Search Results (152)

Due to its efficiency, advanced oxidation processes (AOP), such as photo-Fenton, have become an alternative for removing emerging contaminants like paracetamol. The objective of this work was to perform a life cycle assessment (LCA) according to ISO 14040/44 for a heterogeneous photo-Fenton process catalyzed by Cu/Fe-pillared clays (PILC) for the removal of paracetamol from water. The study covered catalyst synthesis and four treatment scenarios, with inventories built from experimental data and ecoinvent datasets; treatment time was 120 min per functional unit. Environmental impacts for catalyst synthesis were quantified with ReCiPe 2016 (midpoint), while toxicity-related impacts of the degradation stage were assessed with USEtox™ (human carcinogenic toxicity, human non-carcinogenic toxicity, and freshwater ecotoxicity). Catalyst synthesis dominated most midpoint categories, the global warming potential for 1 g of Cu/Fe-PILC was 10.98 kg CO₂ eq. Toxicity results for S4 (photo-Fenton Cu/Fe PILC) showed very low values: 9.73 × 10⁻¹² CTUh for human carcinogenic and 1.29 × 10⁻¹³ CTUh for human non-carcinogenic. Freshwater ecotoxicity ranged from 5.70 × 10⁻⁴ PAF·m³·day at pH 2.7 (≥60 min) to 1.67 × 10⁻⁴ PAF·m³·day at pH 5.8 (120 min). Overall, optimizing pH and reaction time, are key levers to improve the environmental profile of AOP employing Cu/Fe-PILC catalysts. Full article

In this work, the removal of Cu(II) ions from an aqueous effluent was studied using an Mg/Fe layered double hydroxide (LDH) as the adsorbent. The material was synthesized and characterized before and after the adsorption process to identify structural and morphological changes induced by copper uptake. Techniques such as X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, and nitrogen physisorption (BET) were employed to confirm the interaction between the metal ions and the LDH surface. The LDH-Mg/Fe exhibited a high maximum adsorption capacity of 526 mg/g, and the adsorption kinetics followed a pseudo-second-order model, achieving over 90% removal of Cu(II) within 2.5 h. The Cu(II)-loaded material was subsequently evaluated as a sustainable catalyst in two applications: (i) an organic synthesis via “click” chemistry, reaching yields of up to 85%, and (ii) the decoloration of Congo Red via a Fenton-like process, achieving a decoloration efficiency of at least 84%. These dual uses demonstrate the potential of Cu(II)-loaded LDH as a cost-effective and environmentally friendly approach to simultaneous pollutant removal and catalytic valorization. Full article

Despite the immense potential in environmental remediation, the translation of magnetic nanomaterials (MNMs) from laboratory innovations to practical, field-scale applications remains hindered by significant technical and environmental challenges. This is particularly evident in soil environments—which are inherently more complex than aquatic systems and have received comparatively less research attention. Beginning with an outline of the fundamental properties that make iron-based MNMs effective as adsorbents and catalysts for heavy metals and organic pollutants, this review systematically examines their core contaminant removal mechanisms. These include adsorption, catalytic degradation (e.g., via Fenton-like reactions), and magnetic recovery. However, the practical implementation of MNMs is constrained by several key limitations, such as particle agglomeration, oxidative instability, and reduced efficacy in multi-pollutant systems. More critically, major uncertainties persist regarding their long-term environmental fate and biocompatibility. In light of these challenges, we propose that future efforts should prioritize the rational design of stable, selective, and intelligent MNMs through advanced surface engineering and interdisciplinary collaboration. Full article

The selective oxidation of methane to methanol under mild conditions remains a significant challenge due to its stable C-H bond and the propensity for overoxidation of products. Herein, we investigated the Fe- and Cu-modified ZSM-5 catalysts using H₂O₂ as an oxidant for the selective oxidation of methane. It was found that the Fe/Cu ratio had a great impact on methanol yield. The Fe₃Cu₁ displayed the highest methanol yield of 29.7 mmol g_cat⁻¹ h⁻¹ with a selectivity of 80.9% at 70 °C. Further analysis revealed that Fe₃Cu₁ showed the highest Fe³⁺ and Cu⁺ contents. The optimal dual valence cycle not only facilitates the efficient utilization of H₂O₂, promoting the activation of methane to •CH₃ at the Fe site, but also suppresses the deep oxidation caused by the Fenton-like effect of Fe/H₂O₂, thus maintaining the high yield and high selectivity of methanol. Full article

Large amounts of spent, radioactive, ion-exchange resins have been generated worldwide, and their production is expected to grow due to a renaissance of nuclear power. Such waste is being stored at individual plant sites around the world, awaiting a reliable disposal route to overcome the downsides of the state-of-the-art management approaches. In this work, a first-of-its-kind pre-disposal strategy is proposed, based on the integration of a heterogeneous Fenton-like treatment with conditioning in an alkali-activated matrix. In particular, the circular economy is pursued by repurposing two industrial by-products, coal fly ash and steel slag, both as catalysts of the Fenton treatment and precursors of the conditioning matrix. The obtained waste forms have been preliminarily tested for leaching and compressive strength according to the Italian waste acceptance criteria for disposal. The proposed technology, tested at laboratory scale up to 100 g of virgin cationic resin, has proven successful in decomposing the waste and synthesizing waste forms with an overall volume increase of only 30%, thereby achieving a remarkable result compared to state-of-the-art technologies. Full article

This study reports the hydrothermal synthesis, characterization, and Fenton-like catalytic performance of CeO₂–CoFe₂O₄ nanocomposites for degrading Congo Red (CR) dye and the oxytetracycline (OTC) antibiotic. A series of Ce-doped cobalt ferrite samples was prepared using a hydrothermal reaction. Additionally, the 50Ce-CFO sample was further activated with H₂O₂ treatment. XRD, FTIR, and SEM analyses confirmed the formation of a spinel phase alongside segregated CeO₂, which acts as a grain-growth inhibitor. The increased Ce content promotes particle amorphization. FTIR showed changes in the intensity of the M–O stretching band, indicating Ce-induced bond polarization in the spinel lattice. In H₂O₂ decomposition tests, the 50Ce-CFO catalyst fully decomposes H₂O₂ in 160 min, while the activated sample completes it in 125 min. Fenton-like degradation of CR and OTC by untreated and activated 50Ce-CFO sample followed pseudo-first-order kinetics. Catalyst stability was confirmed using post-reaction XRD, FTIR, and SEM analyses. Incorporation of CeO₂ into CoFe₂O₄ refines the crystallite size, increases the BET surface area, and enhances adsorption capacity, while the Ce⁴⁺/Ce³⁺ redox couple promotes reactive oxygen species generation. Owing to this dual structural and catalytic role, the CeO₂-CoFe₂O₄ composites exhibit significantly improved Fenton-like catalytic activity, enabling the efficient degradation of organic pollutants. Full article

Water contamination by emerging pollutants poses a significant environmental challenge, demanding innovative treatment technologies beyond conventional methods. Advanced oxidation processes (AOPs) utilizing niobium-based catalysts, particularly niobium oxide (Nb₂O₅) and its modified forms, are prominent due to their high chemical stability, effective reactive oxygen species (ROS) generation, and versatility. This review systematically examines recent advancements in Nb₂O₅-based catalysts across various AOPs, including heterogeneous photocatalysis, electrocatalysis, and Fenton-like reactions, highlighting their mechanisms, material modifications, and performance. Following PRISMA and InOrdinatio guidelines, 381 papers were selected for this synthesis. The main findings indicate that niobium incorporation enhances pollutant degradation by extending light absorption, reducing electron–hole recombination, and increasing ROS generation. Structural modifications such as crystalline phase tuning, defect engineering, and the formation of heterostructures further amplify catalytic efficiency and stability. These catalysts demonstrate considerable potential for water treatment, effectively degrading a broad range of persistent contaminants such as dyes, pharmaceuticals, pesticides, and personal care products. This review underscores the environmental benefits and practical relevance of Nb₂O₅-based systems, identifying critical areas for future research to advance sustainable water remediation technologies. Full article

This study investigates Fenton-based processes for textile dye degradation, focusing on Direct Red 28 (DR28), Reactive Blue 19 (RB19), and Reactive Black 5 (RBk5). Results reveal varying effectiveness of catalyst–radical combinations, with copper and peroxydisulfate consistently performing well, especially on RBk5 with 100% and 98.5% decolorization and total organic carbon (TOC) reduction, respectively. Iron faces limitations with DR28 due to sediment formation, resulting in 3.5% and 52.7% TOC removal when paired with hydroxyl and peroxydisulfate radicals, correspondingly. Unexpectedly, cobalt shows notable capabilities with RBk5, reaching 87.2% TOC removal, but performs poorly on the other two dyes, with less than 20% TOC removal when paired with hydroxyl radicals. Cost analysis highlights the cost-effectiveness of the standard photo-Fenton process for easy-to-degrade dyes with a cost of $0.174/g TOC removed, while copper emerges as a viable option for recalcitrant dyes, costing $0.371/g TOC removed. Overall, this research enhances understanding of catalyst–radical interactions on various dyes, a topic that is scarcely discussed in other research, and expands upon it by using techno-economic analysis for Fenton-based technologies for textile wastewater treatment, as a consideration for technology selection in actual application. Full article

The production of alumina produces red mud (RM), a highly alkaline solid waste. The majority of it is disposed of in landfills, which seriously pollutes the environment. It needs to be recycled and handled with care to protect the environment. RM is a promising raw material for wastewater and waste gas treatment owing to its high alkalinity and abundant metal compounds. It can efficiently remove diverse pollutants while facilitating large-scale utilization of RM resources. Reviews of the use of RM resources to create catalysts for environmental governance are, nevertheless, scarce. Therefore, this paper analyzes and summarizes the pertinent research on RM-based catalysts to remove pollutants from the environment based on journal literature related to RM resource utilization from 2015 to 2025. This study reviews the application of RM-based catalysts for degrading pollutants in wastewater and exhaust gases via advanced oxidation processes (AOPs)—including photocatalysis, Fenton-like catalysis, ozonation catalysis, and persulfate catalysis—as well as catalytic oxidation, chemical looping combustion (CLC), and selective catalytic reduction (SCR). The paper emphasizes the analysis of modification strategies and catalytic mechanisms of RM-based catalysts in environmental remediation and examines the environmental risks and corresponding mitigation measures related to their preparation from RM resources. Finally, it outlines that future research should prioritize green, low-energy modification processes; catalytic systems for the synergistic removal of multiple pollutants; and efficient, recyclable separation and recovery technologies. These directions aim to promote the sustainable application of RM in large-scale environmental remediation and to achieve the integrated advancement of resource utilization and ecological protection. Full article

This short review provides a focused overview of recent advances in catalytic systems for water purification, with particular attention to photocatalysis, Fenton-like processes, and biocatalysis. While not intended as a comprehensive survey, this review is grounded primarily in recent work from our research group, supported by comparisons with relevant studies from the broader literature. Emphasis is placed on the role of graphene-based materials, particularly aerogels, hydrogels, and xerogels, as functional platforms for catalytic nanoparticles inclusion and enzyme immobilization. This review aims to highlight key insights, practical limitations, and emerging strategies to improve catalyst reusability, stability, and scalability for real-world water treatment applications. Full article

Fenton oxidation can contribute to meeting effluent standards for COD in actual wastewater treatment plant effluents. However, Fenton oxidation is prone to produce iron sludge waste. The application of heterogeneous Fenton-like systems based on Fenton iron mud carbon in wastewater treatment plants is essential for Fenton iron mud reduction and recycling. In this study, a Fenton iron mud carbon catalyst/Ferrate salts/H₂O₂ (FSC/Fe(VI)/H₂O₂) system was developed to remove chemical oxygen demand (COD) from secondary effluents at the pilot scale. The results showed that the FSC/Fe(VI)/H₂O₂ system exhibited excellent COD removal performance with a removal rate of 57% under slightly neutral conditions in laboratory experiments. In addition, the effluent COD was stabilized below 40 mg·L⁻¹ for 65 days at the pilot scale. Fe(IV) and ¹O₂ were confirmed to be the main active species in the degradation process through electron paramagnetic resonance (EPR) and quenching experiments. C=O, O-C=O, N sites and Fe⁰ were responsible for the generation of Fe(IV) and ¹O₂ in the FSC/Fe(VI)/H₂O₂ system. Furthermore, the cost per ton of water treated by the pilot-scale FSC/Fe(VI)/H₂O₂ system was calculated to be only 0.6209 USD/t, further confirming the application potential of the FSC/Fe(VI)/H₂O₂ system. This study promotes the engineering application of heterogeneous Fenton-like systems for water treatment. Full article

As a result of the catalytic decomposition of H₂O₂, hydroxyl radicals are produced. Hydroxyl radicals are strong oxidants and effectively inactivate bacteria, ensuring water disinfection without toxic chlorinated organic by-products. The kinetics of bacterial inactivation were studied in a laboratory-scale flow catalytic reactor. A granular cobalt ferrite catalyst was thoroughly characterized using XRD and XRF techniques, SEM with EDS, and Raman spectroscopy. At lower H₂O₂ concentrations, H₂O₂ decomposition follows first-order reaction kinetics. At higher H₂O₂ concentrations, the obtained kinetics lines suggest that the reaction order increases. The kinetics of bacterial inactivation in the developed flow reactor depends largely on the initial number of bacteria. The initial bacterial concentrations in laboratory tests were within the range typical of real river water. A regression model was developed that relates the degree of bacterial inactivation to the initial number of bacteria, the initial H₂O₂ concentration, and the contact time of water with the catalyst. Full article

In this study, the degradation of Nile Blue dye was investigated using homogeneous and heterogeneous photocatalytic methods based on the photo-Fenton reaction. More specifically, for homogeneous photocatalysis, the classical photo-Fenton (UV/Fe²⁺/H₂O₂) and modified photo-Fenton-like (UV/Fe²⁺/S₂O₈²⁻) systems were studied, while for heterogeneous photocatalysis, a commercial MOF catalyst, Basolite F300, and a natural ferrous mineral, geothite, were employed. Various parameters—including the concentrations of the oxidant and catalyst, UV radiation, and pH—were investigated to determine their influence on the reaction rate. In homogeneous systems, an increase in iron concentration led to an enhanced degradation rate of the target compound. Similarly, increasing the oxidant concentration accelerated the reaction rate up to an optimal level, beyond which radical scavenging effects were observed, reducing the overall efficiency. In contrast, heterogeneous systems exhibited negligible degradation in the absence of an oxidant; however, the addition of oxidants significantly improved the process efficiency. Among the tested processes, homogeneous techniques demonstrated a superior efficiency, with the conventional photo-Fenton process achieving complete mineralization within three hours. Kinetic analysis revealed pseudo-first-order behavior, with rate constants ranging from 0.012 to 0.688 min⁻¹ and correlation coefficients (R²) consistently above 0.90, confirming the reliability of the applied model under various experimental conditions. Nevertheless, heterogeneous techniques, despite their lower degradation rates, also achieved high removal efficiencies while offering the advantage of operating at a neutral pH without the need for acidification. Full article

This paper presents a study on the optimization of 2,4-Dichlorophenoxyacetic (2,4-D) acid removal from synthetic wastewater by batch Fenton-Ozonation. The aim of this study is to evaluate the potential of the catalytic system Fe-L27 coupled to ozonation in the presence and absence of H₂O₂ as an effective and affordable technique for the treatment of organic pollutants in water. Fenton-like catalysts for the removal of 2,4-D in aqueous solutions were elaborated using catalysts synthesized by the wet impregnation method. The ACs and prepared catalysts were characterized by nitrogen adsorption–desorption isotherms at 77 K, TGA, XPS, SEM, and TEM. Their efficiency as Fenton-like catalysts was studied. In a first step, a response surface modeling method was employed in order to find the optimal parameters of the Fenton process, and then the optimal O₃/H₂O₂ ratio was established at laboratory scale. Finally, the investigated advanced oxidation processes were carried out at pilot scale. The results show that Fenton-like catalysts obtained by the direct impregnation method enhance the degradation rate and mineralization of 2,4-D. Full article

Antibiotic resistance has been recognized as a global threat to human health. Therefore, it is urgent to develop effective strategies to address the contamination of water environments caused by antibiotics. In this study, Fe/Mn bimetallic-modified biochar (FMBC) was synthesized through a one-pot oxidation/reduction-hydrothermal co-precipitation method, demonstrating an exceptional photocatalytic-Fenton degradation performance for oxytetracycline (OTC). Characterization techniques including FTIR, SEM, XRD, VSM, and N₂ adsorption–desorption analysis confirmed that the Fe/Mn bimetals were successfully loaded onto the surface of biochar in the form of Fe₃O₄ and MnFe₂O₄ mixed crystals and exhibited favorable paramagnetic properties that facilitate magnetic recovery. A key innovation is the utilization of biochar’s inherent phenol/quinone structures as reactive sites and electron transfer mediators, which synergistically interact with the loaded bimetallic oxides to significantly enhance the generation of highly reactive ·OH radicals, thereby boosting catalytic activity. Even after five recycling cycles, the material exhibited minimal changes in degradation efficiency and bimetallic crystal structure, indicating its notable stability and reusability. The photocatalytic degradation experiment conducted in a Fenton-like reaction system demonstrates that, under the conditions of pH 4.0, a H₂O₂ concentration of 5.16 mmol/L, a catalyst dosage of 0.20 g/L, and an OTC concentration of 100 mg/L, the optimal degradation efficiency of 98.3% can be achieved. Additionally, the pseudo-first-order kinetic rate constant was determined to be 4.88 min⁻¹. Furthermore, this study elucidated the detailed degradation mechanisms, pathways, and the influence of various ions, providing valuable theoretical insights and technical support for the degradation of antibiotics in real wastewater. Full article