Optimization of the efficiency of the photocatalytic degradation of organic and pharmaceutical pollutants represents a matter of fundamental and practical interest. The present experimental and DFT study deals with evaluation of OH radical binding energy as a simple computational descriptor of the catalytic activity of d-metal-decorated TiO₂ photocatalysts for the photodegradation of the widely used antibiotic ciprofloxacin. Five d-metals commonly used in catalytic materials (Zr, Pt, Pd, Fe, and Cu) were deposited on the TiO₂ surface, and the obtained photocatalysts were characterized experimentally (XRPD, ICP-OES, and SEM) and theoretically (DFT). Attention was also paid to the mechanistic insights and degradation byproducts (based on UV-Vis spectrometry and LC/MS analysis) in order to obtain systematic insight into their structure/performance relationships and confirm the proposed model of the degradation process based on OH radical reactivity.

This paper presents a comparative analysis of three carbon-based electrodes: bare multiwalled carbon nanotubes (MWCNT), SnO₂/MWCNT, and PbO₂/graphene-nanoribbons (PbO₂/GNR) composites, as anodes for the electrooxidative degradation of Rhodamine B as a model organic pollutant. Anodic electrooxidation of Rhodamine B was performed on all three electrodes, and the decolorization efficiency was found to increase in the order MWCNT < PbO₂/GNR < SnO₂/MWCNT. The electrodes were characterized by X-ray photoelectron spectroscopy (XPS) and linear sweep voltammetry (LSV). It was proposed that, in the 0.1 M Na₂SO₄ applied as electrolyte, observed decolorization mainly occurs in the interaction of Rhodamine B with OH radical adsorbed on the anode. Finally, the obtained results were complemented with Density Functional Theory (DFT) calculations of OH-radical interaction with appropriate model surfaces: graphene(0001), SnO₂(001), and PbO₂(001). It was found that the stabilization of adsorbed OH-radical on metal oxide spots (SnO₂ or PbO₂) compared to carbon is responsible for the improved efficiency of composites in the degradation of Rhodamine B. The observed ability of metal oxides to improve the electrooxidative potential of carbon towards organic compounds can be useful in the future design of appropriate anodes.

Last decade, a growing emphasis on developing sustainable and environmentally friendly technologies for electro-oxidative wastewater treatment has catalyzed innovation and spurred research efforts worldwide. Researchers may explore the use of renewable energy sources to drive electrochemical processes, as well as the development of eco-friendly electrode materials for wastewater treatments. The integration of nanostructured anodes into the electrolytic system for wastewater treatment has led to significant advancements in the removal of pollutants via electro-oxidation. Despite the great number of research articles related to the development and use of nanostructured anodes for electro-oxidative wastewater treatment, to our knowledge, no bibliometric analysis has been published in this domain. Therefore, this work presents a bibliometric study of publications on the designated theme, retrieved from the Web of Science Core Collection database, which were published over the last decade. The visual and network analysis of co-authorship among authors, organizations, countries, co-citation of authors, citation of documents and sources, as well as the co-occurrence of author keywords was performed using two compatible pieces of scientometric software, namely VOSviewer (version 1.6.18) and CiteSpace (version 6.2.R4). From 2013 to 2023, there has been a gradual increase in the number of publications regarding the development and use of nanostructured anodes for electro-oxidative wastewater treatment. It suggests a steady advancement in this field. The People’s Republic of China emerges as the most productive country, and it is a leader in international collaborations. Also, the United States of America, South Korea, and European Union countries have significant impacts on the research in this domain. The development and application of nanostructured materials for urea electro-oxidation is a main and prospective research theme. This bibliometric analysis allowed for the visualization of the present landscape and upcoming trends in this research field, thereby facilitating future collaborative research endeavors and knowledge exchange.

Rhodamine B is a synthetic dye commonly used in the textile and printing industries, recognized as a significant water pollutant. It enters aquatic environments primarily through untreated wastewater, posing serious threats to both environmental ecosystems and human health due to its toxic, carcinogenic, and non-biodegradable properties. The dye's persistence in water can result in harmful effects on ecosystems and contamination of vital water sources, underscoring the urgent need for effective removal methods. Electrochemical degradation has emerged as an eco-friendly technology to tackle this issue, breaking down Rhodamine B into less harmful byproducts and providing a sustainable approach for mitigating its environmental impacts. This study investigates the electrochemical degradation of Rhodamine B using glassy carbon (GC), stainless steel (SS), and nickel (Ni) electrodes in an undivided two-electrode system operating under a galvanostatic regime at a current density of 15 mA cm⁻². The primary goal was to compare the efficiency and kinetics of degradation across different electrode types. Experimental results demonstrated that GC electrodes, followed by SS, exhibited the highest degradation efficiency, with the process adhering to first-order kinetics. These findings highlight the advantages of GC electrodes in terms of speed and efficiency, offering valuable insights for optimizing treatment processes.

Considering the increasing significance of emerging pollutants in the environment, this research investigates the photodegradation of ciprofloxacin, which ranks among the top three most detected antibiotics in aquatic ecosystems. Therefore, we synthesized TiO2 modified with Fe in three different molar ratios (0.5, 1 and 2 %) and applied it to the photodegradation of the ciprofloxacin infusion solution. The photodegradation process was monitored by UV-Vis spectroscopy for over 240 minutes. The results have shown that the efficiency rate is around 50 % for all three photocatalysts. However, the degradation efficiency can’t be precisely determined with UV-Vis spectroscopy because by-products that occurred in degradation have an absorbance maximum similar to the ciprofloxacin.

Due to its widespread use, bisphenol A (BPA) is commonly found as a contaminant in wastewater, posing significant environmental and health risks. Conventional treatment methods often fail to completely remove it, necessitating the development of more effective technologies. Advanced oxidation processes (AOPs), particularly the Fenton reaction, have garnered considerable attention for the degradation of organic pollutants. The Fenton reagent uses hydrogen peroxide (H₂O₂) and ferrous iron (Fe²⁺) to generate hydroxyl radicals (•OH), which are highly reactive and capable of breaking down BPA. This study investigates the effect of H₂O₂ concentration on the efficiency and kinetics of BPA degradation in sulfate-rich wastewater using the Fenton process. The results show that increasing H₂O₂ concentration enhances BPA degradation, with a pseudo-first-order kinetic model describing the process. These findings support the optimization of the Fenton process for the efficient removal of BPA from wastewater.