Journal of Applied Science and Engineering

Published by Tamkang University Press


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Zurina Zainal AbidinThis email address is being protected from spambots. You need JavaScript enabled to view it., Mahtab Samadi, Dayang Radiah Awang Biak, and Robiah Yunus

Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia



Received: August 23, 2023
Accepted: November 24, 2023
Publication Date: March 2, 2024

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

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Subcritical water extraction (SWE) is gaining popularity due to its ability to manipulate water properties at high pressure and temperature. Here, the essential oil from Aquilaria Malacenssis wood was recovered using the subcritical technique. The aim is to elucidate SWE mechanism or behaviour and mathematically define the process kinetics for future scaling up, designing unit operation and improving efficiency. The extraction processes were carried out at various subcritical conditions such as varying temperature and time. These concentration-time profile data were analyzed using four models namely partitioning coefficient, one-site desorption, two-site desorption and thermodynamic partition with external mass transfer. Concentration (yield)-time profile indicated that the subcritical water extraction occurred in two simultaneous processes of fast and slow desorption. The fast process persisted during the initial 10 minutes with large changes in the essential oil yield. From this onwards until the end of extraction time, a gradual slow increment was seen till a plateau was reached. Three models which are second order, two-site kinetic and partitioning coefficient with external mass transfer were found to give reasonable SSR and R2 values. However, the two-site kinetic/second order model emerged to best fit the experimental data with low SSR of less than 0.002 and high R2 of greater than 0.99. Using the two rate constants of k1 and k2 from the two-site kinetic model, activation energies were calculated and found to be 16.5 KJ/mol and 28 KJ/mol for fast desorption and slow diffusion respectively. In short, SWE has demonstrated good enhancement of the extraction yield and temperature being the critical parameter. These findings on kinetics and modelling can facilitate the reduction of energy and time for scaling up and optimization.


Keywords: Gaharu, Aquilaria Malacenssis, Subcritical, Kinetics, Essential Oil

  1. [1] A. Asbahani, M. El, K. Badri, W. Sala, M. Addi, and E. H. A. Casabianca, (2015) “Essential oils: From extraction to encapsulation" International Journal of Pharmaceutics 483(1-2): 220–243. DOI: 10.1016/j.ijpharm.2014.12.069.
  2. [2] J. S. Raut and S. M. Karuppayil, (2014) “A status review on the medicinal properties of essential oils" Industrial Crops and Products 62: 250–264. DOI: 10.1016/j.indcrop.2014.05.055.
  3. [3] C. B. K. Hüsnü and F. Demirci. “Chemistry of Essential Oils”. In: Flavours and Fragrances: Chemistry, Bioprocessing and Sustainability. Ed. by R. G. ( Berger. Berlin, Heidelberg: Springer, Berlin, Heidelberg, 2007, 43–86. DOI: 10.1007/978-3-540-49339-6_4.
  4. [4] A. Barden, N. A. Anak, T. Mulliken, and M. Song. Heart of the Matter: Agarwood Use and Trade and CITES Implementation for Aquilaria malaccensis. Cambridge: TRAFFIC International, 2000.
  5. [5] W. Dhifi, S. Bellili, S. Jazi, N. Bahloul, and W. Mnif, (2016) “Essential Oils’ Chemical Characterization and Investigation of Some Biological Activities: A Critical Review" Medicines (Basel). 3(4): 25. DOI: 10.3390/medicines3040025.
  6. [6] J. Sharifi-Rad, A. Sureda, G. C. Tenore, M. Daglia, M. Sharifi-Rad, M. Valussi, R. Tundis, M. SharifiRad, M. R. Loizzo, A. O. Ademiluyi, and R. Sharifi-Rad, (2017) “Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems" Molecules 22(1): 70. DOI: 10.3390/molecules22010070.
  7. [7] M. A. Desai, J. Parikh, and A. K. De, (2014) “Modelling and optimization studies on extraction oflemongrass oil from Cymbopogon flexuosus (Steud.) Wats" Chemical Engineering Research and Design 9(5): 793–803. DOI: 10.1016/j.cherd.2013.08.011.
  8. [8] N. Yoswathana, M. N. Eshiaghi, and K. Jaturapornpanich, (2012) “Enhancement of Essential Oil from Agarwood by Subcritical Water Extraction and A Pretreatments on Hydrodistillation" International Journal of Chemical, Molecular, Nuclear, Materials and Metallurgical Engineering 6(5): 453–459. DOI: 10.5281/zenodo.1060381.
  9. [9] N. Sulaiman, M. I. Idayu, A. Z. Ramlan, M. N. Fashya, A. N. N. Farahiyah, J. Mailina, and M. A. N. Azah, (2015) “Effects of extraction methods on yield and chemical compounds of gaharu (aquilaria malaccensis)" Journal of Tropical Forest Science 27(3): 413–419.
  10. [10] K. N. Fazila and K. K. Halim, (2012) “Effects of soaking on Yield and Quality of Agarwood Oil" Journal of Tropical Forest Science 24(4): 557–564.
  11. [11] S. N. Tajuddin and M. M. Yusoff, (2010) “Chemical Composition of Volatile Oils of Aquilaria malaccensis (Thymelaeaceae) from Malaysia" Natural Product Communications 5(12): 1965–1968. DOI: 10.1177/1934578X1000501229.
  12. [12] C. U. Tam, F. Q. Yang, Q. W. Zhang, J. Guan, and S. P. Li, (2007) “Optimization and comparison of three methods for extraction of volatile compounds from Cyperus rotundus evaluated by gas chromatography-mass spectrometry" Journal of Pharmaceutical and Biomedical Analysis 44(2): 444–449. DOI: 10.1016/j.jpba.2006.10.026.
  13. [13] W. Abdelmoez, E. Ashour, S. M. Naguib, A. Hilal, D. A. A. Mahdy, E. A. Mahrous, and E. Abdel-Sattar, (2016) “Kinetic and thermodynamics studies for castor oil extraction using subcritical water technology" Journal of Oleo Science 65(6): 477–485. DOI: 10.5650/jos.ess15298.
  14. [14] R. S. Ayala and M. D. L. de Castro, (2001) “Continuous subcritical water extraction as a useful tool for isolation of edible essential oils" Food Chemistry 75(1): 109–113. DOI: 10.1016/S0308-8146(01)00212-6.
  15. [15] I. Okajima and T. Sako, (2014) “Energy conversion of biomass with supercritical and subcritical water using large-scale plants" Journal of Bioscience and Bioengineering 117(1): 1–9. DOI: 10.1016/j.jbiosc.2013.06.010.
  16. [16] C. C. Teo, S. N. Tan, J. W. H. Yong, C. S. Hew, and E. S. Ong, (2010) “Pressurized hot water extraction (PHWE)" Journal of Chromatography A. 1217(16): 2484–2494. DOI: 10.1016/j.chroma.2009.12.050.
  17. [17] D. Li, Z. Zhang, S. Liu, and S. Li., (2020) “Understanding nano-modification in liquid dielectric from coefficient of viscosity" AIP Advances 10(8): 085009. DOI: 10.1063/5.0015090.
  18. [18] P. W. Carr, D. R. Stoll, and X. Wang, (2011) “Perspectives on recent advances in the speed of high-performance liquid chromatography" Analytical Chemistry 83(6): 1890–1900. DOI: 10.1021/ac102570t.
  19. [19] M. Plaza and C. Turner, (2015) “Pressurized hot water extraction of bioactives" TrAC Trends in Analytical Chemistry 71: 39–54. DOI: 10.1016/j.trac.2015.02.022.
  20. [20] M. Plaza and M. L. Marina, (2019) “Pressurized hot water extraction of bioactives" TrAC Trends in Analytical Chemistry 116: 236–247. DOI: 10.1016/j.trac.2019.03.024.
  21. [21] Y. Wang, Y. Ye, L. Wang, W. Yin, and J. Liang, (2021) “Antioxidant activity and subcritical water extraction of anthocyanin from raspberry process optimization by response surface methodology" Food Bioscience 44: 10139. DOI: 10.1016/j.fbio.2021.101394.
  22. [22] M. E. Yulianto, B. Jos, and B. Budiyono, (2023) “Kinetic modelling of liquid-solid extraction of bioactive compounds from ginger waster using subcritical water" Sainteknol: Jurnal Sains dan Teknologi 21(1): 28–35. DOI: 10.15294/sainteknol.v21i1.44589.
  23. [23] N. Sabil, S. A. Toat, Y. Hiroyuki, and S. Izhar, (2023) “Hydrolysis of blended cotton/polyester fabric from hospital waste using subcritical water" Sains Malaysiana 52(1): 139–151. DOI: 10.17576/jsm-2023-5201-11.
  24. [24] N. A. A. Halim, Z. Z. Abidin, S. I. Siajam, C. G. Hean, and M. R. Harun, (2021) “Optimization studies and compositional analysis of subcritical water extraction of essential oil from citrus hystrix DC. Leaves" The Journal of Supercitical Fluids 178(10538): 1–16. DOI: 10.1016/ j.supflu.2021.105384.
  25. [25] M. Samadi, Z. Z. Abidin, H. Yoshida, R. Yunus, R., and D. R. A. Biak, (2020) “Towards Higher Oil Yield and Quality of Essential Oil Extracted from Aquilaria malaccensis Wood via the Subcritical Technique" Molecules 25(17): 3872. DOI: 10.3390/molecules25173872.
  26. [26] M. A. Bezerra, R. E. Santelli, E. P. Oliveira, L. S. Villara, and L. A. Escaleira, (2008) “Response surface methodology (RSM) as a tool for optimization in analytical chemistry" Talanta 76(5): 965–977. DOI: 10.1016/j.talanta.2008.05.019.
  27. [27] F. Reyes-Jurado, A. Franco-Vega, and N. RamírezCorona, (2014) “Essential Oils: Antimicrobial Activities, Extraction Methods, and Their Modeling" Food Engineering Review 7: 275–297. DOI: 10.1007/s12393-014-9099-2.
  28. [28] A. H. Asl and M. Khajenoori. “Chapter 4: Modelling of Subcritical Water Extraction”. In: Green Extraction in Separation Technology. Boca Raton: CRC Press, 2021, 85–113.
  29. [29] C. Chan, R. Yusoff, and G. Ngoh, (2014) “Modeling and kinetics study of conventional and assisted batch solvent extraction" Chemical Engineering Research and Design 92(6): 1169–1186. DOI: 10.1016/j.cherd.2013. 10.001.
  30. [30] Y. Ho, H. A. Harouna-oumarou, H. Fauduet, and C. Porte, (2005) “Kinetics and model building of leaching of water-soluble compounds of Tilia sapwood" Separation and Purification Technology 45(3): 169–173. DOI: 10.1016/j.seppur.2005.03.007.
  31. [31] H. S. Kusuma and M. Mahfud, (2018) “Kinetic studies on extraction of essential oil from sandalwood (Santalum album) by microwave air-hydrodistillation method" Alexandria Engineering Journal 57(2): 1163–1172. DOI: 10.1016/j.aej.2017.02.007.
  32. [32] M. Khajenoori, A. H. Asl, and F. Hormozi, (2009) “Proposed Models for Subcritical Water Extraction of Essential Oils" Chinese Journal of Chemical Engineering 17(3): 359–365. DOI: 10 . 1016 / S1004 - 9541(08 ) 60217-7.
  33. [33] D. S. Kim and S. B. Lim, (2020) “Kinetic study of subcritical water extraction of flavonoids from citrus unshiu peel" Separation and Purification Technology 250: 117259. DOI: 10.1016/j.seppur.2020.117259.
  34. [34] K. S. Duba, A. A. Casazza, H. B. Mohamed, P. Perego, and L. Fiori, (2015) “Extraction of polyphenols from grape skins and defatted grape seeds using subcritical water: Experiments and modeling" Food Bioproduct Process 94: 29–38. DOI: 10.1016/j.fbp.2015.01.001.
  35. [35] M. N. Islam, Y. T. Jo, S. K. Jung, and J. H. Park, (2013) “Thermodynamic and kinetic study for subcritical water extraction of PAHs" Journal of Industrial Engineering and Chemistry 19(1): 129–36. DOI: 10.1016/j.jiec.2012.07.014.
  36. [36] M. Samadi, Z. Z. Abidin, H. Yoshida, R. Yunus, D. R. A. Biak, C. H. Lee, and E. H. Lok, (2019) “Subcritical water extraction of essential oil from Aquilaria malaccensis leaves" Separation Science and Technology 55(5): 1–20. DOI: 10.1080/01496395.2019.1650768.
  37. [37] D. D. Paunovic, S. S. Mitic, D. A. Kostic, M. N. Mitic, B. T. Stojanovic, and J. L. Pavlovic, (2014) “Kinetics and thermodynamics of the solid-liquid extraction process of total polyphenols from barley" Advanced technologies 3(2): 58–63. DOI: 10.5937/savteh1402058P.
  38. [38] N. Rahimi, M. Shiva, S. A. Mortazavi, A. H. Elhamirad, A. M. Maskooki, and G. Rajabzadeh, (2015) “Kinetic study of superheated water extraction of berberine from Berberis vulgaris root" Bulgarian Chemical Communications 47(D): 140–146.
  39. [39] H. M. Hazwan, C. M. Hasfalina, J. Hishamuddin, and Z. A. Zurina, (2012) “Optimization and Kinetics of Essential Oil Extraction from Citronella Grass by Ohmic Heated Hydro Distillation" International Journal of Chemical Engineering and Applications 3: 173–177. DOI: 10.7763/IJCEA.2012.V3.181.
  40. [40] T. Anekpankul, M. Goto, M. Sasaki, P. Pavasant, and A. Shotipruk, (2007) “Extraction of anti-cancer damnacanthal from roots of Morinda citrifolia by subcritical water" Separation and Purification Technology 55(3): 343–349. DOI: 10.1016/j.seppur.2007.01.004.
  41. [41] Y. Ho and G. McKay, (1999) “Pseudo-second order model for sorption processes" Process Biochemistry 34(5): 451–465. DOI: 10.1016/S0032-9592(98)00112-5.
  42. [42] D. Cox-Georgia, N. Ramadoss, C. Dona, and C. Basu, (2019) “Therapeutic and Medicinal Uses of Terpenes" Medicinal Plants: 333–59. DOI: 10.1007/978-3-030-31269-5_15.
  43. [43] D. L. Sidebottom, (2012) “Introduction to phase transitions" Fundamentals of Condensed Matter and Crystalline Physics: An Introduction for Students of Physics and Materials Science 66(5): 267–288. DOI: 10.1063/PT.3.1980.
  44. [44] T. P. Dao, T. V. N. Y. N. Tran, X. T. Le, T. N. T. An, N. H. T. Anh, and L. G. Bach, (2021) “Central Composite Design, Kinetic Model, Thermodynamics, and Chemical Composition of Pomelo (Citrus Maxima (Burm.) Merr.) Essential Oil Extraction by Steam Distillation" Processes 9(11): 2075. DOI: pr9112075.
  45. [45] A. Ramanathan and V. Thangarasu, (2019) “Effect of high-frequency microwave irradiation on Aegle Marmelos Correa oil extraction: Kinetic and thermodynamic study" Energy Procedia 158: 1046–1051. DOI: 10.1016/j.egypro.2019.01.253.
  46. [46] S. B. D. Santos, M. A. Martins, A. L. Caneschi, P. R. M. Aguilar, and J. S. D. R. Coimbra, (2015) “Kinetics and Thermodynamics of Oil Extraction from Jatropha curcas L. Using Ethanol as a Solvent" International Journal of Chemical Engineering 2015: DOI: 10.1155/2015/871236.
  47. [47] O. S. Stamenkovic, M. D. Kostic, M. B. Tasic, I. G. Djalovic, P. M. Mitrovic, M. O. Biberdži´c, and V. B. Veljkovic, (2020) “Kinetic, thermodynamic and optimization study of the corn germ oil extraction process" Food and Bioproducts Processing 120: 91–103. DOI: 10.1016/j.fbp.2019.12.013.