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The global water crisis, exacerbated by excessive use and pollution, has resulted in energy scarcity and threats. Solar desalination provides a sustainable fix, with researchers developing photothermal materials and designs to improve efficiency and sustainability. Glass materials, with their exceptional chemical stability, are suitable for extreme desalination in acidic and alkaline conditions. In this work, we have developed a porous glass evaporator (PGE) with exceptional water evaporation efficiency, achieved through a novel fabrication method that blends glass powders with soluble salts to create structure with continuous pores. The evaporator's microstructure comprises micrometer‐scale pores that form interconnected porous channels, facilitating efficient water transport and preventing salt deposition. Under one sun irradiation, the PGE exhibits superior solar evaporation performance in pure water, achieving a rate of 2.21 kg m−2 h−1, with an evaporation efficiency of 98%. In more complex media, such as seawater and methylene blue solution, the PGE also displays excellent evaporation capabilities, reaching rates of 2.08 and 2.47 kg m−2 h−1, respectively. Even after sustained alternation between acidic and alkaline treatments, the PGE retains an impressive evaporation rate of over 2.0 kg m−2 h−1, coupled with structural robustness, making it a promising candidate for practical applications in extreme environments. [ABSTRACT FROM AUTHOR]

In response to resource scarcity and environmental challenges, sustainable practices, particularly in recycling and reusing waste materials, have become crucial. This paper reviews the utilization of porous glass, particularly made from recycled waste glass, for manufacturing and environmental applications. Porous glass features a broad size range of tiny pores, offering advantages in recycling due to its inertness, sorption capabilities, and versatility. It can be produced through phase separation, sol–gel, hydrothermal methods, and the use of foaming agents, offering a large surface area and high sorption efficiency. The adsorption capacity, flexibility in enhancing material properties, and reusability of porous glass allow it to be applied in diverse environmental roles, such as contaminant removal from water and wastewater. The controlled release of phosphate from phosphate-porous glass adsorbent enables its use in fertilizing plants while minimizing excess phosphate release into the water bodies. Its unique physicochemical properties also make it suitable for use in construction sectors. Our findings highlight the porous glass's potential to significantly contribute to glass recycling, reduce landfill airspace, and support sustainable material usage. The study underscores the role of porous glass in advancing waste glass recycling and promoting sustainable environmental practices. [ABSTRACT FROM AUTHOR]

In this paper, we prepared three types of porous glasses (PGs) with specific surface areas of 311.60 m2/g, 277.60 m2/g, and 231.38 m2/g, respectively, via borosilicate glass phase separation. These glasses were further modified with amidoxime groups (AO) using the hydroxylamine method, yielding adsorbents named 1.5-PG-AO, 2-PG-AO, and 3-PG-AO. The adsorption performance of these adsorbents under various conditions was investigated, including sorption kinetics and adsorption mechanisms. The results reveal that the number of micropores and specific surface area of PG are significantly reduced after AO modification. All three adsorbents exhibit similar adsorption capabilities. Particularly, pH has a pronounced effect on U (VI) adsorption of PG-AO, with a maximum value at pH = 4.5. Equilibrium adsorption is achieved within 2 h, with a maximum adsorption capacity of 129 mg/g. Notably, a uranium removal rate of 99.94% is attained. Furthermore, the adsorbents show high selectivity in uranium solutions containing Na+ or K+. Moreover, the adsorbents demonstrate exceptional regeneration ability, with the removal rate remaining above 80% even after undergoing five adsorption–desorption cycles. The adsorption reaction of uranium on PG-AO involves a combination of multiple processes, with monolayer chemisorption being the dominant mechanism. Both the complex adsorption of AO and the ion exchange and physical adsorption of PG contribute to the adsorption of uranyl ions on the PG-AO adsorbents. [ABSTRACT FROM AUTHOR]

A Grand Canonical Monte Carlo simulation (GCMC) method is used to study the adsorption of methane and carbon dioxide on porous silica glass in the presence and absence of nickel. Nickel atoms are randomly allocated on pore walls, accounting for approximately 1–5% by weight. Experimental data is collected for various nickel concentrations ranging from 0 to 10%. The preparation of porous glass in the presence of Ni is done both with and without calcination in the furnace. The simulation investigates the adsorption of methane and carbon dioxide at temperatures of 273 K and 298 K for different pore widths. The adsorption of methane increases with higher nickel concentration due to the stronger interaction between methane and nickel. However, the opposite behavior is observed in the case of carbon dioxide. Physical adsorption reveals that fluid adsorption on porous glass surfaces decreases as temperature increases. The adsorption of methane begins at the nickel molecule and then progresses further inside the pore. However, in the experimental work, a similar behavior is found for nickel concentrations less than 5% with calcination, after which the adsorption decreases with increasing Ni concentration. This may be attributed to the blocking of Ni molecules at the pore entrance, resulting in difficulty for methane diffusion through the pore. Regarding the effect of Ni allocation on glass surfaces, it is observed that the isotherm obtained for randomly placed nickels is greater than that for nickels placed at the pore edge. This can also be attributed to the pore-blocking effect. The allocation of Ni does not significantly affect the adsorption of carbon dioxide. The finding of this study are supported by similarity to the results reported by others, for example in the study of methane adsorption on activated carbon in the presence of Ni. It can be concluded that nickel on solid surfaces can enhance the adsorption of methane for energy storage. [ABSTRACT FROM AUTHOR]

We employ computer simulations to study the mechanical response and the associated structural transformations of porous glassy materials under cyclic pure shear deformation. The glassy samples are created via the rapid thermal quench and kinetically arrested solid gas phase separation in the athermal limit. Both the limit of high and low porosity systems are prepared by varying the average density. We consider two different strain amplitudes which correspond to near yielding and the steady state plastic flow regime. Under periodic loading, the system undergoes irreversible plastic rearrangements, leading to a gradual shift towards the lower potential energy minimum state and stress–strain hysteresis. The pore structure changes over consecutive cycles which are demonstrated in terms of pore size distribution function. With increasing shear cycle the distributions become skewed towards higher length scale as the adjacent pores coalesce and form larger pores. These results are found to be strongly dependent on the system density and the strain amplitude. Finally the evolution of the pore structure is studied by analyzing the average pore diameter with shear cycle. [ABSTRACT FROM AUTHOR]

A methodology is developed and ZnO nanoparticles are synthesized in porous glasses. The synthesis is carried out by impregnating silicate porous glasses in an aqueous solution of zinc nitrate and its subsequent thermolysis. The spectral and luminescent properties of the synthesized composites are studied. The ability of ZnO nanoparticles formed in porous glass to produce reactive oxygen species under UV irradiation is studied. [ABSTRACT FROM AUTHOR]

Composite materials (CMs) based on porous glass matrices activated by yttrium in the presence of copper or bismuth are synthesized. It is established that, depending on the composition, the CM samples exhibit UV, blue-green, red, and infrared luminescence due to the presence of various centers, including Bi3+ and Cu+ ions, F centers in Y2O3, and molecular ions associated with cation vacancies Y3+. [ABSTRACT FROM AUTHOR]

Properties of porous materials prepared from glasses of the Na2O–B2O3–SiO2–GeO2 system have been studied using low-temperature nitrogen adsorption/desorption measurements. The results demonstrate that germanium substitution for silicon in the glasses studied leads to an increase in pore volume at SiO2/GeO2 ratios of down to 0.5. The porous glass with this composition has the largest specific surface area and micro- and mesopore volumes. We assume that the observed changes in the porosity parameters of glass in the case of complete germanium substitution for silicon are related to structural features of the borogermanate glass network, associated with B–O–B bond breaking and the formation of non-bridging oxygen atoms. [ABSTRACT FROM AUTHOR]

New vitreous composite materials (CMs) with two magnetic subsystems are synthesized by impregnation magnetite-containing matrices from iron-containing nanoporous glasses in aqueous MnCl2 and H2C2O4 solutions and the subsequent formation of manganese oxides MnxOy (x = 1, 2, 3; y = 1, 2, 3, 4) inside the pore space of the matrices as a result of thermolysis of the reaction product of the dopants (MnC2O4). The chemical (elemental) and phase compositions, the valence-coordination state of iron and manganese, and the characteristics of the magnetic state of the synthesized CMs are studied and compared with the characteristics of nanoporous matrices. [ABSTRACT FROM AUTHOR]

New vitreous composite materials (CMs) with two magnetic subsystems are synthesized by impregnation magnetite-containing matrices from iron-containing nanoporous glasses in aqueous MnCl2 and H2C2O4 solutions and the subsequent formation of manganese oxides MnxOy (x = 1, 2, 3; y = 1, 2, 3, 4) inside the pore space of the matrices as a result of thermolysis of the reaction product of the dopants (MnC2O4). The chemical (elemental) and phase compositions, the valence-coordination state of iron and manganese, and the characteristics of the magnetic state of the synthesized CMs are studied and compared with the characteristics of nanoporous matrices. [ABSTRACT FROM AUTHOR]

With the growth of laser technologies in photonics, the application of ultrashort laser becomes promising and prospective for volume phase elements fabrication in transparent materials. Femtosecond laser writing (FLW) was applied for polarized-sensitive volume phase gratings (VPGs) inscription in a nanoporous silicate matrix (NPSM). The VPGs formed had the thickness L = 54 ± 0.5 μm and 77 ± 0.5 μm, and showed diffraction efficiency of 8% and 14% respectively. VPGs in an NPSM demonstrated polarization sensitivity resulting in different diffraction efficiencies from 2 to 14%. Moreover, the impregnation of the NPSM plate with distilled water, 50% acetone and 10% acetone was investigated. The achieved results provide evidence for a possibility of a VPG in NPSM to be applied as a sensor. [ABSTRACT FROM AUTHOR]

Bismuth containing porous glasses (BPGs) were prepared on the basis of high-silica micro- and macroporous glasses and also of microporous glasses thermally treated at 750°C. The chemical composition of the glasses was determined by standard analytical methods and X-ray fluorescence analysis. Energy dispersive X-ray analysis showed that bismuth is predominantly formed at the half-thickness of the membranes. Characterization of the glass morphology was carried out by scanning electron microscopy. Their structural properties (specific surface area, volume porosity, structural resistance coefficient, average pore radius) and electrosurface ones (specific electrical conductivity, transport numbers of ions in the pore channels, electrokinetic potential) were studied in 10−4–10−1 M KNO3 solutions in a neutral pH range. The results were compared with similar properties of PG membranes not modified with bismuth(III) oxide. Porous glasses doped with bismuth oxide were found to restore their electrosurface characteristics in the neutral pH range in the concentration range of KNO3 solutions under study. [ABSTRACT FROM AUTHOR]

Composite materials (CMs) based on matrices of high-silica nanoporous glasses (NPGs) activated by bismuth and yttrium ions are synthesized. The CMs are studied by IR spectroscopy (1000–400 cm–1), depending on the Bi/Y nitrate ratio in the solution (1 : 1 and 10 : 1) and the heat treatment temperature of the CMs (from 470 to 870°C). The method of IR spectroscopy in composites identifies vibrations characteristic of the cubic modification Y2O3 and for the monoclinic modification of bismuth oxide (α–Bi2O3); for vibrations of Bi–O and Bi–O–Bi bonds, as well as Bi3+ cations in [BiO6] and/or [Bio3] structural units; and for vibrations of Bi–O–Si bonds, and for Y–O–Y and Y–O bonds. It is established that an increase in the yttrium content in CMs heat-treated at 470 and 870°C, (all other things being equal) leads to the appearance of additional absorption bands at 564, 556, 432, and 424 cm–1, which may be related to the formation of the cubic phase Y2O3. [ABSTRACT FROM AUTHOR]

• All Cr ions in Na 2 O-B 2 O 3 -SiO 2 -Cr 2 O 3 glass are octahedrally coordinated Cr3+ ions. • Most Cr 2 O 3 crystallized as eskolaite in silica-rich phase of phase-separated glass. • Leaching of Na 2 O-B 2 O 3 -SiO 2 -Cr 2 O 3 glass is limited by interdiffusion in porous layer. • The Na and B extraction rate for Cr-doped glasses was higher than for Fe-doped ones. • Eskolaite-containing porous glasses were obtained from Na 2 O-B 2 O 3 -SiO 2 -Cr 2 O 3 system. Porous glass (PG) obtained by leaching of sodium borosilicate glass (NBS) is actively used in sorption and separation technologies. Modifying the NBS system with additives can drastically affect the resulting PG. Here, we report on the effect that Cr 2 O 3 had on the leaching behavior of phase-separated glasses in the Na 2 O-B 2 O 3 -SiO 2 -Cr 2 O 3 system in 3 M HCl solution. The structure of these glasses was investigated by means of XRPD, EPR, and SEM. All chromium ions exist in the Cr3+ state and are octahedrally coordinated. Most Cr 2 O 3 crystallized as eskolaite in the silica-rich phase. The leaching process is limited by the interdiffusion in the leached porous layer. Cr 2 O 3 did not get extracted from the glass into a leaching solution. PGs containing a significant amount of eskolaite were obtained. The component extraction rate for Cr-doped glasses was higher than for Fe-containing glasses with similar compositions, which was explained by the difference in their structural roles. [ABSTRACT FROM AUTHOR]

Metal dispersion is key for designing highly active and well-defined catalytic systems. Herein, to shed light on the effects of Nb dispersion on the conversion of fructose into HMF, highly porous silica glasses grafted with niobium oxide were prepared. Preliminary catalytic screening was done for the microwave-assisted conversion of fructose into 5-hydroxymethylfurfural (HMF) in a biphasic system. The highly porous silica glasses impregnated with niobium oxide presented HMF productivities about 10- to 20 times higher than the mesoporous NbOPO4 reference material. Intriguingly, humin formation correlates with HMF yield regardless of the catalyst employed, although metal dispersion influences the acidity profile.

Direct application of TiO 2 nanopowder in water remediation is hindered due to sophisticated separation of the photocatalyst. Therefore, alternative partially crystallized porous glass based photocatalysts were prepared on the basis of combined phase separation and partial crystallization of 55.4SiO 2 –23B 2 O 3 –7Na 2 O-14.6TiO 2 (mol.-%) initial glass composition followed by selective leaching. The advantage of this glass composition is that, 3-D shaping is possible via selective laser sintering technique. Therefore, various macroscopic shapes were fabricated via selective laser sintering and conventional techniques and their resulting properties and photocatalytic activities were compared. Selective laser sintered glasses contain slightly less content of anatase phase due to formation of rutile during sintering process as opposed to conventional glasses. Textural properties are similar in both selective laser sintered and conventional shaped glasses which indicate similar phase separation mechanism and microstructure. In terms of macroscopic shapes, photocatalytic activity increases in the order: monolith < granulate < "macropowder" due to increase in the surface area to volume ratio. The photocatalytic activity is mainly determined by the amount of the anatase phase, thus conventional glasses exhibit slightly higher activity than selective laser sintered glasses. [Display omitted] [ABSTRACT FROM AUTHOR]

Substrates for enhancing the giant Raman signal (SERS) of light are being actively developed for the purpose of accurate detection of low concentrations of organic molecules. However, the complexity and high cost of fabricating substrates often limit their application. A simple method for obtaining SERS substrates based on nanoporous glass functionalized by means of silver particles is proposed, and the efficiency of the substrates in detecting low concentrations of benzoic acid is demonstrated. [ABSTRACT FROM AUTHOR]

It is well known that below a certain temperature (Ti), local displacements of individual atoms from their original positions occur in ferroelectric crystals with incommensurate phases. They form a spatial wave with a length of l, which is incommensurate with the lattice period a, i.e. the l/a ratio is irrational. The wavelength increases as the temperature decreases. Near the phase transition temperature TC, it reaches a length comparable to the size of the ferroelectric domains, as in the model rubidium tetrachlorozincate crystal (Rb2ZnCl4). In ultrafine Rb2ZnCl4 crystals, the increase in l is hindered by the size of the crystallite. Therefore, the physical properties of nanocrystalline rubidium tetrachlorozincate are expected to be considerably different from those of the bulk sample. One of the methods for producing nanosized ferroelectric materials is a method based on embedding the material from a solution into porous matrices with nanometre-sized through-pores. We applied this method to study the effect of the size of ultrafine rubidium tetrachlorozincate crystallites on its dielectric properties and the phases occurring in the nanocrystallites. For the experiment, we used samples of polycrystalline Rb2ZnCl4 and composites obtained by incorporation of Rb2ZnCl4 salt from aqueous solution into porous silicon oxide matrices with an average through-pore diameter of 46 and 5 nm (RS‑46 and RS-5, respectively). The temperature dependencies of their dielectric permittivity were studied within the range of 100 to 350 K. We determined the temperatures of transition to the incommensurate (Ti) and ferroelectric (TC) phases, as well as the mobility deceleration temperatures of ferroelectric domain boundaries in rubidium tetrachlorozincate nanocrystallites in the RS-46 composite. In Rb2ZnCl4 particles in the RS-5 composite, only the transition to the incommensurate phase occurs. In contrast to the bulk material, it shows features of the first-order phase transition

Dielectric properties and structure of initial nanocomposite based on porous glass with embedded ferroelectric NaNO2 and nanocomposite identical to that but having a TiO2-modified pore surface, have been studied over a temperature range 300 – 450 K (on cooling) and frequency one 0.1 – 3∙106 Hz. X-ray spectroscopy of the samples exhibited that NaNO2 was in the ferroelectric phase in both composites and the percentage of crystalline NaNO2 increased in the pores of the modified one. An increase in permittivity and conductivity was observed in the TiO2-modified nanocomposite. Two relaxation processes were identified and their nature was established. The charge polarization at the interfaces was found to make the main contribution to the dielectric response of the both nanocomposites. The DC-conductivity of both composites was estimated and its activation energies were determined. An activation energy change observed in a vicinity of 400 K was attributed to the phase transition to the low-temperature phase of NaNO2. The possibility to control the properties of nanocomposites through modifying the interfaces was shown.

The structural characteristics, electrical conductivity, counterion transport numbers, and electrokinetic potential of microporous glass subjected to additional heat treatment at 750°С (MIP-750) in 0.1–0.0001 M NaCl solutions have been studied. The results obtained were compared with the properties of micro- and macroporous glasses prepared by the standard methods. It was found that with an increase in the pore size in the series MIP < MIP-750 < MAP, the absolute values of the electrokinetic potential increase. [ABSTRACT FROM AUTHOR]

Porous glasses (PGs) obtained from sodium borosilicate (NBS) phase-separated glasses via leaching are promising inorganic membranes. Introducing Fe2O3 into NBS glasses imparts ferrimagnetic properties due to magnetite crystallization. Leaching of such glasses leads to the formation of magnetic PGs with interesting electro-surface characteristics. This work aimed to investigate the process of obtaining magnetite-containing PGs from NBS glasses depending on silica content, using XRPD and Raman spectroscopy, studying the PG membranes’ structural characteristics and their sorption properties with respect to methylene blue (MB). Obtained PGs were characterized by a polymodal distribution of mesopores and a small number of micropores with specific surface area values of 32–135 m2/g and an average mesopore diameter of 5–41 nm. The kinetic data were analyzed using pseudo-first-order, pseudo-second-order, and intra-particle diffusion equations. The equilibrium isotherms were fitted with Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. MB adsorption was found to be a complex process. The glass with the highest specific surface area demonstrated the maximum sorption capacity (10.5 mg/g). The pore size of PGs allowed them to be considered potential novel magnetic membranes for ultrafiltration.

Based on femtosecond laser glass welding, four different porous structures of welding spots were formed by the manufacturing processes of spatiotemporal beam shaping and alternating high repetition rate transformation. Compared with an ordinary Gaussian beam, the welding spot fabricated by the flattened Gaussian beam had smoother welding edges with little debris, and the bottom of the welding spot pore was flat. Instead of a fixed high repetition rate, periodically alternating high repetition rates were adopted, which induced multiple refractive indices in the welding spot pore. The welding spot pores manufactured by spatiotemporal beam shaping and alternating high repetition rate transformation have a special structure and excellent properties, which correspond to superior functions of porous glass. [ABSTRACT FROM AUTHOR]

This article presents the results of a study of the effect on the adsorption properties of microporous glass of its modification with ZnO–Ag nanocrystals. The adsorption processes from solutions of the Chicago Blue Sky organic dye are studied by spectrophotometric methods. It is found that the introduction of ZnO–Ag nanocrystals into glass pores increases the adsorption capacity of the material. It is shown that in concentrated (>10–6 M) Chicago Blue Sky dye solutions adsorption processes compete with the aggregation of dye molecules in solutions. [ABSTRACT FROM AUTHOR]

A method has been developed to obtain composite membranes based on porous glass. Inside the nanopores of glass membranes, gold nanoparticles are formed that have plasmon resonance. The average size of the obtained particles was 20–25 nm. The obtained membranes are promising for the development of new-generation sensors and investigation of the impact of plasmon resonance effect on ion transport inside nanopores. [ABSTRACT FROM AUTHOR]

Silver/silver halide materials are considered as efficient and highly stable plasmonic photocatalysts for the organic pollutant degradation and hydrogen evolution from water splitting under solar irradiation, and they possess promising antibacterial activity. Ordered mesoporous silica materials including porous glasses are considered as the most promising template for silver-containing structures. In the present work, Ag/AgHal-doped (Hal = Cl, Br) vitreous membranes on a base of the mesoporous glasses were prepared via step-by-step single-stage impregnation procedure. The chemical and phase composition of the modified membranes were identified by the X-ray photoelectron spectroscopy, the X-ray diffraction and the energy-dispersive X-ray spectroscopy. The structure and morphology of inner membrane space were studied by the scanning electron microscopy. Electrokinetic properties of the silver-containing vitreous membranes were determined by the differential method and the streaming potential method. The inner membrane space is modified unevenly with appearance of the clearly defined regions with different silver content. The formation of the Ag/AgCl clusters along with the individual nanoparticles over thickness of the 1-mm membrane with mean pore radius of 23 nm was detected. The modification of the pore space by Ag-containing structures and the type of halogen ion almost do not affect the electrochemical behavior of the mesoporous vitreous membranes.

This paper presents the results of a study of the performance characteristics of the coating formed by the "Primer-enamel for rust 3 in 1" when added to the composition of high-silica porous glass (PG) in various concentrations. The introduction of PGs is driven by the need to regulate humidity in modern living spaces and to reduce the toxicity of building materials. Modification of the coating resulted in improved adhesion, hiding power, and toughness. The results obtained open the prospects for developments in this direction related to the organization of an ergonomic home. [ABSTRACT FROM AUTHOR]

A technique is developed and new composite materials containing manganese oxides MnxOy (x = 1, 2, 3; y = 2, 3, 4) are synthesized based on high-silica nanoporous glasses (NPGs). The synthesis is carried out by successive impregnation of porous glass plates in aqueous solutions of manganese chloride (MnCl2) and oxalic acid (H2C2O4), followed by heat treatment of the samples in an argon atmosphere to decompose the reaction product (MnC2O4). The chemical composition and phase composition of the obtained composites are investigated. [ABSTRACT FROM AUTHOR]

The results of a study of the rheological properties (shrinkage on heating, viscosity) of porous glasses (PGs) obtained as a result of through acid leaching of two-phase sodium borosilicate glass doped with small additives of P2O5 and fluoride ions, as well as bismuth-containing PGs and quartzoid glasses based on them, depending on the temperature of the heat treatment of the PG and in comparison with the characteristics of the samples obtained from sodium borosilicate glass without additives, are presented. It is found that doping glass with the indicated impurities leads to a decrease in the thermal resistance of the obtained PGs and bismuth-containing PGs. The introduction of bismuth nitrate into PG in the case of the low-temperature treatment (at 120°C) lowers the temperature for the same viscosity values of quartzoid glasses by 15–20°C, in contrast to samples without additives, as well as from higher-temperature treatment (at 650°C) PGs with additives. [ABSTRACT FROM AUTHOR]

The generalized regression neural network (GRNN) model of sound absorption coefficient of porous glass was built on data from 16 groups gained by experiments, where 12 groups were randomly selected as trained samples and the other 4 groups were as tested ones. This GRNN model which has two parameters, porosity and thickness as the inputs, was set the maximum iteration number 20, getting the optimal trained spread parameter σ=0.1. The results showed that the average error of this model was 0.003, and this model has high precision and the prediction curve of the sound absorption coefficient was very similar to the experiments. The advantages of this method are simple, needing less trained samples, rapid and accurate.

Monitoring the gases released during breathing or via the skin has gained significance towards diagnosing diseases. In this study, a sensor chip capable of detecting nonanal gas, which is known to be a marker of lung cancer, was developed. The gas detection agent used was vanillin, which underwent aldol condensation with nonanal in the presence of a basic catalyst, resulting in the formation of an unsaturated aldehyde. Porous glass was used as the reaction field to carry the detection agent. Alkali-resistant porous glass was chosen because conventional porous glasses show low durabilities under basic conditions, as they primarily consist of SiO2. Nonanal can be detected through changes in the absorption spectrum of the sensor. An accumulate-type sensor was used in this study, which exhibited a linear relationship between the degree of absorption changes at 470 nm and nonanal concentration in the 60 ppb–1.3 ppm range. Therefore, this biological marker gas sensor is effective for the early diagnosis of diseases. The alkali-resistant porous glass sensor chip exhibited a higher degree of absorption change than the conventional porous glass sensor chip. [ABSTRACT FROM AUTHOR]

Based on femtosecond laser glass welding, four different porous structures of welding spots were formed by the manufacturing processes of spatiotemporal beam shaping and alternating high repetition rate transformation. Compared with an ordinary Gaussian beam, the welding spot fabricated by the flattened Gaussian beam had smoother welding edges with little debris, and the bottom of the welding spot pore was flat. Instead of a fixed high repetition rate, periodically alternating high repetition rates were adopted, which induced multiple refractive indices in the welding spot pore. The welding spot pores manufactured by spatiotemporal beam shaping and alternating high repetition rate transformation have a special structure and excellent properties, which correspond to superior functions of porous glass.

A porous glass (PG) embedded with titanium dioxide (TiO 2) was produced via impregnation of the PG with Titanium (IV) Isopropoxide solution followed by crystallization. N 2 sorption analyses revealed that the specific surface area (SSA) and total pore volume of the PG reached to 358 m2/g and 0.370 cm3/g, respectively. The adsorption capacity of methylene blue (MB) for the glasses was measured in the dark, instead the photocatalytic MB removal efficiency was evaluated by the degradation of MB under UV light illumination using a UV–vis spectrometer. The MB removal efficiency of the TiO 2 synthesized anatase powder was only 32.3 % whereas, for TiO 2 embedded PG (TiPG) it was 91.6 %, and nearly complete (> 99 %) efficacy was achieved for TiO 2 embedded alkaline leached PG (TiPG-AL) under UV illumination 3 h period. Better MB removal efficiency was attributed to high SSA and dispersion of nano size anatase TiO 2 crystallites within the porous structure. [ABSTRACT FROM AUTHOR]

The article presents the results of a study of the biological activity of porous high-silica glass obtained based on two-phase alkali borosilicate glass. The test results show that the toxicity of the investigated porous glass (PG) in relation to Paramecium caudatum varies depending on the concentration and time of contact of the finely dispersed PG powder with water. It is assumed that the revealed pattern is related to, first of all, the extraction of alkaline ions into an aqueous solution. [ABSTRACT FROM AUTHOR]

We report on waveguides laser writing inside porous glass. Depending on applied laser regimes, two types of waveguides are fabricated in the same glass sample. A gradient waveguide type is achieved under the lowest pulse energy regime, which results in gradual densification of a nanoporous framework forming a core with an increased refractive index. The surrounding unirradiated material acts as a cladding. The highest pulse energy applied enables formation of the densified core surrounded by rarefaction regions in the nanoporous framework - a corecladding waveguide type. Laser light guiding is also accomplished for both types to estimate the refractive index contrast. In addition, we determine the temperature distribution based on the thermal conduction model to reveal the difference of temperature gradients for the regimes applied. [ABSTRACT FROM AUTHOR]

Patients with asthma exhale high concentrations of nitric oxide (NO), making the measurement of NO clinically important. Although we previously developed a 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO) chip that relied on the reaction between NO gas and PTIO in the chip, the sensitivity and accuracy were insufficient for measuring NO in air exhaled by asthma patients. In this study, we focus on the conversion of NO to NO2 in the reaction with PTIO, and devise a new method to measure the converted NO2 using our previously developed NO2 analytical chip. NO is converted to NO2 in the PTIO chip and immediately released upon exposure to the atmosphere. This released NO2 is trapped on the adjacent NO2 analytical chip and reacts with diazo-coupling reagents to form an azo dye; a linear relationship was identified between the NO concentration and the change in absorbance at 525 nm due to production of the azo dye. The NO concentration could be measured in the 0−142 ppb range with a maximum error of ± 10 ppb at 142 ppb using the devised method, demonstrating sufficient sensitivity and accuracy for measuring NO in exhaled air. Furthermore, we successfully measured NO in the exhaled air of seven healthy adults, and detected ~19 ppb of NO, thus illustrating its feasibility for clinical use.

The results are presented on studies of the content of Lewis and Brønsted centers on the internal surface of high-silica porous glass (PG) obtained by the through chemical etching of alkali-borosilicate glass with the two-frame structure, including the one modified by an isothermal treatment in an electric furnace in air in the temperature range from 120 to 750°C. The content of the active surface centers is determined by the adsorption of the acid-base indicators with different рKа values. For all samples under investigation, the predominance of hydroxyl groups over siloxane ones is established, which indicates a high degree of surface hydroxylation; and the extreme dependence of the content of surface centers on the heat treatment temperature with the pronounced maximum at 650°C is found. [ABSTRACT FROM AUTHOR]

Bismuth-containing composite materials based on high-silica porous glasses (PGs) of various types are prepared. Their structural parameters and electrokinetic potential in 10–2 М KNO3 solutions in the pH range 1.5–8.5 are studied. The results are compared with the analogous properties of matrices not modified with bismuth oxide, as well as the pH dependence of the zeta-potential for SiO2 particles and the sols of synthesized and industrial bismuth(III) oxide. It is determined that modification of larger-pore particles not containing secondary silica with bismuth(III) oxide results in the deviation of the form of the ζ–рН dependences from those intrinsic for high-silica PG and SiO2 particles. [ABSTRACT FROM AUTHOR]

The article studies the adsorption of iron ions from solutions of iron(III) chloride with a concentration of 10–4–10–3 M at pH 3 on micro- and macroporous glass, as well as on microporous glass heat-treated at 750°C, obtained from two-phase sodium borosilicate glass. It is found that the adsorption values at a constant concentration of the iron chloride solution are a function of the structural parameters of the porous glass (PG). It is shown that the Freindlich and Langmuir adsorption isotherms can be used to analyze the experimental data and the constants of these isotherms are found. In the systems studied, adsorption mainly occurs via the monolayer mechanism. [ABSTRACT FROM AUTHOR]

A sodium borosilicate glass (SBG) was produced by conventional melt-quenching. As cast glass was heat treated to induce phase separation (SBG-HT), followed by acid leaching with HCl to dissolve one of the separated phases; i.e. alkali rich borate phase, so that a porous glass (PG) was obtained. In order to alter the pore structure, produced PG was subsequently alkali (NaOH) leached or alternatively heat treated. The samples were characterized by techniques including XRD, SEM, N 2 adsorption/desorption. The total pore volume for PG was found to be 0.314 cm3/g, reached to 0.370 cm3/g by alkali leaching, instead decreased to 0.227 cm3/g by heat treatment. The microhardness and tribological properties of SBG-HT and all PGs were evaluated by Vickers hardness and by pin on disk tribometer. For all PGs the microhardness values were lower, instead the wear rates were higher than that of the parent SBG-HT. [ABSTRACT FROM AUTHOR]

A-type zeolite membranes were synthesized on porous glass hollow fibers that prepared using the in-situ hydrothermal process. The porous glass hollow fibers were prepared using the phase inversion and sintering technique with the addition of yttria stabilized zirconia (YSZ) to improve their porosity. The glass hollow fibers were characterized using the scanning electron microscope (SEM), Fourier transform infrared (FTIR), mechanical properties and water permeability. The porosities of pure glass hollow fiber were improved by the addition of YSZ particles, which lead to an increase in the pure water permeability. The water permeability shows that the glass hollow fiber prepared form spinning suspension E, which has 30 wt% zeolite particles and 20 wt% YSZ particles, has the highest permeability of 155.65 L m−2 hr−1 bar−1 compared to the previous work, which was only 4.0 L m−2 hr−1 bar−1. This glass hollow fiber was later used as the support for the incorporation of zeolite membrane for the desalination application. The performance of membranes is separating sodium chloride (NaCl) salt solution were tested using two different setups, namely pressure driven reverse osmosis (RO) and sweeping liquid assisted reverse osmosis (SLRO). The solute flux for 5,000 and 10,000 ppm NaCl salt solutions were 24.45 and 17.86 L m−2 hr−1, respectively. Both operations enabled the solute rejection up to 98%. [ABSTRACT FROM AUTHOR]

Porous materials have received significant attention for catalyst, electrochemical energy storage, sensing and compound capture. Large surface area and connected inner channel make porous materials outstanding in the applications of catalyst, batteries and biomedicine. Glass is a traditional material and has the advantages of high stability and other physical properties. By combining the advantages of porous materials and glass, porous glass has been researched widely and applied to many leading-edge fields, such as batteries and sensors. This review presents common methods for synthesizing porous glass, including phase separation process (PSP), direct leaching process (DLP) of acid, sintering and so on. Three main steps for fabrication of each process are concluded. The recent applications are support, capturer and matter transport, and they are highlighted in this review. Future directions for preparing these materials are also discussed. [ABSTRACT FROM AUTHOR]

The research of the hydrolytic polycondensation kinetics of tetraethoxysilane (TEOS) is required in order to understand the sol-gel synthesis processes and identify the factors determining the direction of these processes. An extensive analysis of these problems permits us to predict appropriate ways for the synthesis of new substances with the predetermined properties. Studying the kinetics of the polycondensation of TEOS above the gel point will allow solving problems of the gels' strength and the gels' degree of structuring and thus optimizing the conditions of the further processing materials for the production of the final synthesis products. In this paper the results of the research on the structuring kinetics of the silica in the modeled aqueous-alcoholic solutions of TEOS, including boron-containing solutions, before and after the gel point at various molar ratios of H2O : SiO2 and pH values of 2.0 and 6.0 by the differential kinetic spectrophotometry are presented. The kinetic scheme developed by the authors and the mathematical tool allow determining the degree of the direction of the process of silica polycondensation. The data obtained on the model systems were applied to the description of the silica structuring process in the acid solutions resulting from the treatment of the single-phased sodium borosilicate glass. The obtained results will form the base for the interpretation of the experimental data on the kinetics of the silica structuring contained in the unstable phase of the two-phased alkali-borosilicate glass during the leaching process; i.e., it will allow predicting the dissolution rate, forms of existance, gelation time, strata formation time and, as a consequence, the formation of some porous structure of the resulting porous glass. [ABSTRACT FROM AUTHOR]

• Inverse gas chromatography for determining the surface free energy of porous glass (PG). • Estimation of thermodynamic parameters of pristine and silane-modified PG using non-polar and polar probes. • The specific interaction parameters has been obtained using both monopolar and amphoteric probe molecules. • The Lewis acid-base parameters showed a more acidic character of pristine PG. • Isopropanol revealed a bimodal distribution function of PG adsorption site energies. Surface modification of porous glass beads by ethanol-based 3-mercaptopropyltrimethoxysilane (MPTMS) grafting solutions is directly evidenced by nitrogen adsorption, elemental analysis, thermogravimetry, infrared and 29Si CP MAS NMR spectroscopy. Furthermore, the energetic characterization of the surface is essential to understand comprehensively the physico-chemical interactions between the pristine and MPTMS-modified surface and its gas/liquid-phase environment. In this study, inverse gas chromatography (IGC) is used to characterize the surface properties of porous glass (PG). By means of IGC at infinite dilution (IGC-ID), the dispersive component of the surface energy (γ s d), the enthalpy and entropy of adsorption of C 6 -C 10 hydrocarbon probes were determined at temperatures between 30 and 120 °C. The specific component of the surface energy (γ s s p) at the temperature of 120 °C has been obtained via the Van Oss theory and a least-squares procedure evaluating the IGC data of 8 polar probe molecules collectively. After surface silylation, the total surface energy (γ s t) decreased from 402 to 255 mJ/m² indicating both a reduced wettability and an increased hydrophobicity of the MPTMS-modified PG. Moreover, the acidity/basicity parameters according to the Van Oss and the Gutmann approach indicated that the acidity of the PG surface decreases by MPTMS grafting. Using n-octane and isopropanol probes, IGC at finite concentration (IGC-FC) was applied to obtain their adsorption isotherms and subsequently the BET specific surface areas. In addition, the surface heterogeneity of the studied PGs was also computed. The energy distribution functions of adsorption sites were monomodal (peak maximum at about 22 kJ/mol) for the n-octane probe, while isopropanol revealed a bimodal distribution function (maxima at about 18 and 25 kJ/mol) on both pristine and MPTMS-modified PG. Furthermore, the proportion of high energy sites (apparently assigned to Si OH groups) has been reduced by surface modification from 65% to only 35% despite a high surface coverage of ˜10 MPTMS species/nm2. These findings are in agreement with the results of 29Si CP MAS NMR measurements and are supported by DFT calculations on the adsorption of isopropanol and n-octane on the surface of a silica cluster model. [ABSTRACT FROM AUTHOR]