Skip to content
Licensed Unlicensed Requires Authentication Published by De Gruyter July 20, 2020

Development and validation of mathematical model of hydrotropic-reactive extraction of lignin

Indah Hartati, Wahyudi Budi Sediawan, Hary Sulistyo, Muhammad Mufti Azis and Moh Fahrurrozi


Hydrotropes have been largely explored as reactive extraction agent for lignin separation. In this paper, a mathematical model of hydrotropic-reactive extraction of sugarcane bagasse lignin was proposed and validated by experimental data from literature. The mathematical model was developed by assuming the particle is in slab shape, and by considering simultaneous processes of hydrotrope intra particle diffusion, second order reaction of lignin-hydrotrope, and intra-particle soluble delignification product diffusion. The proposed model results in a set of partial differential equations which were then solved by explicit finite difference approximation method. The mathematical model parameters were determined by fitting the model to the hydrotropic reactive extraction experimental data reported by Ansari and Gaikar (2014). Simulations show that the mathematical model of the hydrotropic-reactive extraction were well fitted to the experimental data with the obtained hydrotrope effective diffusivity (DeA) of 5.0 × 10−11 m2/s, effective diffusivity of soluble lignin product (DeC) of 9.0 × 10−12 m2/s and reaction rate constant (kr) of 1.78 × 10−10 m3/(g.s). It was also observed that the reaction was first order to the hydrotrope (n = 1), and one half order to the lignin (m = 0.5). Meanwhile the pseudo-stoichiometric mass ratio of hydrotrope to lignin was 6.4 g hydrotrope/g lignin.

Corresponding author: Wahyudi Budi Sediawan, Gadjah Mada University, Faculty of Engineering, Chemical Engineering Department, Yogyakarta, Indonesia, E-mail:

Funding source: PDUPT

Award Identifier / Grant number: 2572/UN1/DITLIT/DIT-LIT/LT/2019


The research team would like to thanks for The Ministry of Research, Technology and Higher Education of Republic of Indonesia which support this work through PDUPT research grant of 2019, with contract number of 2572/UN1/DITLIT/DIT-LIT/LT/2019.

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: None declared.

  3. Employment or leadership: None declared.

  4. Honorarium: None declared.

  5. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.


hydrotrope compound (sodium xylene sulfonate)




soluble lignin product


concentration of hydrotrope (sodium xylene sulfonate) in the liquid in the pore of the solid (g/m3)


concentration of the hydrotrope (sodium xylene sulfonate) in the bulk of the liquid (g/m3)


concentration of unreacted lignin in the liquid in the pore of the solid (g/m3)


concentration of soluble lignin product in the liquid in the pore of the solid (g/m3)


concentration of soluble lignin in the bulk of the liquid (g/m3)


effective diffusivity of A and C, respectively (m2/s)


lab porosity


reaction rate constant (m3/(g.s))


slab thickness (m)


the number of thin slabs


cross sectional of slab, perpendicular to x axis (m2)


volume of liquid (m3)

n, m

reaction order of hydrotrope (sodium xylene sulfonate) and lignin, respectively


pseudo-stoichiometric mass ratio of hydrotrope (sodium xylene sulfonate) to lignin (g hydrotrope/g lignin)


1. Ansari, KB, Gaikar, VG. Green hydrotropic extraction technology for delignification of sugarcane bagasse by using alkybenzene sulfonates as hydrotropes. Chem Eng Sci 2014;115:157–66. in Google Scholar

2. Banoub, J, Delmas, GHJr, Joly, N, Mackenzie, G, Cachet, N, Benjelloun-Mlayah, B, et al.. A critique on the structural analysis of lignins and application of novel tandem mass spectrometric strategies to determine lignin sequencing. J Mass Spectrom 2015;50:5–48. in Google Scholar

3. Renault, H, Werck-Reichhart, D, Weng, JK. Harnessing lignin evolution for biotechnological applications. Curr Op in Biotechnol 2019;56:105–11. in Google Scholar

4. Carvajal, JC, Gómez, A, Cardona, CA. Comparison of lignin extraction processes: economic and environmental assessment. Bioresour Technol 2016;214:468–76. in Google Scholar

5. Moubarik, A, Grimi, N, Boussetta, N, Pizzi, A. Isolation and characterization of lignin from Moroccan sugar cane bagasse : production of lignin – phenol-formaldehyde wood adhesive. Ind Crop Prod 2013;45:296–302. in Google Scholar

6. Al Arni, S. Extraction and isolation methods for lignin separation from sugarcane bagasse: a review. Ind Crop Prod 2018;115:330–39. in Google Scholar

7. Macfarlane, AL, Farid, MM, Chen, JJJ. Process intensification kinetics of delignification using a batch reactor with recycle. Chem Eng Proc 2009;48:864–70. in Google Scholar

8. Devendra, LP, Kumar, MK, Pandey, A. Evaluation of hydrotropic pretreatment on lignocellulosic biomass. Bioresour Technol 2016;213:350–58. in Google Scholar

9. Devendra, LP, Pandey, A. Hydrotropic pretreatment on rice straw for bioethanol production. Renew Energy 2016;98:2–8. in Google Scholar

10. Denisova, MN, Kukhlenko, AA, Orlov, SE. Investigation into the process of hydrotropic delignification of oat straw in the universal thermobaric unit. Theor Found Chem Eng 2018;52:661–3. in Google Scholar

11. Gabov, K, Hemming, J, Fardim, P. Industrial crops & products sugarcane bagasse valorization by fractionation using a water-based hydrotropic process. Ind Crop Prod 2017;108:495–504. in Google Scholar

12. Denisova, MN, Kukhlenko, AA, Orlov, SE, Sakovich, GV. The characteristics of the hydrotropic Miscanthus pulp. Russ Chem Bull 2015;64:2182–8. in Google Scholar

13. Hartati, I, Sediawan, WB, Sulistyo, H, Azis, MM,Fahrurrozi, M. Mathematical modelling and simulation of hydrotropic delignification. J Rekayasa Proses 2019;13:31–40. in Google Scholar

14. Dang, VQ, Nguyen, KL. A universal kinetic equation for characterising the fractal nature of delignification of lignocellulosic materials. Cellulose 2007;14:153–60. in Google Scholar

15. Chang, CW, Webb, C. Production of a generic microbial feedstock for lignocellulose biorefineries through sequential bioprocessing. Bioresour Technol 2017;227:35–43. in Google Scholar

16. Pérez, NP, Pedroso, D, Machin, EB, Antunes, JS, Tuna, CE, Silveira, JL. Geometrical characteristics of sugarcane bagasse for being used as fuel in fluidized bed technologies. Renew Energy 2019;143:1210–24. in Google Scholar

17. Morais, AB, Jayakumar, C, Gandhi, NN. Hydrotropic effect and thermodynamic analysis on the solubility and mass transfer coefficient enhancement of ethylbenzene. Korean J Chem Eng. 2013;30:925–30. in Google Scholar

18. Cui, Y. Hydrotropic solubilization by urea derivatives: a molecular dynamics simulation study. J Pharm 2013;2013:1–15. in Google Scholar

19. Nguyen, KL, Dang, VQ. The fractal nature of kraft pulping kinetics applied to thin Eucalyptus nitens chips. Cellulose 2006;64:104–11. in Google Scholar

20. Huang, G, Shi, JX, Langrish, TAG. NH4OH-KOH pulping mechanisms and kinetics of rice straw. Bioresour Technol 2007;98:1218–23. in Google Scholar

21. Sun, JX, Sun, XF, Sun, RC, Fowler, P, Baird, MS. Inhomogeneities in the chemical structure of sugarcane. J Agric Food Chem 2003;51:6719–25. in Google Scholar

22. Rezende, CA, De Lima, MA, Maziero, P, deAzevedo, ER, Garcia, W, Polikarpov, I. Chemical and morphological characterization of sugarcane bagasse submitted to a delignification process for enhanced enzymatic digestibility. Biotechnol Biofuels 2011;54:1–18. in Google Scholar

23. Zeng, J, Tong, Z, Wang, L, Zhu, JY, Ingram, L. Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis. Bioresour Technol 2014;154:274–81. in Google Scholar

24. Makavana, JM, Agravat, VV, Balas, PR, Makwana, PJ, Vyas, VG. Engineering properties of various agricultural residue. Int J Curr Microbiol App Sci 2018;7:2362–67. in Google Scholar

25. Zhang, Y, Ghaly, AE, Li, B. Availability and physical properties of residues from major agricultural crops for energy conversion. Am J Agric Biol Sci 2012;7:312–21. in Google Scholar

26. Karthyani, S, Pandey, A, Devendra, LP. Delignification of cotton stalks using sodium cumene sulfonate for bioethanol Delignification of cotton stalks using sodium cumene sulfonate for bioethanol production. Biofuels 2017;0:1–10. in Google Scholar

27. Qi, G, Xiong, L, Li, H, Huang, Q, Luo, M, Tian, L, et al.. Biomass and bioenergy hydrotropic pretreatment on wheat straw for efficient biobutanol production. Biomass and Bioenergy 2018;122:76–83. in Google Scholar

28. Zhao, X, Wu, R, Liu, D. Evaluation of the mass transfer effects on delignification kinetics of atmospheric acetic acid fractionation of sugarcane bagasse with a shrinking– layer model. Bioresour Technol 2018;261:52–61. in Google Scholar

29. Winitsorn, A, Douglas, PL, Douglas, S, Pongampai, S, Teppaitoon, W. Modeling the extraction of valuable substances from natural plants using solid - Liquid extraction. Chem Eng Commun 2008;195:1457–64. in Google Scholar

30. Jokić, S, Velić, D, Bilić, M, Bucić-kojić, A, Planinić, M. Modelling of the process of solid-liquid extraction of total polyphenols from soybeans. Czech J Food Sci 2010;28:206–12. in Google Scholar

31. Salmi, T, Grénman, H, Wärnå, J, Murzin, DY. New modelling approach to liquid – solid reaction kinetics: from ideal particles to real particles. Chem Eng Res Des 2013; 91:1876–89. in Google Scholar

32. Bucić-Kojic, A, Planinić, M, Tomas, S, Bilić, M, Velić, D. Study of solid-liquid extraction kinetics of total polyphenols from grape seeds. J Food Eng 2007;81:236–42. in Google Scholar

Received: 2019-11-20
Accepted: 2020-04-01
Published Online: 2020-07-20

© 2020 Walter de Gruyter GmbH, Berlin/Boston