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Abstract-- Titanium was introduced into the montmorillonite structure by cation exchange with polymeric Ti cations, formed by partial hydrolysis of TIC1, in HC1. On further hydrolysis and heating, TiO2 pillars in the form of anastase were formed between the montmorillonite layers. The resulting TiOE-Cross-linked montmorillonites possessed surface a...
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... procedure was repeated until the supematant was free of chloride ions as determined by AgNO3. The conditions used for the preparations discussed in this presentation are specified in Table 1. ...
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... analysis of Na+-Ca2+-montmorillonite, HCl-treated montmorillonite, and TiO:cross-linked montmo- Metal oxide ~ Na*-Ca2+-mont - TiB5 TiB4 TiB3 TiB 1 (%) morillonite 2 H+-montmorillonite 3 (4 mmole/ Table 1. ...
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... analysis of Na+-Ca2+-montmorillonite, HCl-treated montmorillonite, and TiO:cross-linked montmo- Metal oxide ~ Na*-Ca2+-mont - TiB5 TiB4 TiB3 TiB 1 (%) morillonite 2 H+-montmorillonite 3 (4 mmole/ Table 1. ...
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... in Table 1). The uptake of Ti in the montmoril- lonite first increased with increasing amount added but then reached a constant value, corresponding to about 40% TiO2 in the products, indicating saturation of the montmorillonite with respect to polymeric Ti-cafions. ...
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... about 7 mmole Ti was taken up per gram of mont- morillonite, 1 g TiO:CLM contained about 0.65 g of montmorillonite and 0.35 g of TIP2, indicating that . Nitrogen adsorption-desorpfion isotherm for TiA1 (see Table 1). Sample prepared using 40 mmole Ti/g mont- morillonite. ...
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... series of samples was prepared from solutions 0.82 M with respect to TIC14 and 0.t 1-1.0 M with respect to HC1. Amounts corresponding to 10 mmole Ti/g montmorillonite were used in all preparations, and all solutions were used after standing for 3 hr at room temperature (see preparations TiC1-TiC4 in Table 1). ...
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... distributions were calculated for some of the prepa- rations in this investigation, A general decrease in av- erage pore size with increasing surface area and de- creasing HC1 concentration was noted. Table 1), calculated from the N2-desorp- tion isotherm shown in Figure 1. Surface area of TiO~-cross-linked montmorillon- ites vs. HC1 concentration in cross-linking solution (see prep- arations TiC1-TiC5 in Table 1). . . . . . . . ...
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... 1), calculated from the N2-desorp- tion isotherm shown in Figure 1. Surface area of TiO~-cross-linked montmorillon- ites vs. HC1 concentration in cross-linking solution (see prep- arations TiC1-TiC5 in Table 1). . . . . . . . ...
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... areas were measured on samples prepared from solutions aged 3, 24, 96,240, and 480 hr at room temperature. The Ti and HC1 concentrations of the solutions were 0.82 and 1.0 M, respectively, and amounts of solution corresponding to 40 mmole Ti/g montmorillonite were used in all preparations (see preparations TiA 1-TiA5 in Table 1). A minor increase in surface area from about 220 to 250 m2/g was ob- served with an increase in aging time from 3 to 480 hr. ...
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... thermal stability of TiOE-CLM was investigated for a sample prepared using Ti and HC1 concentrations of 0.82 and 1.0 M, respectively, in the cross-linking solutions. Ten millimoles of Ti per gram of mont- morillonite was used in the preparation, and the so- lution was aged for 3 hr before use (see preparation TiB3 in Table 1). Surface areas and pore volumes of heat-and steam-treated samples as a function of tem- perature are shown in Figure 1. ...
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... TiO2-CLM showed a higher INTERLAYER SPACING, "s (A) Figure 6. X-ray powder diffractograms (upper) and pore- volume distribution (lower) for TiB3 (see Table 1) vs. tem- perature of heat treatment (CuKa radiation). ...
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Citations
... Pillaring is a process of preserving a layered system while simultaneously converting it into a heat-resistant micro-or mesoporous material. The basic ideas about the structure of ivory clays were formed in the studies of Pinnaway [12][13], Sturt [14][15][16] and other scientists. ...
The study of the possibility of using modified clinoptilolite as an adsorbent and the adsorption properties of zeolite in the purification of natural gas supplied to gas processing plants from sulfur compounds contained in it is an urgent task. In the experimental study, the adsorbent fraction was chosen as 0.5÷1.0 mm, density - 0.8 g/cm ³ , adsorbent layer height - 600 mm. Optimal conditions are selected in such a way that the pressure in the experimental process is 0.2-5.0 MPa, the amount of mercaptans in the purified natural gas is 50÷400 mg/nm ³ , the temperature is 20÷25°C, the gas flow rate is 0.2÷250°C. 0.25 m/s. Experiments IR spectroscopic studies were carried out on a NikoletIS-10 IR spectrometer in the frequency range 400-5000cm ⁻¹ . The phase composition was studied using a 2DPHASER Bruker X-ray analyzer (CuKa - radiation, 2nd, 20-80 degrees). Electron microscopic images were taken under a Hitachi TM-3000 microscope. Elemental analysis was performed at Oxford Science. The intensity and accuracy of desorption of sulfur compounds adsorbed on clinoptilolite at 250°C, the same results were obtained on NaX zeolite at 320°C. The catalytic activity of regeneration of clinoptilolite at lower temperatures than that of NaX zeolite, although small, made it possible to minimize the decomposition of mercaptans. The purpose of this work is to study the adsorption properties of the sorbent obtained in the process of modifying clinoptilotite during the purification of natural gas from sulfur compounds.
... It is generally believed that the large specific surface area, pore volume or pore diameter of PILC materials is not only beneficial to more active sites but also improves the dispersion of the loaded active components on the surface of the carrier, thus also contributing to the form of isolated M n+ metal ions (Valverde et al., 2003a;Ye et al., 2011). As reported in previous studies (Sterte, 1986;Ming-Yuan et al., 1988;Bahranowski et al., 2015), Ti-PILC catalysts are well-known materials with high surface acidity (the Brønsted and Lewis type) as compared to other PILC (Al-PILC or Zr-PILC). On the other hand, Li et al. (2011) found that when the Ti/clay ratio was 10 mmol/g, the largest number of TiO 2 oxide columns could be formed between the layer of Ti-PILC carrier, which is beneficial to the bonding of Cu II on the surface of the TiO 2 column to form the active site for SCR activity. ...
... The BET-specific surface area (m 2 /g) displayed a similar trend: Ti-PILC (210) > Zr-PILC (156) > Al-PILC (151). Overall, these Mt-based Ti-PILC catalysts are well known to have a large specific surface area with high surface acidity (Lewis and Brønsted type), as compared to other Zr-and Al-PILC catalysts (Sterte, 1986;Ming-Yuan et al., 1988;Bahranowski et al., 2015). As previously stated, the large specific surface area with the high acid function is crucial for designing alternative SCR catalysts for LT-SCR of NO x with HC. ...
Strict air pollution restrictions have increased the need for effective low-temperature selective catalytic reduction (LT-SCR) of NOx with hydrocarbons (HC), and as such, mixed metal oxides and clay minerals supported catalysts have received significant attention. Pillared interlayered clay (PILC) materials use clay mineral as a raw material for catalyst support coupled with metal oxide particles to provide a porous structure between clay mineral layers through ion exchange. PILC has been widely used in catalysis and adsorption applications, due to its meso-microporous structure, good surface acidity, large specific surface area, adjustable pore size, interlayer ion-exchange nature, and good thermal stability. It is a widely used catalyst carrier material with excellent performance for LT-SCR of NOx with HC. Notably, the montmorillonite (Mt) based Cu-and Fe-PILC catalysts exhibited a high LT-SCR activity, which can be assigned to the excellent redox capability of the co-existing Fe III / Fe II and Cu II /Cu I. In addition, the presence of Cu II isolated species, as well as the strong interaction between Fe, Cu, and PILC support is believed to increase the SCR activity. This review study is primarily focused on the clay mineral importance and Mt-based PILC-supported catalysts for LT-SCR of NO x with HC. In addition, the SCR performances of various metals-supported PILC-based catalysts were compiled, in order to study their proposed reaction mechanisms, the influence of metal loading, effects of O2 , H2O, and SO2 poisoning for HC-SCR of NOx conversion. This study provides a detailed review of Mt-based PILC catalysts for LT-SCR technology, including recent challenges and future prospects.
... To remove excess water, the organic derivative, denoted as CTA-Mt, was washed three times with isopropanol, then three times with 1-hexanol, and stored in the form of a gelatinous paste (ca. 10 wt.% of clay); C. The inverse Ti-containing microemulsion was prepared by adapting the approach proposed for the microemulsion synthesis of hydrous zirconia nanoparticles [22]. First, the Ti-containing aqueous phase was obtained by controlled hydrolysis of TiCl 4 [23]. In a typical experiment, 6.5 mL of 6 M HCl was added to 9 mL of TiCl 4 and diluted with 100 mL of distilled water. ...
TiO2/montmorillonite composites were synthesized using inverse micellar route for the preparation of titania nanoparticles (4–6 nm diameter) in 1-hexanol and for the dispersion of one of the clay components. Two series of composites were obtained: one derived from cetyltrimethylammonium organomontmorillonite (CTA-Mt), exfoliated in 1-hexanol, and the other from sodium form of montmorillonite (Na-Mt) dispersed by formation of an inverse microemulsion in 1-hexanol. The TiO2 content ranged from 16 to 64 wt.%. The composites were characterized with X-ray diffraction, scanning/transmission electron microscopy/energy dispersive X-ray spectroscopy, thermal analysis, and N2 adsorption-desorption isotherms. The Na-Mt-derived component was shown to undergo transformation to CTA-Mt, as indicated by basal spacing of 17.5 nm, due to the interaction with the CTABr surfactant in inverse microemulsion. It was also better dispersed and intermixed with TiO2 nanoparticles. As a result, the TiO2/Na-Mt series displayed superior textural properties, with specific surface area up to 256 m2g−1 and pore volume up to 0.247 cm3g−1 compared with 208 m2g−1 and 0.231 cm3g−1, respectively, for the TiO2/CTA-Mt counterpart. Members of both series were uniformly mesoporous, with the dominant pore size around 5 nm, i.e., comparable with the dimensions of titania nanoparticles. The advantage of the adopted synthesis method is discussed in the context of other preparative procedures used for manufacturing of titania-clay composites.
... The use of titanium as pillaring agents was reported to produce product with higher surface area, attaining up to 150 m 2 /g when compared to the product made from the most widely utilized metal pillaring agents. (14,15). ...
... The Ti-PiLC material was synthesized following the Sterte and Valverde method with and without modification (14,16). A Ti-polyoxocation pillaring solution was prepared by slowly dropping 8.53 g of Ti(OC3H7) into 12 ml of HCl solution (5 M) and stirring it for 3 hours at room temperature. ...
Ultrasonication technique has been used to synthesize Titanium pillared Clay (Ti-PiLC) from bentonite. The effect of ultrasonication time (10, 30, 50 minutes) was investigated and compared with the conventional method to prepare Ti-PiLC. Nitrogen adsorption/desorption isotherms, temperature-programmed ammonia desorption, and X-ray Fluorescence were used to characterized the produced samples. The results indicated that the surface area of all Ti-PiLC enhanced 4-6 times as compared to the parent Ca bentonite. The surface area, pore volume, acidity, and Ti content of Ti-PiLC increase with increasing the sonication time where sample prepared for 50 min contained 20.86%wt of Ti and displayed surface area of 204.061 m²/g, pore volume of 0.2621 ml/g, and acidity of 0.598 mmol NH3/g. Ultrasonication technique requires much shorter pillarization time to produce samples having large higher surface parameters than the conventional mechanical stirring technique.
... In addition to Al, Ti and Zr have also been used to prepare PILM ( Table 5). The successful formation of Ti pillars in MMT was first reported by Sterte (1986). [145] Ti polycations ([(TiO) 8 (OH) 12 ] 4+ ) may be obtained from TiCl 4 or Ti(OiPr) 4 with HCl, which are then transformed into Ti pillars after intercalation and calcination. ...
... The successful formation of Ti pillars in MMT was first reported by Sterte (1986). [145] Ti polycations ([(TiO) 8 (OH) 12 ] 4+ ) may be obtained from TiCl 4 or Ti(OiPr) 4 with HCl, which are then transformed into Ti pillars after intercalation and calcination. [26] TiO 2 possesses peculiar properties in photostability and photocatalysis. ...
Montmorillonite, a ubiquitous clay mineral, has been engineered into a variety of porous and nanostructured catalysts, owing to its peculiar layered structure with characteristic surface and intercalation chemistry. Such a class of catalysts have continuously received considerable attention in both science and industry. This review examines recent advance in engineering montmorillonite into metal ion-exchanged montmorillonite catalysts, acid-activated montmorillonite catalysts, organo-montmorillonite catalysts, pillared interlayered montmorillonite catalysts and montmorillonite-supported catalysts. The former two types of montmorillonite-based catalysts have been used in the catalytic cracking, dehydration, hydrolysis, esterification, polymerization, alkylation, and Fischer-Tropic synthesis. The introduction of oxide pillars in the interlayer space of montmorillonite and the immobilization of metal oxides or zero-valent metals on the surface of montmorillonite allow montmorillonite to be used in the catalytic oxidation, reduction, isomerization and coupling reactions. Currently, the role of montmorillonite in acid catalysis, redox catalysis, and free radical catalysis have been partly revealed. The effect of the structures and the active sites of modified montmorillonite on its catalytic performance need to be investigated in more detail. Future work is suggested to focus on solving engineering problems and exploring novel catalytic applications of montmorillonite, in particular exfoliated montmorillonite nanolayers.
... All aqueous solutions were prepared with deionized water. The chemical structure of the Linuron is shown in The TiO2 pillared clays were prepared as reported by the literature [16]. The titanium polycation was prepared in a chlorhydric acid (HCl, 1 M) aqueous solution by addition of titanium isopropoxide drop by drop. ...
... The titanium polycation was prepared in a chlorhydric acid (HCl, 1 M) aqueous solution by addition of titanium isopropoxide drop by drop. The molar ratio HCl/Ti was 4. The obtained solution was then dropped slowly into the swelled clay with molar ratio Ti/clay=10 mmol/g [15,16]. The reaction temperature was maintained at 50 °C with a continuous mechanical agitation for 3 h; the obtained solid suspension was stirred for 15 additional hours. ...
... The X-ray Diffraction patterns of the initial clay (Mont-Na) and the pillared sample (Mont-TiO2) are shown in Figure 2. The ordered pillaring of layered materials results in the shift of the (001) to lower 2θ region [15,16]. Before intercalation, the typical diffraction peak of Mont-Na at 6.4° corresponds to a basal spacing of 13.81 Å. ...
TiO2 pillared clay was prepared by intercalation of titan polyoxocation into interlamelar space of an Algerian montmorillonite and used for the photocatalytic degradation of the linuron herbicide as a target pollutant in aqueous solution. The TiO2 pillared montmorillonite (Mont-TiO2) was characterized by X-ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD), X-Ray fluorescence (XRF), scanning electronic microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), Fourier transformed infra-red (FT-IR), specific area and porosity determinations. This physicochemical characterization pointed to successful TiO2 pillaring of the clay. The prepared material has porous structure and exhibit a good thermal stability as indicated by its surface area after calcination by microwave. The effects of operating parameters such as catalyst loading, initial pH of the solution and the pollutant concentration on the photocatalytic efficiency and COD removal were evaluated. Under initial pH of the solution around seven, pollutant concentration of 10 mg/L and 2.5 g/L of catalyst at room temperature, the degradation efficiency and COD removal of linuron was best then the other operating conditions. It was observed that operational parameters play a major role in the photocatalytic degradation process. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
... The rocketing oil prices caused by the 1973 oil crisis forced the petrochemical industry to search for catalysts The most widespread method of TiO 2 nanoparticles preparation involves a sol-gel method based on the controlled hydrolysis of Ti(IV) compounds. Although currently the majority of works describe the use of titanium alkoxides as precursors of titania species, the first reported synthesis of TiO 2 -clay mineral composite, a Ti-pillared montmorillonite, involved the hydrolysis of an inorganic precursor, TiCl 4 , for the generation of Ti pillars [44]. The first use of Ti alkoxide hydrolysis for the preparation of titania pillars was reported one year later [45]. ...
... The pillaring process is schematically illustrated in Figure 4. The pillaring of montmorillonite with Ti species has been first described by Sterte [44], who used for intercalation polymeric Ti cations formed by the partial hydrolysis of TiCl4 in HCl. The TiO2 pillars formed upon calcination were poorly crystalline, but nucleation of the anatase structure was indicated. ...
... For instance, the synthesis variant designed by Lin et al. [47], consisting of the preparation of TiCl4 solution in ethanol and inducing hydrolysis with a solution of glycerin and water, found a number of followers e.g., [49,56,57]. On the other hand, an undoubtedly resourceful but technically more demanding approach, consisting of the intercalation of titanium isopropoxide dissolved in The pillaring of montmorillonite with Ti species has been first described by Sterte [44], who used for intercalation polymeric Ti cations formed by the partial hydrolysis of TiCl 4 in HCl. The TiO 2 pillars formed upon calcination were poorly crystalline, but nucleation of the anatase structure was indicated. ...
The use of titania-based composite materials in the field of heterogeneous catalysis and photocatalysis has a long and rich history. Hybrid structures combining titania nanoparticles with clay minerals have been extensively investigated for nearly four decades. The attractiveness of clay minerals as components of functional materials stems primarily from their compositional versatility and the possibility of using silicate lamellae as prefabricated building blocks ready to be fitted into the desired nanoconstruction. This review focuses on the evolution over the years of synthetic strategies employed for the manufacturing of titania–clay mineral composites with particular attention to the role of the adopted preparative approach in shaping the physical and chemical characteristics of the materials and enabling, ultimately, tuning of their catalytic and/or photocatalytic performance.
... Mortland (1986) used organic species as a precursor between clay layers in order to produce an adsorbent for phenolic compounds (Mortland, 1986). In 1986, Sterte started researches on titanium-pillared clay and the first method of titanium pillared montmorillonite synthesis was reported by utilization of HCl and TiCl 4 (Sterte, 1986). Furthermore, the problem of pillared clays instability at high temperatures was solved by the usage of metal polyoxycations and pillared clay development entered a new phase. ...
Pillared clays are special kinds of modified clays with significant and permanent porosity, produced by embedding columns or pillars between the layers of clay. However, these materials are very well-known for their catalytic properties; their adsorptive characteristics in wastewaters towards different classic and growing contaminants need to be studied comprehensively. The present work is performed to introduce different methods for clays' pillaring, the main steps of the process, comparison of various pillaring agents, etc. During recent years, several investigations have been carried out to find a way for pillared clays' modification (by introducing active chemical functional groups, doping, heat treatment, etc.) to achieve selective adsorbents towards specific pollutants. Therefore, the main modification techniques including surfactant modification, metal doping, etc. are introduced and classified in the present work. Furthermore, adsorptive applications of (modified) pillared clays towards organic, pharmaceutical, and metal ions pollutants, the relationship between physicochemical properties and adsorption performance of pillared clays, adsorption mechanisms, and quantitative comparison of pillared clays' ability for pollutants removal are the other issues that have been considered in the present work.
... Prevalent Ti and Si counts are interpreted as a local inherited siliciclastic material from the erosion and weathering of mineralogical assemblages (such pyroxene and feldspar), mainly represented by basalts. Additionally, in clayey layers, which is the case of the majority of pedogenic deposits investigated here, Ti can indicate the prevalence of primary mineral such a Chlorite (Montero-Serrano et al., 2010;Neal, 2002) or secondary minerals such as Smectite/Montmorillonite (Sterte, 1986) rather than other terrestrial siliciclastic fine materials. Differently, K element can be associated to primary minerals such Mica, with potassium mica, but also with potassium feldspar (microcline, orthoclase, sanidine) if sediments are coarser (silty-sand fraction). ...
During the last fourteen thousand years, East Africa was the locus of significant climatic and cultural changes, which highly affected landscape evolution and prehistoric ways of life. Enhanced monsoonal precipitations over the tropics, mainly driven by Earth’s precessional and eccentricity orbital parameters, were the primary causes of the African Humid Period (AHP; ~14 - ~6 ka). This humid period led to the transgression of continental lacustrine waterbodies, the increase of fluvial discharge and the spread of vegetation cover over the present-day desertic regions. The onset and the end of this wetter phase were not homogeneous across the continent, and the AHP was punctuated by centennial-scale episodes of hyper-aridity which varied in time and in space. This highly variable environmental scenario was the theatre of one of the most important socio-economic changes in human history, that of the transition between the last hunters-gatherers and the first food production societies. The concomitance of such cultural transformations and climatic disruptions raises the question of the role of changing environmental conditions on the distribution patterns of new socio-economic practices, namely herding.The Ethiopian Highlands (EH) represent a major receiver of monsoonal precipitations in East Africa. During the AHP, substantial variations of the monsoon regime affected the functioning of the hydro-systems originating in the EH. This included the Blue Nile River and Lake Abhe, the endorheic receptacle of the Awash River waters, and located in the northern East African Rift System (EARS). Additionally, the Nile valley and the EARS, constituted the main corridors for prehistoric human trajectories across the Horn of Africa. With the aim to better understand human-climate coevolution during this crucial period a multiscale and multidisciplinary approach is proposed.First, I decipher Holocene climatic variations from the functioning of the two main EH-originated hydro-systems by: a) tracking exceptional Blue Nile paleo-flood frequencies using a high resolution study of a laminated sequence from the Nile Deep Sea Fan deposits, and b) reconstructing the hydrological fluctuations of paleo-Lake Abhe (Ethiopia, Djibouti), from the study of wave-dominated clastic paleo-shoreline sequences. Second, I characterize the impact of hydro-climatic changes on littoral paleolandscape evolution along the Lake Abhe basin. And finally, I estimate the interactions between climatic induced landform dynamics and human occupations with respect to the main socio-economic shifts that occurred over the same lacustrine basin.This study improves our comprehension of the spatial-temporal patterns of Holocene hydro-climate in East Africa: a strong and stable monsoonal regime has been evidenced between ~11 and ~9 ka BP, followed by a stepwise ardification until the end of the AHP. Moreover, belated Mid-Holocene humid conditions in the Northern Rift suggest that the Congo Air Boundary had a significant role on rainfall controls in this area. Additionally, evaluating the interplay between climatic-, geomorphic- and tectonic-induced sedimentary transfer mechanisms over the investigated basins allowed us to localise some hydro-sedimentary processes decoupled from climatic forcing and to propose a diachronic palaeolandscape reconstitution of the Lake Abhe basin for this period.Early Holocene Lake Abhe waters and environments were strongly exploited by hunter-fisher-gatherers until the last lake drop around ~4.5 ka BP, when herding practices were integrated in this region. Associations between prehistoric settlements and Holocene hydrological variations demonstrate how humans were extremely reactive to fluctuating lake environments and how new socio-economic practices were often adapted to specific local to regional environmental trajectories.
... In our previous work, we have proposed [21] an appropriate approach to the preparation of biomorphic TiO 2 with a hierarchical structure based on the impregnation of the biotemplate-wood pulp-with a solution of large-sized hydrolytic forms of titanium, which are formed at the intermediate stage of the transition of the solution to sol and are effectively being sorbed by cellulose fiber. It should be noted that in practice solutions of titanium hydroxocomplexes were previously used only for the preparation of pillared clays, which are effective catalysts and sorbents [22][23][24]. In our previous study [25], the production of TiO 2 -pillared montmorillonite using solutions of titanium hydroxocomplexes was described. ...
... It was found that application of hydrothermal treatment at the stage of pillaring allows for increasing the degree of crystallinity of TiO 2 and thereby improves the photocatalytic properties of the obtained material. When using hydrothermal treatment in biotemplate synthesis, it is necessary to take into account the fact that the preparation of stable forms of titanium hydroxocomplexes requires high concentration of an acid [22]. Under these conditions, some biotemplates, for example wood pulp, can be decomposed. ...
... The fiber was the waste remaining after machining the linen trust. Precursor solutions were prepared by hydrolysis of titanium chloride (TiCl 4 ) (Sigma-Aldrich Rus, Moscow, Russia) at room temperature in accordance with the procedure described in [22]. For this purpose, initially, TiCl 4 was added dropwise to a 6 M HCl solution in order to obtain a solution with a concentration of Ti 4+ 4.92 M (the concentration of solutions 4.92 M was the limit of ash formation). ...
A biomimetic solution technology for producing a photocatalytic material in the form of biomorphic titanium oxide fibers with a hierarchical structure using short flax fiber as a biotemplate is proposed. The impregnation of flax fibers intensified under hydrothermal conditions with a precursor was performed in an autoclave to activate the nucleation of the photoactive TiO2 phases. The interaction between precursor and flax fibers was studied by using infrared spectroscopy (IR) and differential scanning calorimetry/thermogravimetry analysis (DSC/TG). The morphology, structure, and textural properties of the TiO2 fibers obtained at annealing temperatures of 500–700 °C were determined by X-ray diffraction analysis, scanning electron microscopy, and nitrogen adsorption/desorption. It is shown that the annealing temperature of the impregnated biotemplates significantly affects the phase composition, crystallite size, and porous structure of TiO2 fiber samples. The photocatalytic activity of the obtained fibrous TiO2 materials was evaluated by using the decomposition of the cationic dye Rhodamine B in an aqueous solution (concentration 12 mg/L) under the influence of ultraviolet radiation (UV). The maximum photodegradation efficiency of the Rhodamine B was observed for TiO2 fibers annealed at 600 °C and containing 40% anatase and 60% rutile. This sample ensured 100% degradation of the dye in 20 min, and this amount significantly exceeds the photocatalytic activity of the commercial Degussa P25 photocatalyst and TiO2 samples obtained previously under hydrothermal conditions by the sol-gel method.
