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A Green Plastic Formed Directly from A Green Plastic Formed Directly from Carbon Dioxide and Sunlight Carbon Dioxide and Sunlight
Jian Yu
School of Ocean & Earth Science & Technology
University of Hawaii at Manoa
Hawaii, USA
Presented at Biopolymers & Bioplastics 2015
San Francisco
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Conventional bioplastics from biomass Conventional bioplastics from biomass
• Land farming to produce renewable feedstock
• Producing bioplastics from starch, sugar and oil
• Low energy efficiency of plants (<1% solar radiation )
Photosynthetic COPhotosynthetic CO22 fixation in plant fixation in plant cell cell
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Our conclusions:•Light capture and CO2 fixation should be decoupled•The light capture is replaced by artificial device for more efficient use of solar energy
CO2 + H2O + hv CH2O + O2
Artificial photosynthetic systemArtificial photosynthetic system
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CO2 + H2O + hv CH2O (biopolymers)
H2O
O2H2
+
-
e
eCO2
Electrolyzer Fermenter
PV assembly
hv
O2
H2
HH22 from Intermittent solar energy from Intermittent solar energy
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Anode: 2H2O (l) O2 (g) + 4H+(aq) + 4e
Cathode: 4H+(aq) + 4e 2H2 (g)
Overall: 2H2O(l) O2(g) + 2H2 (g)
COCO22 fixation by a chemautotrophic fixation by a chemautotrophic bacterium bacterium
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H2/CO2 = 4 - 6 mole/mole (energy efficiency 41% - 28%)
For biomass synthesis (CH1.74O0.46N0.19):
CO2 + 6H2 + 1.94O2 + 0.19NH3 CH1.74O0.46N0.19 + 5.42H2O
For PHB synthsis (CH1.5O0.5):
CO2 + 6H2 + 1.875O2 CH1.5O0.5 + 5.25H2O
Conventional versus novel bioreactor Conventional versus novel bioreactor
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Conventional BR Novel BR
Cell density (g/L) 24 27
PHB (wt%) 59 52
Cell productivity (g/L.hr) 0.23 0.42
PHB yield (g/g H2) 0.1 0.38
CBRGas in
Gas out
A Bioplastic of 100% COA Bioplastic of 100% CO22 carbon carbon
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Fate of residual biomass?
Residual biomass as nutrients in COResidual biomass as nutrients in CO22 fixationfixation
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After PHB recovery, the residual cell mass becomes N-rich hydrolysates.
CO2 + 6H2 + 1.94O2 + 0.19NH3 CH1.74O0.46N0.19 + 5.42H2O
Life cycle analysis (LCA)Life cycle analysis (LCA)
1. Cradle to gate 2. Gate to grave
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• CO2
• H2O• Sunligh
t• Mineral
s• NH3
Biodegradation for clean environment
Solid waste disposal via incineration (heat), composting (soil)
CO2, H2O
Question: •Can PHB bioplastic be reused for more value?
Bio-based chemicals from PHB Bio-based chemicals from PHB platformplatform
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[OCHCH2C]n
OCH3
HO OHPolyhydroxybutyrate
HO-CH-CH2-C-OH
OCH3
R-3-hydroxybutyric acidCH3CH=CH2COH
O
Crotonic acid
CH3CCH2COH
OO
Acetoacetic acidCH3CHCH2CH2OH
OH
1,3-butanediol
Heat-H2O+H2O
CH2=CHCH2COH
O
3-butenoic acid
+-H2O
CH3-C - C-OH
O
CH3
HO
2-hydroxyisobutyric acid
Isomerization
CH2=C-C-OH
O
CH3Methacrylic acid
-H2O
-H2
CH3CH2CH2COH
O
Butyric acid
-H2O
+H2
+2H2
CH3CCH3
O
-CO2
CH3CH=CH2
Propylene
Acetone
CnH2nGasoline(n=6-18)
CO2, H2O
hv
CH3CH2CH2CH2OHButanol
+H2
-CO2
CH3CH2CHCOH
HO O
2-hydroxybutyric acid
+H2O
CH3CH2CCOH
O
2-oxobutyric acidO
-H2
C6H6Aromatics
-CO2
Alkenes
PHB Thermal Degradation & Reaction PHB Thermal Degradation & Reaction MechanismMechanism
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R-CH-CH2-C-O-OCH3
CH-CH2-C-OHOCH3
R-CH-CH2-COCH3
CH-C-OH
O
CH3
CH
H
OR-CH-CH2-C
OCH3
CH-C-OH
O
CH3
CH
H
O
Crotonic acid
H+ CH3-CH-CH3
CO2
CH3-CH=CH2
+
H+
R
CO2
Aromatics from PHB Aromatics from PHB
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CA (C4H6O2)
Compound 5 (C7H10O)
Compound 6 (C7H10O)
KetonizationOH
O
2
OCO2 + H2O
O
+
CO2 + H2O +
R R
+
R R
+
'
'' '''
Aromatics
Aromatics
C3H6
S Kang, J Yu. RSC Advances 2015, 5, 3005-30013.
Alkenes from PHB Alkenes from PHB
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Catalyst
O-containing
Chemicals
(%)*
Alkenes
(%)*
Benzenes
(%)*
Naphthalenes
(%)*
A 19.6 2.6 65.8 11.2
B 9.9 57.0 31.1 2.0
*Based on percentage of peak areas in GCMS chromatograms
100% H3PO4230 oC
Gasoline-grade Biofuel from PHBGasoline-grade Biofuel from PHB
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Fuels Gasolinea Light-oil Heavy-oil Biodiesel b
BP (oC) 40-240 40-240 240-310 182-338
C (wt%) 80.40 81.37 79.38 76.96
H (wt%) 12.30 11.30 9.67 11.85
N (wt%) 0.15 0.14 0.23 -
O (wt%)c 6.35 7.19 10.72 9.41
HHV (MJ/kg) 41.8 41.4 38.4 39.7
a Commercial gasoline with ethanol, light-oil and heavy-oil analyzed by Hazen Research Inc b Properties of biodiesel from referencesc Roundup to 100 wt%
PHB (C4H6O2)240 oC, H+
CO2
Oil(C6-C16)
Light oil (77 wt%, 40-240 oC)
Heavy oil (23 wt%, 240-310 oC)
Closing remark: reducing the costClosing remark: reducing the cost
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CO2
H2O
O2H2
CO2
Electrolyzer Fermenter
O2
H2
BioplasticChemicals
Fuels
AcknowledgementAcknowledgement
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Students and post-doctors
Office of Naval Research for financial
support
Thank You !!!
