Electrochemical oxidation of polycyclic aromatic hydrocarbons in concrete and toxicity estimation of their degradation products

Policiklični aromatični ugljovodonici (engl. Polycyclic Aromatic Hydrocarbons, PAHs) predstavljaju grupu organskih jedinjenja koja se sastoje od dva ili više kondenzovanih benzenovih prstenova. Istraživanja ukazuju da PAH-ovi imaju kancerogen i mutagen uticaj na ljude i druge žive organizme. Perzistentni su i bioakumulativni i kao takvi predstavljaju opasnost po životnu okolinu. Dodatni problem predstavljaju proizvodi degradacije policikličnih aromatičnih ugljovodonika, koji nastaju tokom prirodne transformacije ili fizičko-hemijskih tretmana za njihovo uklanjanje. Novoformirana jedinjenja često imaju izraženiji toksični uticaj na ljude i druge žive organizme u poređenju sa polaznim jedinjenjem. Zato se posebna pažnja posvećuje razvoju novih metoda za njihovo što bezbednije uklanjanje. Do sada su razvijene metode za analizu sledećih kontaminiranih medijuma: voda, zemljište, vazduh, sedimenti i dr. Kako je zagađenost PAH-ovima u životnoj sredini rasla, uglavnom usled antropogenih faktora, tako su se pojavili i na drugim mestima, poput betona u stambenim zgradama. Cilj istraživanja doktorske disertacije je razvijanje nove, efikasne, neinvazivne metode za uklanjanje PAH-ova iz betona, koja je zasnovana na elektrohemijskoj oksidaciji. Da bi se osigurala bezbednost metode za praktičnu primenu, posebna pažnja posvećena je proceni toksičnosti PAH-a i njihovih produkata razgradnje nastalih tokom procesa elektrooksidacije. Kao laboratorijski model sistem za elektrohemijsku degradaciju PAH-ova koristi se elektrolitička ćelija sa niklenim elektrodama. Praćenje koncentracije PAH-ova u betonu izvedeno je primenom novopostavljene i validirane metode na uređaju tečni hromatograf ultravisokih performansi sa fotodiodnim detektorom (UPLCPDA). Efikasnost uklanjanja za pojedine PAH-ove dostiže vrednost i preko 90 %. Za procenu toksičnosti elektrohemijskog tretmana određuje se citotoksični i genotoksični potencijal na limfocitima i eritrocitima periferne krvi čoveka. Testoviobuhvataju određivanje učestalosti mikronukleusa i proliferacioniog potencijala ćelija, ispitivanje antioksidativne zaštite enzima (katalaze) kao i uticaja na oksidativni stres (određivanjem sadržaja malondialdehida). Rezultati ispitivanja potvrđuju toksičnost početne smeše PAH-ova - pre elektrohmijske oksidacije - uzrokujući značajno povećanje niva DNK oštećenja, smanjujući potencijal ćelija za deobu i indukujući oksidativni stres što se ogleda kroz povećanje malondialdehida u procesu lipidne peroksidacije ćelijskih membrana i povećanju aktivnosti katalaze, enzima antioksidativne odbrane. Procesom elektrohemijske oksidacije PAH-ova nastaju produkti koji ispoljavaju različit stepen citotoksičnosti zavisno od vremena nastanka. Najtoksičniji efekti su utvrđeni u prvih 15 minuta što se manifestuje kroz povećanje učestalosti genomskih ozleda, suprimiranje proliferativnog potencijala i/ili indukciju oksidativnog stresa, kao i značajanu modifikaciju aktivnosti enzima antioksidativne zaštite. Nakon 60 minuta produkti oksidacije su manje citotoksični u odnosu na početno jedinjenje, ali i dalje su toksičniji u poređenju sa netretiranom kontrolom.Polycyclic Aromatic Hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused benzene rings. Research indicates that PAHs have a carcinogenic and mutagenic effect on humans and other living organisms. They are persistent and bioaccumulative and, as such, pose a threat to the environment. Products that are formed upon natural degradation or physicochemical procedures for their removal represent a particular problem. Newly formed compounds often have a more pronounced toxic effect on humans and other living organisms compared to the initial compound. Consequently, the development of new methods for their safe removal has been the subject of extensive research. So far, methods for efficient PAH removal from the various media were developped, including: water, soil, air, sediments, etc. As the environmental pollution by PAHs is continuously increasing due to the various, mainly anthropogenic factors, they also have occurred in other places, such as concrete in residential buildings. The aim of the doctoral dissertation is to develop novel, efficient, noninvasive method for PAHs removal in concrete, based on electrochemical oxidation. In order to ensure safeness of the method for practical application, particular attention was paid to the estimation of the toxicity of PAHs and their degradation products generated during the electrooxidation process. Electrochemical cell consisting of two nickel electrodes was used for the laboratory model of PAH oxidation in concrete. Concentration of PAHs in concrete was monitored with the novel, particularly developed and validated method, based on ultra performance liquid chromatography (UPLC) with photo-diode array (PDA) detector. The removal efficiency for individual PAHs exceeds 90 %. Estimation of the toxicity of electrochemically treated samples was performed by determination of the cytotoxic and genotoxic potential of human peripheral blood lymphocytes and erythrocytes. The tests included determination the micronucleusfrequency and the proliferative potential of cells, determining the antioxidant protection of enzyme catalase, as well as the impact on oxidative stress (by determining the content of malondialdehyde). The results of the study confirm the toxicity of initial PAHs showing that - before electrochemical oxidation - they significantly increase the level of DNA damage, reduce the potential of cells to divide and induce oxidative stress, which is reflected by the increase of malondialdehyde in the process of lipid peroxidation of cell membranes and the increase of the activity of catalase, an antioxidant defense enzyme. Products which are formed during electrochemical oxidation of PAHs exhibit different degrees of cytotoxicity depending on the time of their formation. The most toxic effects were determined in the first 15 minutes, which is manifested by an increased incidence of genomic lesions, suppression of proliferative potential and/or induction of oxidative stress, as well as substantial modification of the antioxidant enzyme activity. After 60 minutes, the oxidation products are less cytotoxic than the parent compound, but still more toxic compared to the untreated control

Testing the electrochemical behavior of BPA on GC, WO3 and MWCNT electrodes

Bisphenol A (BPA) is an organic compound used in large scale at the plastics industry and as a precursor in the synthesis of polycarbonates and epoxy resins, which lead to frequent detections of BPA in surface waters. Therefore, it is necessary to develop and improve methods for BPA detection and monitoring. The electrochemical behavior of Bisphenol A at WO3 and carbon-based electrodes, like glassy carbon (GC) and multi-walled carbon nanotubes (MWCNT), were compared using cyclic voltammetry (CV). Therefore, WO3 nanoparticles were obtained by hydrothermal method and characterization was done using XRDP. The results showed that the responses of the WO3 electrode were 30 times larger compared to another examined electrode. This implies that WO3 electrode can be useful for the detection BPA in nature media

Investigation Of ZrO2 And ZrO2/TiO2 Electrodes By Cyclic Voltammetry

The subject of this study were electrochemical characteristics of transition metal oxide electrodes, consisting specifically of ZrO2 and TiO2, which have different crystallographic structure and lattice parameters. Metal oxides are a significant class of materials which have found vast applications in electrocatalysis. Composites of diverse semiconductors typically display much enhanced electronic conductivity and decreased charge transfer resistance. The goal of this study was to hopefully prepare and investigate electrodes with improved properties, through combination of heterostructures of chemically and structurally dissimilar and wide-bandgap semiconductors. Electroactive surface area was determined by employing cyclic voltammetry peak current method.29th International Conference Ecological Truth and Environmental Research – EcoTER’22" Sokobanja, June 21-24, 2022

Investigation Of Benzophenone-3 Electrochemical degradation On Titanium Electrode

Benzophenone - 3 is a well - known molecular UV filter, main- ly found in commercial cosmetic preparation for sunscreen and skincare. Due t o increased use of sunscreens, it could be found in surface water and wastewater, which could affect the water quality and human health. Research indicates that benzophenone - 3 act as endocrine disruptor and has a carcinogen- ic and mutagenic effect on humans and other living organisms. As such, poses a health risk to all living beings and need to be removed from the environment. Electrochemical techniques for wastewater treatment of organic pollutants show advantages over commercial techniques as practicality , safety, and simple application on both, small and large systems. Aim of the presented research is to examine the possibility of using titanium anode plates for electrochemical degradation of benzophenone - 3 in 0.05M aqueous sodium chloride solution. Elect rolysis was performed in galvanostatic mode at a current density of 25 mA cm - 2 . During 40 minutes of electrolysis, the degradation efficiency of benzo- phenone - 3 is 98.3 %. Additional studies of process kinetics show that degrada- tion of benzophenone - 3 follow s first - order kinetics.Contemporary Materials, Banja Luka Republic of Srpska, September 9-10, 2021

Detection of bisphenol a intermediates during fenton process and prediction of reaction pathways

Bisphenol A (BPA), extensively used in the production of polycarbonate plastic and epoxy resin, poses significant threats to aquatic ecosystems and human health. Advanced oxidation processes (AOPs), which generate reactive species in situ, offer promising alternatives for wastewater treatment. Among these, the Fenton process, generating OH radicals, stands out. This study aims to explore the oxidative degradation of BPA by detecting its intermediates and elucidating its degradation pathway. Our findings reveal the existence of two interconnected degradation pathways. This study underscores the importance of advanced oxidation processes in mitigating the detrimental effects of BPA contamination, emphasizing the need for further research to optimize wastewater treatment methods and safeguard both ecosystems and human health.31st International Conference Ecological Truth and Environmental Research : Sokobanja, Serbia, 18-21 June 2024

Advanced oxidation processes (AOPs) for wastewater treatment: bibliometric study

Advanced oxidation processes (AOPs) represent promising technologies for solving complex challenges in wastewater treatment, using powerful oxidants to degrade a wide range of pollutants. However, achieving a comprehensive understanding of the research landscape in this area is crucial. This paper presents a bibliometric analysis of publications related to AOPs for wastewater treatment, in order to map research trends, identify key contributors and highlight new areas of research. By analyzing data obtained from the Web of Science Core Collection using CiteSpace software, significant insights into publication trends and collaboration are revealed. Key results include the dominance of chemical engineering and environmental sciences as primary research categories. In addition, institutional contributions and author co-citations highlight the significant role of specific subjects and researchers. Furthermore, keyword analysis sheds light on prominent research topics, with degradation and wastewater treatment emerging as central themes. Cluster mapping identifies the main research points, highlighting wastewater treatment as a primary focus, followed by the development and application of photocatalytic methods and graphene oxide. This study provides valuable insights to guide future research directions and collaborative efforts to advance AOP-based wastewater treatment technologies.31st International Conference Ecological Truth and Environmental Research : Sokobanja, Serbia, 18-21 June 2024

Kinetic study of degradation bisphenol a by fenton process

The degradation of bisphenol A in aqueous solutions using the Fenton reagents (H2O2 and Fe2+) was investigated. The molar ratio of the catalyst has been 1:50 (H2O2:Fe2+). The treatment experiment was performed for 300 min to evaluate the kinetics of this process. The kinetics data showed the best fit with the second-order kinetics model.31st International Conference Ecological Truth and Environmental Research : Sokobanja, Serbia, 18-21 June 2024

Is It Possible to Restrain OER on Simple Carbon Electrodes to Efficiently Electrooxidize Organic Pollutants?

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

MALDI TOF and AFM studies of DNA/SWNT hybrids

A primer is a strand of nucleic acid that serves as a starting point for DNA synthesis. DNA, as a large molecule, is very difficult for analysis by means of mass spectrometry. However, primer, as a short sequence of nucleic acid, is much more convinient for e.g. MALDI TOF MS analysis. Mass spectrometric experiment resulted in quality MALDI TOF spectra of 3 primers. Compound 3-HPA (3- hydroxypicolinic acid) showed the best results as matrix. AFM studies were also conducted, for both pure primer samples and hybrids of primer molecule with single wall carbon nanotubes (SWNT). Thus, obtained functionalisation of SWNT with DNA primers was confirmed by AFM imaging. AFM images clearly showed wrapping of DNA structures around nanotube „template“. Functionalisation of SWNT is very important for potential applications of nanotubes in biomedical field. MALDI TOF mass spectrometry, in combination with AFM imaging, proved its great potential in analysis of short DNA sequences, and indicated the possibility of investigating more complex DNA structures.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

New Strategies For Development Of Highly Selective Materials For Carbon Dioxide Capturective materials for carbon dioxide capture

Selective separation of CO2 is a field of intensive research due to emerging emissions from fire coaled and natural gas power plants. In the focus of development efforts is a design of regenerable CO2 capture material where adsorption technologies and advanced solid adsorbents are again in the centre of interest. Short screening of composite zeolite/activated carbon material in the terms of its selectivity for CO2 towards water is presented in this research. Adsorption rate of CO2 and H2O is determined and analysed at two different temperatures and equilibrium pressure of 3.5 kPa which corresponds to flue gases contents. The results imply the water should be removed from treated gas before CO2 separation and capture. Design of advanced materials can be facilitated by implementation of DFT calculations. A preview of DFT analysed materials with higher affinity for CO2 than for water adsorption is presented within this research. It underscores the possibility of defining future strategies for the design of novel carbon dioxide capture materials more resistant to water compared to currently used zeolites.29th International Conference Ecological Truth and Environmental Research – EcoTER’22" Sokobanja, June 21-24, 2022