Abstract
Industrial wastewater containing high concentrations of ethylene glycol (EG) represents a major treatment challenge due to its high solubility, elevated chemical oxygen demand, and limited removal by conventional treatment systems. In this study, a multistage treatment strategy is proposed to overcome the demonstrated limitations of an existing industrial wastewater treatment plant for EG removal. The approach integrates solvent-assisted phase separation, coagulation–precipitation, and nanomaterial-based polishing. An external solvent-assisted phase separation step was applied as a pretreatment stage, achieving substantial reduction of the organic load (≈ 75–80% COD removal) and enabling partial recovery of an EG-rich fraction through association-driven co-extraction mechanisms rather than classical liquid–liquid extraction. Subsequent coagulation–precipitation removed suspended and colloidal matter, while tertiary polishing using nano zero-valent aluminum (nZVAl) achieved complete decoloration (100%). Kinetic analysis indicated that color removal followed Avrami-type behavior, reflecting a heterogeneous and multistep adsorption mechanism. Pilot-scale validation using real industrial wastewater confirmed the robustness of the proposed system. A preliminary techno-economic screening showed that the multistage process can operate at a net treatment cost comparable to conventional high-strength industrial wastewater treatment systems, with solvent recovery and partial EG reuse contributing to operational cost reduction rather than direct profit. Overall, the proposed framework provides a practical and scalable upgrade for industrial EG-laden wastewater treatment.
Data availability
All data generated or analyzed during this study are included in this published article.
References
Khan, A. et al. Equilibrium adsorption studies of some aromatic pollutants from dilute aqueous solutions on activated carbon at different temperatures. J. Colloid Interface Sci. 194 (1), 154–165 (1997).
Mantzavinos, D. et al. Enhancement of biodegradability of industrial wastewaters by chemical oxidation pre-treatment. J. Chem. Technol. Biotechnology: Int. Res. Process. Environ. Clean. Technol. 79 (5), 431–454 (2004).
Yang, Q. et al. Optimal integration design of sustainable ethylene glycol production process considering economic benefit and environmental impact. 396: p. 136540. (2023).
Chen, J. et al. Physical–Chemical–Biological Pretreatment for Biomass Degradation and Industrial Applications: A Review. in Waste. MDPI. (2024).
Al-Salihi, S. A. et al. Synthetic Biology: Pioneering the Next Bio Revolution for a sustainable planet. (2024).
Noor, M. H. M., N.J.J.o.W, P. E. & Ngadi Global research landscape on coagulation-flocculation for wastewater treatment: A 2000–2023 bibliometric analysis. 64: p. 105696. (2024).
Li, C. et al. Treatment of high-salinity organic wastewater by advanced oxidation processes: Research progress and prospect. 60: p. 105272. (2024).
Mantzavinos, D. & Kalogerakis, N. J. E. Treatment of Olive mill effluents: part I. Organic matter degradation by chemical and biological processes—an overview. Environment international, 31(2): pp. 289–295. (2005).
Pignatello, J. J. et al. Advanced oxidation processes for organic contaminant destruction based on the Fenton reaction and related chemistry. Critical reviews in environmental science and technology. 36(1): pp. 1–84. (2006).
Nidheesh, P. J. R. A. Heterogeneous Fenton catalysts for the abatement of organic pollutants from aqueous solution: a review. RSC Adv. 5 (51), 40552–40577 (2015).
Srivastava, R. R. et al. Challenges, regulations, and case studies on sustainable management of industrial waste. Minerals 13 (1), 51 (2022).
Van der Bruggen, B. & Vandecasteele, C. J. E. Removal of pollutants from surface water and groundwater by nanofiltration: overview of possible applications in the drinking water industry. 122(3): pp. 435–445. (2003).
Chaturvedi, A. et al. A comprehensive review on the integration of advanced oxidation processes with biodegradation for the treatment of textile wastewater containing Azo dyes. Rev. Chem. Eng. 38 (6), 617–639 (2022).
Plan, C. & Belgium For a cleaner and more competitive Europe. 28. (2020).
Plant, H. W. T. The US Environmental Protection Agency (EPA) Proposes to Reissue a National Pollutant Discharge Elimination System (NPDES) Permit to Discharge Pollutants Pursuant to the Provisions of the Clean Water Act (CWA) to.
Sciences, N. A. et al. Improving the EPA Multi-Sector General Permit for Industrial Stormwater Discharges (National Academies, 2019).
LU, S. et al. Progress and prospect on monitoring and evaluation of united nations SDG 6 (Clean water and Sanitation). Target 36 (8), 904–913 (2021).
European Commission, E. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 Establishing a framework for community action in the field of water policy. EC Directive. 327 (43), 1–72 (2000).
Farag, R. S., Elshfai, M. M. & Mahmoud, A. S. Adsorption and kinetic studies using nano zero valent iron (nZVI) in the removal of chemical oxygen demand from aqueous solution with response surface methodology and artificial neural network approach. J. Environ. Biotechnol. Res. 7 (2), 12–22 (2018).
Jason, A. et al. AOP Performance at Wastewater Treatment Plants. in. Proc. 2018 Annual AIChE Meeting, Pittsburgh, PA, (October 28 – November 2). (2018).
Mahmoud, A. S. et al. Nano zero-valent aluminum (nZVAl) preparation, characterization, and application for the removal of soluble organic matter with artificial intelligence, isotherm study, and kinetic analysis. Air Soil. Water Res. 12, 1178622119878707 (2019).
Rabie, S. et al. Green Synthesis of Nano Iron Carbide: Preparation, Characterization and Application for Removal of Phosphate from Aqueous Solutions. in Proc. 2018 Annual AIChE Meeting, Pittsburgh, PA, (October 28 – November 2). (2018).
Harter, T. Groundwater Quality and Groundwater Pollution (UCANR, 2003).
Philander, S. G. Encyclopedia of Global Warming and Climate Change (Sage, 2008).
PEDDI, P. K. Pilot-scale demonstration of hzvi process for treating (Texas A&M University, 2011).
Wijesekara, S. et al. Fate and Transport of Selection Nutrients and Heavy Metals in Nanoscale Zero Valent Iron Amended Sand Columns. (2014).
Jahan, N. et al. A comprehensive review on the sustainable treatment of textile wastewater: zero liquid discharge and resource recovery perspectives. 14(22): p. 15398. (2022).
Macarthur, E. & Heading, H. J. E. M. F. How Circular Econ. Tackles Clim. Change 1: 1–71. (2019).
Rabie S. Farag, M.M.E., Ahmed S. Mahmoud, Mohamed K. Mostafa, Ahmed Karam, and R.W. Peters. Study the Degradation and Adsorption Processes of Organic Matters from Domestic Wastewater using Chemically Prepared and Green Synthesized Nano Zero-Valent Iron. in 2019 Annual AIChE Meeting; Orlando, FL, November 10–15, 2019. 2019. https://www.researchgate.net/publication ….
Baird, R.B., Standard methods for the examination of water and wastewater, 23rd. 2017, Water Environment Federation, American Public Health Association, American….
Maha M. Elshfai, A.S.M. and M.A. Elsaid. Comparative Studies of using nZVI and Entrapped nZVI in Alginate Biopolymer (Ag/ nZVI)for Aqueous Phosphate Removal. in 12th international conference on nano-technology for green and sustainable construction. 2021. https://www.researchgate.net/publication ….
Zeldowitsch, J. Über Den mechanismus der Katalytischen oxydation von CO an MnO2. Acta Physicochim URSS. 1, 364–449 (1934).
Avrami, M. Kinetics of phase change. II transformation-time relations for random distribution of nuclei. J. Chem. Phys. 8 (2), 212–224 (1940).
Ho, Y. S. & McKay, G. Kinetic models for the sorption of dye from aqueous solution by wood. Process Saf. Environ. Prot. 76 (2), 183–191 (1998).
Ho, Y. S. & McKay, G. Pseudo-second order model for sorption processes. Process Biochem. 34 (5), 451–465 (1999).
Fola, A. T., Idowu, A. A. & Adetutu, A. Removal of Cu2 + from aqueous solution by adsorption onto quail eggshell: kinetic and isothermal studies. J. Environ. Biotechnol. Res. 5 (1), 1–9 (2016).
Mahmoud, A. S. et al. Isotherm and kinetic studies for heptachlor removal from aqueous solution using Fe/Cu nanoparticles, artificial intelligence, and regression analysis. Sep. Sci. Technol., 55 (4), 684-696. (2020)
Mahmoud, M. et al. Comparison of aluminum and iron nanoparticles for chromium removal from aqueous solutions and tannery wastewater, empirical modeling and prediction. Emergent Mater., 5 (6), pp.1729-1744. (2022)
Tomaszewski, K., Szymanski, A. & Lukaszewski, Z. J. T. Separation of Poly (ethylene glycols) into fractions by sequential. liquid–liquid Extr. 50 (2), 299–306 (1999).
Tratnyek, P. G. And R.L.J.N.t. Johnson. Nanotechnologies Environ. Cleanup. 1 (2), 44–48 (2006).
Phenrat, T. et al. Aggregation and sedimentation of aqueous nanoscale zerovalent iron dispersions. Environ. Sci. Technol. 41 (1), 284–290 (2007).
Fu, F. & Wang Q.J.J.o.e.m. Remov. Heavy Metal Ions Wastewaters: Rev. 92(3): 407–418. (2011).
Mahmoud, A. S. et al. Innovative Decentralized Wastewater Treatment: Coupling Coagulation, nZVAl Adsorption, Sand Filtration, and ANN-Based Optimization. 18: p. 11786221251392205. (2025).
Mahmoud, M. et al. Comparison of aluminum and iron nanoparticles for chromium removal from aqueous solutions and tannery wastewater. Empir. Model. Prediction. 5 (6), 1729–1744 (2022).
Mahmoud, A. S., Farag, R. S. & Elshfai, M. M. J. E. J. P. Reduction of organic matter from municipal wastewater at low cost using green synthesis nano iron extracted from black tea: Artificial intelligence with regression analysis. 29(1): pp. 9–20. (2020).
El-Shafei, M. et al. Effects of entrapped nZVI in alginate polymer on BTEX removal. in AIChE Annual Meeting. San Francisco, CA. (2016).
Mahmoud, M. & A.S.J.E.m. Mahmoud Wastewater treatment using nano bimetallic iron/copper, adsorption isotherm, kinetic studies, and artificial intelligence neural networks. Emergent Mater. 4 (5), 1455–1463 (2021).
Lanz, K. & Scheuer, S. EEB handbook on EU water policy under the Water Framework Directive. (2001).
Mahmoud, A. S. et al. Effective chromium adsorption from aqueous solutions and tannery wastewater using bimetallic Fe/Cu nanoparticles: response surface methodology and artificial neural network. 14: p. 11786221211028162. (2021).
Acknowledgements
The authors thank the Egyptian Knowledge Bank for publication support. The Science, Technology, and Innovation Funding Authority (STDF Applied Sciences Research Grant Call 2, Project ID: 47353) provided experimental funding for this study. Also, the authors would like to thank the Egyptian Russian University, Housing and Building National Research Center, and Arish University for supporting this research.
Funding
Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). The authors thank the Egyptian Knowledge Bank for publication support.
Author information
Authors and Affiliations
Contributions
Each author contributed equally to this work, including the establishment of the standard solution, the synthesis, characterization, and use of nanomaterial.
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 4.0 International License, which permits use, sharing, adaptation, 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 changes were made. 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/4.0/.
Reprints and permissions
About this article
Cite this article
Mahmoud, A.S., Khamis, E., Mahmoud, M.S. et al. Multistage treatment of industrial ethylene glycol (EG) effluent: integrating chemical extraction, coagulation/precipitation, and decolouration for enhanced wastewater remediation.
Sci Rep (2026). https://doi.org/10.1038/s41598-026-35153-w
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-35153-w
Keywords
- Industrial effluent
- Circular economy
- Climate action
- Nanotechnology
- Ethylene glycol
- Decentralized system
- Wastewater treatment.
Source: Resources - nature.com
