HKUST pioneers novel water purification technology for selective pollutant polymerization
Enhances pollutant removal efficiency and potentially doubles economic value compared with conventional methods
Hong Kong University of Science and Technology
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A research team, led by Prof. Irene LO Man-Chi (first right), Chair Professor of the Department of Civil and Environmental Engineering at HKUST and formed by HKUST Research Associate Dr. ZHENG Zexiao (second left), PhD candidate ZHANG Jin (center), postdoctoral fellow Dr. Jonathan J. CALVILLO SOLÍS (first left), and MPhil student Howard Y. M. CHEUNG (second right), has recently achieved a major breakthrough by discovering a novel oxidant-free electrocatalytic mechanism, opening up a new direction for water purification technologies.
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Wastewater treatment is a critical issue for global environmental protection and public health. Researchers from The Hong Kong University of Science and Technology (HKUST) have recently achieved a major breakthrough by discovering a novel oxidant-free electrocatalytic mechanism, opening up a new direction for water purification technologies. The findings are set to significantly improve pollutant identification efficiency and potentially double the economic feasibility compared with existing methods.
The research team, led by Prof. Irene LO Man-Chi, Chair Professor of the Department of Civil and Environmental Engineering at HKUST, has published the study in Nature Communications titled "Iodine-mediated proton-coupled electron transfer enables selective polymerization of organic pollutants in an oxidant-free electrocatalytic system". Members of the research team include HKUST Research Associate Dr. ZHENG Zexiao, PhD candidate ZHANG Jin, postdoctoral fellow Dr. Jonathan J. CALVILLO SOLÍS, and MPhil student Howard Y. M. CHEUNG, along with alumni Prof. Ashutosh KUMAR, Prof. GUAN Xiaohong, and Prof. DONG Haoran.
Advanced oxidation processes (AOPs) are widely used to degrade organic pollutants in wastewater. However, conventional AOPs typically require large amounts of oxidant, achieve only limited removal of total organic carbon (TOC), and generate toxic intermediate by-products. Although polymerization can address these problems by converting soluble phenolic pollutants into insoluble and hydrophobic polymerized products, the inefficiency of the process caused by a kinetic imbalance, together with its poor selectivity, poses key challenges.
Prof. Lo said, "A paradigm shift is needed to correct the kinetic imbalance and enhance selectivity, thereby unlocking the complete potential of polymerization processes for wastewater treatment. The key breakthrough of our work is that the newly discovered mechanism can transform harmful soluble contaminants by selectively polymerizing them into insoluble, value-added products, opening new pathways for environmental resource recovery."
Using a custom-engineered iodine-enriched bismuth-oxyiodide-coated carbon cloth (I-BiOI@CC) anode as a case study, the team found that highly selective polymerization arises from the synergy of two distinct transport dynamics. First, an iodine-terminated surface acts as a molecular hook, forming targeted hydrogen bonds (Hδ+···Iδ⁻) specifically with phenolic hydroxyl groups to ensure exceptional target affinity even in complex matrices. Meanwhile, under mild anodic polarization, surface iodine undergoes a highly stable, reversible redox transition (3I⁻ ⇌ I₃⁻).
The synergistic action of these two mechanisms creates an optimized electronic shuttle that smoothly captures electrons from the adsorbed phenols, causing localized radicals to self-couple through a thermodynamically favored ortho C–O coupling pathway. This coordinates a clean separation of recoverable polymers from the water, and at the same time completely avoids over-oxidation.
Prof. Lo noted, "By utilizing the coupled dynamics of proton and electron transfer, this electrocatalytic system enables polymerization with a high selectivity of 97.1%. We have effectively demonstrated that water treatment can be shifted from a destructive, chemical‑heavy process into a target‑selective, resource‑recoverable purification technology."
In terms of removal efficiencies, the system demonstrated uncompromised performance across broad pH bounds (pH 5-9) and complex chemical environments. It also nearly doubled the economic feasibility of treatment—by achieving an outstanding energy demand that is 2 to 4 orders of magnitude lower than that of mineralization-oriented counterparts.
The energy requirement of 2.93 kWh/kg TOC translates to an operational cost of just US$0.3 per kg of TOC removed, indicating strong potential for practical applications.
Beyond its economic viability, the new system excels in both operational and ecological safety. Simulations and experiments conducted by the research team showed that the absence of any external oxidants in operation significantly reduced secondary pollution risks and eliminated chemical shipping hazards, ensuring it can be employed safely across varying engineering conditions.
Furthermore, the present study establishes a more general sustainability model to predict environmental impact and ecological safety. While conventional life-cycle assessments focus primarily on carbon emissions in isolated domains, the research team evaluated this system across 18 distinct environmental impact domains, boasting a negative carbon footprint of 42.78 kg CO2-eq compared to standard Fenton systems. In 96-hour zebrafish embryo assays and Vibrio fischeri tests, the treated wastewater exhibited significantly suppressed biotoxicity, supporting healthy, normal development from embryo to fry, thereby providing a more universal physical standard for ecological protection.
Looking toward the future implementation of this framework, Prof. Lo concluded, "As the next step, we look forward to scale-up investigations to assess the techno-economic feasibility and sustainability of this technology for real-world industrial applications."
The paper by Prof. Lo and her team has been published in the journal Nature Communications.
The study discovers that highly selective polymerization arises from proton-coupled electron transfer using an I-BiOI anode.
Credit
HKUST
Journal
Nature Communications
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Iodine-mediated proton-coupled electron transfer enables selective polymerization of organic pollutants in an oxidant-free electrocatalytic system
New membrane accelerates purification of industrial solvents
Researchers from the Department of Chemical Engineering, working with an international team led by KU Leuven, have developed a membrane technology to improve the efficiency of purifying widely used solvents.
The researchers show how water can be separated more quickly from isopropanol, a solvent used worldwide in the pharmaceutical and electronics industries. The results, published in Nature Communications, offer an alternative to current purification methods that require high energy input.
Separating chemical mixtures into pure components is a crucial but energy-intensive process in industrial chemistry, accounting for 10 to 15% of global energy use. One example is the purification of isopropanol, a widely used solvent in sectors such as pharmaceuticals and electronics. Current purification methods, mainly based on heating and distillation, have a significant impact on both energy consumption and CO₂ emissions in the chemical industry.
Professor Bart Van der Bruggen, lead researcher on the project at KU Leuven, said: “With the growing demand for more sustainable production processes, more efficient separation techniques are essential to continue using isopropanol—also in its bio-based forms from renewable resources—on a large scale.”
Not too small, not too large
The research team developed a new type of membrane based on graphene oxide, a material made of ultrathin carbon layers. By combining conventional graphene oxide sheets with new variants containing smaller pores, they created an internal structure with two functions: narrow channels that block larger molecules and regions that attract and allow water to pass through.
Lei Jiang, a doctoral researcher at KU Leuven, said: “The main challenge is to design a structure where the channels are not too small, which would slow down the separation and require more energy, but also not too large, which would reduce the purity of the final product.
“The new membrane combines both efficient and high-quality separation in a single structure.”
Dr Pengrui Jin, a Prize Fellow and researcher in the Department of Chemical Engineering and an independent principal investigator on the study, said: “The new membrane efficiently removes water from a mixture containing 90% isopropanol and 10% water. It selectively transports the water through the membrane, producing a permeate containing about 99.6% water. In addition, the process is faster than existing techniques and requires less energy, as it does not rely on high temperatures.”
Broad applicability
“The membrane delivers gains across the board: purity, energy consumption and economic efficiency,” added Professor Van der Bruggen.
“We are eager to test the technology on other chemical mixtures as well.”
Thanks to the combination of high purity levels and lower energy demand, this new membrane could support the transition toward a more climate-friendly chemical industry. The researchers are currently exploring options to scale up the technology and are assessing the possibility of filing a patent.
ENDS
Notes to editors:
For more information, please contact Sarah Baker-Gaunt at the University of Bath Press Office on press@bath.ac.uk
Research contacts:
Professor Bart Van der Bruggen, Department of Chemical Engineering, KU Leuven, bart.vanderbruggen@kuleuven.be, +32471 38 00 26
Dr. Pengrui Jin, Department of Chemical Engineering, University of Bath, pj665@bath.ac.uk
Lei Jiang, Process Engineering for Sustainable Systems, KU Leuven, lei.jiang@kuleuven.be
The study “Solvent dehydration with structurally engineered nanoporous graphene oxide membranes” by Jiang et al. was published in Nature Communications (DOI: 10.1038/s41467-026-72660-w).
The research was conducted by scientists from KU Leuven, the University of Bath, Huazhong University of Science and Technology, Nanjing University, Monash University, Korea University and VSB-Technical University of Ostrava. The study was led by doctoral researcher Lei Jiang, Dr. Pengrui Jin, Professor Shushan Yuan, and Professor Bart Van der Bruggen.
Journal
Nature Communications
Article Title
Solvent dehydration with structurally engineered nanoporous graphene oxide membranes
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