Key Takeaways & Executive Findings
- •• • Mechanically alloyed AlCrFeMnTiZr0.5 HEA achieves excellent catalytic performance for malachite green degradation, demonstrating the effectiveness of mechanical alloying in producing active HEA catalysts (Ren et al., 2022). • • Low-bandgap HEAs enable visible light-assisted photocatalytic degradation of pharmaceutically active compounds, offering a route to solar-driven wastewater treatment (Das et al., 2023). • • Strongly tribocatalytic dye degradation using high-entropy powder harnesses mechanical friction, providing a novel energy source for pollutant removal (Yang et al., 2024). • • Nanoparticles of MnFeNiCuBi HEA serve as effective catalysts for Fenton and photo-Fenton decomposition of p-nitrophenol, showcasing the versatility of HEAs in advanced oxidation processes (Anuraag et al., 2024).
Abstract
High-entropy alloys (HEAs) have emerged as promising catalytic materials for organic wastewater treatment owing to their unique catalytic activity, structural stability, and corrosion resistance. This review systematically elaborates the physicochemical properties of HEAs and their multi-path degradation mechanisms, with emphasis on Fenton reactions, photocatalysis, and tribocatalysis. The influence of mainstream preparation techniques—mechanical alloying, arc melting, gas atomization, and impregnation adsorption—on catalytic performance is critically compared. To overcome practical bottlenecks such as low powder recovery and rapid active-site deactivation, synergistic optimization strategies including metal doping, morphological modification, and composite engineering are proposed. The review identifies key challenges in enhancing degradation efficiency, scaling up production, and designing composite materials, and outlines future research directions for HEAs in wastewater treatment. This work provides a theoretical foundation for developing efficient and stable HEA-based environmental catalysts.
1. Introduction
Conventional wastewater treatment technologies, including physical adsorption, sedimentation, and microbial degradation, exhibit inherent limitations such as low degradation efficiency and prolonged processing times. These methods often fail to completely mineralize recalcitrant organic pollutants, particularly dyes and pharmaceuticals, which pose severe ecological and health risks. Advanced catalytic oxidation technologies, based on radical chain reactions mediated by active species like hydroxyl radicals (·OH) and superoxide radicals (·O2−), have emerged as more effective alternatives. However, the practical deployment of these technologies is often constrained by catalyst stability, recovery, and cost.
High-entropy alloys (HEAs), composed of five or more principal elements in near-equimolar ratios, offer a paradigm shift in catalyst design. Their multi-elemental composition creates a complex surface chemistry with abundant active sites, high configurational entropy, and exceptional corrosion resistance, making them ideal candidates for harsh wastewater environments. This review systematically examines the degradation mechanisms of HEAs in Fenton, photocatalytic, and tribocatalytic systems, and evaluates the impact of synthesis methods on performance. By addressing critical challenges such as powder recovery and active-site stability, and proposing synergistic optimization strategies, this work aims to bridge the gap between laboratory research and industrial application of HEA-based catalysts for water purification.
Loading authentic research manuscript (Pages 1–5)...
SU Qiong, NIE Hongjie, SUN Ke, ALIDAN·Ruzahong, ZHENG Yunhua, ZHAO Bowen (2026). Research Progress on Degradation of Pollutants in Water by High-Entropy Alloy Catalytic Materials. Environmental Chemistry. https://doi.org/10.7524/j.issn.0254-6108.2025041409
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What are the primary degradation mechanisms of high-entropy alloys in Fenton-like reactions, and how do they compare to conventional Fenton catalysts?
HEAs in Fenton-like reactions typically facilitate the generation of hydroxyl radicals via the Fenton reaction (Fe2+ + H2O2 → Fe3+ + OH− + ·OH) and its heterogeneous counterparts. The multi-elemental composition of HEAs can enhance electron transfer and provide multiple active sites, potentially improving radical generation efficiency compared to single-metal catalysts. For instance, MnFeNiCuBi HEA nanoparticles have shown effective Fenton and photo-Fenton decomposition of p-nitrophenol, indicating their capability to drive such reactions. However, quantitative comparisons with conventional catalysts require further systematic studies under identical conditions.
How does the preparation method (e.g., mechanical alloying vs. arc melting) influence the catalytic activity and stability of HEAs?
Mechanical alloying typically yields nanocrystalline or amorphous structures with high surface area and defect density, which can enhance catalytic activity. For example, mechanically alloyed AlCrFeMnTiZr0.5 HEA exhibited excellent performance for malachite green degradation. In contrast, arc melting often produces bulk alloys with larger grain sizes, which may reduce active surface area but improve structural stability. Gas atomization produces fine powders with spherical morphology, beneficial for slurry reactors. The choice of method directly impacts phase composition, particle size, and defect concentration, thereby affecting catalytic performance and long-term stability.
What are the main challenges in scaling up HEA production for industrial wastewater treatment, and what cost-effective synthesis routes are viable?
Scalability challenges include high energy consumption and cost of raw materials, especially for refractory elements like Ta, Nb, and W. Mechanical alloying is relatively scalable but time-consuming. Arc melting is energy-intensive and limited to small batches. Gas atomization offers continuous production but requires specialized equipment. Impregnation adsorption methods may be more cost-effective for supported catalysts. To achieve industrial viability, it is crucial to optimize alloy compositions using abundant elements (e.g., Fe, Al, Cr) and develop low-energy synthesis routes, such as high-energy ball milling with process control agents, to reduce costs.
How do HEAs maintain catalytic stability in harsh wastewater conditions, and what mechanisms lead to deactivation?
HEAs exhibit excellent corrosion resistance due to the formation of protective oxide layers and the high-entropy effect that stabilizes the solid solution phase. However, deactivation can occur via active-site poisoning by adsorbed intermediates, surface oxidation, or leaching of certain elements. For instance, in Fenton reactions, iron leaching can lead to loss of catalytic activity. Strategies to mitigate deactivation include doping with stabilizing elements (e.g., Ti, Cr) to enhance passivation, and morphological modification to increase surface area while maintaining structural integrity. Composite engineering with supports can also improve dispersion and reduce agglomeration.
What is the potential of HEAs in photocatalytic degradation under visible light, and how does their bandgap engineering compare to conventional photocatalysts like TiO2?
HEAs can be engineered to have low bandgaps, enabling visible light absorption. For example, low-bandgap HEAs have been used for visible light-assisted photocatalytic degradation of pharmaceutical compounds. Unlike TiO2, which has a wide bandgap (~3.2 eV) and requires UV light, HEAs can be tailored by adjusting elemental composition to achieve bandgaps in the visible range (1.8-2.5 eV). This allows utilization of solar energy more efficiently. However, the photocatalytic efficiency of HEAs may be lower than optimized TiO2-based systems, but their multi-elemental nature offers opportunities for enhanced charge separation and surface reactivity.
Related Chinese Research & Cross-Citations
Exploring the Potential Molecular Mechanisms of Eight Environmental Pollutants in Lung Adenocarcinoma through Network Toxicology, Machine Learning, and Multi-Omics Analysis
Epidemiological studies have established a significant association between exposure to environmental pollutants (EP) and the risk of lung adenocarcinoma (LUAD). This study integrates network toxicology and multi-omics analysis to elucidate the EP-LUAD molecular regulatory network and identify key regulatory genes, thereby revealing novel mechanisms of environmental carcinogenesis. Transcriptomic data from GEO and TCGA databases yielded 4,971 and 4,488 disease-related targets, respectively. Integration of toxicology databases (TargetNet, Swiss Target Prediction, CTD, SEA) identified 24,860 potential targets for eight common pollutants (SO2, NO, CO, NO2, O3, benzene, toluene, and polycyclic aromatic hydrocarbons). Intersection of these datasets produced 1,536 EP-LUAD common target genes. Protein-protein interaction network analysis identified 247 core targets. Machine learning selected five key genes: AGER, CAV1, CD44, CEP55, and GNB3, which demonstrated robust diagnostic and prognostic efficacy. Their expression correlated with immune cell infiltration, including CD4+ memory T cells and macrophages. Single-cell RNA sequencing revealed epithelial cell-specific expression patterns. Molecular docking confirmed stable pollutant-target binding, with PAH showing highest affinity for CD44 (binding energy −9.32 kcal·mol−1) and GNB3 (−8.32 kcal·mol−1). These findings establish AGER, CAV1, CD44, CEP55, and GNB3 as core molecular mediators of pollution-related LUAD. The high-affinity binding of PAH to CD44 and GNB3 underscores its carcinogenic potential. This study constructs a multi-level regulatory network for EP-LUAD, revealing underlying molecular mechanisms and providing novel potential targets and theoretical basis for early warning and intervention.
Effects of Different Functionalized Nanoplastics on the Transformation of Extracellular Antibiotic Resistance Genes in Aquatic Environments
The rapid dissemination of antibiotic resistance genes (ARGs) in aquatic environments poses serious threats to public health and environmental safety under the 'One Health' framework. Nanoplastics (NPs), as co-occurring pollutants, can exacerbate ARG risks by promoting horizontal gene transfer (HGT), yet the influence of different functional groups on extracellular ARG (eARG) transformation remains unclear. This study investigated the effects of carboxy-modified polystyrene NPs (PS-COOH) and amino-functionalized polystyrene NPs (PS-NH2) compared to unmodified polystyrene NPs (PS) on the transformation of the extracellular resistance plasmid IE-V1955 (carrying an ampicillin resistance gene) into Escherichia coli DH5α. Results showed that PS-COOH exposure promoted plasmid transformation similarly to PS, with effects increasing over 0.1–20 mg·L−1. Low concentrations (0.1–0.5 mg·L−1) of PS-NH2 also enhanced transformation, with stronger effects than PS-COOH at equal doses, whereas high concentrations (1–20 mg·L−1) inhibited it. Mechanistically, PS-COOH (0.1–20 mg·L−1) and low PS-NH2 induced intracellular reactive oxygen species (ROS), increased cell membrane permeability, elevated the protein-to-polysaccharide ratio in extracellular polymeric substances (EPS), and promoted biofilm formation, thereby facilitating transformation. High PS-NH2 concentrations caused excessive ROS leading to cell lysis and formed aggregates with plasmids larger than membrane pores, blocking uptake. These findings provide a theoretical basis for assessing the combined environmental health risks of NPs and ARGs.
Cardiovascular Toxicity Induced by Micro/Nano-Plastics and Its Mechanisms
Micro/nano-plastics (MNPs) are emerging contaminants widely detected in human circulatory systems, including blood, heart, and vascular endothelium, raising concerns about cardiovascular health risks. This systematic review analyzed 61 peer-reviewed studies (2008–2024) to elucidate the cardiotoxic effects and molecular mechanisms of MNPs. Evidence indicates that MNPs exposure elevates risks of atherosclerosis, thrombosis, and arrhythmias through oxidative stress, inflammatory cascades, endothelial dysfunction, and metabolic dysregulation. Notably, co-exposure with persistent organic pollutants (POPs) or heavy metals may produce synergistic or antagonistic effects. Current research relies predominantly on animal and cell models, with critical gaps in low-dose, long-term exposure data and epidemiological evidence. Future studies should optimize experimental designs, integrate metabolomics and epigenetics, and explore transgenerational effects and combined toxicity mechanisms to inform pollution control policies and mitigate cardiovascular risks.
Body Burden of Polybrominated Diphenyl Ethers and Joint Effects on Thyroid Function in a Physical Examination Population in Shenzhen
This study characterized the body burden of polybrominated diphenyl ethers (PBDEs) in a physical examination population in Shenzhen and evaluated its impact on thyroid function. Serum samples from 368 residents were analyzed for eight PBDE congeners using atmospheric pressure gas chromatography-tandem mass spectrometry (APGC-MS/MS). The median concentration of ∑8PBDEs was 10.2 ng·g⁻¹ lipid weight (lw), ranging from 0.13 to 2089.4 ng·g⁻¹ lw, with BDE-209 predominating (59.7% of total). Multiple linear regression revealed that a 1.7-fold increase in serum BDE-153 was associated with a 0.4% increase in free triiodothyronine (FT3) (P<0.05), while a 1.7-fold increase in BDE-183 was associated with a 0.9% decrease in total triiodothyronine (T3) and a 0.7% decrease in FT3 (P<0.05). Bayesian kernel machine regression (BKMR) indicated a negative correlation between mixed PBDE exposure and thyroid-stimulating hormone (TSH) at high exposure levels. Weighted quantile sum (WQS) regression showed that mixed exposure was associated with decreased T3 levels and T3/FT3 ratio, with BDE-153 and BDE-183 as the primary contributors. These findings suggest that PBDE exposure may adversely affect thyroid function and disrupt thyroid hormone homeostasis, with BDE-183 and BDE-153 playing key roles. This study provides a scientific basis for PBDE health risk assessment and thyroid protection.
Mechanisms of Natural Organic Matter in Regulating Microplastic Aggregation and Transport in Soil-Groundwater Systems: A Review
Microplastics (MPs) are persistent emerging contaminants ubiquitously distributed in soil-groundwater environments, where their aggregation and transport critically govern pollutant fate and ecological risks. Natural organic matter (NOM), a complex assemblage of organic compounds, interacts with MPs and porous media via hydrogen bonding, π-π interactions, hydrophobic effects, and electrostatic binding, thereby modulating MP surface properties and environmental behavior. This review systematically synthesizes the mechanisms by which NOM influences MP aggregation and transport, with emphasis on the distinct roles of humic substances, proteins, and extracellular polymeric substances (EPS), and their synergistic modulation with solution chemistry (pH, ionic strength, ion type). Additionally, NOM accelerates MP aging and alters surface characteristics, consequently impacting transport capacity. Current research limitations are identified, and future directions are proposed to inform MP pollution risk assessment and management strategies. Key findings indicate that NOM generally enhances MP stability and mobility at low ionic strengths, while high ionic strengths may induce aggregation depending on NOM type and ion valence. Humic substances predominantly increase electrostatic repulsion, whereas proteins and EPS can bridge particles, promoting aggregation. Aging processes, accelerated by NOM photochemical activity, increase surface oxygen functionality and hydrophilicity, further altering transport. The review underscores the need for systematic studies under environmentally relevant conditions to predict MP fate accurately.
Neurotoxicity of Carboxyl-Modified Polystyrene Microplastics on Zebrafish at Early Developmental Stage
Carboxyl-modified polystyrene microplastics (PS-COOH) are negatively charged particles formed by surface oxidation and functional group modification of polystyrene microplastics (PS), widely used in biomedical and analytical chemistry. However, studies on their neurotoxic effects on aquatic organisms are scarce. This study employed zebrafish (Danio rerio) as a model organism, exposing embryos to environmentally relevant concentrations (0.1, 1, 10, 100 μg·L−1) of PS and PS-COOH. Neurotoxic effects were assessed by measuring tail coiling frequency at 24 hpf and swimming velocity under alternating light/dark cycles at 120 hpf. Results demonstrated that both PS and PS-COOH induced neurotoxicity, with PS-COOH significantly reducing tail coiling frequency and average swimming speed compared to PS (P<0.05). Exposure to 10 μg·L−1 PS-COOH disrupted neurotransmitter homeostasis, altering levels of acetylcholine (ACh), serotonin (5-HT), and γ-aminobutyric acid (GABA). Transgenic zebrafish Tg(huc:EGFP) fluorescence assays revealed that PS-COOH (0.1–100 μg·L−1) caused damage to central neurons. These findings indicate that PS-COOH exposure impairs cholinergic, serotonergic, and GABAergic neurotransmission, induces neuronal damage, and exerts neurotoxic effects on zebrafish larvae. This study provides a theoretical basis for assessing the ecological and health risks of modified microplastics.