Effect of Pyrolysis Temperature on the Properties of Biochar and Bio-oil Derived from Conocarpus and Sugarcane Bagasse

Document Type : Research Paper

Authors

1 Department of Soil Science, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

2 Department of Soil Sciences,, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

3 Soil and Water Research Department, West Azarbaijan Agricultural and Natural Resources Research and Education Center, AREEO, Urmia, Iran

4 Department of Horticulture, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

The conversion of biomass into biochar and bio-oil via pyrolysis requires a precise understanding of the temperature effect on product yield and quality. This study aimed to investigate the effect of pyrolysis temperature on the properties of biochar and bio-oil derived from two biomasses, conocarpus and sugarcane bagasse, at 250, 400, and 550°C. After biochar and bio-oil production, several physicochemical and structural characteristics were measured for both products. Surface morphology (FE-SEM) confirmed morphological changes at higher temperatures. Higher temperature intensified thermal degradation, reducing volatile matter, yield, cation exchange capacity (CEC), and electrical conductivity (EC), while pH (the retention of alkaline ash) and specific surface area (pore development) increased. The maximum CEC was observed for Conocarpus at 250°C, which increased by 51.69% compared to 550°C. Elemental analysis of both products confirmed an increase in carbon and decreases in hydrogen and the atomic O/C ratio with increasing temperature, but the oxygen trend depended on biomass type. Results showed that by increasing the temperature from 250 to 550°C, the biochar yield of conocarpus decreased by 63.14%. The highest specific surface area was observed for sugarcane bagasse at 550°C, which was 9.8 times higher than that of conocarpus at 250°C. Overall, due to its higher lignin content, conocarpus showed a greater tendency to form a stable solid phase, whereas bagasse, with its higher volatile matter content, produced a more dominant bio-oil fraction. The results emphasize the key role of temperature and biomass type in determining the quality and physicochemical properties of bio-oil and biochar.

Keywords

Main Subjects

Introduction

Pyrolysis is an effective thermochemical method for converting biomass into value-added products such as biochar and bio-oil. The yield and physicochemical characteristics of these products are strongly influenced by pyrolysis temperature and biomass type. Therefore, understanding the temperature effect is essential for improving product quality and optimizing pyrolysis performance. Despite numerous studies on the pyrolysis of various wastes, most research has focused on common biomass such as wood or certain agricultural wastes. Limited research has simultaneously investigated both biochar and bio-oil obtained from the pyrolysis of Conocarpus and sugarcane bagasse. Furthermore, comprehensive characterization—including ash content, volatile matter, fixed carbon, elemental analysis, electrical conductivity (EC), pH, cation and anion exchange capacity (CEC/AEC), specific surface area (BET), FE-SEM, and FTIR for biochar, as well as viscosity, density, CH/O elemental analysis, pH, and water content for bio-oil at different temperatures—has not yet been adequately reported. Therefore, this study aims to investigate the effect of three temperatures (250, 400, and 550 °C) on the performance and properties of biochar and bio-oil derived from Conocarpus and sugarcane bagasse. This evaluation can help to better understand the thermal behavior of these biomasses and develop their industrial applications.

Materials and Methods

In this study, two biomass feedstocks—Conocarpus (CW) and sugarcane bagasse (SB)—were pyrolyzed at 250, 400, and 550 °C. The produced biochars were characterized for specific surface area, morphology (FE-SEM), and surface functional groups (FTIR). In addition, biochar yield, ash content, volatile matter, and fixed carbon were measured. Elemental composition, pH, electrical conductivity (EC), and cation and anion exchange capacities (CEC/AEC) were also determined. For bio-oil, yield, water content, viscosity, density, and pH were evaluated. The experiment was conducted as a factorial experiment in a completely randomized design with two factors: 1) biomass type at two levels (CW and SB) and 2) pyrolysis temperature at three levels (250, 400, and 550 °C), with three replications. Treatments were designated as SB250, SB400, SB550, CW250, CW400, and CW550. Data were statistically analyzed using SPSS 26, and means were compared using Duncan's test at a 5% probability level. Graphs were prepared in Excel.

Results

FTIR results showed a decrease in oxygen-containing functional groups in biochars produced at higher temperatures. FE-SEM observations confirmed clear morphological changes at high temperatures. Increasing pyrolysis temperature significantly reduced volatile matter, biochar yield, and CEC, while fixed carbon, pH, and specific surface area increased significantly. The highest ash percentage was observed in CW550 (Conocarpus biochar at 550 °C), which was three times higher than that of CW250. The highest volatile matter content was found in SB250 and the lowest in SB550, with a 3.54-fold difference. Fixed carbon content in sugarcane bagasse showed a 3.64-fold increase when the temperature increased from 250 to 400 °C. The highest EC value was recorded for CW250 and the lowest for SB550, with the latter being 2.97 times lower, indicating a statistically significant difference between these two biomass types. The highest CEC was observed in CW250, which decreased by a factor of 1.45 compared to the lowest value (CW550), attributed to the removal of reactive oxygen-containing groups at higher temperatures. At 550 °C, Conocarpus biochar exhibited lower CEC than bagasse biochar, which may be related to differences in mineral composition and primary structure. The highest AEC was recorded for SB550, and the lowest for CW250, representing a 3.87-fold difference. The highest specific surface area was observed for SB550, which was 9.8 times higher than that of CW250. This increase at higher pyrolysis temperatures is attributed to the development of a porous structure and the formation of new pores. Elemental analysis confirmed an increase in carbon and oxygen contents and a decrease in hydrogen content and the atomic O/C ratio in both biochar and bio-oil as temperature increased. Bio-oil yield, water content, and viscosity significantly decreased for both feedstocks. Overall, Conocarpus—due to its higher lignin content—showed a greater tendency to form a stable solid phase (biochar), whereas sugarcane bagasse, due to its higher volatile matter content, produced a more dominant bio-oil fraction.

Conclusion

This study investigated the effect of pyrolysis temperature on the performance and properties of biochar and bio-oil produced from two lignocellulosic biomasses: Conocarpus and sugarcane bagasse. Surface property analysis showed that increasing temperature increased specific surface area and developed a porous structure. BET results and FE-SEM images indicated the formation of more pores and a more regular surface structure at higher temperatures. Changes in pH and EC showed that biochars produced at higher temperatures were more alkaline and exhibited greater potential for environmental applications and soil remediation. CEC/AEC values indicated improved ion exchange capacity under certain temperature conditions, which plays an important role in agricultural applications and pollutant treatment. Regarding bio-oil, the results showed that pyrolysis temperature directly affected its yield, water content, viscosity, density, and elemental composition. Bio-oils produced at higher temperatures exhibited distinct changes in viscosity, density, and C, H, and O contents, which can influence fuel quality and upgrading potential. The low pH values of bio-oils indicate their acidic nature, necessitating upgrading for fuel applications. Overall, both Conocarpus and sugarcane bagasse demonstrated good potential for biochar and bio-oil production via pyrolysis; however, biomass type and process temperature play decisive roles in final product quality. The appropriate temperature can be optimized according to the target application (biochar vs. bio-oil). The findings indicate that both pyrolysis temperature and biomass type are key factors determining biochar quality and bio-oil physicochemical properties. Higher temperatures improved biochar stability and surface characteristics while reducing bio-oil yield and related properties. Therefore, selecting an appropriate pyrolysis temperature should be based on the intended product and the characteristics of the biomass feedstock.

Funding

This study was funded by Shahid Chamran University of Ahvaz, Iran (Grant Number SCU.AS1403.449)

This work is based upon research funded by Iran National Science Foundation (INSF) under project No. 4029610.Authorship contribution

  1. Hazbiyan: Gathering the experimental data, Data curation, Methodology, Investigation, Conceptualization, Writing-Original draft preparation, Analyzing the experimental data.
  2. Moezzi: Supervision, Conceptualization, Methodology, Analyzing the experimental data, Validation, Writing-Reviewing and Editing.
  3. Moradi: Supervision, Conceptualization, Methodology, Analyzing the experimental data, Validation, Writing-Reviewing and Editing.
  4. Alemzadeh Ansari: Methodology, Analyzing the experimental data.

All authors have read and agreed to the published version of the manuscript.

Data availability statement

Data available on request from the authors.

Acknowledgements

The authors would like to thank the Research council of Shahid Chamran University of Ahvaz, Ahvaz, Iran for the financial support of this research (grant number: SCU.AS1403.449).

The authors gratefully acknowledge the Research Council of Shahid Chamran University of Ahvaz, Ahvaz, Iran (Grant Number SCU.AS1403.449) and the Iran National Science Foundation (INSF) (Project No. 4029610) for their financial support in conducting this research.

Ethical considerations

The authors avoided data fabrication, falsification, and plagiarism, and any form of misconduct.

Conflict of interest

The authors declare no conflict of interest.

References

Ahmad, M., Rajapaksha, A. U., Lim, J. E., Zhang, M., Bolan, N., Mohan, D., Vithanage, M., Lee, S. S., and Ok, Y. S. (2014). Biochar as a sorbent for contaminant management in soil and water: A review. Chemosphere, 99, 19–33.
Al-Wabel, M. I., Al-Omran, A., El-Naggar, A. H., Nadeem, M., and Usman, A. R. A. (2013). Pyrolysis temperature induced changes in characteristics and chemical composition of biochar produced from conocarpus wastes. Bioresource Technology, 131, 374-379.
Antal, M. J., and Gronli, M. (2003). The art, science, and technology of charcoal production. Industrial and Engineering Chemistry Research, 42(8), 1619–1640.
Bridgwater, A. V. (2012). Review of fast pyrolysis of biomass and product upgrading. Biomass and Bioenergy, 38, 68–94.
Brewer, C. E., Unger, R., Schmidt-Rohr, K., and Brown, R. C. (2011). Criteria to select biochars for field studies based on biochar chemical properties. BioEnergy Research, 4(4), 312–323.
Cai, N., Zhang, H., Nie, J., Deng, Y., and Baeyens, J. (2020). Biochar from Biomass Slow Pyrolysis. IOP Conference Series: Earth and Environmental Science, 586(1), 012001.
Chen, B., Zhou, D., and Zhu, L. (2008). Transitional adsorption and partition of nonpolar and polar aromatic contaminants by biochars of pine needles with different pyrolytic temperatures. Environmental Science and Technology, 42(14), 5137–5143.
Chen, Y. Z., Tan, Y., Su, L. Z., Zou, W. Q., Wu, B. H., Gao, W. B., Hu, Z., Li, A. X., Zhou, Z., and Zhou, N. (2023). Oxygen-limited pyrolysis and incineration impact on biochar transport. Environmental Science and Pollution Research, 30(48), 105247–105258.
Cheng, C. H., et al. (2006). Oxidation of black carbon by biotic and abiotic processes. Organic Geochemistry, 37, 1477–1488.
Cheng, C. H., Lehmann, J., Thies, J. E., and Burton, S. D. (2008). Stability of black carbon. Soil Science Society of America Journal, 72, 106–115.
Czernik, S., and Bridgwater, A. V. (2004). Overview of biomass fast pyrolysis. Fuel Processing Technology, 83(1–3), 1–17.
Czernik, S., and Oasmaa, A. (1999). Fuel oil quality of biomass pyrolysis oils—state of the art for the end users. Energy and Fuels, 13(4), 914–921.
Das, P. (2025). A review on the catalytic upgradation of vegetable/pyrolysis bio-oil from renewable sources: Kinetic studies and environmental impact assessment. Catalysis Science and Technology, 15, 1406–1433.
De Jesus Paula, R., de Almeida Pereira, V., Latorre, F. L., Oliveira de Souza Nogueira, C., de Almeida, I. A., Freitas e Silva, P. A., Ferreira, O. E., de Lima, R. P., da Silva Bezerra, A. C., and Machado, A. R. T. (2025). Pyrolysis converts urban pruning waste into biochar with soil and climate benefits. Scientific Reports, 15, Article 23340.
Demirbas, A. (2005). Potential applications of renewable energy sources, biomass combustion problems in boiler power systems and combustion related environmental issues. Progress in Energy and Combustion Science, 31, 171–192.
Domingues, R. R., Trugilho, P. F., Silva, C. A., Melo, ICNAd., Melo, LCA., and Magriotis, Z.M. (2017). Properties of biochar derived from wood and high-nutrient biomasses with the aim of agronomic and environmental benefits. PLoS ONE, 12(5), 0176884.
Downie, A., Munroe, P., and Farrell, C. (2009). Production and characterization of biochar for application in soil and environmental management: A review. Australian Journal of Soil Research, 47(6–7), 711–726.
Elshareef, H., Tursunov, O., Ren, S., Spiewak, K., Mohamed, A. R., Fu, Y., Dong, R., and Zhou, Y. (2025). Investigation of bio-oil and biochar derived from cotton stalk pyrolysis: Effect of different reaction conditions. Resources, 14(5), 75.
Enders, A., Hanley, K., Whitman, T., Joseph, S., and Lehmann, J. (2012). Characterization of biochars to evaluate recalcitrance and agronomic performance. Bioresource Technology, 114, 644–653.
Frikha, K., Limousy, L., Bouaziz, J., Bennici, S., Chaari, K., and Jeguirim, M. (2019). Elaboration of alumina-based materials by solution combustion synthesis: A review. Comptes Rendus. Chimie, 22(2–3), 206–219.
Gaskin, J. W., Steiner, C., Harris, K., Das, K. C., and Bibens, B. (2008). Effect of low-temperature pyrolysis conditions on biochar for agricultural use. Transactions of the ASABE, 51 (6), 2061–2069.
Hassan, N. S., Jalil, A. A., Hitam, C. N. C., Vo, D. V. N., and Nabgan, W. (2020). Biofuels and renewable chemicals production by catalytic pyrolysis of cellulose: a review. Environmental Chemistry Letters, 18, 1625–1648.
Iaccarino, A., Gautam, R., and Sarathy, S. M. (2021). Bio-oil and biochar production from halophyte biomass: Effects of pre-treatment and temperature on Salicornia bigelovii pyrolysis. Sustainable Energy and Fuels, 5(8), 2234–2248.
Jahangiri, A., Zilouei, H., and Karimi, K. (2022). Biochar and bioenergy production by pyrolysis of Conocarpus and Eucalyptus wastes: a case study, Khuzestan province, Iran. International Journal of Environmental Science and Technology, 19, 5839-5848.
Keiluweit, M., Nico, P. S., Johnson, M. G., and Kleber, M. (2010). Dynamic molecular structure of plant biomass-derived black carbon. Environmental Science and Technology, 44(4), 1247–1253.
Khajavi-Shojaei, S., Moezzi, A., Norouzi Masir, M., and Taghavi, M. (2020). Characteristics of conocarpus wastes and common reed biochars as a predictor of potential environmental and agronomic applications. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 1-18.
Kim, H., Choi, J., and Lee, J. (2025). Improving bio-oil quality from durian husk pyrolysis: optimization of esterification process using K2CO3/talc catalyst for sustainable biofuel production. Biomass Conversion and Biorefinery, 15, 23155–23168.
Lehmann, J., and Joseph, S. (2015). Biochar for environmental management: Science, technology and implementation (2nd ed.). Routledge.
Li, X. H., Li, K. Q., Geng, C. L., El Mashad, H., Li, H., and Yin, W. Q. (2019). Biochar from Microwave Pyrolysis of Artemisia Slengensis: Characterization and Methylene Blue Adsorption Capacity. Applied Sciences, 9(9), 1813.
Lin, C. Y., and Ma, L. (2022). Effects of Water Removal from Palm Oil Reactant by Electrolysis on the Fuel Properties of Biodiesel. Processes, 10(1), 115.
Lowell, S., Shields, J. E., Thomas, M. A., and Thommes, M. (2004). Characterization of Porous Solids and Powders: Surface Area, Pore Size and Density. Springer.
Lua, A. C., and Yang, T. (2004). Effects of pyrolysis conditions on properties of activated carbons prepared from pistachio-nut shells. Journal of Colloid and Interface Science, 274(2), 594–601.
Mabrouki, J., Guedri, K., Abbassi, M. A., Omri, A., and Jeguirim, M. (2016). International Renewable Energy Congress 2015: Focus on biomass energy, environment and sustainable development. Comptes Rendus. Chimie, 19, 466–474.
Mohan, D., Pittman C. U., and Steele, P. H. (2006). Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review. Energy and Fuels, 20(3), 848-889
Mohan, D., Abhisheka, K., Sarswata, A., Patel, M., Singha, P. and Pittman, Ch. (2018). Biochar production and applications in soil fertility and carbon sequestration – a sustainable solution to crop-residue burning in India. RSC Advances, 8, 508-520.
Mukherjee, A., Zimmerman, A. R., and Harris, W. G. (2011). Surface chemistry variations among a series of laboratory-produced biochars. Soil Science Society of America Journal, 75(1), 132-140
Mukherjee, A., and Lal, R. (2014). Biochar impacts on soil properties and greenhouse gas emissions. Soil Science Society of America Journal, 78(1), 1–15.
Novak, J. M., Warren J B, David, L., Mohamed, A., Don W, W., and Mohamed A, N. (2009). Impact of Biochar Amendment on Fertility of a Southeastern Coastal Plain Soil. Soil Science 174(2), 105-112
Oasmaa, A., and Czernik, S. (1999). Fuel oil quality of biomass pyrolysis oils. Energy and Fuels, 13(4), 914–921.
Oasmaa, A and Peacocke, C (2001). A guide to physical property characterisation of biomass- derived fast pyrolysis liquids. Espoo. Technical Research Centre of Finland, VTT Publica- tions 450, 65-34.
Oasmaa, A., and Peacocke, C. (2001). A guide to physical property characterisation of biomass-derived fast pyrolysis liquids (VTT Publications No. 450). VTT Technical Research Centre of Finland.
Oasmaa, A., and Meier, D. (2005). Norms and standards for fast pyrolysis liquids: 1. Round robin test. Journal of Analytical and Applied Pyrolysis, 73(2), 323–334.
Oasmaa, A., Sundqvist, T. Kuoppala, E. Garcia-Perez, M. Solantausta, Y. Lindfors, Ch., and Paasikallio, V. (2015). Controlling the Phase Stability of Biomass Fast Pyrolysis Bio-oils. Energy and Fuels, 29(7), 4373–4381.
Park, J., Lee, Y., and Kim, S. (2021). Hydrothermal Treatment of Empty Fruit Bunches to Enhance Fuel Characteristics. Energies, 14(5), 1467.
Putun, A. E., Uzun, B. B., Apaydin, E., and Putun, E. (2005). Bio-oil from olive oil industry wastes: Pyrolysis of olive residue under different conditions. Fuel processing technology, 87(1), 25-32.
Sharma, P., Singh p, S., Parakh, Sh., and Tong W, Y. (2022). Health hazards of hexavalent chromium (Cr (VI)) and its microbial reduction. Bioengineered, 13(3), 4923–4938.
Singh, B., Macdonald B, L., Kookana B, R., Zwieten C, L., Butler D, G., Joseph E,F, S., WeatherleyG, A., KaudalG B., ReganH, A., CattleI, J., DijkstraA, F., BoersmaJ, M., Kimber C, S., Keith A, A., and Esfandbod, M. (2010). Characterisation and evaluation of biochars for their application as a soil amendment. Soil Research, 48, 516–525.
Singh, B. P., Cowie, A. L., and Smernik, R. J. (2012). Biochar Carbon Stability in a Clayey Soil As a Function of Feedstock and Pyrolysis Temperature. Environmental Science & Technology, 46 (21), 11770–11778.
Singh, B., Camps-Arbestain, M., and Lehmann, J. (2017). Biochar: A guide to analytical methods. CRC Press.
Spokas, K. A. (2010). Review of the stability of biochar in soils: predictability of O:C molar ratios. Carbon Management, 1(2), 289–303.
Standardization Administration of China. (1988). Petroleum products—Determination of water soluble acids and alkalis (GB/T 259-1988). China Standards Press.
potentialSpokas, K. A. (2010). Review of the stability of biochar in soils: Predictability of O:C molar ratios. Carbon Management, 1(2), 289–303.
Tomczyk, A., Sokołowska, Z., & Boguta, P. (2020). Biochar physicochemical properties: Pyrolysis temperature and feedstock kind effects. Reviews in Environmental Science and Bio/Technology, 19, 191–215.
Wakatuntu, J., Olupot, P. W., Jjagwe, J., Menya, E., and Okure, M. (2024). Optimal Bio-Oil Production Using Triplochiton scleroxylon Sawdust Through Microwave-Assisted Pyrolysis. BioEnergy Research, 17, 2362–2373.
Williams, P. T. (2013). Pyrolysis of waste tyres: A review. Waste Management, 33(8), 1714–1728.
Yuan, J. H., Xu, R. K., and Zhang, H. (2011). The forms of alkalis in the biochar produced from crop residues at different temperatures. Bioresource Technology, 102(3), 3488–3497.
Zhou, S., Wang, Z., and Li, Y. (2022). Investigation of the combination of fractional condensation and water extraction for improving the storage stability of pyrolysis bio-oil. Fuel, 314, 123019.
Zhang, X., Gao, B., Zheng, Y., Hu, X., Creamer, A. E., Annable, M. D., and Li, Y. (2017). Biochar for volatile organic compound (VOC) removal: Sorption performance and governing mechanisms. Bioresource Technology, 245, 606–614.
Iranian Journal of Soil and Water Research
Volume 57, Issue 5
July 2026
Pages 1075-1098

Files

Share

How to cite

Statistics