DOI: https://doi.org/10.61435/ijred.2026.62466
View PDF Download fulltext

Continuous closed-circuit removal of methylene blue and methyl orange dyes by activated Pomelo peel biochar alginate hydrogel beads

Institute of Environmental Science, Engineering and Management, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Viet Nam

Received: 5 Mar 2026; Revised: 28 Jun 2026; Accepted: 15 Jul 2026; Available online: 4 Aug 2026; Published: 1 Sep 2026.
Editor(s): H Hadiyanto
Open Access Copyright (c) 2026 The Author(s). Published by Centre of Biomass and Renewable Energy (CBIORE)
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

Citation Format:
Abstract

The successful fabrication of composite hydrogel beads was realized through the integration of activated pomelo peel biochar (PBC) into a sodium alginate (NaAlg) polymeric matrix, a process facilitated by Ca2+-induced ionic cross-linking. Morphological evaluations of the resulting material confirmed a highly textured surface, demonstrating that the PBC particles were effectively and uniformly embedded within the alginate framework. In terms of performance, the composite formulation consisting of 3.3% (w/v) PBC and NaAlg exhibited exceptional adsorption affinity for both methylene blue (MB) and methyl orange (MO) dyes. The equilibrium data showed a superior fit to the Langmuir isotherm model, which implies a predominantly homogeneous monolayer adsorption process; under continuous flow conditions at 30°C, the maximum adsorption capacities were recorded at 279.68 mg/g for MB and 179.02 mg/g for MO. Furthermore, kinetic modeling indicated that the adsorption behavior strictly followed a pseudo-second-order mechanism, suggesting that the rate-limiting step is governed by chemisorption rather than physical forces alone. The fundamental removal mechanism is believed to be a synergistic interplay of various physicochemical forces, including pore-filling within the biochar structure, π-π interactions between aromatic rings, and the formation of hydrogen bonds between the dye molecules and the composite surface.

Keywords: Acitvated pomelo peel biochar; bead composite; flow-continuous adsorption; methylene blue; methyl orange

Article Metrics:

Article Info
Section: Original Research Article
Language : EN
Recent articles
Mathematical model to evaluate the effect of key operating conditions on proton exchange membrane fuel cell performance Economic environmental optimization in multiple renewable energy sources with demand response based on multi-objective optimization algorithm A multi-objective metaheuristic framework for reactive power market optimization in distributed renewable systems More recent articles
Most cited articles
A Novel Integration of PCM with Wind-Catcher Skin Material in Order to Increase Heat Transfer Rate Batch and Fed-Batch Fermentation System on Ethanol Production from Whey using Kluyveromyces marxianus Utilization of Iles-Iles and Sorghum Starch for Bioethanol Production Biofixation of Carbon dioxide by Chlamydomonas sp. in a Tubular Photobioreactor Economic Impact of CDM Implementation through Alternate Energy Resource Substitution More cited articles
  1. Agarwala, R. & Mulky, L. (2023). Adsorption of dyes from wastewater: A comprehensive review. ChemBioEng Reviews, 10(3), 326-335. https://doi.org/10.1002/cben.202200011
  2. Akter, T., Protity, A.T., Shaha, M., Al Mamun, M., & Hashem, A. (2023). The impact of textile dyes on the environment. Nanohybrid materials for treatment of textiles dyes, Springer: 401-431
  3. Al-Asadi, S.T., Mussa, Z.H., Al-Qaim, F.F., Kamyab, H., Al-Saedi, H.F.S., Deyab, I.F., & Kadhim, N.J. (2025). A comprehensive review of methylene blue dye adsorption on activated carbon from edible fruit seeds: A case study on kinetics and adsorption models. Carbon Trends, 20, 100507. https://doi.org/10.1016/j.cartre.2025.100507
  4. Al-Gheethi, A.A., Azhar, Q.M., Kumar, P.S., Yusuf, A.A., Al-Buriahi, A.K., Mohamed, R.M.S.R., & Al-Shaibani, M.M. (2022). Sustainable approaches for removing Rhodamine B dye using agricultural waste adsorbents: A review. Chemosphere, 287, 132080. https://doi.org/10.1016/j.chemosphere.2021.132080
  5. Al-Ghouti, M.A. & Da'ana, D.A. (2020). Guidelines for the use and interpretation of adsorption isotherm models: A review. Journal of hazardous materials, 393, 122383. https://doi.org/10.1016/j.jhazmat.2020.122383
  6. Al-Tohamy, R., Ali, S.S., Li, F., Okasha, K.M., Mahmoud, Y.A.G., Elsamahy, T., Jiao, H., Fu, Y., & Sun, J. (2022). A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety. Ecotoxicology and environmental safety, 231, 113160. https://doi.org/10.1016/j.ecoenv.2021.113160
  7. Bal, G. & Thakur, A. (2022). Distinct approaches of removal of dyes from wastewater: A review. Materials Today: Proceedings, 50, 1575-1579. https://doi.org/10.1016/j.matpr.2021.09.119
  8. Bashir, T., Dutta, J., Masarat, S., Rafatullah, M., Asthana, N., Khan, A.A., & Fatima, S. (2025). Application of novel Chitosan-Lignin hydrogel beads for optimized removal of textile dye DB-218. Journal of Molecular Structure, 1324, 140892. https://doi.org/10.1016/j.molstruc.2024.14089
  9. Bellaj, M., Aziz, K., El Achaby, M., El Haddad, M., Gebrati, L., Kurniawan, T.A., Chen, Z., Yap, P.S., & Aziz, F. (2024). Cationic and anionic dyes adsorption from wastewater by clay-chitosan composite: an integrated experimental and modeling study. Chemical Engineering Science, 285, 119615. https://doi.org/10.1016/j.ces.2023.119615
  10. Benhalima, T., Sadi, A., Dairi, N., & Ferfera-Harrar, H. (2024). Multifunctional carboxymethyl cellulose-dextran sulfate/AgNPs@ zeolite hydrogel beads for basic red 46 and methylene blue dyes removal and water disinfection control. Separation and Purification Technology, 342, 127001. https://doi.org/10.1016/j.seppur.2024.127001
  11. Biswas, S., Mohapatra, S.S., Kumari, U., Meikap, B.C., & Sen, T.K. (2020). Batch and continuous closed circuit semi-fluidized bed operation: Removal of MB dye using sugarcane bagasse biochar and alginate composite adsorbents. Journal of Environmental Chemical Engineering, 8, 103637. https://doi.org/10.1016/j.jece.2019.103637
  12. Chen, J., Ouyang, J., Cai, X., Xing, X., Zhou, L., Liu, Z., & Cai, D. (2021). Removal of ciprofloxacin from water by millimeter-sized sodium alginate/H3PO4 activated corncob-based biochar composite beads. Separation and Purification Technology, 276, 119371. https://doi.org/10.1016/j.seppur.2021.119371
  13. Das, E., Rabha, S., Talukdar, K., Goswami, M., & Devi, A. (2023). Propensity of a low-cost adsorbent derived from agricultural wastes to interact with cationic dyes in aqueous solutions. Environmental Monitoring and Assessment, 195(9), 1044. https://doi.org/10.1007/s10661-023-11656-1
  14. Faried, M., Shameli, K., Miyake, M., Zakaria, Z., Hara, H., Khairudin, N., & Etemadi, M. (2016). Ultrasound-assisted in the synthesis of silver nanoparticles using sodium alginate mediated by green method. Digest Journal of Nanomaterials and Biostructures, 11(2), 547-552
  15. Haleem, A., Shafiq, A., Chen, S.Q., & Nazar, M. (2023). A comprehensive review on adsorption, photocatalytic and chemical degradation of dyes and nitro-compounds over different kinds of porous and composite materials. Molecules, 28(3), 1081. https://doi.org/10.3390/molecules28031081
  16. Hao, R., Ji, H., Gao, L., Chen, J., Shi, Y., Yang, J., & Yuan, C. (2023). Grafted natural melanin κ-carrageenan hydrogel bead adsorbents: New strategy for bioremediation of cationic dye contamination in aqueous solutions. Chemical Engineering Research and Design, 199, 1-10. https://doi.org/10.1016/j.cherd.2023.09.016
  17. Haque, A.N.M.A., Sultana, N., Sayem, A.S.M., & Smriti, S.A. (2022). Sustainable adsorbents from plant-derived agricultural wastes for anionic dye removal: a review. Sustainability, 14(17), 11098. https://doi.org/10.3390/su141711098
  18. Hosny, N.M., Gomaa, I., & Elmahgary, M.G. (2023). Adsorption of polluted dyes from water by transition metal oxides: A review. Applied Surface Science Advances, 15, 100395. https://doi.org/10.1016/j.apsadv.2023.100395
  19. Islam, T., Repon, M.R., Islam, T., Sarwar, Z., & Rahman, M.M. (2023). Impact of textile dyes on health and ecosystem: a review of structure, causes, and potential solutions. Environmental Science and Pollution Research, 30(4), 9207-9242. https://doi.org/10.1007/s11356-022-24398-3
  20. Jorge, A.M., Athira, K., Alves, M.B., Gardas, R.L., & Pereira, J.F. (2023). Textile dyes effluents: A current scenario and the use of aqueous biphasic systems for the recovery of dyes. Journal of Water Process Engineering, 55, 104125. https://doi.org/10.1016/j.jwpe.2023.104125
  21. Kathing, C. & Saini, G. (2022). A review of various treatment methods for the removal of dyes from textile effluent. Recent Progress in Materials, 4(4), 1-15. https://doi.org/10.21926/rpm.2204028
  22. Kumari, H., Sonia, Suman, Ranga, R., Chahal, S., Devi, S., Sharma, S., Kumar, S., Kumar, P., & Kumar, S. (2023). A review on photocatalysis used for wastewater treatment: dye degradation. Water, Air, & Soil Pollution, 234(6), 349. https://doi.org/10.1007/s11270-023-06359-9
  23. Kurczewska, J. (2022). Chitosan-montmorillonite hydrogel beads for effective dye adsorption. Journal of Water Process Engineering, 48, 102928. https://doi.org/10.1016/j.jwpe.2022.102928
  24. Li, K., Wu, J., Li, X., Li, B., & Zhou, D. (2024). Preparation of porous composite hydrogel with ultra-high dye adsorption capacity based on biochar: Adsorption behaviors and mechanisms. Chemical Engineering Science, 295, 120115. https://doi.org/10.1016/j.ces.2024.120115
  25. Liao, J., Li, Y., Li, H., Liu, J., Xie, Y., Wang, J., & Zhang, Y. (2018). Preparation, bioactivity and mechanism of nano-hydroxyapatite/sodium alginate/chitosan bone repair material. Journal of applied biomaterials & functional materials, 16(1), 28-35
  26. Lin, J., Ye, W., Xie, M., Seo, D.H., Luo, J., Wan, Y., & Van der Bruggen, B. (2023). Environmental impacts and remediation of dye-containing wastewater. Nature Reviews Earth & Environment, 4(11), 785-803. https://doi.org/10.1038/s43017-023-00489-8
  27. Liu, Q. (2020). Pollution and treatment of dye waste-water. IOP conference series: earth and environmental science, iop publishing. https://doi.org/10.1088/1755-1315/514/5/052001
  28. Lu, C., Yang, J., Khan, A., Yang, J., Li, Q., & Wang, G. (2022). A highly efficient technique to simultaneously remove acidic and basic dyes using magnetic ion-exchange microbeads. Journal of Environmental Management, 304, 114173. https://doi.org/10.1016/j.jenvman.2021.114173
  29. Lu, H., Butler, J.A., Britten, N.S., Venkatraman, P.D., & Rahatekar, S.S. (2021). Natural antimicrobial nano composite fibres manufactured from a combination of alginate and oregano essential oil. Nanomaterials, 11(8), 2062. https://doi.org/10.3390/nano11082062
  30. Maheshwari, K., Agrawal, M., & Gupta, A.B. (2021). Dye pollution in water and wastewater. Novel materials for dye-containing wastewater treatment, Springer, 1-25
  31. Makarova, A.O., Derkach, S.R., Khair, T., Kazantseva, M.A., Zuev, Y.F., & Zueva, O.S. (2023). Ion-induced polysaccharide gelation: Peculiarities of alginate egg-box association with different divalent cations. Polymers, 15(5), 1243. https://doi.org/10.3390/polym15051243
  32. Nayagam, J.O.P. & Prasanna, K. (2022). Utilization of shell-based agricultural waste adsorbents for removing dyes: A review. Chemosphere, 291, 132737. https://doi.org/10.1016/j.chemosphere.2021.132737
  33. Ohemeng-Boahen, G., Sewu, D.D., & Woo, S.H. (2019). Preparation and characterization of alginate-kelp biochar composite hydrogel bead for dye removal. Environmental Science and Pollution Research, 26(32), 33030-33042. https://doi.org/10.1007/s11356-019-06421-2
  34. Rather, R.A., Bhat, M.A., & Shalla, A.H. (2023). Development of sodium alginate-guar-gum-tannic acid based nanocomposite hydrogel beads for removal of malachite green dye. Materials Today Communications, 36, 106358. https://doi.org/10.1016/j.mtcomm.2023.106358
  35. Rathi, B.S. & Kumar, P.S. (2022). Sustainable approach on the biodegradation of azo dyes: a short review. Current Opinion in Green and Sustainable Chemistry, 33, 100578. https://doi.org/10.1016/j.cogsc.2021.100578
  36. Saravanan, P., Josephraj, J., Thillainayagam, B.P., Ravindiran, G. (2023). Evaluation of the adsorptive removal of cationic dyes by greening biochar derived from agricultural bio-waste of rice husk. Biomass Conversion and Biorefinery, 13(5), 4047-4060. https://doi.org/10.1007/s13399-021-01415-y
  37. Shi, Y., Chang, Q., Zhang, T., Song, G., Sun, Y., & Ding, G. (2022). A review on selective dye adsorption by different mechanisms. Journal of Environmental Chemical Engineering, 10(6), 108639. https://doi.org/10.1016/j.jece.2022.108639
  38. Solayman, H., Hossen, M.A., Abd Aziz, A., Yahya, N.Y., Leong, K.H., Sim, L.C., Monir, M.U., & Zoh, K.D. (2023). Performance evaluation of dye wastewater treatment technologies: A review. Journal of Environmental Chemical Engineering, 11(3), 109610. https://doi.org/10.1016/j.jece.2023.109610
  39. Soltani, A., Faramarzi, M., & Mousavi Parsa, S.A. (2021). A review on adsorbent parameters for removal of dye products from industrial wastewater. Water Quality Research Journal, 56(4), 181-193. https://doi.org/10.2166/wqrj.2021.023
  40. Stachowiak, N., Kowalonek, J., Kozlowska, J., & Burkowska-But, A. (2023). Stability studies, biodegradation tests, and mechanical properties of sodium alginate and gellan gum beads containing surfactant. Polymers, 15(11), 2568. https://doi.org/10.3390/polym15112568
  41. Subrahmanya, T., Widakdo, J., Mani, S., Austria, H.F.M., Hung, W.S., HK, M., Nagar, J.K., Hu, C.C., & Lai, J.Y. (2022). An eco-friendly and reusable syringe filter membrane for the efficient removal of dyes from water via low pressure filtration assisted self-assembling of graphene oxide and SBA-15/PDA. Journal of Cleaner Production, 349, 131425. https://doi.org/10.1016/j.jclepro.2022.131425
  42. Tran, M.L. (2025). One-step preparation of activated pomelo peel biochar by using H3PO4 for removal of methylene blue: performance, isotherm, and kinetic studies. Biomass Conversion and Biorefinery, 15(7), 10305-10317. https://doi.org/10.1007/s13399-024-05848-z
  43. Tran, M.L., Nguyen, C.H., Tran, T.T.V., & Juang, R.S. (2025). One‐step facile synthesis of pomelo peel biochar activated by KOH under air atmosphere for adsorptive removal of methylene blue and oxytetracycline. Journal of Chemical Technology & Biotechnology, 100, 1335-1345. https://doi.org/10.1002/jctb.7865
  44. Wang, J. & Guo, X. (2020). Adsorption kinetic models: Physical meanings, applications, and solving methods. Journal of Hazardous materials, 390, 122156. https://doi.org/10.1016/j.jhazmat.2020.122156
  45. Wu, S., Shi, W., Li, K., Cai, J., Xu, C., Gao, L., Lu, J., & Ding, F. (2023). Chitosan-based hollow nanofiber membranes with polyvinylpyrrolidone and polyvinyl alcohol for efficient removal and filtration of organic dyes and heavy metals. International Journal of Biological Macromolecules, 239, 124264. https://doi.org/10.1016/j.ijbiomac.2023.124264
  46. Yagub, M.T., Sen, T.K., Afroze, S., & Ang, H.M. (2014). Dye and its removal from aqueous solution by adsorption: a review. Advances in colloid and interface science, 209, 172-184. https://doi.org/10.1016/j.cis.2014.04.002
  47. Zari, R., Rathi, T., Gomase, V., EL Kaim Billah, R., Alhamami, M.A., Algethami, J.S., & Jugade, R. (2025). Eco-friendly synthesis of sodium alginate modified zeolite from fly ash composite hydrogel for efficient removal of methyl orange from water: batch studies and RSM optimization. International Journal of Environmental Analytical Chemistry, 1-31. https://doi.org/10.1080/03067319.2025.2553751
  48. Zhang, Y., Wang, P., Hussain, Z., Zhang, H., Wang, H., Chang, N., & Li, F. (2022). Modification and characterization of hydrogel beads and its used as environmentally friendly adsorbent for the removal of reactive dyes. Journal of Cleaner Production, 342, 130789. https://doi.org/10.1016/j.jclepro.2022.130789
  49. Zhao, Q., Zhang, H., Zhao, X., Wang, X., Zhang, K., Binguo, Z., Wang, S., Wang, B., Guo, F., & Ma, Y. (2024). Sodium alginate-based biochar gel spheres: synthesis, structural analysis, and ofloxacin adsorption efficiency. Materials Research Express, 11, 125507. https://doi.org/10.1088/2053-1591/ad988d

Last update:

No citation recorded.

Last update: 2026-08-15 08:22:55

No citation recorded.