONONONO

ACF (0.100g)

Including of O2 (21%)

NONONOContact time: 0.3 sec

15NO exhaust (10ppm)

10NO2 exhaust

500123456789 10 11 1 2 13 1 4 15 1 6 1 7 18 1 9 20 2 1 22 23 2 4 2 5Lapse of time (hr)Breakthrough time(ppm)

(ppm)

20

20
15NO exhaust1050

NO2 exhaust0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Breakthrough time

Half amount of adsorbed NO2 is exhausted as NO.

Lapse of time (hr)

0.5 h r9

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The characteristics of NOx purification
0.100gNONONO2NO NO8mm

23cm in length

Cont. time 0.3sec

NONO NO
2NO NO

0.300g 9cm in length

NONO NO
2NO NO

0.600g 18cm in length

NONO NO
2NO NO20.900g 27cm in length

Characterization of ACF purification

NONONONONO
NO

Forced ventilation
Natural ventilation

NO2NO2

NOACF

NO

SPM
Hazardous
chemicals
Odor
NH3
SO20.9 sec

2NO
1.8 sec

2Room temperature, ozonizer is no need,no light irradiation, compact design

2.7 sec
NOx is fixed as HNO3Three-dimensional
wind vectors

Novel applications of ACs
ACF fence
Natural ventilation system (Fixed type)

1．HCHO（Removal of sick-house gases)
2．Super capacitor
3．Medicine
4．Capacitive De-ionization （CDI)
5．Heat Pump （adsorptive heat pump）

Natural wind

3940102012/12/18

Removal of HCHO using ACs

1．HCHO & Toluene （Sickhouse gases)

4142

Micro ATRATR-FTIR analysis of ACs

Micro
Microcro-ATR FTIR
Relative amount of pyridinic nitrogen functional groups for PAN based ACFs by micro-ATR FTIR analysis

Internal Standard

Pyridinic N a

Internal Standard/Pyridinic NFE100279134

0.48

FE2002761080.39FE300

332

700.21FE400

330

640.19Sample

a Wavenumber related with pyridinic nitrogen: 1610 ~ 1600 cm-1

434411

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Effect of humidity

7DryWetBreakthrough Time (h)6543210JOURNAL OF APPLIED POLYMER SCIENCE 106 (4):2151-2157 NOV 15 2007

FE100 FE200 FE300

OG5A

OG7A OG15A

4645

Novel concept of pore（pore（shallow pore）pore）

PAN based activated carbon nanofiber

4748

12

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Removal of HCHO using PANPAN-ACNF

Shallow pore（pore（?）

Carbon, 48, 4248-4255 (2010).

4950

Complete removal of HCHO using MnOx/ACNF

Catalysis Today, in press (2012).
52

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2．Super capacitor

53

54

55

56

Study of super capacitor using NMR

14

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57

58

19F MAS SolidSolid-State NMR Spectra

59

60

15

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T1 Values Measured from 2H MAS SolidSolid-State NMRSpectra

2H MAS SolidSolid-State NMR Spectra

61

Surface modified PCNFs

62

Langmuir

Capacitances of PCNF series

2006, 22(22), 9086.

63

Langmuir
2006, 22(22), 9086.

64

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Research backgroundAC- medicine

Chronic Kidney Desease
Renal function decrease for removal poisons from body
Artificial dialysis

Characteristics of activated carbons for theselective adsorption behaviors for Indoleand Amylase

big burden topatient
To prolong the introduction of dialysis, AC medicine was developed
AC internal medicine
・ To remove the entro-poisons like indole through the excretion
with activated carbon.
・ Very hard to take a dose (6g/day)
66

Samples

How to decrease the dosage amountOG series (Osaka Gas)

Relatively similar shapes of pores but different surface
area and pore size distribution
・Surface area and pore・Surface property
H2-OG series

Factors for selective adsorption
・Surface area and pore size

Hydrogenation of OG series to remove the oxygen functionalgroups(600℃, 1h)・Shape・Surface property

Ball type activated carbons
Model adsorption materials

Ball type activated carbons with diameters of 100～300μm
・Not to be removed

Indole (MW: 117.15)

Amylase (MW: about 46000)⇒ a kind of poisons⇒Digestive enzyme

研究目標

αs analysis
OG5A OG7A OG10A OG15A OG20A

PoreSA (m2/g)
size (nm)・To be removed

67

H2-OG H2-OG H2-OG H2-OG H2-OG5A
7A
10A
15A
20A

SACOAC

Scmep SACmip

A micro 646 982 1283 1688 1928 728 1247 1305 1548 1802 1254 1585 570 1409
A meso0000000000560108 143
A external 0.3 0.3 0.1 0.3 0.3 0.4 0.1 0.3 0.3 0.5 6.6 1.4 0.2 0.4
W micro 0.65 0.68 0.74 0.90 1.11 0.65 0.70 0.75 0.91 1.11 0.69 0.96 0.64 0.74
d mesoOxygen contents(%)

00000000

12.0

05.85 3.24

14.3 19.0 22.2 12.8 12.1

006.0

5.2

4.5

2.5

2.6

15.1

4.7

6.068

4.4

172012/12/18

Adsorption selectivityof Indole

Effect of functional groups for binary solutions
H2-OG (Small functional groups)
H2OGシリーズ
OGシリーズOG (Large functional groups)

54
32

Capacitive De-ionization (CDI)

10
OG5A OG7A OG10A OG15A OG20A

Removal ratio of Indole (%)

OG5A

OG7A

OG10A

OG15A

OG20A

Small functional groups

49.9

70.1

69.3

70.9

72.1

Large functional groups

43.1

63.3

63.8

69.9

68.6

Removal ratio of amylase (%)

OG5A

OG7A

OG10A

OG15A

OG20A

Small functional groups

16.5

26.7

26.6

26.3

24.7

Large functional groups

10.5

17.4

17.8

20.46917.4

Principle of electrical desalination

70

Experimental setup

Sea water(separator)(electrode)- Na+

Cl-- Na+Cl-- Na+- Na+- Na+ (electrode)(electrode)-++Cl-+++ Na

Cl-+Cl+(separator)++Cl-(electrode)-Na+

Cl-NaCl
Distilled water

Concentrated water

CHARGEDISCHARGE• Diffusion of ions inside of pores- Rapid electrochemical adsorption and desorption18

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Cl- ions in the city water

Nitric ion removal behaviors
Maxsorb series-112080

400-112080

400-1240360480-1

Electrolyte : NO3-N (20 mg L ), Flow rate : 5 g min-1Electrolyte : NO3-N (20 mg L ), Flow rate : 5 g min

120

600

Time (min)

0120

240

360

480

600

Time (min)

Total
-1

Ionic conductivity (mS m )160

max-II
max-III
OG-10A
OG-20A
2 -1
Mitsui cokes (350 m g )120

Effect of flow rate

OG-5A
OG-7A
OG-10A
OG-15A
OG-20A

Desalination rate (%)

Ionic conductivity (mS m )-1Ionic conductivity (mS m )160

max-II
max-III0

Up to 1.0V
1.0V

OG series160

 硝酸性窒素イオンにおける脱塩特性は90.582.368.4

51.3

28.1
20.1

MaxMax-IIIが最大特性
IIIが最大特性を示した。
が最大特性
180

 三井鉱産のコークスがOGシリーズより良かった。
40

 Maxsorb > Mitsui cokes > OG series

510203040(flow rate :10㎖/min)

0-1-1Electrolyte : NO3-N (20 mg L ), Flow rate : 5 g min

0120

240

360

480

600

Time (min)73Points• How to increase lifetime• How to increase adsorption selectivity and amountof ions⇒
 Optimization of pore and its distribution
 How to increase molecular diffusivity
 Preparation of high electric conductive ACApplication of activated carbons to Heatpump
for energy-free operation19

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吸着式ヒートポンプの性能と材料特性

Thermal Powered Cooling System
Principle of Heat Pump

Static analysis of adsorptive HP

Adsorption

How to increase power• Increasing effective adsorption
How to increase COP• Making temperature change smaller

Desorption

7778

吸着式ヒートポンプの性能と材料特性
Performance test results
Silica gel- water

Points• How to increase adsorption amount of molecules
such as water, methanol and ethanol

Activated carbon - ethanol⇒ Optimization of pore and its distribution
 How to increase molecular diffusivity
 Preparation of high thermal conductive AC79202012/12/18Carbons from now
Era of nano-carbons are almost finished. Only special applications are promising!
Era of GOOD Raw material to GOOD Product are almost finished. China andother developing countries will take over whole markets!

Era of BAD Raw material to GOOD Product are coming. Developed countries only
have chances on such materials
Novel carbon, if it can be found, still has a chance to change the paradigm.
But what is that?

Nano-carbons(Concept, methodology)

FusionConventional carbons(Waste Materials)

New carbon materials, New processes for manufacturing, Newmarkets for carbon applications
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