The paper presents the results of studying the efficiency of the bisphenol A transformation in water exposed to ultraviolet radiation and a high-energy-pulse-electron beam (e-beam). It has been shown ...that in both cases, degradation of dissolved bisphenol A occurs, accompanied by an increase in the absorption coefficient in the wavelength region of more than 300 nm. After exposure, products were recorded that fluoresced in the region of more than λ = 400 nm. The fluorescent transformation product of bisphenol A in water (λ = 425 nm) was maximum formatted after an KrCl excilamp irradiated, and under the action of an e-beam, the accumulation of this product was minimal. Under e-beam radiation (170 keV) the efficiency of bisphenol A (1 mM) removal reached 97%. The data obtained allow us to develop ideas about photolysis and radiolysis in natural water systems when knowledge about targeted and optimal conditions for the degradation of bisphenol A is needed.
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•Removal of Bisphenol A using electron beam (170 keV) is a promising, environmentally friendly and simple approach.•Removal of Bisphenol A by UV irradiation was modeled using both KrCl and Xe2 simultaneously.•The end-products of Bisphenol A transformation fluoresced at 425 and 480 nm.•A photolytic pathway for the degradation of Bisphenol A has been proposed.•Energy barriers reduce the efficiency of direct photolysis of bisphenol A.
Gd@C82OxHy endohedral complexes for advanced biomedical applications (computer tomography, cancer treatment, etc.) were synthesized using high-frequency arc plasma discharge through a mixture of ...graphite and Gd2O3 oxide. The Gd@C82 endohedral complex was isolated by high-efficiency liquid chromatography and consequently oxidized with the formation of a family of Gd endohedral fullerenols with gross formula Gd@C82O8(OH)20. Fourier-transformed infrared (FTIR) spectroscopy was used to study the structure and spectroscopic properties of the complexes in combination with the DFTB3 electronic structure calculations and infrared spectra simulations. It was shown that the main IR spectral features are formed by a fullerenole C82 cage that allows one to consider the force constants at the DFTB3 level of theory without consideration of gadolinium endohedral ions inside the carbon cage. Based on the comparison of experimental FTIR and theoretical DFTB3 IR spectra, it was found that oxidation of the C82 cage causes the formation of Gd@C82O28H20, with a breakdown of the integrity of the parent C82 cage with the formation of pores between neighboring carbonyl and carboxyl groups. The Gd@C82O6(OOH)2(OH)18 endohedral complex with epoxy, carbonyl and carboxyl groups was considered the most reliable fullerenole structural model.
The work presents a spectral-luminescent study of the sulfaguanidine transformation in water under a pulsed e-beam and UV irradiation of an UVb-04 bactericidal mercury lamp (from 180 to 275 nm), KrCl ...(222 nm), XeBr (282 nm) and XeCl (308 nm) excilamps. Fluorescent decay curves have been used in our analysis of the sulfaguanidine decomposition. The conversion of antibiotic under e-beam irradiation for up to 1 min was more than 80%, compared with UV radiation: UVb-04-26%, XeBr - 20%. KrCl and XeCl - about 10%. At the end of 64 min of irradiation with UVb-04 and XeBr lamps, the conversion was 99%. During irradiation with these lamps, sulfaguanidine almost completely decomposed and passed into the final fluorescent photoproducts. After e-beam irradiated at the end of 13 min the decrease in sulfaguanidine was 93%. At the same time, the formation of sulfaguanidine transformation products was minimal compared to UV irradiation. The effect of UV irradiation and a powerful e-beam on the decomposition mechanisms of sulfaguanidine are significantly different, which is manifested in various changes in the absorption and fluorescence spectra.
Gd endohedral complexes of C82 fullerenols were synthesized and mass spectrometry analysis of their composition was carried out. It was established that the synthesis yields a series of fullerenols ...Gd@C82Ox(OH)y (x = 0, 3; y = 8, 16, 24, 36, 44). The atomic and electronic structure and properties of the synthesized fullerenols were investigated using the density functional theory calculations. It was shown that the presence of endohedral gadolinium increases the reactivity of fullerenols. It is proposed that the high-spin endohedral fullerenols are promising candidates for application in magnetic resonance imaging.
Gd@C
O
H
endohedral complexes for advanced biomedical applications (computer tomography, cancer treatment, etc.) were synthesized using high-frequency arc plasma discharge through a mixture of ...graphite and Gd
O
oxide. The Gd@C
endohedral complex was isolated by high-efficiency liquid chromatography and consequently oxidized with the formation of a family of Gd endohedral fullerenols with gross formula Gd@C
O
(OH)
. Fourier-transformed infrared (FTIR) spectroscopy was used to study the structure and spectroscopic properties of the complexes in combination with the DFTB3 electronic structure calculations and infrared spectra simulations. It was shown that the main IR spectral features are formed by a fullerenole C
cage that allows one to consider the force constants at the DFTB3 level of theory without consideration of gadolinium endohedral ions inside the carbon cage. Based on the comparison of experimental FTIR and theoretical DFTB3 IR spectra, it was found that oxidation of the C
cage causes the formation of Gd@C
O
H
, with a breakdown of the integrity of the parent C
cage with the formation of pores between neighboring carbonyl and carboxyl groups. The Gd@C
O
(OOH)
(OH)
endohedral complex with epoxy, carbonyl and carboxyl groups was considered the most reliable fullerenole structural model.
► MCPA rapidly phototransformated in water under KrCl and XeBr excilamps. ► 2-Metylhydroquinone is one of the main photoproducts of MCPA. ► Biodegradability of phototreated MCPA solutions increased.
...The effect of UV radiation of a KrCl and a XeBr on the photodegradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) was studied. The main photoproducts were identified by gas chromatograph/mass spectrometry (GC/MS). The variation of chlorine-ion and active chlorine in MCPA aqueous solution exposed to excilamp radiation was also defined by analytical methods. Irradiation of MCPA solution with a KrCl excilamp emitting mainly at 222
nm yield 2-methylhydroquinone and lactone of 2-hydroxy-3-methyl-5-chlorophenoxyacetic acid as the main photoproducts. Irradiation of MCPA solution with a XeBr excilamp emitting mainly at 283
nm yield 2-methylhydroquinone as the main photoproduct. Biological processes are not suitable for MCPA removal due to low or total absence of biodegradability of this class of pollutants. Estimation of biodegradability of phototreated MCPA solution was carried out according to ratios of biological oxygen demand (BOD
5) to chemical oxygen demand (COD). The biodegradability of MCPA solutions increased after irradiation.
Electron beam irradiation is of great interest to researchers as it opens up new opportunities for meaningful interdisciplinary collaboration between scientists from fields such as chemistry, ...physics, ecology, engineering, biology, nanotechnology, and materials science. The interaction of electrons with matter ensures the formation of highly efficient reactive particles. A setup for studying the interaction of an electron beam with a liquid is presented. The efficiency of transformation of dissolved organic compounds under the action of electron beam irradiation was evaluated using pulsed cathodoluminescence. The novelty of the study lies in the fact that the irradiation of solutions and the excitation of luminescence, which is used for diagnostics, are carried out simultaneously by the same electron beam. This setup is a tool for studying the physicochemical utilization of toxic dissolved compounds. The decay process, stimulated by pulsed electron beams from 50 to 3200 pulses, proceeded intensively in aqueous solutions with the addition of crystal violet or bisphenol A. Some of the transformation products were emitted into the air, changing the composition and intensity of its luminescence. The conversion of the studied compounds was carried out using electron absorption spectroscopy and stationary fluorescence.
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•The TM atoms adsorption in g-CNx and double-vacancy bigraphene was investigated.•Fe/Mn atoms penetrate g-CN2 nanosheet, while at g-CN1 they stay at the surface.•In case of the ...bigraphene the formation of inner-sorbed complexes is preferable.•Formed metallic clusters are of interest in catalysis and medicine as biosensor.
First-row transition metal (TM) atoms adsorption and migration on nanoporus 2D materials like bigraphene with double vacancies and g-C3N4 as the active sites for TM nanocluster’s growth was studied within the framework of density functional theory. Both thermodynamic and kinetic aspects of composite synthesis were discussed. It was found that potential barriers of adatom’s migration from bigraphene’s outer surface to the interlayer space through the double vacancy are rather low values. High potential barriers of TM migration along the carbon plane prevents TM clusterization due to enhanced chemical activity of double vacancies which gives a possibility to capture the surface adatoms. As was shown for the monolayer graphene, the decrease of vacancies concentration reduces the barrier of adatom migration along the surface while the second graphene sheet in bigraphene stabilizes the structure. The behavior of TM-atom regarding g-CN2 and g-CN1 nanosheets was investigated. Potential energy surfaces were obtained and discussed. The migration barriers were found surmountable that means high probability of migration of TM adatoms to global minima and formation of TM vacancies. Comparison of barriers values with Boltzmann factor demonstrated that just standalone temperature fluctuations cannot initiate structural transitions. The properties of designed structures can be of interest of catalysts and biosensors for biomedical applications.
Photodegradation of 5-Methoxypsoralen (5-MOP), 4', 5'-dimethyl-3,4-cyclogeksilpsoralen (KC5) and 4'-methyl-3,4 cycloheptylpsoralen (KC4) has been carried out in an XeBr exilamps, both in the presence ...of H2O2, and a kinetic model, which explains the dependence of the pseudo-first order kinetic parameter on the substrate concentration and other operational variables, has been developed. In the development of the model, mass transfer of 5-MOP, KC5 and KC4from the bulk solution to the wall of the vessel was assumed as the step determining the rate of the photodegradation process, which successfully explains some singularities observed in the experimental results.By fitting the experimental data to the model, a detailed study of the influence of all operational variables on the pseudo-first order kinetic parameter has been done, in good agreement with the model hypotheses.
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