by-product from the lowly soybean creates jobs and saves the planet canada - mexico water workshop...
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By-Product From the Lowly Soybean Creates Jobs and Saves the Planet
Canada - Mexico Water Workshop March 30, 2010
byKeith Taylor
Department of Chemistry and Biochemistry
People & Money
Collaborators J.K. Bewtra and N. Biswas, Civil & Environmental Engineering
Recent Students Katy Modaressi Beeta Saha Aaron Steevensz Mohammad Mousa Al-Ansari Ram Mantha Joey Patapas
Funding Natural Sciences and Engineering Research Council Ontario Ministry of Agriculture and Food
Canada - Mexico Water Workshop March 30, 2010
Wastewater – Process Water
Introduction
These compounds are considered to be toxic and have been classified as hazardous pollutants.
Phenolic and aryl amine compounds in process- and wastewater streams from various industries such as:
• petroleum refining.• coal conversion• wood products & preseservation.• metal casting.• pulp, paper, dyes, resin, plastics and textiles manufacturing.
Canada - Mexico Water Workshop March 30, 2010
Water Treatment Strategy
Phenols in Solution
enzyme +
oxidant
Oligomer/Polymer
(separate solid)
Capture solid precipitate, use as pre-adhesive, etc.
Immobilize solid on soil organic matter (Bollag)
Canada - Mexico Water Workshop March 30, 2010
Enzyme-based Wastewater Treatment
Capture organic material in minimally-modified form Remediation but not degradation Enabling technology: availability of enzymes as commodities
(peroxidases, but not HRP, and laccases) By recombinant fermentation techniques (ARP, laccase) Cheaper wild-type sources (SBP)
Cost-effective?
Canada - Mexico Water Workshop March 30, 2010
Advantages over conventional biological treatment: Easy to handle and store; simpler process control High and low concentrations of contaminant No shock loading effects Broad range of pH and temperature Contact time of seconds to minutes, small footprint Reduced burden on biox plant and gravity separators
Advantages over chemical/physical treatments: High specificity and efficiency in removing target pollutants Operation under milder, less corrosive, conditions Reduced consumption of oxidants, sludge formation
Advantages of Enzyme-Based Treatment
Canada - Mexico Water Workshop March 30, 2010
SBPLaccase
- Fungal source- Requires molecular oxygen
- Crude extract from seed hulls- Requires hydrogen peroxide
Enzymes
Oxidase-catalyzed Phenol Removal(Klibanov, Bollag)
Phenols (solution)
Peroxidase/H2O2 (or, Laccase/O2)
O
R
OH OHOH OH
O
OH
+ o,p- + o-
+ +
enzyme/oxidant
Oligomer/Polymer (solid)Canada - Mexico Water Workshop March 30, 2010
Experimental Parameters
substrates at 1.0 mM (94 ppm for parent, 128 ppm for chloroderivatives)
examine: pH effect enzyme dose (activity “units”/mL = U/mL) peroxide stoichiometry influence of PEG in reaction, alum in settling (reactor design)
analysis by UV and colorimetric tests; HPLC
Canada - Mexico Water Workshop March 30, 2010
Minimum Enzyme Concentrations (U/mL)
0
0.1
0.2
0.3
0.4
0.5
phenol
o-cresol
m-cresol
p-cresol
o-chloro
m-chloro
p-chloro
2,4-diCl-
bis-A
aniline
o-tol
m-tol
p-tol
2,4-DA
T
2,6-DA
T
HRPARPSBP
Canada - Mexico Water Workshop March 30, 2010
Operating Cost - Incremental, but Offset
• Water Environment Research 73 165 (2001) with ARP
• 600 bbl/h@100 ppm phenols; 100 m3/h with 10kg/h phenols
• SBP needed at 0.5 MU/m3; 50 MU/h; $100/h*
• Peroxide required at $0.25/m3 for treatment, possibly $0.25/m3 for additive (eg. PEG or surfactant); ca. $50/h
• Expendables cost, $150/h ($0.25/bbl)
• * Could SBP be produced at a profit for $2/MU??
Canada - Mexico Water Workshop March 30, 2010
Continuous-flow System for Phenol Water Environment Research 73 165 (2001)
Canada - Mexico Water Workshop March 30, 2010
Broadening the Scope
• Convert other aromatics into phenols or anilines
• Chemical ‘front end’ for the enzymic process
• For nitro- and azo-aromatics:
zero-valent iron to produce anilines
• For unfunctionalized aromatics (BTEX)
hydroxylation (via limited Fenton reaction) to phenols
Canada - Mexico Water Workshop March 30, 2010
Save the Planet? Jobs Too?
Refinery case: 5 MU/kg phenol, a bit much; $2/MU, a bit low Processing at higher [phenol], eg. 2000 ppm, more efficient,
1.5 mU/kg room to pay more for enzyme?
SBP is in the seedcoat, the first thing stripped off before beans are crushed for oil and protein
SBP easily extracted with water; remaining hull still as good a fibre source for animal feed
Value of hulls more than doubled A business opportunity!
Canada - Mexico Water Workshop March 30, 2010
Lots of Cheap SBP
120,000 tonnes of hulls in Ontario (Michigan, two-thirds; Iowa, 4-fold)
Could they be “borrowed”, or “rented”, to extract SBP? Trillions of U of catalytic activity (many refineries!)
Costs: “rent”, concentrating extract, re-drying hulls
Environmental stewardship of the petroleum economy aided by bioproducts
Including non-conventional sources: oil sands, oil shale, upgrading by-products (stranded carbon), coal gasification
Canada - Mexico Water Workshop March 30, 2010
Save the Planet
Improve existing refinery aqueous streams with a green process
Begin to address air emissions by capture and treatment
Products of enzyme-based treatment captured and used
Optimal and responsible use of existing carbon sources
Canada - Mexico Water Workshop March 30, 2010
Typical Batch Reactor Data: pH Effect(phenol, 1.0 mM; peroxide,1.2 mM; PEG, 400 mg/L)
0
20
40
60
80
100
3 5 7 9 11
pH
Per
cent
Phe
nol R
emai
ning
SBP = 0.5 U/mL SBP = 0.3 U/mL
Canada - Mexico Water Workshop March 30, 2010
Typical Batch Reactor Data: Enzyme Dose(phenol, 1.0 mM; peroxide,1.2 mM)
0
20
40
60
80
100
0.00 1.00 2.00
SBP Dose (U/mL)
Per
cent
Phe
nol R
emai
ning
PEG = 400 mg/L NO PEG
Canada - Mexico Water Workshop March 30, 2010
Anilines, analogously
NH2R
enzyme
oxidant
NH
R
o-, p- coupling products
Canada - Mexico Water Workshop March 30, 2010
Zero-valent Iron Reduction of Nitrobenzene
(Agrawal & Tratnyek, 1996)
(also, azobenzene + Feo aniline; Weber, 1996)
NO2 NO NHOH NH2
2e- 2e- 2e-
NO2+ 3 Feo + 6 H+
NH2+ 3 Fe2+ + 2 H2O
Canada - Mexico Water Workshop March 30, 2010
Combined Strategy for Nitroaromatics
NO2 NH2
Feo
H2O2
peroxidaseoligomer/polymer (solid)
(soln) (soln)
Canada - Mexico Water Workshop March 30, 2010
The Pollutant BTEX (Benzene, Toluene,
Ethylbenzene and Xylene) Models for others (PAHs, PCBs, dioxins and furans)
Wastewater Source Petroleum industry Solvent for organic synthesis
The Problem Effect on humans Release to environment
Unfunctionalized Aromatics
Benzene
H3C
Toluene
H3C
CH3
H3C
CH3
H3C
CH3
o-xylene m-xylene p-xylene
H5C2
Ethylbenzene
Canada - Mexico Water Workshop March 30, 2010
Fenton Reaction
Hydroxyl radical a strong oxidant Fenton reagent often used for mineralization of organics Can we limit it to hydroxylation?
OHHOFeOHFe 3H22
2
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Toluene – limited Fenton reaction
H3C
Toluene
H3C
OH
H3C
OH
H3C
OH
H3C
OHOH
Orcinol
H3C
OH
OH
3-methylcatechol
OH
OHCH3
4-methylcatechol
OHOH
CH3
2-methylresorcinol
+
+ +
+ +
Canada - Mexico Water Workshop March 30, 2010Canada - Mexico Water Workshop March 30, 2010