Abstract
Unfortunately, with the expansion of oil industries, the damage caused by oil-in-water emulsions on the environment and people’s lives has increased. In this study, using different ratios of iron oxide nanoparticles and modified aniline (4:1 (Fe41), 1:1 (Fe11), and 1:4(Fe14)), demulsifiers were fabricated that could destabilize oil-in-water emulsions in three acidic, alkaline, and neutral environments. The characteristics of the made magnetic demulsifiers were evaluated by X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), etc. tests. The turbidity results, Fe41, indicate that the pH = 7 demulsifier can be reduced to below 100 NTU. Also, changing nanoparticles to modify the aniline ratio can improve the efficiency of demulsifiers in different environments. While, in pH = 4, the turbidity result for Fe41 is 153 NTU, the turbidity result for Fe14 is 114 NTU. Moreover, zeta potential, contact angle, and optical microscope tests were used to understand the demulsification mechanism better. These evaluations showed that in the neutral environment (pH = 7), electrostatic interactions play the most crucial role in the performance of the demulsifier. but in acidic conditions other parameters (such as pi-pi interaction) are also involved. Moreover, the magnetic property of the demulsifier made it possible to use this demulsifier up to four times.
Data availability
The datasets used and/or analysed during the current study available from the corresponding author on reasonable request.
References
Javadian, S., Ramezani, A., Sadrpoor, S. M. & Dehaghani, A. H. The effect of chemical bond and solvent solubility parameter on stability and absorption value of functionalized PU sponge. Chemosphere 340, 139936 (2023).
Xu, L. et al. Heterogeneous wettability membrane for efficient demulsification and separation of oil-in-water emulsions. Chem. Eng. J. 489, 151466 (2024).
Wang, C. et al. Oil removal from wastewater with biomass-derived hydrochars laboratory insights. Sci. Rep. 15, 22176 (2025).
Al-Husaini, I. S. & Al Haddabi, M. H. Recent advances in functionalized electrospun nanofiber membranes for enhanced oily water treatment. J. Environ. Chem. Eng. 115391 (2025).
Gosiamemang, T. & Heng, J. Y. Simple one-pot fabrication of durable superhydrophobic cotton wool using octadecyltrimethoxysilane modified silica-sol for oil-water separation. Sep. Purif. Technol. 336, 126185 (2024).
Liu, S. et al. Efficient oil-water separation with amphipathic magnetic nanoparticles of Fe3O4@ TiO2. J. Dispers. Sci. Technol. 44, 1965–1971 (2023).
Zhang, Z. et al. Hyperbranched Poly (amido amine) demulsifiers using diaminonaphthalene as the central core and their demulsification performance in oil-in-water and water-in-oil emulsions. Energy Fuels. 35, 3095–3103 (2021).
Sun, H., Li, X. & Li, X. Magnetically recyclable polydopamine-polyquaternium modified Fe3O4 nanoparticles for demulsification of asphaltene-rich ASP flooding produced water. J. Water Process. Eng. 56, 104460 (2023).
Zhang, J. & Kang, Y. Demulsification of dilute O/W emulsion by DC electric field. Pet. Sci. Technol. 36, 1058–1064 (2018).
Zolfaghari, R. F. R., Ahmadun, Abdullah, L. C., Elnashaie, Said, S. E. H., Pendashteh, A. & and and Demulsification techniques of water-in-oil and oil-in-water emulsions in petroleum industry. Sep. Purif. Technol. 170, 377–407 (2016).
Javadian, S. & Sadrpoor, S. M. Functionalized graphene oxide with core-shell of Fe3O4@ Oliec acid nanospheres as a recyclable demulsifier for effective removal of emulsified oil from oily wastewater. J. Water Process. Eng. 32, 100961 (2019).
Hamedi, H., Rezaei, N. & Zendehboudi, S. A comprehensive review on demulsification using functionalized magnetic nanoparticles. J. Clean. Prod. 380 https://doi.org/10.1016/j.jclepro.2022.134868 (2022).
Xu, H., Wang, J., Yang, X. & Ning, L. Magnetically recyclable graphene oxide demulsifier adapting wide pH conditions on detachment of oil in the crude oil-in-Water emulsion. ACS Appl. Mater. Interfaces. 13, 6748–6757. https://doi.org/10.1021/acsami.0c18115 (2021).
Elmobarak, W. F. & Almomani, F. Application of Fe3O4 magnetite nanoparticles grafted in silica (SiO2) for oil recovery from oil in water emulsions. Chemosphere 265, 129054 (2021).
Wang, R., Cai, Y., Su, Z., Ma, X. & Wu, W. High positively charged Fe(3)O(4) nanocomposites for efficient and recyclable demulsification of hexadecane-water micro-emulsion. Chemosphere 291, 133050. https://doi.org/10.1016/j.chemosphere.2021.133050 (2022).
Xiong, Y. et al. Destructing surfactant network in nanoemulsions by positively charged magnetic nanorods to enhance oil-water separation. J. Environ. Sci. (China). 118, 112–121. https://doi.org/10.1016/j.jes.2021.08.039 (2022).
Zhang, X. et al. Demulsification of surfactant-rich emulsion systems by using amphiphilic or positively charged magnetic nanoparticles. Sep. Purif. Technol. 347, 127587 (2024).
Xu, Z., Zhu, Q. & Bian, J. Preparation of a recyclable demulsifier for the treatment of emulsified oil wastewater by Chitosan modification and sodium oleate grafting Fe3O4. J. Environ. Chem. Eng. 9, 105663 (2021).
Takai, Z. I., Mustafa, M. K., Sekak, K. A. & Asman, S. Ultrasonic assisted Preparation and characterization of conductive Polyaniline-Modified magnetite nanocomposites (PAni/Fe3O4 nanocomposites). Int. J. Nanoelectron Mater. 12, 401–412 (2019).
Ghasemi, H. & Eslami, F. Design of industrial wastewater demulsifier by HLD-NAC model. Sci. Rep. 11, 16111 (2021).
Li, H., Li, J., Peng, X., Zhang, C. & An, X. Hydrophobic modification of carbon microspheres and their demulsification performance in oily wastewater. Colloids Surf., A. 700, 134823 (2024).
Liu, J. et al. Demulsification of crude oil-in-water emulsions driven by graphene oxide nanosheets. Energy Fuels. 29, 4644–4653 (2015).
Javadian, S., Bahri, M., Sadrpoor, S. M., Rezaei, Z. & Kakemam, J. Structure effect in the demulsification performance of cationic surfactants. J. Petrol. Sci. Eng. 218, 110895 (2022).
Xin, K. et al. Amphiphilic modification of oleic imidazoline for corrosion inhibition and demulsification performances investigation. J. Mol. Liquids, 127981 (2025).
Biswal, N. R. & Singh, J. K. Interfacial behavior of nonionic tween 20 surfactant at oil–water interfaces in the presence of different types of nanoparticles. RSC Adv. 6, 113307–113314 (2016).
Javadian, S., Ramezani, A. & Sadrpoor, S. M. Scalable production of Eco-friendly modified SiO2 as demulsifier of crude oil. Nanochemistry Res. 9, 103–112 (2024).
Javadian, S. & Sadrpoor, S. M. Demulsification of water in oil emulsion by surface modified SiO2 nanoparticle. J. Petrol. Sci. Eng. 184. https://doi.org/10.1016/j.petrol.2019.106547 (2020).
Khyave, A. E., Mafigholmi, R., Davood, A., Mahvi, A. & Salimi, L. Photocatalytic degradation of Azithromycin and ceftriaxone using synthesized Ag/g-C3N4/Fe3O4 nanocomposites in aqueous solution. Sci. Rep. 15, 18726 (2025).
Javadian, S. et al. Graphene quantum Dots based magnetic nanoparticles as a promising delivery system for controlled doxorubicin release. J. Mol. Liq. 331, 115746 (2021).
Sing, K. S. Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984). Pure Appl. Chem. 57, 603–619 (1985).
Wang, F. H., Jiang, W., Fang, Y. & Cheng, C. W. Preparation of Fe3O4 magnetic porous microspheres (MPMs) and their application in treating mercury-containing wastewater from the Polyvinyl chloride industry by calcium carbide method. Chem. Eng. J. 259, 827–836 (2015).
Iles, A. et al. Removal of pollutants by Olive stones-derived activated carbon@ Fe3O4 nanocomposites: effect of calcination temperature on adsorption properties. J. Water Process. Eng. 66, 105960 (2024).
Fang, S. et al. An innovative method to introduce magnetism into demulsifier. Chem. Eng. J. 314, 631–639 (2017).
Lu, X. et al. Aniline dimer–COOH assisted Preparation of well-dispersed polyaniline–Fe3O4 nanoparticles. Nanotechnology 16, 1660 (2005).
Yang, C. et al. Polyaniline/Fe3O4 nanoparticle composite: synthesis and reaction mechanism. J. Phys. Chem. B. 113, 5052–5058 (2009).
Xu, H., Wang, J. & Ren, S. Removal of oil from a crude oil-in-water emulsion by a magnetically recyclable diatomite demulsifier. Energy Fuels. 33, 11574–11583 (2019).
Liu, J. et al. Recyclable magnetic graphene oxide for rapid and efficient demulsification of crude oil-in-water emulsion. Fuel 189, 79–87. https://doi.org/10.1016/j.fuel.2016.10.066 (2017).
Li, Y. et al. Asphaltenes and hydrolysed polyacrylamide at the oil–water interface behaviour and emulsion stability. Sep. Purif. Technol. 352, 128145 (2025).
Javadian, S., Sadrpoor, S. M. & Khosravian, M. Taking a look accurately at the alteration of interfacial asphaltene film exposed to the ionic surfactants as demulsifiers. Sci. Rep. 13, 12837 (2023).
Mahdavi, M. S. & Dehaghani, A. H. Experimental study on the simultaneous effect of smart water and clay particles on the stability of asphaltene molecule and emulsion phase. Sci. Rep. 15, 3393 (2025).
Funding
The fund for this study has been provided by Tarbiat modares university.
Author information
Authors and Affiliations
Contributions
Soheila Javadian: supervision, validation, resources, review & editing, Project administration, Funding acquisition. Aynaz Nobakht: interpretation, methodology, writing, data curation, investigation. S.Morteza Sadrpoor: writing, investigation, interpretation. Sedigeh Kiani: interpretation. Amir Hossein Saeedi Dehaghani: methodology.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Javadian, S., Nobakht, A., Sadrpoor, S.M. et al. pH-responsive modified magnetic nanoparticles for treatment of oily wastewater. Sci Rep (2026). https://doi.org/10.1038/s41598-026-38651-z
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-38651-z
