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Sustainable Valorization of Phragmites australis and Cyperus papyrus Phytoremediation Biomass into Biochar for Methylene Blue Removal

Keneilwe Motlakatlala, Stephen Majoni, Venecio U. Ultra, Phillip Oladijo

Abstract


Mining activities at the copper nickel Bamangwato Concessions Limited (BCL) mine have contributed to the accumulation of heavy metals in areas surrounding the mining town. Although phytoremediation plants naturally help remediate contaminated soils, they generate large amounts of biomass that require sustainable management. This study explored the use of biochar obtained from phytoremediation biomass of Cyperus papyrus (CP) and Phragmites australis (PA) collected from the BCL mine site for the adsorption of Methylene Blue from aqueous solutions as a sustainable strategy for managing phytoremediation waste. The effects of several parameters, including contact time, adsorbent dosage, temperature, and initial dye concentration, on the adsorption process were investigated. The results showed that adsorption efficiency for both biochars had a positive correlation with contact time, higher initial dye concentration, increased adsorbent dosage, and solution pH. To better understand the adsorption mechanism, kinetic and thermodynamic analyses were conducted. The adsorption behavior was best described by the Langmuir isotherm model and the Elovich kinetic model. The maximum adsorption capacities were determined to be 128.21 mg/g for CP biochar and 79.35 mg/g for PA biochar. The results demonstrate that biochar produced from phytoremediation biomass of CP and PA can effectively remove organic contaminants such as methylene blue dye from water. This approach offers a sustainable method for managing phytoremediation biomass while simultaneously contributing to water purification.

Keywords



[1] B. K. Asare and M. B. K. Darkoh, “Socio-economic and environmental impacts of mining in Botswana: A case study of the Selebi-Phikwe copper-nickel mine,” Eastern Africa Social Science Research Review, vol. 17, no. 2, pp. 1–41, Jun. 2001.

[2] M. Letshwenyo, “Sulphur and heavy metals contents in soils and Grewia bicolor leaves around the Selibe Pikwe Cu-Ni mine (BCL), Botswana,” Journal of Environmental Chemistry and Ecotoxicology, vol. 8, no. 8, pp. 73–81, Aug. 2016, doi: 10.5897/jece2013.0306.

[3] M. Rosas-Ramírez et al., “Phytoremediation potential of heavy metals using biochar and accumulator plants: A sustainable approach towards cleaner environments,” Plants, vol. 14, no. 22, art. no. 3470, Nov. 2025, doi: 10.3390/plants14223470.

[4] L. Wang, B. Ji, Y. Hu, R. Liu, and W. Sun, “A review on in situ phytoremediation of mine tailings,” Chemosphere, vol. 184, pp. 594–600, Oct. 2017, doi: 10.1016/j.chemosphere.2017.06.025.

[5] B. Nedjimi, “Phytoremediation: a sustainable environmental technology for heavy metals decontamination,” SN Applied Sciences, vol. 3, no. 3, art. no. 286, Feb. 2021, doi: 10.1007/s42452-021-04301-4.

[6] L. Saha, J. Tiwari, K. Bauddh, and Y. Ma, “Recent developments in microbe–plant-based bioremediation for tackling heavy metal-polluted soils,” Frontiers in Microbiology, vol. 12, art. no. 731723, Oct. 2021, doi: 10.3389/fmicb.2021.731723.

[7] T. Manyiwa et al., “Heavy metals in soil, plants, and associated risk on grazing ruminants in the vicinity of Cu–Ni mine in Selebi-Phikwe, Botswana,” Environmental Geochemistry and Health, vol. 44, no. 5, pp. 1633–1648, May 2022, doi: 10.1007/s10653-021-00918-x.

[8] P. R. Yaashikaa, P. S. Kumar, S. Varjani, and A. Saravanan, “A critical review on the biochar production techniques, characterization, stability and applications for circular bioeconomy,” Biotechnology Reports, vol. 28, art. no. e00570, Dec. 2020, doi: 10.1016/j.btre.2020.e00570.

[9] M. Ahmad et al., “Biochar as a sorbent for contaminant management in soil and water: A review,” Chemosphere, vol. 99, pp. 19–33, Mar. 2014, doi: 10.1016/j.chemosphere.2013.10.071.

[10] E. N. Bakatula, D. Richard, C. M. Neculita, and G. J. Zagury, “Determination of point of zero charge of natural organic materials,” Environmental Science and Pollution Research, vol. 25, no. 8, pp. 7823–7833, Mar. 2018, doi: 10.1007/s11356-017-1115-7.

[11] A. I. Abd-Elhamid et al., “Enhanced removal of cationic dye by eco-friendly activated biochar derived from rice straw,” Applied Water Science, vol. 10, no. 1, art. no. 43, Jan. 2020, doi: 10.1007/s13201-019-1128-0.

[12] Z. A. Zahara, I. Royani, N. R. Palapa, R. Mohadi, and A. Lesbani, “Treatment of methylene blue using Ni-Al/magnetite biochar layered double hydroxides composite by adsorption,” Bulletin of Chemical Reaction Engineering & Catalysis, vol. 18, no. 4, pp. 659–674, Dec. 2023, doi: 10.9767/bcrec.20049.

[13] L. Largitte and R. Pasquier, “A review of the kinetics adsorption models and their application to the adsorption of lead by an activated carbon,” Chemical Engineering Research and Design, vol. 109, pp. 495–504, May 2016, doi: 10.1016/j.cherd.2016.02.006.

[14] L. Sellaoui, S. Knani, A. Erto, M. A. Hachicha, and A. Ben Lamine, “Equilibrium isotherm simulation of tetrachlorethylene on activated carbon using the double layer model with two energies: Steric and energetic interpretations,” Fluid Phase Equilibria, vol. 408, pp. 259–264, Jan. 2016, doi: 10.1016/j.fluid.2015.09.022.

[15] N. F. Al-Harby, E. F. Albahly, and N. A. Mohamed, “Kinetics, isotherm and thermodynamic studies for efficient adsorption of congo red dye from aqueous solution onto novel cyanoguanidine-modified chitosan adsorbent,” Polymers, vol. 13, no. 24, art. no. 4446, Dec. 2021, doi: 10.3390/polym13244446.

[16] A. Y. Al Haj Ahmed, H. Al Najar, and N. A. Ghalwa, “Boron adsorption from aqueous solutions using chemically activated kaolin clay adsorbents kinetics isotherm and thermodynamic studies,” Scientific Reports, vol. 15, no. 1, art. no. 26758, Jan. 2025, doi: 10.1038/s41598-025-26758-8.

[17] K. Jedynak and B. Charmas, “Adsorption properties of biochars obtained by KOH activation,” Adsorption, vol. 30, no. 2, pp. 167–183, Feb. 2024, doi: 10.1007/s10450-023-00399-7.

[18] T. Wang, X. Quan, Z. Sun, and Z. Sun, “Sustainable biochar synthesis via synergistic H2O2-KOH modification for enhanced CO2 physisorption,” Carbon Capture Science and Technology, vol. 15, art. no. 100438, Jun. 2025, doi: 10.1016/j.ccst.2025.100438.

[19] W. H. Xie, X. Yao, H. Li, H. R. Li, and L. N. He, “Biomass-based N-rich porous carbon materials for CO2 capture and in-situ conversion,” ChemSusChem, vol. 15, no. 18, art. no. e202201004, Sep. 2022, doi: 10.1002/cssc.202201004.

[20] G. Murtaza et al., “Recent trends and economic significance of modified/functionalized biochars for remediation of environmental pollutants,” Scientific Reports, vol. 14, no. 1, art. no. 1231, Jan. 2024, doi: 10.1038/s41598-023-50623-1.

[21] K. Liepins et al., “Enhancing the wetting properties of activated biochar by oxidation with hydrogen peroxide,” Chemistry (Switzerland), vol. 6, no. 5, art. no. 53, Oct. 2024, doi: 10.3390/chemistry6050053.

[22] M. Gale, T. Nguyen, M. Moreno, and K. L. Gilliard-Abdulaziz, “Physiochemical properties of biochar and activated carbon from biomass residue: Influence of process conditions to adsorbent properties,” ACS Omega, vol. 6, no. 15, pp. 10224–10233, Apr. 2021, doi: 10.1021/acsomega.1c00530.

[23] S. K. Shahcheragh, M. M. Bagheri Mohagheghi, and A. Shirpay, “Effect of physical and chemical activation methods on the structure, optical absorbance, band gap and urbach energy of porous activated carbon,” SN Applied Sciences, vol. 5, no. 12, art. no. 317, Nov. 2023, doi: 10.1007/s42452-023-05559-6.

[24] T. Prakoso et al., “The Study of Hydrothermal Carbonization and Activation Factors' Effect on Mesoporous Activated Carbon Production From Sargassum sp. Using a Multilevel Factorial Design,” Reaktor, vol. 22, no. 2, pp. 59–69, Dec. 2022, doi: 10.14710/reaktor.22.2.59-69.

[25] N. A. M. Barakat, M. S. Mahmoud, and H. M. Moustafa, “Comparing specific capacitance in rice husk-derived activated carbon through phosphoric acid and potassium hydroxide activation order variations,” Scientific Reports, vol. 14, no. 1, art. no. 49675, Jan. 2024, doi: 10.1038/s41598-023-49675-0.

[26] A. M. Dehkhoda, E. Gyenge, and N. Ellis, “A novel method to tailor the porous structure of KOH-activated biochar and its application in capacitive deionization and energy storage,” Biomass and Bioenergy, vol. 87, pp. 107–121, Apr. 2016, doi: 10.1016/j.biombioe.2016.02.023.

[27] A. Gezahegn et al., “Pyrolysis temperature changes the physicochemical characteristics of water hyacinth-based biochar as a potential soil amendment,” Biomass Conversion and Biorefinery, vol. 15, no. 3, pp. 3737–3752, Feb. 2025, doi:10.1007/s13399-024-05338-2.

[28] H. Chaudhary, J. Dinakaran, T. Notup, K. Vikram, and K. S. Rao, “Comparison of adsorption performance of biochar derived from urban biowaste materials for removal of heavy metals,” Environmental Management, vol. 73, no. 2, pp. 408–424, Feb. 2024, doi: 10.1007/s00267-023-01866-1.

[29] M. Rehali, N. El Ghachtouli, S. F. Lange, and R. Bouamri, “Valorization of date palm residues for biochar production: Assessing biochar characteristics for agricultural application,” Scientific African, vol. 27, art. no. e02599, Mar. 2025, doi: 10.1016/j.sciaf.2025.e02599.

[30] B. D. Zdravkov, J. J. Čermák, M. Šefara, and J. Janků, “Pore classification in the characterization of porous materials: A perspective,” Central European Journal of Chemistry, vol. 5, no. 2, pp. 385–395, Jun. 2007, doi: 10.2478/s11532-007-0017-9.

[31] M. Thommes et al., “Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report),” Pure and Applied Chemistry, vol. 87, no. 9–10, pp. 1051–1069, Sep. 2015, doi: 10.1515/pac-2014-1117.

[32] T. I. Ojonimi, F. Asuke, M. A. Onimisi, and C. Y. Onuh, “Acid Mine Drainage (AMD): an environmental concern generated by coal mining,” Journal of Degraded and Mining Lands Management, vol. 6, no. 4, pp. 1875–1881, Jul. 2019, doi: 10.15243/jdmlm.2019.064.1875.

[33] S. A. Bhat et al., “Phytoremediation of heavy metals in soil and water: An eco-friendly, sustainable and multidisciplinary approach,” Chemosphere, vol. 303, pt. 2, art. no. 134788, Sep. 2022, doi: 10.1016/j.chemosphere.2022.134788.

[34] E. Hubert and C. Wolkersdorfer, “Establishing a conversion factor between electrical conductivity and total dissolved solids in South African mine waters,” Water SA, vol. 41, no. 4, pp. 490–500, Jul. 2015, doi: 10.4314/wsa.v41i4.08.

[35] V. M. Ngole-Jeme and J. Ndava, “The implications of AMD induced acidity, high metal concentrations and ochre precipitation on aquatic organisms,” Polish Journal of Environmental Studies, vol. 32, no. 4, pp. 2959–2980, Jul. 2023, doi: 10.15244/pjoes/161323.

[36] S. Chellappan, V. Nair, V. Sajith, and K. Aparna, “Synthesis, optimization and characterization of biochar based catalyst from sawdust for simultaneous esterification and transesterification,” Chinese Journal of Chemical Engineering, vol. 26, no. 12, pp. 2654–2663, Dec. 2018, doi: 10.1016/j.cjche.2018.02.034.

[37] R. Vurayai, B. Nkoane, B. Moseki, and P. Chaturvedi, “Assessment of heavy metal pollution/contamination in soils east and west of the Bamangwato Concessions Ltd (BCL) Cu/Ni mine smelter in Selebi-Phikwe, Botswana,” Journal of Biodiversity and Environmental Sciences, vol. 7, no. 6, pp. 111–120, Dec. 2015, [Online]. Available: http://www.innspub.net

[38] G. Ishmael, V. U. Ultra, G. Rantong, O. A. Keitshweditse, and K. L. Sefatlhi, “Heavy metal accumulation of aquatic grasses from mine tailing's wastewater drainage spillway of BCL Cu-Ni mine in Selebi Phikwe, Botswana,” Environmental Quality Management, vol. 34, no. 2, pp. 1–17, Dec. 2024, doi: 10.1002/tqem.22271.

[39] M. Saa-Aondo et al., “Efficiencies of heavy metal hyper-accumulation plants as potential land remediators for heavy metal polluted soils,” Asian Journal of Current Research, vol. 9, no. 1, pp. 60–70, Feb. 2024, doi: 10.56557/ajocr/2024/v9i18525.

[40] N. Arveti, K. S. Kumar, and P. J. C. Favas, “Phytoremediation potential of native plant species for heavy metal contamination in the abandoned Kolar gold fields, Karnataka, South India,” Discover Geoscience, vol. 3, art. no. 200, Feb. 2025, doi: 10.1007/s44288-025-00318-z.

[41] R. Huang, B. Zhang, E. M. Saad, E. D. Ingall, and Y. Tang, “Speciation evolution of zinc and copper during pyrolysis and hydrothermal carbonization treatments of sewage sludges,” Water Research, vol. 132, pp. 260–269, Apr. 2018, doi: 10.1016/j.watres.2018.01.009.

[42] E. M. C. C. Batista et al., “Effect of surface and porosity of biochar on water holding capacity aiming indirectly at preservation of the Amazon biome,” Scientific Reports, vol. 8, art. no. 10677, Jul. 2018, doi: 10.1038/s41598-018-28794-z.

[43] J. A. Ippolito, T. F. Ducey, K. A. Spokas, K. M. Trippe, and M. G. Johnson, “A biochar selection method for remediating heavy metal contaminated mine tailings,” International Journal of Environmental Science and Technology, vol. 21, no. 15, pp. 9611–9622, Dec. 2024, doi: 10.1007/s13762-024-05621-9.

[44] E. Sørmo et al., “Heavy metals in pyrolysis of contaminated wastes: Phase distribution and leaching behaviour,” Environments, vol. 11, no. 6, art. no. 130, Jun. 2024, doi: 10.3390/ environments11060130.

[45] J. Doble, G. Wilson, and J. W. Wainman, “Kinetic and thermodynamic analysis of the adsorption of methylene blue onto biochar,” Journal of Chemical Education, vol. 100, no. 10, pp. 4040–4046, Oct. 2023, doi: 10.1021/acs. jchemed.3c00518.

[46] H. Lee, S. Fiore, and F. Berruti, “Adsorption of methyl orange and methylene blue on activated biocarbon derived from birchwood pellets,” Biomass and Bioenergy, vol. 191, art. no. 107446, Dec. 2024, doi: 10.1016/j.biombioe. 2024.107446.

[47] N. Vasiljević, S. Panić, G. Tadić, J. Vuković, N. Novaković, and V. Mićić, “Investigation of the kinetics of the adsorption of methylene blue on activated carbon,” Engineering Proceedings, vol. 99, no. 1, art. no. 4, Feb. 2025, doi: 10.3390/engproc2025099004.

[48] M. A. O. Y. Weeratunge, M. D. N. Dinusha, R. M. M. K. Karunathilaka, and N. Priyantha, “Comparative adsorption characteristics of methylene blue on raw leaves and biochar of guinea grass (Megathyrsus maximus),” Discover Chemistry, vol. 3, art. no. 50, Feb. 2026, doi: 10.1007/s44371-026-00496-w.

[49] P. S. Kumar, S. Ramalingam, and K. Sathishkumar, “Removal of methylene blue dye from aqueous solution by activated carbon prepared from cashew nut shell as a new low-cost adsorbent,” Korean Journal of Chemical Engineering, vol. 28, no. 1, pp. 149–155, Jan. 2011, doi: 10.1007/s11814-010-0342-0.

[50] E. Duque-Brito, D. R. Lobato-Peralta, J. A. Okolie, D. M. Arias, P. J. Sebastian, and P. U. Okoye, “Fast-kinetics adsorption of a binary solution containing cationic and ionic pollutants using high-surface area activated carbon derived from macadamia nutshell,” Energy, Ecology and Environment, vol. 9, no. 1, pp. 84–99, Feb. 2024, doi: 10.1007/s40974-023-00304-6.

[51] A. F. Alshekhli, H. A. Hasan, M. H. Muhamad, and S. R. Sheikh Abdullah, “Development of adsorbent from phytoremediation plant waste for methylene blue removal,” Journal of Ecological Engineering, vol. 21, no. 8, pp. 207–215, Nov. 2020, doi: 10.12911/22998993/126873.

[52] A. A. Basaleh, M. H. Al-Malack, and T. A. Saleh, “Methylene Blue removal using polyamide-vermiculite nanocomposites: Kinetics, equilibrium and thermodynamic study,” Journal of Environmental Chemical Engineering, vol. 7, no. 3, art. no. 103107, Jun. 2019, doi: 10.1016/j.jece.2019.103107.

[53] Z. Liu, M. Azharul Islam, and J. Huang, “Study of the adsorption of methylene blue by phytoremediation-plant biomass carbon,” Journal of Molecular Liquids, vol. 366, art. no. 120273, Nov. 2022, doi: 10.1016/j.molliq.2022.120273.

[54] O. S. Olugbenga, P. G. Adeleye, S. B. Oladipupo, A. T. Adeleye, and K. I. John, “Biomass-derived biochar in wastewater treatment- a circular economy approach,” Waste Management Bulletin, vol. 1, no. 4, pp. 1–14, Jan. 2024, doi: 10.1016/j.wmb.2023.07.007.

[55] N. S. Pham et al., “Adsorption of orange G using activated carbon derived from common reed (Phragmites australis) in Mekong Delta, Vietnam,” Desalination and Water Treatment, vol. 317, art. no. 100095, Mar. 2024, doi: 10.1016/j.dwt.2024.100095.

[56] Z. Bu, Y. Fang, H. Chen, M. Zhang, and F. Wang, “Study on the adsorption properties of organically modified diatomite for methylene blue,” Scientific Reports, vol. 15, art. no. 13768, Jan. 2025, doi: 10.1038/s41598-025-13768-9.

[57] M. A. Islam, A. Benhouria, M. Asif, and B. H. Hameed, “Methylene blue adsorption on factory-rejected tea activated carbon prepared by conjunction of hydrothermal carbonization and sodium hydroxide activation processes,” Journal of the Taiwan Institute of Chemical Engineers, vol. 52, pp. 57–64, Jul. 2015, doi: 10.1016/j.jtice.2015.02.010.

[58] N. Mekonen, S. Gebrearegawi, Y. Syraji, and K. Tsegaye, “Low cost adsorbent derived from agricultural byproduct and its application for the removal of cationic dye from waste water: A review,” American Journal of Biological and Environmental Statistics, vol. 10, no. 3, pp. 67–75, Sep. 2024, doi: 10.11648/j.ajbes.20241003.14.

[59] L. Ton-That et al., “Kinetic studies of the removal of methylene blue from aqueous solution by biochar derived from jackfruit peel,” Environmental Monitoring and Assessment, vol. 195, no. 11, art. no. 1266, Oct. 2023, doi: 10.1007/s10661-023-11867-6.

[60] F. C. Wu, R. L. Tseng, and R. S. Juang, “Characteristics of Elovich equation used for the analysis of adsorption kinetics in dye-chitosan systems,” Chemical Engineering Journal, vol. 150, no. 2–3, pp. 366–373, Aug. 2009, doi: 10.1016/j.cej.2009.01.014.

[61] C. H. C. Tan, S. Sabar, and M. H. Hussin, “Development of immobilized microcrystalline cellulose as an effective adsorbent for methylene blue dye removal,” South African Journal of Chemical Engineering, vol. 26, pp. 11–24, Oct. 2018, doi: 10.1016/j.sajce.2018.08.001.

[62] J. Ghasemi and S. Asadpour, “Thermodynamics’ study of the adsorption process of methylene blue on activated carbon at different ionic strengths,” Journal of Chemical Thermodynamics, vol. 39, no. 6, pp. 967–971, Jun. 2007, doi: 10.1016/j.jct.2006. 10.018.

[63] V. J. Inglezakis and A. A. Zorpas, “Heat of adsorption, adsorption energy and activation energy in adsorption and ion exchange systems,” Desalination and Water Treatment, vol. 39, no. 1–3, pp. 149–157, Feb. 2012, doi: 10.5004/dwt.2012.3000.

[64] S. Mabrouk and H. Dhaouadi, “Experimental study and theoretical modelling based on DFT of the elimination of ceftriaxone by an activated carbon synthesized from grape seeds waste,” Scientific Reports, vol. 15, art. no. 27184, Feb. 2025, doi: 10.1038/s41598-025-27184-6.

[65] S. Satyam and S. Patra, “Innovations and challenges in adsorption-based wastewater remediation: A comprehensive review,” Heliyon, vol. 10, no. 9, art. no. e29573, May 2024, doi: 10.1016/j.heliyon.2024.e29573.

[66] W. H. Lee, J. S. Park, J. H. Sok, and P. J. Reucroft, “Effects of pore structure and surface state on the adsorption properties of nano-porous carbon materials in low and high relative pressures,” Applied Surface Science, vol. 246, no. 1–3, pp. 77–81, Jun. 2005, doi: 10.1016/j.apsusc.2004.10.038.

[67] J. Wang, Y. Tan, H. Yang, L. Zhan, G. Sun, and L. Luo, “On the adsorption characteristics and mechanism of methylene blue by ball mill modified biochar,” Scientific Reports, vol. 13, art. no. 21085, Nov. 2023, doi: 10.1038/s41598-023-48373-1.

[68] S. Sahu et al., “Adsorption of methylene blue on chemically modified lychee seed biochar: Dynamic, equilibrium, and thermodynamic study,” Journal of Molecular Liquids, vol. 315, art. no. 113743, Oct. 2020, doi: 10.1016/j.molliq.2020.113743.

[69] S. P. Viswanthan et al., “Removal efficiency of methylene blue from aqueous medium using biochar derived from Phragmites karka, a highly invasive wetland weed,” Biomass Conversion and Biorefinery, vol. 12, no. 8, pp. 3257–3273, Aug. 2022, doi: 10.1007/s13399-020-00877-w.

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DOI: 10.14416/j.asep.2026.08.010

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