Dragana Vasić Anićijević

This research investigates sustainable water treatment by evaluating competitive adsorption of Zn, Cd, and Hg using nitrogen-doped and nitrogen co-doped carbon cryogels. The synthesized materials exhibited high specific surface areas (up to 1530 m²/g) and a maximum multicomponent adsorption capacity of 1.03 mmol/g for the CCNS₃ sample. The practical applicability of these adsorbents was successfully validated in a real water sample, achieving up to 93% removal efficiency for the investigated metals despite the presence of background ions. Kinetic analysis confirmed that the adsorption process was predominantly controlled by the pseudo-second-order model while intraparticle diffusion modeling revealed a multi-stage adsorption process in which N, S co-doping significantly accelerated the initial mass transfer. The extended Sips isotherm best described multicomponent adsorption, indicating heterogeneous multi-site adsorption on sample surfaces. Concurrently, FTIR spectroscopy and DFT modeling confirmed a dual mode mechanism: while physisorption occurs on basal planes (E_ads > −0.8 eV, no charge transfer), the adsorption energy increases significantly at structural defects (N- and S-defects: E_ads < −2 eV, significant charge transfer). Excellent reusability properties of samples were confirmed over four consecutive adsorption–desorption cycles. These findings present a highly sustainable approach for competitive heavy metal removal establishing tailored doped and co-doped carbon cryogels as efficient, robust and reusable adsorbents.

Organophosphate removal is crucial for protection of human health, preservation of biodiversity, and prevention of long-term contamination of soil and water systems. Organophosphate removal using carbon-based materials is widely investigated and employed because these materials are widely available, low-cost, and simple to use, making them practical for treating contamination under diverse conditions. The density functional theory (DFT) is a common tool of computational chemistry to assess the molecular aspects of the interaction between organic molecules and ordered supports such as graphene and modified graphene, including: adsorption geometry, adsorption energetics, nature of interaction (chemisorption of physisorption), and mechanistic insights. On the other hand, such task becomes more complex when the adsorbate and the support are rich in functional groups and diverse in steric properties. This contribution deals with the DFT investigation of adsorption of several selected and commonly used organophosphate model molecules on graphene oxide. The goal was to find the optimal binding geometry among several selected input positions and to find energetically most stable orientations. The obtained output geometries were further analyzed and discussed in order to design more precise carbon-based materials for advanced purposes, such as reusable adsorbents or catalysts for irreversible organophosphate hydrolysis.

Apricot kernel shells were evaluated as a sustainable activated carbon precursor for wastewater treatment using experimental and theoretical methods. Two adsorbents were synthesized: physically activated with CO₂ (AKS-CO₂) and chemically activated with H₃PO₄ (AKS-H₃PO₄). Comprehensive materials characterization and adsorption tests using Pb²⁺ ions and Rhodamine B dye (RhB) as model pollutants revealed that AKS-H₃PO₄ significantly outperformed its physically activated counterpart. With an exceptionally high specific surface area (1159.4 m²/g) enriched with phosphorus-containing functional groups, the chemically activated carbon demonstrated outstanding removal efficiencies of 85.1% for Pb²⁺ and 80.3% for RhB. Kinetic studies showed Pb²⁺ adsorption followed pseudo-second-order kinetics, indicating chemisorption, while RhB adsorption fitted pseudo-first-order kinetics, suggesting intra-particle diffusion control. The thermodynamic analysis confirmed the spontaneity of both processes: Pb²⁺ adsorption was exothermic under standard conditions with positive isosteric heat at higher concentrations, reinforcing its chemisorption nature, whereas RhB adsorption was endothermic, consistent with physisorption. Density Functional Theory (DFT) calculations further elucidated the mechanisms, revealing that Pb²⁺ preferentially binds to oxygen-containing functional groups, while RhB interacts through hydrogen bonding and π–π stacking. These findings establish chemically activated apricot kernel shell carbon as a high-performance adsorbent, exhibiting exceptional removal capacity for both ionic and molecular contaminants through distinct adsorption mechanisms.

The efficiency of electrochemical advanced oxidation processes (EAOPs) is fundamentally governed by hydroxyl-radical (•OH) generation. While direct experimental measurements of these transient species remain complex and impractical, robust computational methods for predicting their temporal profiles are notably scarce. This work presents a semi-empirical methodology based on H₂O₂ measuring experiments that enables indirect •OH quantification. We employed a recently developed carbon-based electrode and the priority pollutant bisphenol A (BPA) as the model system. The system achieved 92.3% BPA degradation with 84% mineralization efficiency during 5-h electrooxidation at 15 mA/cm². Gas chromatography/mass spectrometry (GC/MS) was used for tracking BPA and detection of intermediates. On this basis, we developed a computational model that successfully predicts temporal concentration profiles of all reactive species interacting with •OH, along with degradation kinetics across current densities (10–20 mA/cm²). By incorporating predictions from the Toxicity Estimation Software Tool (T.E.S.T.), the developed model accurately simulates time-dependent evolution of relative toxicity throughout the treatment process. The presented approach has a general character and requires rather simple experimental input to predict and optimize degradation outcome in terms of input concentration, degradation time, current density, and final toxicity. Further modifications of the model would enable widening to other EAOPs systems.

In recent years, the issue of emerging pollutants, particularly antibiotics, in aquatic ecosystems has garnered significant attention due to their potential environmental and public health impacts. To address this, we synthesized TiO2 modified with Cu at three different molar ratios (0.5%, 1%, and 2%) and applied these photocatalysts to degrade ciprofloxacin in an infusion solution. The photodegradation process was monitored over 240 minutes using UV-Vis spectroscopy. The results indicated that the degradation efficiency of all three photocatalysts was approximately 50%. However, determining the precise degradation efficiency solely through UV-Vis spectroscopy proved challenging. This is because some degradation by-products exhibited absorbance maxima similar to ciprofloxacin, leading to potential inaccuracies in measuring the true extent of degradation. Further analysis, such as high-performance liquid chromatography (HPLC) or mass spectrometry, would be required to more accurately quantify the degradation products and assess the overall efficiency of the photodegradation process. This study highlights the complexity of using UV-Vis spectroscopy alone for analyzing antibiotic degradation in aquatic environments.

Bisphenol S (BPS) is a synthetic compound frequently used as an alternative to Bisphenol A (BPA) in the manufacture of various plastics and resins. Its widespread use has led to its detection in environmental samples, raising concerns about its potential endocrine-disrupting effects and toxicity. Recent research shows that BPS can leach from consumer products and accumulate in aquatic ecosystems, posing risks to both aquatic organisms and human health. Electrochemical oxidation of BPS has emerged as a promising approach for its degradation. This study examines the electrochemical oxidation of Bisphenol S utilizing SnO₂-MWCNT (multi-walled carbon nanotubes) electrodes in a galvanostatic regime at different current densities (10, 15 and 20 mA cm⁻²). The main objective of this study was to compare the removal efficiency and energy consumption during the degradation of BPS on various current densities. Experimental results indicated that an increase in current density corresponds to a rise in both removal efficiency and energy consumption. However, this observation highlights the necessity for careful optimization to balance efficiency and energy consumption in real-world applications.

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.

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.

Electrochemical advanced oxidation processes (EAOPs) are at the forefront of scientific research as green technologies aimed at effectively purifying polluted aquatic environments. These methods utilize electrochemical processes to generate reactive oxygen species (ROS), such as the hydroxyl radical (•OH), either on the anode surface or within the bulk solution, which can partially degrade or completely mineralize organic pollutants. The aim of the article is to provide a bibliometric analysis of research articles specifically focused on the application and development of EAOPs in wastewater treatment over the past five years. Utilizing the most extensive database for literature searches, Web of Science Core Collection (WoS), which encompasses 95% of global publications, a total of 649 research articles were retrieved by limiting the search results to words associated with EAOPs in titles, keywords, and abstracts. The bibliometric dataset was then processed using CiteSpace and VOSviewer software. The People’s Republic of China is emerging as the country with the highest production in the field, demonstrating a strong commitment to research and a leading role in international cooperation. This leadership is evident through China’s substantial contributions to the body of literature and its extensive network of collaborations with researchers worldwide. Meanwhile, Australia, despite producing fewer publications, has achieved a high citation rate, underscoring the significant impact and influence of its research within the scientific community. One of the most promising and extensively studied topics in this field is the electro-Fenton process, which has garnered considerable attention due to its potential applications and remarkable efficiency in various contexts. The bibliometric analysis conducted in this study allowed for a detailed visualization of the currently available literature data and corresponding developing trends. By mapping out the key areas of focus, prominent researchers, influential journals, and collaborative networks, this analysis provides valuable insights. These insights can facilitate future joint research endeavors, enhance collaboration, and promote the sharing of knowledge and best practices among researchers globally.

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.