Influence of the RuO2 layer thickness on the physical and electrochemical properties of anodes synthesized by the ionic liquid method

Optimizing difenoconazole degradation via sequential photoelectrochemical oxidation and biodegradation treatments

The growing global demand for food has intensified the use of pesticides in conventional agriculture, raising concerns about their environmental contamination and persistence. This study proposes an integrated strategy for the degradation of difenoconazole (DFZ), combining photoelectrochemical oxidation (PECO) with biodegradation. A mixed metal oxide anode, Ti/(RuO2)0.8(Sb2O4)0.1(TiO2)0.1 was successfully synthesized via the ionic liquid method, and a mangrove-derived Bacillus sp. isolate was employed in a sequential treatment process. Individually, the Bacillus strain degraded 74.56 % of DFZ1 and 72.52 % of DFZ2, while PECO alone achieved a lower removal efficiency of 32 %. Notably, the sequential application of PECO followed by biodegradation enhanced the degradation rates to 77.81 % for DFZ1 and 74.45 % for DFZ2. Additionally, this combined approach significantly reduced chemical oxygen demand (70.6 %) and toxicity, as evidenced by improved lettuce seed germination indices. These findings underscore the potential of integrating PECO with biodegradation as a promising strategy for the remediation of difenoconazole (DFZ), offering new perspectives for the treatment of recalcitrant triazole compounds in contaminated environments.

Dipropyl ammonium ionic liquids to prepare Ti/RuO2-Sb2O4 anodes at different calcination temperatures

The development of technologies capable of producing efficient and economically viable anodes is essential for the electrochemical treatment of water contaminated with complex organic pollutants. In this context, the use of ionic liquids as solvents to prepare mixed metal oxide (MMO) anodes has proven to be an up-and-coming alternative. Here, we analyze the influence of the temperature of calcination (300, 350, and 400 ºC) on the production of Ti(RuO2)0.8-(Sb2O4)0.2 anodes made using the thermal decomposition method using three ionic liquids (IL) as solvents: dipropyl ammonium acetate (DPA-Ac), dipropyl ammonium propionate (DPA-Pr), and dipropyl ammonium butyrate (DPA-Bu). The decomposition temperature for all IL, accessed by thermogravimetry, is below 200 ºC. Physical and electrochemical analyses demonstrate that the calcination temperature of the anodes is decisive for their durability and electrochemical properties. Anodes prepared with DPA-Bu at 350 ºC show higher stability (around 35 h) than those made with other ILs at temperatures of 300 and 400 ºC and improved results in terms of 4-NP mineralization, where 97% of TOC removal was achieved in 120 min. It could be verified that the calcination temperature and IL employed had a decisive influence on the characteristics of the presented anodes. Therefore, the anode prepared with DPA-Bu at 350 ºC is promising for application in the degradation of organic compounds.

Innovative sustainable solutions for detoxifying textile industry effluents using advanced oxidation and biological methods

Textile dye wastewater poses significant environmental and public health challenges, particularly in regions with inadequate treatment infrastructure, necessitating a comprehensive evaluation of detoxification technologies. Existing methods often focus on decolorization and chemical oxygen demand (COD) reduction but fail to address persistent toxicity and incomplete mineralization, leaving harmful byproducts in treated effluents. This review critically consolidates advancements of past 15 years, emphasizing the integration of Advanced Oxidation Processes (AOPs) and biological technologies as solutions to these challenges. A key contribution is the introduction of the Net Toxicity Outcome (NTO) metric, a novel framework that quantifies and compares detoxification efficacy across diverse effluent compositions and toxicity endpoints, providing an evidence-based approach for selecting optimal treatment technologies. Analysis reveals that standalone treatments, such as UV-assisted ozonation, often exacerbate toxicity due to byproduct formation, whereas integrated approaches, including bio-photo-Fenton methods and anaerobic biofilm reactors coupled with ozonation, achieve superior detoxification. To bridge gaps in current practices, the review proposes a multi-level ecological assessment framework, enabling evaluations from molecular responses to ecosystem-level impacts. By aligning technological advancements with ecological safety and sustainability, the study offers actionable insights for researchers, industry stakeholders, and policymakers, ensuring scalable solutions for cleaner textile production and sustainable wastewater management.

Efficient photoelectrochemical real textile wastewater detoxification using photoanodes of C3N4-BiVO4

Photoelectrochemical systems utilizing solar energy have garnered significant attention for their sustainability in remediating contaminated water. This study focuses on advancing photoanode development through the utilization of carbon nitrides (C3N4) and bismuth vanadate (BiVO4), two promising semiconductor materials renowned for their efficient electron-hole pair separation leading to enhanced photocatalytic activity. Four distinct materials were synthesized and compared: BiVO4 over C3N4, C3N4 over BiVO4, and pristine BiVO4 and C3N4. Upon electrochemical analysis, the C3N4-BiVO4 heterostructure exhibited the highest photoelectrocatalytic charge transfer constant, mobility, and lifetime of charge carriers. Capitalizing on these exceptional properties, the composite was applied to remove organic matter real effluent from the textile industry. The photoelectrodegradation of the effluent demonstrated substantial removal of Total Organic Carbon (TOC) and the generation of low toxicity degradation products, accompanied by low energy consumption. The compelling results underscore the high potential of the synthesized C3N4-BiVO4 heterostructure for industrial applications, particularly in addressing environmental challenges associated with textile industry effluents.

Enhanced HCB removal using bacteria from mangrove as post-treatment after electrochemical oxidation using a laser-prepared Ti/RuO2-IrO2-TiO2 anode

The environmental persistence of hexachlorobenzene (HCB) is a challenge that promotes studies for efficient treatment alternatives to minimize its environmental impact. Here, we evaluated the HCB removal by electrochemical, biological, and combined approaches. The electrochemical treatment of 4 μM HCB solutions was performed using a synthesized Ti/RuO₂-IrO₂-TiO₂ anode, while the biological treatment using mangrove-isolated bacteria was at 24, 48, and 72 h. The HCB degradability was assessed by analyzing chemical oxygen demand (COD), microbial growth capacity in media supplemented with HCB as the only carbon source, gas chromatography, and ecotoxicity assay after treatments. The synthesized anode showed a high voltammetric charge and catalytic activity, favoring the HCB biodegradability. All bacterial isolates exhibited the ability to metabolize HCB, especially Bacillus sp. and Micrococcus luteus. The HCB degradation efficiency of the combined electrochemical-biological treatment was evidenced by a high COD removal percentage, the non-HCB detection by gas chromatography, and a decrease in ecotoxicity tested with lettuce seeds. The combination of electrochemical pretreatment with microorganism degradation was efficient to remove HCB, thereby opening up prospects for in situ studies of areas contaminated by this recalcitrant compound.

Improved 4-nitrophenol removal at Ti/RuO2-Sb2O4-TiO2 laser-made anodes

In this study, binary and ternary mixed metal oxide anodes of Ti/RuO₂-Sb₂O₄ and Ti/RuO₂-Sb₂O₄-TiO₂ were prepared using two different heating methods: conventional furnace and alternative CO₂ laser heating. The produced anodes were physically and electrochemically characterized by using different techniques. The main difference found in the laser-made anodes was their more compact morphology, without the common deep cracks found in anodes made by typical thermal decomposition, which showed an important correlation with the prolonged accelerated service life. The correlation between the physicochemical properties of the anodes with their performance towards the 4-nitrophenol oxidations is discussed. The results demonstrated that the ternary anode (Ti/RuO₂-Sb₂O₄-TiO₂) is very promising, presenting a kinetic 5.7 times faster than the respective binary anode and the highest removal efficiency when compared with conventionally made anodes. Also, the lowest energy consumption per unit of mass of contaminant removed is seen for the laser-made Ti/RuO₂-Sb₂O₄-TiO₂ anode, which evidences the excellent cost-benefit of this anode material. Finally, some by-products were identified, and a degradation route is proposed. Graphical abstract.

Synthesis of Ti(OH)OF ⋅ 0.66 H2 O in Imidazolium-based Ionic Liquids

The influence of the cation of imidazolium-derived ionic liquids (ILs) on a low-temperature solution-based synthesis of hexagonal tungsten bronze (HTB) type Ti(OH)OF ⋅ 0.66 H2 O and bronze-type TiO2 (B) is investigated. The IL (Cx mim BF4 ) acts as solvent and also as reaction partner with respect to the decomposition of [BF4 ]- , releasing F- . In the present study, the chain length of the alkyl chain side groups attached to the imidazolium ring was varied (C2 mim BF4 to C10 mim BF4 ), and the obtained solids were analyzed by Powder X-Ray diffraction (PXRD) followed by Rietveld refinement. As a main finding these analyses indicate a transformation of Ti(OH)OF ⋅ 0.66 H2 O into TiO2 (B), and upon prolonged reaction time finally also into anatase TiO2 . Rietveld analysis suggests that when using ILs with longer alkyl chains, the conversion of Ti(OH)OF ⋅ 0.66 H2 O is slower compared to syntheses performed with smaller alkyl chains. Hence, Ti(OH)OF ⋅ 0.66 H2 O appears to be metastable and is stabilized by long-chain ILs serving as surfactant attached to the crystallites' surface. In this view, the ILs shield the nanoparticles and thus slow down the conversion into the more stable compounds. This confirms previous findings that ILs act as both, solvent and reaction medium in this reaction, thus enabling the synthesis of peculiar Ti-oxides.