Synthesis and Characterization of Activated Carbon from Coconut Pulp via Physicochemical Activation and Its Potential for Biogas Purification
DOI:
https://doi.org/10.22437/chp.v10i1.48610Keywords:
Activated carbon, biogas, coconut pulp, CO2 and H2S adsorption, physicochemical activationAbstract
The increasing global demand for renewable energy and the urgent need to reduce greenhouse gas emissions highlight the importance of developing sustainable technologies for biogas upgrading. Coconut pulp, a plentiful agro-industrial residue rich in cellulose, hemicellulose, and lignin, offers a promising precursor for activated carbon production while addressing agricultural waste challenges. This study aimed to synthesize and characterize coconut pulp–based activated carbon through a combined physicochemical activation process and to evaluate its theoretical potential for CO₂ and H₂S adsorption in biogas purification. The preparation involved carbonization at 400 °C, sequential chemical activation using 3 N H₃PO₄ and 3 N KOH, followed by physical activation at 600 °C under semi-closed conditions. Proximate analysis revealed a moisture content of 4.665%, ash content of 0.637%, and a final yield of 12.38%, all within the Indonesian National Standard (SNI 06-3730-1995) limits except for volatile matter, which remained high due to the soft lignocellulosic nature of coconut pulp. BET surface analysis demonstrated a specific surface area of 345.57 m² g⁻¹, total pore volume of 0.1595 cc g⁻¹, and a dominant micropore area of 282.80 m² g⁻¹, indicating strong potential for small-molecule adsorption. The iodine number of 161.973 mg g⁻¹ confirmed micropore prevalence. FTIR spectra showed a marked decrease in –OH and C=O groups and the emergence of a new band near 900 cm⁻¹ (=C–H aromatic), evidencing the formation of stable aromatic domains. SEM–EDX images revealed a hierarchical pore network (macro–meso–micro) with uniform distribution and high carbon purity (96.65%) and minimal mineral residues. These structural and chemical features suggest enhanced interaction with acidic (H₂S) and non-polar (CO₂) gases through physisorption mechanisms. Compared with single-stage activation methods, the dual chemical–physical strategy provided superior surface area, pore connectivity, and carbon purity, representing a novel approach for biomass-derived adsorbents. Overall, coconut pulp–derived activated carbon synthesized via integrated physicochemical activation exhibits favorable physicochemical properties for efficient CO₂ and H₂S removal, supporting its application as a sustainable and low-cost adsorbent for biogas upgrading. Future work should include dynamic adsorption studies under real biogas conditions to validate the theoretical predictions and to optimize activation parameters for large-scale deployment.
References
[1] Asadollahzadeh, P., Hamedi, M. H., and Jazayeri, S. A., “Investigation of Biogas Composition Effects on Combustion Characteristics of an RCCI Engine. Gas Processing Journal. 2020. 8(2): 61-67. http://10.22108/gpj.2020.123076.1086
[2] Santos-Clotas, E.,Cabrera-Codony, A., Ruiz, E., Fuente, B., and Martín, M. J., “Sewage Biogas Efficient Purification by Means of Lignocellulosic Waste-Based Activated Carbons. Bioresource Technology. 2019. 275: 207–215, https://doi.org/10.1016/j.biortech.2018.12.060
[3] Sawalha, H., Maghalseh, M., Qutaina, J., Junaidi, K., and Rene, E. R., “Removal of Hydrogen Sulfide from Biogas Using Activated Carbon Synthes- ized from Different Locally Available Biomass wastes - a case study from Palestine,” Bioengineered. 2020. 11(1):607–618. https://doi.org/10.1080/21655979.2020.1768736
[4] Badan Pusat Statistik Provinsi Sulawesi Barat. Luas Tanaman Perkebunan Menurut Provinsi - Tabel Statistik Badan Pusat Statistik Indonesia. .2023. [Online]. Available: https://www.bps.go.id/id/statisticstable/2/MTMxIzI=/luastanamanperkebunanmenurut- provinsi.html. (Accessed: Jul. 16, 2023).
[5] Murtius, W. S., Argo, B. D., Nurika, I., and Sukardi, S., “Identification of Availability and Lignocellulosic Properties in Coconut Dregs Waste. Journal of Applied Agricultural Science and Technology. 2024. 8(1): 92–105, https://doi.org/10.55043/jaast.v8i1.248
[6] Basha, N. A., Rathinavel, T., and Sridharan, H., “Activated Carbon from Coconut Shell: Synthesis and Its Commercial Applications - A Recent Review. Applied Science and Engineering Progress. 2023. 16(2): 1–19. https://doi.org/10.14416/j.asep.2022.07.001
[7] Prawiranti, Y., Mandasari, W., Shofiyah, S. S., Febrianty, I. R., and Utami, N. T., “Pembuatan Karbon Aktif Ampas Kelapa dengan Aktivator Asam Fosfat (H3PO4) untuk Mengadsorpsi Ion Logam Besi (Fe),” Akta Kimia Indonesia.2024. 9(2):133. https://doi.org/10.12962/j25493736.v9i2.22084
[8] Saadi, W., Ruiz, B., Najar-Souissi, S., Ouederni, A., and Fuente, E., “High- Pressure Gas Adsorption on Activated Carbons from Pomegranate Peels Biochar: A Promising Approach for Biogas Purification,” Biomass and Bioenergy. 2024. 186(107258):1–10. https://doi.org/10.1016/j.biombioe.2024.107258
[9] Pinchaipat, R., Koedthong, P., Boonpian, P., Vitidsant, T., and Owkusumsirisakul, J., “Chemical and electrical properties of activated carbon from Samui Island young coconut waste,” Journal of Physics: Conference Series. 2023. 2653(1), https://doi.org/10.1088/1742-6596/2653/1/012069
[10] Masthura, Jumiati, E., and Daulay, A. H., “Effects of Activation Temperature on Characteristics and Microstructure of Coconut Shell-Based Activated Carbon,” Eurasian Journal of Analytical Chemistry. 2018. 13(4): 384–390.
[11] Mian, I., Rehman, N., Li, X., Ullah, H., Khan, A., Choi, C., and Han, C., “Effect of Heating Rate on the Pyrolysis Behavior and Kinetics of Coconut Residue and Activated Carbon: A Comparative Study,” Energies. 2024. 17(18):1–11, https://doi.org/10.3390/en17184605
[12] Madojemu, G. O., Eze, C. B., and Okieimen, F. E., “Optimization of Surface Area of Activated Carbons Prepared From Coconut Shells By Response Surface Methodology, Journal of Chemical Society of Nigeria. 2020. 45(2):354–364, 2020
[13] Purba, E., and Safitri, F., “Characteristics of Banana Stem Adsorbent (Musa Paradisiaca) For Biogas Purification With Variation of Adsorption Contact Time,” Jurnal Bahan Alam Terbarukan. 2023. 12(1):25–31. https://doi.org/10.15294/jbat.v12i1.39600
[14] Budihardjo, M. A., Syafrudin, Samadikun, B. P., Wardhana, I. W., Ramadan, B. S., and Humaira, N. G., “Purification of Biogas from Tofu Waste Using Zeolite and Activated Carbon (AC) as Adsorbent,” Global Nest Journal. 2021. 23(4): 491–496, https://doi.org/10.30955/gnj.003906
[15] Chen, H., Liu, L. C., Dong, S., Zhang, Y., and He, P., “Development of a New Type of Phosphoric Acid Based Geopolymer/Activated Carbon Composite for Selective CO2 Capture,” Materials Letters. 2022. 325: 132869. https://doi.org/10.1016/j.matlet.2022.132869.
[16] Susanti, D., Nurdiansah, H., Pramata, A. D., Rohmanuddin, T. N., Fajarin, R., Rakhmawati, Y. W., Kusuma, G. E., and Bahfie, F., “Utilization of Biomass Wastes: Coconut and Pangium edule Shells as Activated Carbon for Energy Storage Device Material. E3S Web of Conferences, 2023. 467(04001):1–6. https://doi.org/10.1051/e3sconf/202346704001
[17] Racero-Galaraga, D., Rhenals-Julio, J. D., Sofan-German, S., Mendoza, J. M., and Bula-Silvera, A., “Proximate Analysis in Biomass: Standards, Applications and Key Characteristics,” Results in Chemistry. 2024. 12:101886,https://doi.org/10.1016/j.rechem.2024.101886
[18] Mohammaad, A. H., and Kijevčanin, M., “Synthesis of Activated Carbons from Water Hyacinth Biomass and Its Application as Adsorbents in Water Pollution Control,” Journal of the Serbian Chemical Society. 2022.88(1): 69–82. https://doi.org/10.2298/JSC212121006M
[19] Yahya, M. A., Ngah, C. W. Z. C. W., Hashim, M. A., and Al-Qodah, Z., “Preparation of Activated Carbon from Desiccated Coconut Residue by Chemical Activation with NaOH. Journal of Materials Science Research. 2015. 5(1): 24, http://dx.doi.org/10.5539/jmsr.v5n1p24
[20] da Silva, J. C. G., Alves, J. L. F., Galdino, W. V. de A., de Sena, R. F., and Andersen, S. L. F., “Pyrolysis Kinetics and Physicochemical Characteristics of Skin, Husk, and Shell from Green Coconut Wastes,” Energy, Ecology and Environment. 2019. 4(3): 125–132, https://doi.org/10.1007/s40974-019-00120-x
[21] Pawar, A., Panwar, N. L., Jain, S., Jain, N. K., and Gupta, T., “Thermal Degradation of Coconut Husk Waste Biomass under Non-isothermal Condition,” Biomass Conversion and Biorefinery. 2023. 13: 7613–7622, https://doi.org/10.1007/s13399-021-01657-w
[22] Fatmawati, A., Nurtono, T., and Widjaja, A., “Thermogravimetric kinetic-based computation of raw and pretreated coconut husk powder lignocellulosic composition. Bioresource Technology Reports. 2023. 22: 101500, https://doi.org/10.1016/j.biteb.2023.101500
[23] Anuwar, N. A., and Khamaruddin, P. F. M., “Optimization of Chemical Activation Conditions for Activated Carbon From Coconut Shell Using Response Surface Methodology (RSM) and Its Ability to Adsorb CO2. Proceedings of the Third International Conference on Separation Technology 2020 (ICoST 2020). 2020. 234–248, https://doi.org/10.2991/aer.k.201229.032
[24] Ismail, B. P., “Ash Content Determination,” in Food Analysis Laboratory Manual, Food Science Text Series. 2017:17–119. https://doi.org/10.1007/978-3-319-44127-6_11
[25] Kim, S., Lee, S. E., Baek, S. H., Choi, U., and Bae, H. J., “Preparation of Activated Carbon from Korean Anthracite: Simultaneous Control of Ash Reduction and Pore Development,” Processes, 2023. 11:1–14. https://doi.org/10.3390/pr11102877
[26] Kong, Z., Zhang, H., Zhou, T., Xie, L., Wang, B., and Jiang, X., “Preparation, Functionalization, and Applications in Adsorption and Catalytic Separation of Carbon Dioxide and Other Atmospheric Pollutants,” Separation and Purification Technology. 2025. 354, 129099. https://doi.org/10.1016/j.seppur.2024.129099
[27] Zhang, L., Tu, L.-y., Liang, Y., Chen, Q., Li, Z.-s., Li, C.-h., Wang, Z.-h., and Li, W., “Coconut-based activated carbon fibers for efficient adsorption of various organic dyes,” RSC Advances. 2018. 8(74): 42280–42291, https://doi.org/10.1039/C8RA08990F
[28] Bakti, A. I., Gareso, P. L., and Rauf, N. Characterization of Active Carbon from Coconut Shell using X-Ray Diffraction (X-RD) and SEM-EDX Techniques. Jurnal Penelitian Fisika dan Aplikasinya. 2018. 8(2):115. https://doi.org/10.26740/jpfa.v8n2.p115-122
[29] Anggita, S. R., Prahesti, A. Y. P., Azizah, T. S., and Arsini, “Morphological, Crystallinity, and Functional Group Analysis of Coconut Shell-Based Activated Carbon with Carbonization Temperature Variations for Supercapacitor Electrode Potential,” Journal of Physics and Its Applications. 2025. 7(3):59–64, https://doi.org/10.14710/jpa.v7i3.25118
[30] Sujiono, E. H., Zabrian, D., Zurnansyah, Mulyati, Zharvan, V., Samnur, and Humairah,N.A.. Fabrication and Characterization of Coconut Shell Activated Carbon using Variation Chemical Activation for Wastewater Treatment Application,” Results in Chemistry. 2022. 4. 100291, https://doi.org/10.1016/j.rechem.2022.100291
[31] Suprianti, Y., Pangestu, Y. R., and Iriani, P., “Pengaruh Variasi Bentuk Adsorben Karbon Aktif dan Scale-up Kolom Terhadap Kinerja Adsorpsi CO2 Dalam Biogas. Jurnal Energi dan Manufaktur. 2023. 15(1): 26-31, https://doi.org/10.24843/JEM.2022.v015.i01.p04
[32] Pratiwi, V. D., Kamal, N., and Juhanda, S., “Analisis Pengaruh Waktu Aktivasi dan Adsorpsi dalam Pemanfaatan Karbon Aktif dari Serutan Kayu menjadi Adsorben Limbah Cair. Jurnal Rekayasa Hijau. 2019. 3(1):71–78, https://doi.org/10.26760/jrh.v3i1.2822
[33] Zulkefli, N. N., Masdar, M. S., Wan Isahak, W. N. R., Jahim, J. M., Md Rejab, S. A., and Lye, C. C., “Removal of Hydrogen Sulfide From a Biogas Mimic By Using Impregnated Activated Carbon Adsorbent,” PLOS One. 2019. 14(2): 1–25, https://doi.org/10.1371/journal.pone.0211713
[34] Tuerhong, T., and Kuerban, Z., “Preparation and characterization of cattle manure-based activated carbon for hydrogen sulfide removal at room temperature. Journal of Environmental Chemical Engineering. 2022. 10(2): 107177, https://doi.org/10.1016/j.jece.2022.107177
[35] Suprianti, Y., “Pemurnian Biogas untuk meningkatkan Nilai Kalor melalui Adsorpsi Dua Tahap Susunan Seri dengan Media Karbon Aktif,” ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika. 2016. 4(2): 185–196. https://doi.org/10.26760/elkomika.v4i2.185
