Effects of Salt-Assisted (Ferric Chloride) Steam Versus Salt-Assisted Microwave Pretreatments on Delignification and Morphology of Napier Grass (Pennisetum purpureum)

Pitiporn Manokhoon; Thaneeya Rangseesuriyachai

Authors

Pitiporn Manokhoon Department of Environmental Engineering, Faculty of Engineering and Architecture, University of Technology Suvanabhumi, Nonthaburi, Thailand
Thaneeya Rangseesuriyachai Department of Civil Engineering, Faculty of Engineering, Rajamangala University of Technology Thanyaburi, Pathumtani, Thailand

Keywords:

Pretreatment, Steam, Microwave, Ferric Chloride, Napier Grass

Abstract

This research studied the delignification process and its effect on the morphology of Napier grass (Pennisetum purpureum); salt-assisted (ferric chloride) steam (SS) and salt-assisted microwave (SM) were the selected delignification methods. SS involved steaming at temperatures of 105, 110, 115, 120 and 125 °C for 20, 40, and 60 min. SM was conducted at different microwave power levels viz. 300, 450, and 800 W for 2, 5, and 8 min. Both delignification methods were performed at the ferric chloride concentrations of 1 and 2 M. The results showed that untreated Napier grass consisted of 33.13% cellulose, 9.73% hemicellulose, 16.7% lignin; 40.45% of other components made up the rest. The cellulose content was noted to be suitable for ethanol production; the lignin content was nevertheless excessive. Delignification with 2 M ferric chloride in combination with the use of microwave at 600 W for 8 min gave the best delignification result of 52.5%. SS pretreatment at 125 °C for 40 min in combination with 2 M ferric chloride yielded the highest percentage of lignin removal of 45.5%. After pretreatment, Napier grass was noted to be porous, with cracked and uni-directionally separated surface, which implied the destroyed structure between lignin and cellulose. Both methods of delignification did not alter the chemical composition of lignin. By considering the power consumption and required pretreatment time, SM is superior since it requires much shorter time consumption than SS.

References

Rengsirikul, K., Ishii, Y., Kangvansaichol, K., Sripichitt, P., Punsuvon, V., Vaithanomsat, P., Nakamanee, G. and Tudsri, S., 2013, "Biomass Yield, Chemical Composition and Potential Ethanol Yields of 8 Cultivars of Napiergrass (Pennisetum purpureum Schumach.) Harvested 3-Monthly in Central Thailand," Journal of Sustainable Bioenergy Systems, 3, pp. 107-112.

Rocha-Meneses, L., Otor, F.O., Bonturi, N., Orupõld, K. and Kikas, T., 2020, "Bioenergy Yields from Sequential Bioethanol and Biomethane Production: An Optimized Process Flow," Sustainability, 12 (1), pp. 272-291.

Moodley, P. and Gueguim Kana, E.B., 2017, "Development of a Steam or Microwave-assisted Sequential Salt-alkali Pretreatment for Lignocellulosic Waste: Effect on Delignification and Enzymatic Hydrolysis," Energy Conversion and Management, 148, pp. 801-808.

Phitsuwan, P., Sakka, K. and Ratanakhanokchai, K., 2016, "Structural Changes and Enzymatic Response of Napier Grass (Pennisetum purpureum) Stem Induced by Alkaline Pretreatment," Bioresource Technology, 218, pp. 247-256.

Hosseini Koupaie, E., Dahadha, S., Bazyar Lakeh, A.A., Azizi, A. and Elbeshbishy, E., 2019, "Enzymatic Pretreatment of Lignocellulosic Biomass for Enhanced Biomethane Production-A Review," Journal of Environmental Management, 233, pp. 774-784.

Sindhu, R., Binod, P. and Pandey, A., 2016, "Biological Pretreatment of Lignocellulosic Biomass – An overview," Bioresource Technology, 199, pp. 76-82.

Cheng, J., Su, H., Zhou, J., Song, W. and Cen, K., 2011, "Microwave-assisted Alkali Pretreatment of Rice Straw to Promote Enzymatic Hydrolysis and Hydrogen Production in Dark- and Photo-fermentation," International Journal of Hydrogen Energy, 36 (3), pp. 2093-2101.

Diaz, A.B., Moretti, M.M.S., Bezerra-Bussoli, C., Carreira Nunes, C.D.C., Blandino, A., da Silva, R. and Gomes, E., 2015, "Evaluation of Microwave-Assisted Pretreatment of Lignocellulosic Biomass Immersed in Alkaline Glycerol for Fermentable Sugars Production," Bioresource Technology, 185, pp. 316-323.

Moodley, P. and Kana, E.B.G., 2017, "Microwave-assisted Inorganic Salt Pretreatment of Sugarcane Leaf Waste: Effect on Physiochemical Structure and Enzymatic Saccharification," Bioresource Technology, 235, pp. 35-42.

Chen, L., Chen, R. and Fu, S., 2015, "FeCl3 Pretreatment of Three Lignocellulosic Biomass for Ethanol Production," ACS Sustainable Chemistry and Engineering, 3 (8), pp. 1794-1800.

Kang, K.E., Park, D.-H. and Jeong, G.-T., 2013, "Effects of Inorganic Salts on Pretreatment of Miscanthus Straw," Bioresource Technology, 132, pp. 160-165.

Anonymous, 1999, Technical Association of the Pulp and Paper Industry: Sampling and Preparing Wood for Analysis Technical Association of the Pulp and Paper Industry, TAPPI Standard T203 om-88, Atlanta, USA.

Anonymous, 2002, Technical Association of the Pulp and Paper Industry: Sampling and Preparing Wood for analysis Technical Association of the Pulp and Paper Industry, TAPPI Standard T222 om-02, Atlanta, USA.

Minmunin, J., Limpitipanich, P. and Promwungkwa, A., 2015, "Delignification of Elephant Grass for Production of Cellulosic Intermediate," Energy Procedia, 79, pp. 220-225.

Binod, P., Sindhu, R., Singhania, R.R., Vikram, S., Devi, L., Nagalakshmi, S., Kurien, N., Sukumaran, R.K. and Pandey, A., 2010, "Bioethanol Production from Rice Straw: An overview," Bioresource Technology, 101 (13), pp. 4767-4774.

Eliana, C., Jorge, R., Juan, P. and Luis, R., 2014, "Effects of the Pretreatment Method on Enzymatic Hydrolysis and Ethanol Fermentability of the Cellulosic Fraction from Elephant Grass," Fuel, 118, pp. 41-47.

Mohammed, I.Y., Abakr, Y.A., Kazi, F.K., Yusup, S., Alshareef, I. and Chin, S.A., 2015, "Comprehensive Characterization of Napier Grass as a Feedstock for Thermochemical Conversion," Energies, 8 (5), pp. 3403-3417.

He, C.-R., Kuo, Y.-Y. and Li, S.-Y., 2017, "Lignocellulosic Butanol Production from Napier Grass Using Semi-Simultaneous Saccharification Fermentation," Bioresource Technology, 231, pp. 101-108.

Kumar, P., Barrett, D.M., Delwiche, M.J. and Stroeve, P., 2009, "Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production," Industrial and Engineering Chemistry Research, 48 (8), pp. 3713-3729.

Norgren, M., Edlund, H., Wågberg, L., Lindström, B. and Annergren, G., 2001, "Aggregation of Kraft Lignin Derivatives under Conditions Relevant to the Process, Part I: Phase Behaviour," Colloids and Surfaces A: Physicochemical and Engineering Aspects, 194 (1), pp. 85-96.

Kamireddy, S.R., Li, J., Tucker, M., Degenstein, J. and Ji, Y., 2013, "Effects and Mechanism of Metal Chloride Salts on Pretreatment and Enzymatic Digestibility of Corn Stover," Industrial and Engineering Chemistry Research, 52 (5), pp. 1775-1782.

Mamman, A.S., Lee, J.-M., Kim, Y.-C., Hwang, I.T., Park, N.-J., Hwang, Y.K., Chang J.-S. and Hwang, J.-S., 2008, "Furfural: Hemicellulose/xylosederived biochemical," Biofuels, Bioproducts and Biorefining, 2 (5), pp. 438-454.

Pang, F., Xue, S., Yu, S., Zhang, C., Bing Li, B. and Kang, Y., 2012, “Effects of Microwave Power and Microwave Irradiation Time on Pretreatment Efficiency and Characteristics of Corn Stover Using Combination of Steam Explosion and Microwave Irradiation (SE–MI) pretreatment,” Bioresource Technology, 118, pp. 111–119.

Kurian, J.K., Gariepy, Y., Orsat, V. and Raghavan, G.S.V., 2015, "Comparison of Steam-assisted Versus Microwave-assisted Treatments for the Fractionation of Sweet Sorghum Bagasse," Bioresources and Bioprocessing, 2 (1), p. 30.