Silica-based Materials Research Articles

Trialkoxysilane Grafting in Alcohols: A Simple Approach towards Modified Silica-Based Materials.

The grafting of trialkoxysilanes is the most common method for the surface functionalization of silica gel, and it is usually carried out in the presence of toluene or other solvents such as acetonitrile or acetone. Here, we replaced these solvents with alcohols to afford silica materials containing alkoxy groups linked to the silicon atom. The grafting of N,N-dimethyl-3-amino- or 3-amino-propyltrimethoxysilane was carried out in the presence of several alcohols containing an unsubstituted alkyl chain (C7 and C14), a PEG functionalized chain, or an amino-substituted chain (N,N-dimethylamino, pyridyl). Materials were characterized via solid-state 13C- and 29Si CPMAS NMR and thermogravimetric analysis to prove that alcohols are not "innocent" solvents but take part in the reaction and lead to [RSi(OR1)-(OSi)2] systems where the OR1 group proceeds from the alcohol used in the synthesis. As a proof of concept, we briefly studied the catalytic activity of some of these materials with the aim of showing how different modifications can influence the course of a selected reaction. Finally, a quaternary ammonium salt (QAS)-based silica was prepared containing both an alkyl-QAS and an alkoxy-QAS linked to silicon atoms. This could represent an interesting approach for the development of new antifouling-based materials and, overall, the described strategy could be useful for the preparation of new organosilica materials.

Functionalized mesoporous biosilica for immobilizing D-allulose 3-epimerase: A multienzyme cascade strategy for calorie reduction in fruit tea drinks

D-allulose, a low-calorie rare sugar, can be biosynthesized by D-allulose 3-epimerase (DAE). Here, DAE was covalently immobilized on polyethyleneimine-modified diatomite using two methods: a biopolymer coating approach (DAE@PEI-GA@PDP) and a direct attachment method (DAE-GA@PEI@PDP). Both immobilized DAE enzymes exhibited enhanced thermal stability and broader pH tolerance compared to the free DAE. They also exhibited excellent reusability and maintained more than 70% of their activity after 10 cycles. Additionally, a multienzyme cascade system was developed to produce D-allulose from low-cost D-glucose using immobilized glucose isomerase (GI) and immobilized DAE enzymes. This system obtained 76 g/L D-allulose from 500 g/L D-glucose. Notably, the application was extended to fruit tea drinks, successfully transforming high-calorie sugars (D-glucose and D-fructose) into D-allulose. This research offers a promising immobilization strategy for DAE on silica-based materials and provides robust biocatalysts for creating functional fruit tea drinks aimed at diabetics and individuals with specific dietary needs.

Comparative study of silica-based porous materials in the purification of radioactive wastewater

A significant challenge in the treatment of low-level radioactive wastewater is the effective purification of low-concentration radionuclides. Silica-based adsorbents are advantageous for the deep-purification of low-concentration metal ions. This study investigates three primary types of silica-based adsorbents: functionalized mesoporous silica, various modified zeolites, and mesoporous calcium silicate hydrate (C-S-H). These adsorbents were synthesized and their deep-purification effects on heavy metals and radionuclides were compared. The results indicated that mesoporous silica showed relatively poor adsorption for most metal ions. Zeolites outperformed mesoporous silica, with Zn framework-modified zeolites showing enhanced adsorption for several metal ions. Notably, C-S-H displayed superior adsorption performance, achieving high adsorption capacities for various metal ions and radionuclides. Specifically, at a dose of 0.5 g/L, the adsorption efficiency of C-S-H for numerous radionuclides in nuclear power plant wastewater exceeded 92–99 %, highlighting its potential for practical applications. An in-depth analysis of the physical and chemical structure and the adsorption mechanisms of C-S-H revealed its large mesoporous structure and electrostatic attraction to cations across a wide pH range. Multivalent cations were removed through exchange with Ca2+ in C-S-H, whereas monovalent cations were removed through exchange with Na+ in C-S-H. The cyclic structure of silica-oxygen tetrahedra in C-S-H, which promotes large pore formation and provides abundant ion exchange sites, underpins its excellent adsorption properties. This study offers valuable insights for the selection and application of silica-based materials in radioactive wastewater treatment.

Preparation of Porous Composite Materials through Silicon Component Foaming and Special Heat Treatment.

This study proposes a foaming method along with calcination to produce silica-based porous materials. The high-silicon-content waste residue reacts with sodium hydroxide for hydrogen evolution foaming reactions. Then, the foaming green bodies are embedded and calcined in the calcination powder consisting of silicon, silicon carbide, graphite, and activated carbon at 1200 °C. The calcination powder creates a reducing atmosphere and prevents adhesion of the foaming green bodies to the crucible during calcination. Furthermore, the addition of activated carbon and calcination improve the macroporosity issue of the prepared sample through a gas-liquid-solid transformation. The BET surface area measurement is 64.197 m2/g, and the mercury intrusion porosimetry measurement indicates a porosity of 56.48%, with an average pore diameter of 396.48 nm. The porous composite materials exhibit the capability to adsorb methylene blue in solution. The porous materials possessing functional groups suggest promising potential for future development and application prospects.

Detection of riboflavin concentration by sol-gel silica coated dual-peak long period fiber grating sensor

A dual-peak long period fiber grating (DP-LPFG)-based sensor was designed and fabricated for the sensitive detection of riboflavin concentration. LPFGs with a period of 163 μm and a cladding mode of LP0, 12 were inscribed on a standard single-mode silica fiber using a femtosecond laser direct writing technique. Coatings of silica-based materials doped with β-cyclodextrin (β-CD), prepared via the sol-gel method, were applied to the surface of the LPFGs for the detection of riboflavin. To investigate the impact of coating thickness on the sensing sensitivity, sol-gel coatings of different thicknesses were applied to the surface of the LPFG sensor. Experimental findings revealed that the sensor with a thickness of approximately 540 nm sol-gel coatings exhibited superior sensing performance. The detection limit of the prepared DP-LPFG sensor was tested to be 0.08 nM, and it exhibits a response time of less than 3 minutes, along with high sensitivity, excellent repeatability, and selectivity. Thus, this sensor holds significant promise for applications in disease treatment and diagnosis, as well as in ensuring food quality.

Sintesis Zeolit dari Abu Sekam Padi (OryzaSativa L.) Serta Uji Efektifitasnya Sebagai Material Antiseptik

Rice husks are obtained from 20% rice milling and have a silica content of 94-99% of ashed rice husks. Zeolite is a silica-based material and is known as an aluminosilicate compound, because it is formed from two main components, namely tetrahedral AlO4- and SiO4¬-. Synthetic zeolite is obtained by reacting Sodium Silicate (A) with Sodium Aluminate (B) which is then aged at 100oC for 24 hours to produce white synthetic Zeolite powder. Zeolite synthesis will be made with three variations of mixture ratios, namely 30A:70B, 50A:50B, 70A:30B and the characteristics of each will be evaluated. To test the success of this synthetic zeolite as an antiseptic material, its ability to reduce the infectious value of Bacteriuria and Candiduria will be tested, which will be represented by Escherecia coli and Candida albicans. The results obtained from the three variations of synthetic zeolite that were made had the same characteristics and had a ratio of less than two or type A. Synthetic zeolite made at a dose of 600 mg had the ability to act as an antiseptic material against Escherichia coli 104 by reducing the number of colonies to 72-79 %, as well as Candida albicans 103 was able to reduce the number of C. albicans colonies by 74-80%, this value is lower than Attapulgite 600mg in reducing the same number of colonies, namely 90% for bacteriuria and 94.90% for candiduria. To equalize its capabilities with Attapulgite 600 mg, the dosage of the synthetic zeolite obtained in the research was increased to 700 mg

Impact of aminopropyl units on physisorption in mesostructured silica is larger for CH4 than CO2 and depends on pore curvature

Mesoporous silica-based materials attract great interest for diverse applications, including capture, storage, and catalysis due to their large surface area, uniform pore size distribution, and customizable surface. The regular 2D hexagonal pore symmetry of MCM-41 makes it an ideal model. Amine groups are introduced to enhance CO2 adsorption, but the interplay of factors influencing overall performance, including pore size, remains unclear. This computational study explores the physisorption of CO2 and CH4, shedding light on the microscopic details underlying adsorption capacity and selectivity. Three aminopropyl-functionalized MCM-41 models with different pore size are compared through Grand Canonical Monte Carlo and Molecular Dynamics simulations. Aminopropyl chains affect CO2 adsorption, but its affinity for the preserved silanol groups is larger. In addition, the competitive interaction between amine and silanol groups emerged, and it is pore curvature dependent. Surprisingly, CH4 physisorption is influenced even more by surface functionalization. Results show a non-monotonic trend as a function of pore size. Local density of the alkyl chains plays the major role. Overall, the intermediate pore size demonstrates the best performance, thanks to the balance among the various effects. The study emphasizes the importance of understanding the interplay between material texture and gas interactions to optimize adsorption performance.

Investigation of transformer oil aging using no-core optical fiber (NCF) sensor

Transformer oil plays a crucial role in insulation and cooling within high-voltage transformers, but it degrades over time. This research proposes a durable sensor capable of detecting the refractive index (RI) of transformer oil when it exceeds the RI of the sensor structure, known as high refractive index (HRI) sensing. The study utilizes a no-core optical fiber (NCF) to monitor the quality of transformer oil. In this setup, single mode fiber (SMF) is employed as both the input and output of the NCF, forming an SMF-NCF-SMF (SNS) sensor. To date, to the use of an NCF in the SMF-NCF-SMF scheme has not been reported for high RI fiber sensing and transformer oil degradation detection. Additionally, this study provides an analysis of the influence of different diameters and lengths of NCF on the sensor’s sensitivity. The HRI sensing performance of the sensor was evaluated both numerically and experimentally by observing power spectrum changes due to leaky modes interference in response to varying transformer oil RI values from 1.4600 RIU to 1.5500 RIU. The NCF, with a geometry of 1 cm in length and 100 μm in diameter, demonstrated remarkable sensitivity, achieving up to 88.285 dBm/RIU for HRI values within the specified range. The sensor effectively discerned various aging levels of transformer oil in power transformer applications. Additionally, since the NCF structure is entirely composed of silica-based materials, it exhibited significant temperature resistance. These characteristics make the SNS structure well-suited for reliable deployment in challenging thermal environments.

Sorption kinetics and stability of conventional adsorbents for mercury remediation

In-situ remediation of mercury at numerous contaminated sites worldwide is a challenging and costly endeavor due to the persistency of this contaminant. In this study, we evaluated eight commercially available sorbent media ranging from carbon-, clays- and silica-based materials (PBC– Biochar, eSorb – Sorbster, nsPAC – Powdered Activated Carbon, fsPAC – Powdered Activated Carbon with Mackinawite, F300 – Filtrasorb 300, Si-SH – Silica Thiol, eBind – RemBind, Q-Clay – Organoclay PM-199), for their effectiveness in sorbing mercury (Hg2+) and mercury complexed with dissolved organic matter (Hg-DOM). Under the chosen experimental conditions of this study, results showed that in the absence of DOM, the kinetic rates of Hg2+ sorption onto the evaluated sorbents were in the order of 0.31 min−1(Si-SH) to 2.98 min−1 (nsPAC), whereas in the presence of DOM, the rates varied from 0.16 min−1 (F300) to 0.95 min−1 (nsPAC). The measured sorption capacity for Hg2+ in the absence of DOM varied from 3.02 mg/g (Q-Clay) to 35.15 mg/g (Si-SH), whereas in the presence of DOM, calculated partition coefficient (KD) ranged from 69.7 mL/g (Q-Clay) to 41,510 mL/g (Si-SH). Furthermore, kinetic data suggest liquid film diffusion was the rate-limiting steps governing mercury sorption onto the studied media. Overall, the obtained study parameters (kinetics/isotherm) are particularly important in informing robust engineering designs for deployment of the vast majority of evaluated sorbents. Thus, sorbent-based strategies offer viable solutions for cost-effective cleanup of mercury at industrially contaminated sites.

A new sol-gel fluorescent sensor to track carbonyl compounds

Carbonyl compounds are ubiquitous quality trackers that provide information about food product degradation as well as air and water pollution levels. In addition, they are used as biomarkers for medical diagnoses. With more user-friendly sensors, their fast detection and easy quantification are highly relevant. The synthesis, characterization, and performance assessment of a new sensor based on aniline fluorescence to monitor carbonyls in real time is reported. A cost-effective synthesis using a straightforward sol-gel process led to the construction of a nontoxic silica-based material with high porosity, which can be used with almost no sample preparation. The material exhibits a rapid (< 1 min) fluorescence decrease upon interaction with carbonyl groups. The limit of detection is as low as ca. 5 × 10−4 mol·L−1 for hexanal, while fluorescence extinction occurs at much higher concentrations (5 × 10−1·mol L−1), which enables the sensor to be used with a very broad range of detection. Real-time monitoring is possible since the fluorescence loss correlates with the concentration of carbonyl moieties. The performance was validated in simulating as well as in real media, making this sensor suitable for use in a wide range of applications.

16 × 112 Gbps directly modulated membrane laser array for co-packaged interconnects.

A low-cost and low-power-consumption optical transmitter with a narrow shoreline is crucial for short-reach optical communication. To increase the shoreline bandwidth density (Gbps/mm) at low cost, multiple optical components, including lasers, should be integrated on a single chip. In this study, we develop a sixteen-channel membrane laser array integrated with silica-based spot-size convertors on a SiO2/Si substrate, with a footprint of 1.11 × 2.75 mm2. A thin (340 nm) membrane buried-heterostructure sandwiched between low-index silica-based materials provides high carrier and optical confinement, which contributes to reducing power consumption. We demonstrated direct modulation with 28- and 56-GBaud PAM4 signals and verified that 2-km data transmission is feasible for all sixteen channels.

Smart and responsive nano copper oxide–PDMS composite for “three-in-one” synergistic adsorptive–oxidative / reductive degradation of the persistence of organic pollutants, elimination of nanoparticles and heavy metal ion

Copper-and silica-based materials have been used globally as environmental catalysts and adsorbents for centuries. Despite their differences in their properties and roles in the participation of environmental activity, both have been combined to create various types of functional materials, ranging from copper oxides and polydimethylsiloxane (PDMS) sponge (PS) cores to advanced hybrid composite materials. In this work, CuO was incorporated onto SiO2 (CPC) by calcination of PDMS-Cu2O sponge, and the physicochemical properties and application of CPC were investigated. The CPC was homogeneous in a surface area (326.69 m2g-1), pore size (33.16 Å), pore volume (0.056 cm³g−1), and particle size (183.66 Å). This CPC has been used for the degradation (oxidation/reduction) and adsorption of azithromycin (AZM), 1,4-dichlorobenzene (DCB), rhodamine B (RB), methylene blue (MB), 4-nitrophenol (4-NP), gold nanoparticles (AuNPs), and chromium (VI). Efficiencies of CPC for the above persistence of organic pollutants (POPs) and adsorption of AuNPs and Cr(VI) were ∼72–100% under optimized conditions. CPC followed the pseudo-second-order (PSO) degradation kinetics with a higher r2 (>0.99) with eight cycles of reusability. Moreover, this synthetic strategy can be tailored to produce nanostructured composite materials and/or those associated with other species for diverse environmental and industrial applications.

Mesoporous Oxidized Mn-Ca Nanoparticles as Potential Antimicrobial Agents for Wound Healing.

Managing chronic non-healing wounds presents a significant clinical challenge due to their frequent bacterial infections. Mesoporous silica-based materials possess robust wound-healing capabilities attributed to their renowned antimicrobial properties. The current study details the advancement of mesoporous silicon-loaded MnO and CaO molecules (HMn-Ca) against bacterial infections and chronic non-healing wounds. HMn-Ca was synthesized by reducing manganese chloride and calcium chloride by urotropine solution with mesoporous silicon as the template, thereby transforming the manganese and calcium ions on the framework of mesoporous silicon. The developed HMn-Ca was investigated using scanning electron microscopy (SEM), transmission electron microscope (TEM), ultraviolet-visible (UV-visible), and visible spectrophotometry, followed by the determination of Zeta potential. The production of reactive oxygen species (ROS) was determined by using the 3,3,5,5-tetramethylbenzidine (TMB) oxidation reaction. The wound healing effectiveness of the synthesized HMn-Ca is evaluated in a bacterial-infected mouse model. The loading of MnO and CaO inside mesoporous silicon enhanced the generation of ROS and the capacity of bacterial capture, subsequently decomposing the bacterial membrane, leading to the puncturing of the bacterial membrane, followed by cellular demise. As a result, treatment with HMn-Ca could improve the healing of the bacterial-infected wound, illustrating a straightforward yet potent method for engineering nanozymes tailored for antibacterial therapy.

Unusual species of methane hydrate detected in nanoporous media using solid state 13C NMR.

Methane is considered to be a cubic structure I (CS-I) clathrate hydrate former, although in a number of instances, small amounts of structure II (CS-II) clathrate hydrate have been transiently observed as well. In this work, solid-state magic angle spinning 13C NMR spectra of methane hydrate formed at low temperatures inside silica-based nanoporous materials with pores in the range of 3.8-20.0nm (CPG-20, Vycor, and MCM-41) show methane in several different environments. In addition to methane encapsulated in the dodecahedral 512 (D) and tetrakaidecahedral 51262 (T) cages typical of the CS-I clathrate hydrate phase, methane guests in pentakaidecahedral 51263 (P) and hexakaidecahedral 51264 (H) cages are also identified, and these appear to be stabilized for extended periods of time. The ratio of methane guests among the D and T cages determined from the line intensities is significantly different from that of bulk CS-I samples and indicates that both CS-I and CS-II are present as the dominant species. This is the first observation of methane in P cages, and the possible structures in which they could be present are discussed. Broad and relatively strong methane peaks, which are also observed in the spectra, can be related to methane dissolved in an amorphous component of water adjacent to the pore walls. Nanoconfinement and interaction with the pore walls clearly have a strong influence on the hydrate formed and may reflect species present in the early stages of hydrate growth.

Paradigm Shift: Major Role of Ion-Pairing-Dependent Size Exclusion Effects in Bottom-Up Proteomics Reversed-Phase Peptide Separations.

Can reversed-phase peptide retention be the same for C8 and C18 columns? or increase for otherwise identical columns with a smaller surface area? Can replacing trifluoroacetic acid (TFA) with formic acid (FA) improve the peak shape? According to our common understanding of peptide chromatography, absolutely not. Surprisingly, a thorough comparison of the peptide separation selectivity of 100 and 120 Å fully porous C18 sorbents to maximize the performance of our in-house proteomics LC-MS/MS setup revealed an unexpectedly higher peptide retentivity for a wider pore packing material, despite it having a smaller surface area. Concurrently, the observed increase in peptide retention─which drives variation in separation selectivity between 100 and 120 Å pore size materials─was more pronounced for smaller peptides. These findings contradict the central dogmas that underlie the development of all peptide RP-HPLC applications: (i) a larger surface area leads to higher retention and (ii) increasing the pore size should benefit the retention of larger analytes. Based on our intriguing findings, we compared reversed-phase high-performance liquid chromatography peptide retention for a total of 20 columns with pore sizes between 60 and 300 Å using FA- and TFA-based eluents. Our results unequivocally attest that the larger size of ion pairs in FA- vs TFA-based eluents leads to the observed impact on selectivity and peptide retention. For FA, peptide retention peaks at 200 Å pore size, compared to between 120 and 200 Å for TFA. However, the decrease in retention for narrow-pore particles is more profound in FA. Our findings suggest that common assumptions about analyte size and accessible surface area should be revisited for ion-pair RP separation of small peptides, typical for proteomic applications that are predominantly applying FA eluents. Hybrid silica-based materials with pore sizes of 130-200 Å should be specifically targeted for bottom-up proteomic applications to obtain both superior peak shape and peptide retentivity. This challenging task of attaining the best RPLC column for proteomics calls for closer collaboration between LC column manufacturers and proteomic LC specialists.

A universal strategy for constructing high-performance silica-based AIE materials for biomedical application

As an emerging fluorophore, aggregation-induced emission luminogens (AIEgens) have received widespread attention in recent years, but the inherent drawbacks of AIEgens, such as the poor water-solubility and insufficient fluorescence stability in complex environments, restrict their performance in practical applications. Herein, we report a universal strategy based on hydrophobic dendritic mesoporous silica (HMSN) that can integrate different AIE molecules to construct multi-color fluorescent AIE materials. Specifically, HMSN with central radial pores was used as a powerful carrier for direct loading AIE molecules and restricting their intramolecular motions. Due to the pore-domain restriction effect and hydrophobic interaction, the obtained silica-based AIE materials have bright fluorescence with a maximum quantum yield of 68.38%, high colloidal/fluorescence stability, and excellent biosafety. Further, these silica-based AIE materials can be conjugated with functional antibodies to obtain probes with different targetability. After integration with immunomagnetic beads, the prepared detection probes achieved the quantitative detection of cardiac troponin I with the limit of detection (LOD) of 0.508 ng/mL. Overall, the targeting probes stemming from silica-based AIE materials can not only achieve cell-specific imaging, but quantify the number of Jurkat cells (LOD = 270 cells/mL) to further determine the specific etiology of the disease.

Enhancing creep resistance performance in silica-based ceramic core materials through shell-core structure

The creep behavior of silica-based ceramic cores significantly impacts dimensional precision in investment casting. This study focuses on synthesizing an alumina coating on fused silica surfaces to create a shell-core structure. The creep behavior of silica-based ceramic cores was explored. Specifically, the influence of the shell-core structure on their creep mechanism was investigated. The results revealed the excellent creep resistance of silica-based ceramic cores with shell-core structures. The softening deformation of particles and the viscous flow of the glass phase were observed to account for the differences in creep behavior. The alumina shell structure reinforced the powders, effectively inhibiting the softening deformation of the core structure. Notably, the shell-core structure not only suppressed the viscous flow of the glass phase, thereby weaking the pore filling process, but also promoted the mullitization reaction. This reaction accelerated the consumption of the glass phase, enhancing the creep resistance of the silica-based ceramic cores.

A green synthesis method of a mussel-inspired polyphenol-functionalized silica-based material and its highly efficient adsorption of gallium

Three-dimensional mesoporous silica is a distinctive nanomaterial celebrated for its unique structure, substantial specific surface area, enhanced utilization of active surfaces, and improved adsorption and catalytic reaction capabilities. Nevertheless, its limited surface functional groups often impede its effective ion adsorption capacity. Here, inspired by the mussel-adhesive phenomenon, in this study, we introduced a straightforward layer-by-layer assembly approach to fabricate a new series of KIT-6@x-catechol/polyethyleneimine composites, the catechol/polyethyleneimine is the shell and KIT-6 is the core. Importantly, catechol(CA) and polyethyleneimine(PEI) polymers as selective layers with dense structures and abundant cation exchange groups, resulting in outstanding adsorption performance for our material. At a pH of 3.0, Ga(III) exhibited a maximum adsorption capacity of 88.65 mg g−1 on the adsorbent. Furthermore, the adsorbent demonstrated selective adsorption capabilities for Ga(III) over Ge(IV), Al(III), Cu(II), Zn(II), and Co(II). The primary adsorption mechanism of KIT-6@x-CA/PEI is chelation that occurs through coordination between the O atom on the phenolic hydroxyl group of CA and Ga3+, Ga(OH)2+, Ga(OH)2+ under pH 3.0 conditions. In summary, the synthesized KIT-6@x-CA/PEI exhibits significant potential for water treatment containing Ga(III) through adsorption processes.

Ultra-high performance concrete alleviates ecotoxicological effects in aquatic organisms

With the advancement of cementitious material technologies, ultra-high performance concretes incorporating nano- and(or) micro-sized particle materials have been developed; however, their environmental risks are still poorly understood. This study investigates the ecotoxicological effects of ultra-high performance concrete (UC) leachate by comparing with that of the conventional concrete (CC) leachate. For this purpose, a dynamic leaching test and a battery test with algae, water flea, and zebrafish were performed using standardized protocols. The conductivity, concentration of inorganic elements (Al, K, Na, and Fe), and total organic concentration were lower in the UC leachate than in the CC leachate. The EC50 values of the CC and UC leachates were 44.9 % and >100 % in algae, and 8.0 % and 63.1 % in water flea, respectively. All zebrafish exposed to the CC and UC leachates survived. A comprehensive evaluation of the ecotoxicity of the CC and UC leachate based on the toxicity classification system (TCS) showed that their toxicity classification was “highly acute toxicity” and “acute toxicity”, respectively. Based on the hazard quotient and principal component analysis, Al and(or) K could be significant factors determining the ecotoxicity of concrete leachate. Furthermore, the ecotoxicity of UC could not be attributed to the use of silica-based materials or multi-wall carbon nanotubes. This study is the first of its kind on the ecotoxicity of UC leachate in aquatic environments, and the results of this study can be used to develop environment-friendly UC.

Thermal analysis of aerogels and their vacuum-formed forms, their potential uses, and their effects on the environment

The main topic of the paper is to investigate the thermal examination of aerogels and their vacuumed forms, application possibilities, and environmental impact. In the paper, the thermal conductivity of homemade vacuum insulation panels was tested with different silica-based core materials. Three types of fibrous aerogel materials were used as core materials; another silica-based microporous insulation was used as a filling material. Microscopic images were taken from the core materials; furthermore, the thermal conductivities of both base materials and their vacuumed form were also tested at different mean temperatures (0, 10 and 20 °C). The results regarding the applicability of these materials as filling-core materials for vacuum insulation panels are interesting. The results showed that for microtherm and pyrogel, the thermal conductivities decreased more than 15%, while for the spaceloft and slentex it was about 8 and 2%, respectively, after evacuating the air. The paper also presents compressibility changes of the samples after vacuumization. The results were used as a basis for building energetic calculations; furthermore, the comparison of different materials from their carbon footprint point of view was also presented. These calculations depicted aerogel's very long payback time with a current market price.