Removal of Chloride in Saline Water by Bismuth Oxide Nanoparticles
Abstract
Climate change intensifies saltwater intrusion in coastal and delta regions, notably the Mekong Delta, thereby increasing the concentration of chloride ions (Cl-) in water. Elevated Cl- concentrations pose serious environmental challenges, inhibiting plant growth and impacting human health. While various conventional methods for chloride treatment exist, challenges persist concerning high cost, complex procedures, and secondary waste. Therefore, developing a simple, cost-effective, and highly efficient method using novel adsorbent materials is imperative. The primary objective of this study was to prepare and evaluate the efficacy of bismuth oxide nanoparticles (Bi2O3) as a novel, highly effective adsorbent for the removal of Cl- from saline water sources. Bi2O3 nanoparticles were synthesized using the solid dispersion evaporation technique with sorbitol as a support. FTIR, XRD, SEM, and EDX were used to characterize the physicochemical and structural properties of the material. The Cl- removal capacity was systematically studied under diverse operational conditions, including contact time, solution pH, adsorbent dosage, initial Cl- concentration, and temperature, to determine appropriate adsorption conditions. The material was also subjected to adsorption-desorption cycling tests to evaluate its regeneration potential and long-term durability. The kinetic study showed that the Bi2O3 material reached adsorption equilibrium efficiently after 90 minutes. The maximum Cl- adsorption capacity was 40.89 mg/g at an optimum solution pH of 4, under optimized conditions (initial Cl- concentration of 50 mg/L, 25 °C). Other investigated factors significantly influenced the adsorption kinetics and capacity. Crucially, the Bi2O3 adsorbent maintained its high removal efficiency over 10 regeneration cycles, confirming its excellent durability and potential for real-world applications. The results clearly demonstrate that the synthesized Bi2O3 nanoparticles have excellent potential as a robust, high-performing adsorbent for Cl- removal, suggesting a viable and practical solution to the challenges posed by saltwater intrusion.
References
Balint, R., Bartoli, M., Jagdale, P., Tagliaferro, A., Memon, A. S., Rovere, M., and Martin, M., 2021. "Defective bismuth oxide as effective adsorbent for arsenic removal from water and wastewater." Toxics, 9(7), 158. https://doi.org/10.3390/toxics9070158
Be, N. V., Trien, T. V., Tri, V. P. D., and Hang, T. T. L., 2017. "Impacts of saline intrusion on agriculture and aquaculture in the Tran De district, Soc Trang province." CTU J. Sci., 50, 94-100. https://doi.org/10.22144/ctu.jvn.2017.071
Be, T. T., Sinh, B. T., and Miller, F., 2007. Challenges to sustainable development in the Mekong Delta: Regional and national policy issues and research needs: Literature analysis, Sustainable Mekong Research Network (Sumernet)., Vietnam
Binh, N. T., Phanh, T. S., and Huan, L., 2012. "Participatory vulnerability analysis: A case study from saline intrusion in the Mekong Delta." CTUJ. Sci., 24(b), 229-239.
Christina, P. J. D., 2016. Preparation of Bi2O3 nanostructures and their light driven catalytic activity towards the erasure of textile dyes. Final Year Project, Universiti Tunku Abdul Rahmam, Malaysia.
Dao, N. V., and Binh, P. T. T., 2019. "Evaluation of the situation and impact of climate change on the salinity intrusion at Ben Tre province." J. Hydrometeorol., 700, 12-22.
Das, T. R., and Sharma, P. K., 2020. "Bimetal oxide decorated graphene oxide (Gd2O3/Bi2O3@GO) nanocomposite as an excellent adsorbent in the removal of methyl orange dye." Mater. Sci. Semicond. Process, 105, 104721. https://doi.org/10.1016/j.mssp.2019.104721
Hoa, N. M., Giang, N. H., Tung, T. S., and Guong, V. T., 2016. "Salinisation of soil and water on agricultural and aquacultural systems in Binh Dai district, Ben Tre province," CTU J. Sci., 42, 40-49.
Huang, Q., Zhang, S., Cai, C., and Zhou, B., 2011. "β- and α-Bi2O3 nanoparticles synthesized via microwave-assisted method and their photocatalytic activity towards the degradation of rhodamine B." Mater Lett., 65(6), 988-990. https://doi.org/10.1016/j.matlet.2010.12.055
Mallahi, M., and Vaezi, M. "Synthesis and characterization of bismuth oxide nanoparticles via sol-gel method." Am. J. Eng. Res., 3(4), 162-165.
Nguyen, T. T., Le, T. T., Nguyen, T. B. T., Thi, T. N., Tran, L. B., Nguyen, T. Q. A., and Nguyen, N. H. 2022. "Effect of pH on the performance of Bi2O2CO3 nanoplates for methylene blue removal in water by adsorption and photocatalysis." Bull. Chem. React. Eng. Catal., 17(2), 331-339. https://doi.org/10.9767/bcrec.17.2.13370.331-339
Oudghiri-Hassani, H., Rakass, S., Al Wadaani, F. T., Al-ghamdi, K. J., Omer, A., Messali, M., and Abboudi, M. 2015. "Synthesis, characterization and photocatalytic activity of α-Bi2O3 nanoparticles." J. Taibah Univ. Sci., 9(4), 508-512. https://doi.org/10.1016/j.jtusci.2015.01.009
Phuong, N. M., Verplancke, H., Khoa, L. V., and Guong, V. T. 2009. "Physical soil degradation on intensive rice cultivation areas in the Mekong Delta and the effects of crop rotation on aggregate stability of paddy soil." CTU J. Sci., 11(a), 194-199.
Queensland Government, 2013. Impacts of salinity. https://www.qld.gov.au/environment/land/management/soil/degradation/salinity/impacts
Rahaman, M. A., Rahman, M. M., and Nazimuzzaman, M. 2020.Impact of salinity on infectious disease outbreaks: experiences from the global coastal region. In W. Leal Filho, T. Wall, A. M. Azul, L. Brandli, & P. G. Özuyar (Eds.), Good Health and Well-Being, Springer International Publishing, Cham. pp. 415-424).
Schlesinger, M., Schulze, S., Hietschold, M., and Mehring, M. 2013. "Metastable β-Bi2O3 nanoparticles with high photocatalytic activity from polynuclear bismuth oxido clusters." Dalton Trans., 42(4), 1047-1056. https://doi.org/10.1039/C2DT32119J
Schlesinger, M., Weber, M., Schulze, S., Hietschold, M., and Mehring, M. 2013. "Metastable β-Bi2O3 nanoparticles with potential for photocatalytic water purification using visible light irradiation." ChemistryOpen, 2(4), 146-155. https://doi.org/10.1002/open.201300013
Shi, M., Guo, C., Li, J., Li, J., Zhang, L., Wang, X., Ju, Y., Zheng, J., and Li, X. 2017. "Removal of bromide from water by adsorption on nanostructured δ-Bi2O3." J. Nanosci. Nanotechnol., 17(9), 6951-6956. https://doi.org/10.1166/jnn.2017.14473
Shirkhanloo, H., Safari, M., Amini, S. M., and Rashidi, M. 2017. "Novel semisolid design based on bismuth oxide (Bi2O3) nanoparticles for radiation protection." Nanomed. Res. J., 2(4), 230-238. https://doi.org/10.22034/nmrj.2017.04.004
Trivedi, M. K., Branton, A., Trivedi, D., Nayak, G., Bairwa, K., and Jana, S. 2015. "Spectroscopic characterization of disodium hydrogen orthophosphate and sodium nitrate after biofield reatment." J. Chromatogr, Sep. Tech., 6(5), 1000282. http://dx.doi.org/10.4172/2157-7064.1000282
Vengosh, A. 2014. 11.9 - Salinization and saline environments. In H. D. Holland & K. K. Turekian (Eds.), Treatise on Geochemistry 2nd Eds., Elsevier, Oxford, pp. 325-378.
Vo, T. A. N., and Son, T. Q. T. 2022. "Impacts of saltwater intrusion on crop yield in the Mekong River Delta." J. Vietnam Agric. Sci. Technol., 03(136), 24-33.
Zhou, L., Gao, C., and Xu, W. 2010. "Magnetic dendritic materials for highly efficient adsorption of dyes and drugs," ACS Appl. Mater. Interfaces, 2(5), 1483-1491. https://doi.org/10.1021/am100114f
Copyright (c) 2026 ASEAN Journal of Chemical Engineering
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Copyright holder for articles is ASEAN Journal of Chemical Engineering. Articles published in ASEAN J. Chem. Eng. are distributed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.
Authors agree to transfer all copyright rights in and to the above work to the ASEAN Journal of Chemical Engineering Editorial Board so that the Editorial Board shall have the right to publish the work for non-profit use in any media or form. In return, authors retain: (1) all proprietary rights other than copyright; (2) re-use of all or part of the above paper in their other work; (3) right to reproduce or authorize others to reproduce the above paper for authors’ personal use or for company use if the source and the journal copyright notice is indicated, and if the reproduction is not made for the purpose of sale.
