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Degradation of phorbol esters with an atmospheric pressure plasma jet. ISPlasma 201 3 ( 201 3 / 2 / 1 、 Nagoya). Osaka Prefecture University H.Matsuura, S.Kongmany M.Furuta, K.Imamura,Y.Maeda and S.Okuda. Background.
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Degradation of phorbol esters with an atmospheric pressure plasma jet ISPlasma 2013 (2013/2/1、Nagoya) • Osaka Prefecture University • H.Matsuura, S.Kongmany M.Furuta, K.Imamura,Y.Maeda and S.Okuda
Background Jatropha curcas (J. curcas) currently is the best candidate as the raw material for producing biodiesel since it contains lots of oil of approximately 60%. But the Jatropha oil produced contains the toxic components of phorbol esters that act a cancer promoter. Nowadays, the solution for solving this problems by various physical and chemical means is investigating all over the world. Sunlight(UV?) Ultrasonic wave Gamma-ray Atmospheric pressure plasma is also found to provide reactive free radicals to convert the phorbol ester into original phorbol. We now start measurement radical concentration in the solution to study the mechanism of degradation and to compare the efficiency of degradation methods.
Introduction J. Curcas seed kernel • One of the exploitation of renewable sources of energy: • The production of biodiesel via esterification or transesterification: • Edible vegetable oils and animal fats, etc. • Non-edible oils: Jatropha curcas oil (J. curcas oil), etc. • In 2015, 12.8 Mt of J. curcas oil will be produced (GEXST, 2008). Phorbol Esters Crude J. curcas Oil Biodiesel production 70-75% PEs Mechanical extraction of oil Containing PEs Livestock feeding • Oil: 40-60% • Proteins: 20-30% • phorbol ester (PEs): 0.8-3.3 mg/g. J. Curcas seed cake 20-25% PEs 3
PlasmaDegradation of phorbol esters Radiation Research Center • Mixed 4 standard phorbol ester in methanol were exposed to plasma channel at constant He flow and applied voltage. The plasma ionizing time was optimized. Fig. 5 Atmospheric pressure plasma jet for degradation of mixed 4 phorbol esters solution.
c a b Radiation Research Center Fig. 11 Degradation profile of mixed 4 phorbol esters before and after plasma ionization: (a) &(b) the comparison of HPLC/UV chromatogram and (c) concentration and degradation of phorbol esters. • PDA: phorbol 12,13-diacetate, PDBu: 12,13-dibutyrate, • PDB: phorbol 12,13-dibenzoate, • PMA (TPA): phorbol 12-myristate 13-acetate
Treatment of aqueous solution HPLC/UV chromatograms of aqueous solution of: (a) TPA and (b) mixed jatropha phorbol esters (4 peaks each peak corresponding to each type of jatropha factor) before and after plasma irradiation for 15 min.
National University of Laos, Faculty of Science, Department of Chemistry Phorbol esters: Expected degradation product 2 (•OH) 2 (•H) US / γ-ray Phorbol TetraDecanoyl Phorbol-13-Acetae (TPA) Phorbol 12-myristate 13-acetate (PMA) • Thephorbol ester may be converted into original phorbol since it has ever taken place during the transesterification process of J. curcas oil with alkaline/methanol. [Y. Maeda (2012)] 8
Conclusion • By using UV Chromatogram, degradation of Phorbol ester with atmospheric plasma and is confirmed. • Concentration of hydroxyl radicals (OH) is estimated with KI-colorimetric method, of which result does not contradict with Prof. Kanazawa's work with the similar plasma device and different measurement method.
Future works • Test using PE with much simpler structure to study degradation mechanism • Control plasma parameters and study the relation between OH concentration and degradation effect • Direct confirm of detoxification with biological manners, not merely disappear of Phorbol Ester
Why is J. curcas used for biodiesel production if it contains PEs? • Jatropha give very highest oil production and it is non-edible oil. • Detrimental impact on food industries could be solved. Oil yield: Jatropha vs other seed crops. Sources: http://www.infinitysource.com/projects/jatropha.shtml , accessed 26-05-2012
How much are PEs present in J. curcas seed oil? • The amounts of PEs present in J. curcas seed oil vary from its source (approx. 0.01-1.58%).
Refined Oil Deacidification Degumming Bleaching Deodorization Oil Refining Degummed oil Acid gums and waste water Oil Refining: Role and Reduction/degradation of PEs Reacting with NaOH to neutralize remaining H3PO4 and/or Free fatty acids. Interacting with H3PO4 to remove phosphatides in the form of gum. Interacting with bleaching agents to remove undesirable coloured impurities, remaining trace phospholipids, soap, metals and oxidation products. Distillation at 260oC under vacuum to remove undesirable volatile and odoriferous materials. Sources: H. Makkar et al., Removal and Degradation of Phorbol Esters during Pre-treatment and Transesterification of Jatropha curcas Oil, J Am Oil Chem Soc (2009) 86:173–181
Refined Oil Transesterification Crude Biodiesel Degummed oil Degumming Bleaching Deodorization Live-stock feeding Oil extraction Fertilizers Clean Biodiesel Waste water Seed cake J. Curcas seed Oil Refining Crude Oil Washing with water Acid gums and wastewater Deacidification Glycerol & Impurities Are there any risks of J. curcas PEs to environment? • The presence of phorbol esters in the acid gums renders this fraction unsuitable for use in animal feed. • The washings obtained during the degumming process are rich in phorbol ester and their disposal into the environment needs due care. • the risk of PE for the people who have to work with these compounds or for humans who come into contact with treated water Degradation of PEs in wastewater from degumming process Sources: H. Makkar et al., Removal and Degradation of Phorbol Esters during Pre-treatment and Transesterification of Jatropha curcas Oil, J Am Oil Chem Soc (2009) 86:173–181
National University of Laos, Faculty of Science, Department of Chemistry Phorbol esters (PEs): Molecular Structure Tigliane Phorbol TetraDecanoyl Phorbol-13-Acetae (TPA) • The PEs’ structure is dependent on the tetracyclic diterpene carbon skeleton (Tigliane). • PEs are hydrophobic, oil soluble and head stable when present in oil or seed cake. 20
Crude J. curcas Oil 70-75% PEs Glycerin, Phorboland etc. Biodiesel production Free Fatty Acid Methyl Esters PEs: Degradation aspects Transesterification MeOH/Alkaline • During Transesterification of J. curcas oil containing PEs, PEs are converted into Phorbol dissolving into glycerin phase. 21
J. Curcas seed cake 20-25% PEs Livestock feeding Degradation by some approach PEs: Degradation aspects • PEs containing in J. curcas seed cake can possibly degraded by several means proposed by some authors. Then it can be used for livestock feed. 22
What are the new methods proposed to do? • According to literature review, the degradations of PEs are based on the conventional and advance oxidative processes (AOP) such as • combination with chemical and heat treatment, • biological oxidation using microbes, • the combination of Aeration and heat treatment, • the combination of chemical and Ozonation or -irradiation. • New methods are based on AOP • Ultrasound irradiation: Sonolytic degradation • Cold Plasma irradiation • -ray irradiation: -Radiolytic degradation of PEs. • The first two methods have not been studies by any author on the degradation of Jatropha PEs. • Even though -irradiation method has been used for degradation of PEs in the J. curcas seed cake, there is not any work on the degradation of PEs in liquid media such as in oil or other solvents as well as in water.
Advance Oxidation Processes (AOP) L. Wojnárovits, E. Takács, Irradiation treatment of azo dye containing wastewater: An overview,Radiation Physics and Chemistry 77 (2008) 225–244
Free Radical Effect Description L. Wojnárovits, E. Takács, Irradiation treatment of azo dye containing wastewater: An overview,Radiation Physics and Chemistry 77 (2008) 225–244
National University of Laos, Faculty of Science, Department of Chemistry Phorbol esters: Proposed Treatment Methods : Ultrasonic irradiation and γ-ray radiation 27
National University of Laos, Faculty of Science, Department of Chemistry The similar bonding structure shows their similarity in reaction (Triglycerides) (TPA or PMA) 28
National University of Laos, Faculty of Science, Department of Chemistry Simplification of Phorbol Ester Structure 29
Radiation Research Center Extraction of J. curcas phorbol ester • 10 g of Jatropha oil was extracted in triplicates each with 10 mL of methanol to give 3 fractional extracts. • 2 mL of each fraction was kept for analyzing fractional extraction profile. • The rest of each fraction was combined. Fig. 1 illustration of the procedure on the extraction of phorbol esters from Jatropha oil.
Radiation Research Center • Only one extraction is not enough to get J. curcas phorbol esters from the J. curcas oil. • There were 2 groups of peaks appear at the retention time: the 1st group (unknown) was between 5.5 and 7 min; and the 2nd group (Jatropha phorbol esters) between 8.5 and 9.5 min. Fig. 6 HPLC/UV chromatogram at 280 nm of each methanolic fractions containing phorbol esters obtained from extraction of Jatropha oil.
Radiation Research Center Transesterification of J. curcas phorbol ester • 2 mL of methanolic fraction containing J. curcas PEs was added onto a graduated tube. • 0.4 mL of 10%(w/w) KOH in methanol was further added the methanolic sample in the tube. • The mixture was gently shaken for 1 min to get homogeneous mixture. Then it was kept in a dark place for 14 hours to complete reaction. Fig. 4 Trans-esterifying methanolic extract containing Jatropha phorbol esters. • After completing reaction, the mixture was neutralized with 85% H3PO4 to the pH ~ 7. • The light-yellowish solution was transferred onto a vial for analysis. • The light-yellowish solution was filtered with filter-unit before analysis by HPLC/PDA. • After analysis, white precipitate was found at the bottom of the vial.
Radiation Research Center • Before transesterification the Jatropha phorbol ester appears at retention time between 8-10 min. • After transesterification the peaks of Jatropha phorbol esters disappear due to conversion into FAME. • The concentration of J. curcas PEs was 3.47 0.07 mg-PEs/g-Oil. Fig. 7 HPLC/UV chromatogram at 280nm of methanolic fraction before and after transesterification.
+ National University of Laos, Faculty of Science, Department of Chemistry Proposed Mechanism on the conversion of phorbol ester to phorbol during transesterification of J. oil in Biodiesel production 36
(a) (b) Sonolytic Degradation of Jatropha PEs • Scope of Results • Degradation at Xn mg/L and kinetic data (ln(C0/C). • UV adsorption spectra before and after degradation • Degradation vs. power density. • Effect of pH, temperature, additives. • Ratio of H2O2 to PEs on degradation. • etc. (c) (d) Sonolysis system for chemical degradation study: (a) front side; (b) top side; (c) Model and max frequency; (d) Temperature control.
Radiolytic Degradation of Jatropha PEs Radiolytic Sampling racks Cherenkov radiation from the 60Co g-ray source A water-pool 60Co -ray irradiation facilities at the Radiation Research Center, Osaka Prefecture University, Japan. • Scope of Results • Absorbed Dose: degradation G-value and constant. • UV absorption: degradation spectra on UV adsorption • Effect of additives and saturation atmosphere vs. degradation • etc.
(c) (a) (d) (b) Radiation Research Center Fig. 9 HPLC/UV chromatogram of TPA’s 30ppm (a-b) and 50ppm (c-d) at r-ray absorption dose of 0, 10 and 20kGy, respectively. • After exposure to -irradiation, the TPA was degraded. • From HPLC/UV chromatogram at 220nm around 50% TPA was degraded at 10 kGy. At 20kGy, TPA degradation was greater than 90% . • In contrast, 56% TPA was observed at HPLC/UV at 280nm when the TPA was irradiated at 10 kGy and complete degradation was observed at 20 kGy -irradiation.
-Radiolytic Degradation of TPA Radiation Research Center • 30 and 50 ppm-TPA solutions was prepared by using 1000ppm TPA standard solution dissolved in methanol. • Vials each separately containing methanol, 30-and-50ppm TPA solution was divided into two parts for 10 and 20 kGy, respectively. • The vials were put onto the stainless steel sample holder and exposed to -ray at absorbed dose of 10 and 20kGy, respectively. • The vial’s color was changed to brown after r-ray exposure. Fig. 4 -irradiation of TPA solution at irradiation rate of ~ 10 kGy/h.
Results on Degradation of Jatropha PEs Effect of -Irradiation