To address the challenging removal of pharmaceutical pollutants from aqueous environment, this study presents the synthesis of apatite-related Ti4+ and CO32--modified calcium phosphates and their TiO2 composites using various Ti4+ precursors. The partial substitution of Ca2+ by Ti4+ ions is confirmed by decreased lattice parameters. Tetraisopropylorthotitanate promotes Ti4+ intercalation, reducing the bandgap energy. The composites demonstrated efficiency in the tetracycline hydrochloride degradation (up to 88%) due to synergistic effects of enhanced adsorption and efficient charge carrier interaction. These findings highlight the potential of the developed materials for the pharmaceutical pollutants' removal from aqueous environments.

The extracts from various types of Camelina sativa plant biomass (camelina seedcake, in situ and in vitro plants) and seedcake-derived lignin solution were prepared. Their composition was characterized using high-performance liquid chromatography (HPLC) and matrix-free or matrix-assisted laser desorption/ionization mass spectrometry (LDI/MALDI MS). The antioxidant/antiradical activity of the extracts was studied using Folin–Ciocalteu method and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The ability of the extracts to inhibit the biodiesel oxidation and to affect the processes of dichromate ions reduction was evaluated. HPLC and LDI/MALDI MS results suggest that all the extracts contain such phenolic compounds as flavonoids (mainly rutin and other quercetin glycosides), hydroxycinnamic and hydroxybenzoic acids. The total phenolic content in the extracts decreased in the following row: seedcake > in situ > in vitro > lignin solution, being in correlation with the DPPH radicals scavenging activity. The camelina seedcake extract, which contained the largest amount of phenols (795.5 mg L−1), was found to effectively decelerate the biodiesel oxidation. Despite the low phenolic content (47.0 mg L−1), the extract from camelina in vitro plant showed the highest hole scavenging capacity in dichromate ion photocatalytic reduction processes. Thus, camelina plant biomass is a promising source of phenolic compounds for various applications.

Crystallization of Ce2Ti2O7 2 Ti 2 O 7 in the mixture of TiO2 2 and CeO2 2 was achieved by the three-layered coating of cerium- titanium mixed sol of the 1 : 1 metals molar ratio on a glass substrate at certain temperature regime in air as proven by XRD, SAED and Raman spectroscopy. Anatase and Ce2Ti2O7 2 Ti 2 O 7 crystallization with XRD undetectable crystallites brought to the increase of the specific surface area of the films. The formation of Ti-O-Ce O -Ce bonds on the surface of the films was proven by the noticeable shift of Ti2p and O1s XPS maxima compared to TiO2 2 ones. The additional peaks in Ti2p, O1s and Ce3d XPS spectra belonging to the common bonds between the metals ions were identified for the first time. The bandgap energy and band-edge positions of Ce2Ti2O7 2 Ti 2 O 7 were firstly determined by photoelectrochemical measurements. The inactivity of the films in photocatalytic reductive and oxidative processes was caused by the unfavorable position of the valence band of Ce2Ti2O7 2 Ti 2 O 7 causing the recombination of the photo-formed electron-hole pair.

The photocatalytic conversion of lignin, obtained from camelina ( Camelina sativa ), over titania and iron titanate films has been studied with analysis of the products using laser desorptiopn/ionization and high-performance liquid chromatography. The photocatalytic reaction over titania films leads to the formation of the mixture of compounds, such as phenol, vanillic acid, resorcinol, and p -coumaryl alcohol. In the presence of iron titanate films, the predominant reaction products are vanillic acid and p -coumaryl. The highest antioxidant activity has been revealed in the case of lignin conversion products obtained over nitrogen-containing iron titanate films under visible light exposure.

The extracts from the leaves of Deschampsia antarctica É. Desv., Camelina sativa (L.) Crantz, and Camellia japonica L. plants, as well as from defatted Camelina sativa and Silybum marianum seedcakes were investigated as potential additives for improvement of biodiesel stability against oxidation. Composition of the extracts was studied by means of HPLC, and antioxidant properties were evaluated using the Folin-Ciocalteu assay and the DPPH test. The oxidation of biodiesel was monitored during the accelerated procedure at 43C, with the changes in the acid number of biodiesel samples being the criteria of this process. In spite of significant distinctions in the content of various phenolic compounds, all the extracts were found to possess high antioxidant activity and decelerate biodiesel oxidation by 9-26%. The data did not reveal a directly proportional relationship between the antioxidants content in the extract, on the one hand, and the enhancement in biodiesel stability, on the other hand; various extracts had different influence on the behaviour of biodiesel from rape and Camelina seed oils. The results obtained are consistent with the assumption that there is no universal stabilizer for different types of biodiesel and indicate the prospects on searching for novel antioxidants of natural origin to inhibit oxidative processes.

Utilization of the second-most abundant biopolymer, lignin, in production of fine chemicals is considered as a strategy for environmental conservation and economic feasibility of technologies. Photocatalytic conversion of sodium lignosulfonate to low molecular weight compounds over eco-friendly semiconducting materials under simulated solar light is a perspective eco-innovative approach for “green technology” development. The more efficient depolymerization of lignosulfonate during photolytic reaction occurs at pH 2 as a result of sulfonic groups’ protonation, whereas the re-polymerization of hydrolyzed fragments to more complex structure in solutions at pH 5 and pH 9 is reported. Photo-sensibilization pathway toward polymer fragmentation is low effective process. It is shown that photocatalytic process is also more effective at pH 2 due to an electrostatic interaction of positively charge surface of metal oxides’ films and negatively charged NaLSA molecules. As shown by LDI MS investigation, the destruction of aromatic component of NaLSA molecule can be achieved in the presence of TiO2 film under simulated solar light due to the strong reductive power of superoxide radicals resulting in the benzoic ring-opening route. The mechanism of photocatalytic reaction over iron titanate films is governed by the presence of two semi-conductive crystalline phases, pseudobrookite and landauite, that are characterized by the anodically shifted energy positions of the conduction and valence bands compared to TiO2 providing an effective oxidation by HO• radicals. Nitrogen-doped iron titanate films are considered as a photocatalyst for the processes of low molecular weight aromatic compounds’ synthesis exhibiting activity under both simulated solar and visible light with the phenol yields of 0.96 μg mL−1 and 1.2 μg mL−1, respectively.

З використанням двох різних процедур екстракції одержано вісім етанольних екстрактів із листя рослин Magnolia X soulangeana Soul.-Bod., Magnolia kobus та двох зразків Camellia japonica L. За допомогою високо- ефективної рідинної хроматографії, методу Фоліна—Чокальтеу і DPPH тесту вивчено склад та анти- оксидантні властивості одержаних екстрактів. Показано, що основними складовими екстрактів магнолій є глікозиди кверцетину та похідні оксикоричних кислот, тоді як у екстрактах камелій переважають катехі- ни і похідні оксибензойних кислот. Склад екстрактів залежить не тільки від виду рослини, а й від способу екстрагування; загалом, екстракти, одержані при температурі 60 °C та під дією ультразвуку, мають біль- ший вміст поліфенолів, ніж екстракти, отримані кип’ятінням рослинного матеріалу у 70 %-му етанолі при ~85 °C ; загальна кількість фенольних сполук у екстрактах змінювалась у діапазоні 50—150 мг/л. Виявлено, що, попри значну різницю у вмісті фенолів, всі екстракти мають дуже високу антиоксидантну актив- ність як у тесті Фоліна—Чокальтеу, так і в реакції з DPPH радикалами. Показано, що екстракти мають загальний фенольний індекс 1,5—7,5, а протягом 30 хв реакції сім з восьми екстрактів інгібують понад 50 % радикалів DPPH навіть після розведення у 10 разів. Екстракт камелії з найвищими антиоксидантними властивостями було протестовано як добавку до біодизелю, що має запобігти його окисненню під час збе- рігання. Стабільність біодизелю, одержаного з Camelina sativa (L.) Crantz, досліджували за прискореною процедурою при 43 °C протягом чотирьох тижнів, критерієм окиснення біопалива слугувало його кислотне число. Попередні результати показали, що екстракт камелії може бути ефективним антиоксидантним агентом — запобіжником окиснення біодизелю.

Iron and nitrogen-iron co-doped titania films (non-porous and mesoporous) on glass substrates were obtained using a sol-gel method via different synthesis routes. The photo catalytic degradation of anthropogenic pollutant tetracycline hydrochloride over synthesized films was studied. It is shown that the photocatalytic response of the films is sharply depended on the synthesis procedure and calcination temperature. The non-porous three layered iron-doped and nitrogen-iron co-doped titania treated at 450 degrees C exhibited the highest photocatalytic activity under UV and simulated solar light, respectively. The crystallization of iron titanates accompanied by the formation of new active sites led the high adsorbability of TC molecules onto the surface that, in turns, stimulate the high conversion of tetracycline hydrohloride.

Co-doping of titania by N and Pt species was employed to tune the electronic structure and enhance the electrocatalytic and photocatalytic activity of the films. Herein, the different approaches of synthesis procedure of Pt- and Pt,N–TiO2 films were used to investigate their effect on the platinum oxidation states. The resulting different species of Pt led to the changes in the electronic structure of TiO2, with consequent bandgap narrowing, anodic shift of the flat band potential, and cathodic shift of the valence band The quantum yield efficiency was correlated with Pt0 atomic content and the relative atomic content of Ptn+–O–Ti fragments, whereas its decrease for some samples can be caused by the presence of N and Ptn+. The highest response for N2O photocatalytic decomposition was observed over Pt,N–TiO2 films. The presence of metal and non-metal species in TiO2 structure resulted in synergistic effect including (1) inhibition of recombination of the electrons and holes and (2) narrowing of the bandgap. Electrocatalytic properties in hydrogen and oxygen evolution reactions were improved by Pt doping. The formed Pt2+–O–Ti bonds rather than Pt nanoparticles are suggested to be responsible for the highest electrocatalytic activity. The additional UV exposure of the electrodes led to Pt NPs aggregation as a result of photodeposition of Pt ions. The mechanism of the Pt2+ photoreduction in TiO2 structure is proposed.

Nitrogen and iron ions co-doped titania films have been synthesized by PLD technique in nitrogen/methane (N2/CH4) (5:1) media at 1 mbar. Most of the samples are XRD amorphous but a certain amount of crystalline rutile is detected by Raman measurements. The presence of rutile phase only and its low crystallinity degree can be caused by nitrogen doping of oxide matrix. The most intensive VIS absorption and the lowest band gap values are observed for 5% Fe2O3 or Fe3O4 titania films that are supported by the highest nitrogen amount on the surface. The strongest photocatalysts in process of dichromate reduction under either UV or VIS irradiation are shown to be the films obtained from 5% iron oxide in titania target and synthesized at 550 °C as a result of optimal content of Ti–N and Ti–O–Fe structural fragments as revealed by XPS. The presence of Fe3+ and Fe2+ surrounded by oxygen as well as Fe–N bonds is confirmed by XPS data.

According to the XPS investigation of titania films co-modified by nitro gen and metal ions obtained via sol-gel method, the formation of common bonds between elements occurs due to the presence of metal ions. The mechanism of urea thermolysis is changed as a result of the ability of metal ions to form the complex compounds with urea molecules under the reported synthesis conditions that, in turn, depends on the nature of metal ions, leading to the different chemical compositions of materials’ surface. The XPS data show that nitrogen atoms are surrounded by nonmetal ones on the surface of the films modi fied by Zn2+ or Zr4+ ions. It is suggested that no formation of the complexes between Ті, Zn, or Zr atoms with urea occurs due to its protonation through an oxygen atom leading to the formation of O,N-containing reaction products. In the case of Pt2+ doping, the substitutional nitrogen incorporation in the titania lattice, as well as the formation of N-containing fragments, have been detected. The chemical nature of Pt ions allows them to interact with urea molecules through an N atom of the amino group. As a result, the transformation of urea molecules in the complexes occurs at higher temperatures concurrently with the titania crystallization that is recognized as a catalyst for the intermediates of the urea decomposition leading to the formation of common bonds between N and Ti atoms.

Platinum and nitrogen co-doped titania films of different surface morphologies obtained via a sol-gel process have been tested for tetracycline hydrochloride photocatalytic decomposition under simulated solar light. Titania crystallization to anatase is shown by XRD for all films. A shift of the bandgap edge toward the visible region in absorption spectra and, consequently, a narrowing of the bandgap is observed for some films doped with nitrogen and/or exposed to UV pretreatment. The surface peculiarities of the samples are presented by an SEM and TEM investigation. The surface saturation by Pt and N with a homogeneous distribution of Pt ions on the surface as well as bulk as established by XPS and EDS data can be achieved with a certain synthesis procedure. The influence of the platinum content and of the pretreatment procedure on the state and atomic surface concentration of incorporated nitrogen and platinum is studied by XPS analysis: substitutional and interstitial nitrogen, non-metal containing fragments, Pt0, Pt2+ and Pt4+ ions. The photocatalytic activity of the films is ruled by the presence of Pt2+ ions and N rather than Pt0. The formation of the polycrystalline titania structure and Pt0 nanoparticles (NPs) is confirmed by TEM and electron diffraction images. The mechanism of primary photocatalytic processes is proposed.

Nitrogen and ruthenium co-doped titania films synthesized by sol–gel technique exhibit high photocatalytic activity under both UV and visible light. Incorporation of nitrogen and ruthenium ions in titania lattice is proven by XPS. Both doping agents affected the structural properties of the films.

Mesoporous titania films and powders modified with 3d metal ions have been produced by sol-gel method and characterized by optical spectroscopy, SEM, XRD, XPS and photocatalytic measurements. XRD patterns of mesoporous Co2+, Ni2+, Mn2+ Cu2+ doped films showed the nanocrystalline anatase phase formation (8–20 nm). In the case of Fe3+/TiO2 systems, an amorphous film with traces of the brookite was formed. Nonporous iron titanate films consisted of the crystalline structures of pseudobrookite (Fe2TiO5) and landauite (Fe2Ti2O7). Sol-gel technique promoted high-dispersion states of metal species, the XPS showed that the dopants existed as divalent and trivalent ions in (Co, Mn, Fe)n+/TiO2 and as monovalent and divalent ions in (Ni, Cu)n+/TiO2. The optimal parameters for the doped titania composites synthesis allowing to obtain the more active than TiO2 nontoxic, environmentally friendly, biocompatible nanostructured catalysts for the photocatalytic processes of toxic dichromate ions reduction and tetracycline hydrochloride destruction under UV and visible light is experimentally established.

Nitrogen doped nanosized iron titanate films have been obtained by fast, low cost and precisely controllable synthesis procedure and characterized by XRD, TEM, EPR, optical spectroscopy, photoelectrochemical, electrocatalytic and photocatalytic approaches. The nitrogen doped iron titanate films are crystallized to pseudobrookite (Fe2TiO5) and landauite (Fe2Ti2O7), as revealed by XRD. It is found that nitrogen doping led to stabilization of iron titanate phases at higher temperature preventing their transformation to TiO2 and Fe2O3. The bandgap energy values and the position of the flatband potentials of Fe2TiO5 and Fe2Ti2O7 have been obtained from photoelectrochemical data. Anodic shift of the flatband potentials and the decrease of bandgap energy are noted for iron contained materials. All the iron titanate films exhibit the lower photocurrent quantum yield in UV region compare to iron free films, while the significant photocurrent of the former electrodes has been observed at the lower energy light. The iron titanate films synthesized at certain conditions showed the high photocatalytic activity in the reduction and oxidation processes under both UV and visible light. Adsorption of the pollutant species is established to be considerable for the photocatalytic processes. The influence of doping on the electrocatalytic activity of the films in the processes of oxygen reduction is shown.

Hydrogel-silver nanocomposites are found to be excellent materials for antibacterial applications. For developing of these сomposites, the hydrogel matrices are synthesized first by polymerizing of acrylamide in the presence of cross-linker N,N-methylene-bis-acrylamide using redox initiating system cerium(IV) ammonium nitrate. Silver nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating the silver ion sand subsequent reduction with sodium borohydride or UV irradiation. A series of hydrogel-silver nanoparticle composites are developed and are characterized by using Fourier transform infrared (FTIR) and UV–visible (UV–vis) spectroscopy, scanning electron microscopic methods, as well as swelling.

Electrode materials based on titanium dioxide modified with zinc ions and gold nanoparticles, synthesized by sol-gel method, were used to determine the concentration of Cu (II) in liquids by stripping voltammetry method. Determination of Cu (II) was done using background solutions based on 0.4 M formic acid and ammonium acetate buffer (pH = 7.5) using the standard addition method with a potential scanning speed of 50 mV•s-1. The solution was stirred during the preliminary electrolysis at a potential of -1400 mV (vs silver-chloride reference electrode) for 120 seconds and then the potential was scanned from -1200 mV to + 200 mV. It is shown that the background solution based on ammonium acetate buffer provides a higher sensitivity and a good selectivity of peaks for the determination of copper compared to the background solution based on formic acid. Determined that value of the analytical signal of copper in the studied model solutions based on ammonium acetate and formic acid is proportional to the concentration of copper ions in the solution. To increase the selectivity of stripping voltammetry method in determining copper concentrations in solutions, an inversion spectral photoelectrochemical method was proposed, the essence of which is preliminary electroconcentration of the elements under investigation in the cathode potential region and subsequent measurement of the spectral photoelectrochemical characteristics of electroconcentration products. It has been found that in solutions of 1M ammonium acetate containing Cu2+ ions, the cathodic polarization of TiO2-based photoelectrode leads to the appearance of a cathode photocurrent and the values of photocurrent quantum yield increase with increasing content of copper ions in the solution. The spectral sensitivity of the surface layer corresponds to the absorption spectrum of Cu2O. The sensitivity of stripping voltammetry method to copper Cu (II) using the materials studied was 0.3 mg•l-1. It is shown that the inversion photoelectrochemical method is promising in the selective determination of copper concentration in liquids.