Supplementary data for the article: Kodranov, I. D.; Pergal, M. V.; Avdin, V. V.; Manojlović, D. D. Examination of Degradation and Ecotoxicology of Pethoxamid and Metazachlor after Chlorine Dioxide Treatment. Environ Monit Assess 2020, 192 (7), 422. https://doi.org/10.1007/s10661-020-08392-1

Supplementary material for: [https://doi.org/10.1007/s10661-020-08392-1]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4007

Supplementary data for the article: Pergal, M. V.; Kodranov, I. D.; Dojčinović, B.; Avdin, V. V.; Stanković, D. M.; Petković, B. B.; Manojlović, D. D. Evaluation of Azamethiphos and Dimethoate Degradation Using Chlorine Dioxide during Water Treatment. Environ Sci Pollut Res 2020, 27 (21), 27147–27160. https://doi.org/10.1007/s11356-020-09069-5

Supplementary material for: [https://doi.org/10.1007/s11356-020-09069-5]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4036

Synthesis and Application of Domestic Glassy Carbon TiO2 Nanocomposite for Electrocatalytic Triclosan Detection

Nanoparticles of TiO2 are suitable for many catalytic and photocatalytic applications due to their extraordinary properties such as superhydrophobicity, semiconductivity, electron-rich, and environmental compatibility. The main crystalline phases of TiO2, anatase, and rutile possess different crystal structures, crystallinity, crystalline sizes, and specific surface areas, and these characteristics directly affect the catalytic performance of TiO2. In the present study, domestic carbon material enhanced with TiO2 nanoparticles was synthesized and used for the construction of a modified carbon paste electrode. The electrocatalytic activity of the modified electrodes was investigated depending on the TiO2 crystalline phases in the electrode material. Furthermore, the obtained working electrode was utilized for triclosan detection. Under optimized experimental conditions, the developed electrode showed a submicromolar triclosan detection limit of 0.07 µM and a wide linear range of 0.1 to 15 µM. The relative standard deviations for repeatability and reproducibility were lower than 4.1%, and with satisfactory selectivity, the proposed system was successfully applied to triclosan monitoring in groundwater. All these results confirm that the sustainable production of new and domestically prepared materials is of great benefit in the field of electrocatalysis and that the morphology of such produced materials is strongly related to their catalytic properties

The Effect of Rare-Earth Elements on the Morphological Aspect of Borate and Electrocatalytic Sensing of Biological Compounds

Adjusting the morphological characteristics of a material can result in improved electrocatalytic capabilities of the material itself. An example of this is the introduction of rare-earth elements into the borate structure, which gives a new perspective on the possibilities of this type of material in the field of (bio)sensing. In this paper, we present the preparation of borates including La, Nd and Dy and their application for the modification of a glassy carbon electrode, which is used for the non-enzymatic detection of a biologically relevant molecule, vitamin B6 (pyridoxine). Compared with the others, dysprosium borate has the best electrocatalytic performance, showing the highest current and the lowest impedance, respectively, as determined using cyclic voltammetry and impedance tests. Quantitative testing of B6 was performed in DPV mode in a Britton–Robinson buffer solution with a pH of 6 and an oxidation potential of about +0.8 V. The calibration graph for the evaluation of B6 has a linear range from 1 to 100 μM, with a correlation coefficient of 0.9985 and a detection limit of 0.051 μM. The DyBO3-modified electrode can be used repeatedly, retaining more than 90% of the initial signal level after six cycles. The satisfactory selectivity offered a potential practical application of the chosen method for the monitoring of pyridoxine in artificially prepared biological fluids with acceptable recovery. In light of all the obtained results, this paper shows an important approach for the successful design of electrocatalysts with tuned architecture and opens new strategies for the development of materials for the needs of electrochemical (bio)sensing

Chlorine dioxide use to oxidate and remove pesticides and pharmaceuticals from water

This chapter summarizes the reactivity, mechanism and toxicity assessment of pesticides and pharmaceuticals by chlorine dioxide (ClO2). ClO2 has been successfully employed as disinfectant in water treatment systems due to its antibacterial and antiviral characteristics. Also, ClO2 can be used as an alternative to chlorine, compared with which, it effectively reduces the amount of chlorinated products. As a powerful oxidant, ClO2 can remove effectively many organic and inorganic pollutants from water. Anthropogenic influences on groundwater (mining, industrial, agricultural and urbanization activities, and/or climate change) can affect water quality by production of different contaminants. The quality of surface water is critical because of the importance of raw water quality for all forms of life. Considering the increasing application of ClO2 in water treatment, it is very important to investigate the reactions of ClO2 with the most extensively consumed pharmaceutical drugs and pesticides, which are regularly detected in surface water. Oxidative degradation via ClO2 of pharmaceutical contaminants and pesticides from water solutions is presented. Pollutants on which ClO2 has high or low degradation efficiency are highlighted. The recent developments on the effects of organic substances on pollutant degradation in surface water are addressed. Future trends in pollution degradation using ClO2 are also discussed

Examination of degradation and ecotoxicology of pethoxamid and metazachlor after chlorine dioxide treatment

Chlorine dioxide has been reported as very efficiently removing pesticides and other organic compounds from water matrixes. Due to pesticide toxicity and potential toxicity of their degradation products, it is important to monitor these compounds as environmental pollutants in ground and surface waters. Evaluating the effects of chlorine dioxide treatment is necessary, and toxicity studies are used to ascertain the severity of effects of intermediates due to incomplete degradation of the parent compounds. In this paper, for the first time, chlorine dioxide is applied and evaluated for the removal of chloroacetamide herbicides (pethoxamid and metazachlor) from waters (deionized water and Sava River water). The degradation degree of herbicides was measured by high-performance liquid chromatography, the main degradation products were identified using gas chromatography with a triple quadrupole mass detector, and the degree of mineralization was monitored by total organic carbon analysis. Four and two degradation products were identified after pethoxamid and metazachlor degradation, respectively. Total organic carbon analysis showed mineralization occurred, but it was incomplete. The mineralization and the characteristics of the degradation products obtained were tested using Daphnia magna and showed lower toxicity than the parent herbicides. The advantage of the applied treatment was a very high degradation percentage for pethoxamid removal from deionized water and Sava River water (100% and 97%, respectively), with higher mineralization efficiency (65%) than metazachlor. Slightly lower degradation efficiency in the Sava River water was due to chlorine dioxide oxidizing the herbicides and dissolved organic matter simultaneously.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/4008

Oxidative degradation and mineralization of bentazone from water

Bentazone degradation efficiency and mineralization in water solutions using chlorine dioxide treatment were evaluated. Double distilled water and a river water sample spiked with bentazone were studied and compared after chlorine dioxide treatment. Degradation efficiency was determined using high-performance liquid chromatography (HPLC). Daphnia magna toxicity testing and total organic carbon (TOC) analysis were used to ascertain the toxicity of the degraded solutions and mineralization degree. Bentazone degradation products were identified using gas chromatography with a triple quadrupole mass detector (GC-MS-MS). A simple mechanistic scheme for oxidative degradation of bentazone was proposed based on the degradation products that were identified. Decrease in D. magna mortality, high degradation efficiency and partial bentazone mineralization were achieved by waters containing bentazone degradation products, which indicate the formation of less toxic compounds than the parent bentazone and effective removal of bentazone from the waters. Bentazone degraded into four main degradation products. Humic acid from Sava River water influenced bentazone degradation, resulting in a lower degradation efficiency in this matrix (about 10% lower than in distilled water). Chlorine dioxide treatment of water to degrade bentazone is efficient and offers a novel approach in the development of new technology for removal of this herbicide from contaminated water

Peroxo method for preparation of composite silica-titania spheres

Composite silica–titania spherical particles, from the nanometer to submicron size, have been synthesized via a new template-free method, being achieved by the reaction of aqueous titanium peroxo complex with TEOS (tetraethylorthosilicate) in aliphatic alcohols. The choice of the solvent greatly affects the growth of silica–titania particles. It has been established that size of the spheres increases as carbon chain length of alcohol extends (from methanol to n-propanol). The nanometer size SiO2–TiO2 spheres with mean diameter of about 50 nm are formed in the methanol solution, while n-propanol promotes particle growth up to 400 nm. The synthesized composites retain amorphous structure up to 500 °C due to the formation of Si–O–Ti heterolinkages, whose presence has been confirmed by FTIR and XPS studies.South Ural State University is grateful for financial support of the Ministry of Education and Science of the Russian Federation (grant No 16.2674.2014/K). University of Oviedo gratefully acknowledges financial support from the MINECO (MAT2013-40950-R) and FEDER-FICyT (GRUPIN14-060). IK thanks for the support the Russian Foundation for Basic Research13-03-12188-ofi.Peer Reviewe

A new peroxo-route for the synthesis of Mg-Zr mixed oxides catalysts: Application in the gas phase acetone self-condensation

We propose in this manuscript a new peroxo-mediated procedure for preparing magnesia-zirconia mixed oxides, with Mg/Zr molar ratio between 1 and 3, with enhanced distribution of basic sites. The mixed magnesia-zirconia oxides have been prepared from the gelled complex by Pechini-type method. The MgO-ZrO 2 materials have been characterized and used as catalysts for acetone aldol condensation. The proposed preparation method provides a high degree of molecular homogeneity and favours the formation of magnesia-stabilized zirconia phase. Acetone gas-phase self-condensation was carried out over these catalysts as model reaction requiring the presence of basic sites. The condensation yields diacetone alcohol and mesityl oxide as mean C6 products, and phorones, isophorones and mesitylene as C9 products. In comparison to Mg-Zr oxide prepared by co-precipitation, these new materials present better conversions and higher selectivity to linear dimers and trimers (as mesitylene), whereas the selectivity for isophorones is significantly lower. © 2014 Elsevier B.V.This work was supported by the Spanish Government (contract CTQ2011-29272-C04-02).Peer Reviewe

Evaluation of azamethiphos and dimethoate degradation using chlorine dioxide during water treatment

Chlorine dioxide (ClO2) degradation of the organophosphorus pesticides azamethiphos (AZA) and dimethoate (DM) (10 mg/L) in deionized water and in Sava River water was investigated for the first time. Pesticide degradation was studied in terms of ClO2 level (5 and 10 mg/L), degradation duration (0.5, 1, 2, 3, 6, and 24 h), pH (3.00, 7.00, and 9.00), and under light/dark conditions in deionized water. Degradation was monitored using high-performance liquid chromatography. Gas chromatography coupled with triple quadrupole mass detector was used to identify degradation products of pesticides. Total organic carbon was measured to determine the extent of mineralization after pesticide degradation. Real river water was used under recommended conditions to study the influence of organic matter on pesticide degradation. High degradation efficiency (88–100% for AZA and 85–98% for DM) was achieved in deionized water under various conditions, proving the flexibility of ClO2 degradation for the examined organophosphorus pesticides. In Sava River water, however, extended treatment duration achieved lower degradation efficiency, so ClO2 oxidized both the pesticides and dissolved organic matter in parallel. After degradation, AZA produced four identified products (6- chlorooxazolo[4,5-b]pyridin-2(3H)-one; O,O,S-trimethyl phosphorothioate; 6-chloro-3-(hydroxymethyl)oxazolo[4,5- b]pyridin-2(3H)-one; O,O-dimethyl S-hydrogen phosphorothioate) and DM produced three (O,O-dimethyl S-(2-(methylamino)-2-oxoethyl) phosphorothioate; e.g., omethoate; S-(2-(methylamino)-2-oxoethyl) O,O-dihydrogen phosphorothioate; O,O,S-trimethyl phosphorodithioate). Simple pesticide degradation mechanisms were deduced. Daphnia magna toxicity tests showed degradation products were less toxic than parent compounds. These results contribute to our understanding of the multiple influences that organophosphorus pesticides and their degradation products have on environmental ecosystems and to improving pesticide removal processes from water