Pub Date : 2025-01-31DOI: 10.1016/j.clay.2025.107726
Jiaying Zhong , Weihua Song , Yu Wang , Jing Zhang , Yan Gao , Yanmin Yang , Hailei Zhang
With the advancement of rare-earth luminescent materials, developing composites with tunable luminescent properties poses a significant challenge. In this study, we synthesized HALs@YF3:Eu3+ scintillator material that emits red light by utilizing halloysites (HALs) as base materials and then surface modified with europium-doped YF3 via hydrothermal synthesis. The yielded product HALs@YF3:Eu3+ was characterized by TEM, SEM, XRD, and XPS, and then incorporated into the epoxy resin to endow X-ray scintillating abilities in the obtained composite with enhanced mechanical properties. Moreover, the green-emitting scintillator was also incorporated into the epoxy resin along with HALs@YF3:Eu3+ with varying feed ratios to afford the epoxy resin composites with tunable emission behaviors from red to green. This study demonstrates a valuable approach for applying epoxy resin composite materials in the field of radioluminescence.
{"title":"Developing halloysite-based X-ray scintillating nanocomposite enables red to green tunable emission behavior in epoxy resin","authors":"Jiaying Zhong , Weihua Song , Yu Wang , Jing Zhang , Yan Gao , Yanmin Yang , Hailei Zhang","doi":"10.1016/j.clay.2025.107726","DOIUrl":"10.1016/j.clay.2025.107726","url":null,"abstract":"<div><div>With the advancement of rare-earth luminescent materials, developing composites with tunable luminescent properties poses a significant challenge. In this study, we synthesized HALs@YF<sub>3</sub>:Eu<sup>3+</sup> scintillator material that emits red light by utilizing halloysites (HALs) as base materials and then surface modified with europium-doped YF<sub>3</sub> via hydrothermal synthesis. The yielded product HALs@YF<sub>3</sub>:Eu<sup>3+</sup> was characterized by TEM, SEM, XRD, and XPS, and then incorporated into the epoxy resin to endow X-ray scintillating abilities in the obtained composite with enhanced mechanical properties. Moreover, the green-emitting scintillator was also incorporated into the epoxy resin along with HALs@YF<sub>3</sub>:Eu<sup>3+</sup> with varying feed ratios to afford the epoxy resin composites with tunable emission behaviors from red to green. This study demonstrates a valuable approach for applying epoxy resin composite materials in the field of radioluminescence.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107726"},"PeriodicalIF":5.3,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.clay.2025.107718
Hideo Komine
Based on experimental and theoretical studies of bentonite hydraulic conductivity and swelling behavior, the author proposes a method for theoretical calculation of the interlayer distance of montmorillonite, a main clay mineral. Comparison of the interlayer distance of montmorillonite calculated using this method with the sizes of micromaterials blocked by the interlayer can support quantitative evaluation of the ability of montmorillonite to block the passage of micromaterials. The validity of this method was demonstrated by quantitative evaluation of filtration of seawater components by montmorillonite with permeable bentonite materials in some artificial seawater environments in the author's previous studies. This study has proposed the calculating flow of the filtration ability of montmorillonite interlayers. Furthermore, the method is applied to clay liners at industrial final waste disposal sites to develop necessary specifications for urgently needed clay-liner materials able to block the passage of micro-substances from biological waste into the environment. In addition, several case calculations were performed and depicts specifications of clay-liners which can block permeation of prion diseased brain matter (4 nm micromaterials) and/or can block permeation of Noroviruses (average diameter, 25–30 nm).
{"title":"Quantitative analogism on montmorillonite mineral layer filtration ability against micro-materials","authors":"Hideo Komine","doi":"10.1016/j.clay.2025.107718","DOIUrl":"10.1016/j.clay.2025.107718","url":null,"abstract":"<div><div>Based on experimental and theoretical studies of bentonite hydraulic conductivity and swelling behavior, the author proposes a method for theoretical calculation of the interlayer distance of montmorillonite, a main clay mineral. Comparison of the interlayer distance of montmorillonite calculated using this method with the sizes of micromaterials blocked by the interlayer can support quantitative evaluation of the ability of montmorillonite to block the passage of micromaterials. The validity of this method was demonstrated by quantitative evaluation of filtration of seawater components by montmorillonite with permeable bentonite materials in some artificial seawater environments in the author's previous studies. This study has proposed the calculating flow of the filtration ability of montmorillonite interlayers. Furthermore, the method is applied to clay liners at industrial final waste disposal sites to develop necessary specifications for urgently needed clay-liner materials able to block the passage of micro-substances from biological waste into the environment. In addition, several case calculations were performed and depicts specifications of clay-liners which can block permeation of prion diseased brain matter (4 nm micromaterials) and/or can block permeation of Noroviruses (average diameter, 25–30 nm).</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107718"},"PeriodicalIF":5.3,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.clay.2025.107721
Bassam El-Eswed , Yanal Albawarshi
Green and sustainable alkali-activated aluminosilicates (geopolymers, GPs), with zeolite-like structure were used previously to prepare metal oxides/GP composites by ion-exchange of metal ions with Na+ balancing [AlO4]− in GP. The present work attempts preparing metal oxides embedded in GP, for the first time, by direct mixing of 30 wt% KMnO4, K2CrO4 or CoCl2 with alkali activated Aldrich metakaolin (MK) and local Jordanian metakaolin (JMK) followed by calcination at 650 °C. FTIR, XRD, SEM and TEM of the products showed dispersion of nanostructures of metal oxides (Mn3O4 (II, III), Cr2O3 (III) and Co3O4 (II, III)) suggesting reducing/anti-oxidizing and capping power of aluminosilicate medium. The degradation behavior of acid blue (AB) and Congo red (CR) was studied in the presence of GP samples, H2O2 and absence of illumination. Using 5.0 g/L catalyst dose, 50 mg/L dye concentration, 88 mM H2O2, 30 °C and pH 10; MK-Mn and JMK-Mn catalysts induced degradation of 90 % AB within 65 min. MK-Co and JMK-Co resulted in degradation of 50–74 % of CR within 210 min at 50 °C. Although CR (26.9, 11.0 and 53.3 %) was found to have higher affinity than AB (1.2, 7.7 and 26.4 %) for adsorption onto JMK-Cr, JMK-Mn and JMK-Co, the second order rate constants (k2) of CR (8.14 × 102, 0.0 and 67.93 min−1 M−1) were lower than those of AB (7.29 × 103, 1.81 × 103 and 5.23 × 102 min−1 M−1). In comparison with photocatalytic degradation, the present work exclude electricity and UV lamps cost with relatively lower k2 and longer treatment.
{"title":"Utilization of encapsulating, anti-oxidizing, and green capping features of metakaolin based geopolymers for Mn, Cr and Co salts in catalytic degradation of dyes","authors":"Bassam El-Eswed , Yanal Albawarshi","doi":"10.1016/j.clay.2025.107721","DOIUrl":"10.1016/j.clay.2025.107721","url":null,"abstract":"<div><div>Green and sustainable alkali-activated aluminosilicates (geopolymers, GPs), with zeolite-like structure were used previously to prepare metal oxides/GP composites by ion-exchange of metal ions with Na<sup>+</sup> balancing [AlO<sub>4</sub>]<sup>−</sup> in GP. The present work attempts preparing metal oxides embedded in GP, for the first time, by direct mixing of 30 wt% KMnO<sub>4</sub>, K<sub>2</sub>CrO<sub>4</sub> or CoCl<sub>2</sub> with alkali activated Aldrich metakaolin (MK) and local Jordanian metakaolin (JMK) followed by calcination at 650 °C. FTIR, XRD, SEM and TEM of the products showed dispersion of nanostructures of metal oxides (Mn<sub>3</sub>O<sub>4</sub> (II, III), Cr<sub>2</sub>O<sub>3</sub> (III) and Co<sub>3</sub>O<sub>4</sub> (II, III)) suggesting reducing/anti-oxidizing and capping power of aluminosilicate medium. The degradation behavior of acid blue (AB) and Congo red (CR) was studied in the presence of GP samples, H<sub>2</sub>O<sub>2</sub> and absence of illumination. Using 5.0 g/L catalyst dose, 50 mg/L dye concentration, 88 mM H<sub>2</sub>O<sub>2</sub>, 30 °C and pH 10; MK-Mn and JMK-Mn catalysts induced degradation of 90 % AB within 65 min. MK-Co and JMK-Co resulted in degradation of 50–74 % of CR within 210 min at 50 °C. Although CR (26.9, 11.0 and 53.3 %) was found to have higher affinity than AB (1.2, 7.7 and 26.4 %) for adsorption onto JMK-Cr, JMK-Mn and JMK-Co, the second order rate constants (<em>k</em><sub><em>2</em></sub>) of CR (8.14 × 10<sup>2</sup>, 0.0 and 67.93 min<sup>−1</sup> M<sup>−1</sup>) were lower than those of AB (7.29 × 10<sup>3</sup>, 1.81 × 10<sup>3</sup> and 5.23 × 10<sup>2</sup> min<sup>−1</sup> M<sup>−1</sup>). In comparison with photocatalytic degradation, the present work exclude electricity and UV lamps cost with relatively lower <em>k</em><sub><em>2</em></sub> and longer treatment.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107721"},"PeriodicalIF":5.3,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Acid sites of clay minerals are active to catalyze numerous organic reactions. Previous studies had focused on the types and strength of these sites by correlating them with acid, pillaring or heat treatments, but the relation of acid sites with clay mineral morphology is not well understood. In this study, the synthesis of samples having similar chemical composition and structure, but different morphology characteristics was realized. The surface of samples was characterized by low-pressure argon adsorption at 77 K. The acid sites were probed by thermal desorption of 2-phenylethylamine. Three sites of different acid strength were identified. Whereas the assignment of these sites to basal and edge surfaces remains debatable, the method of thermal desorption of 2-phenylethylamine could clearly distinguish different sites related to homogenous and heterogeneous surfaces.
{"title":"Correlation of acid sites with morphology of layered silicates","authors":"Liva Dzene , Martine Lanson , Bruno Lanson , Sebastian Meyer , Angelina Razafitianamaharavo , Frédéric Villiéras , Severinne Rigolet , Cyril Vaulot , Simona Bennici","doi":"10.1016/j.clay.2025.107714","DOIUrl":"10.1016/j.clay.2025.107714","url":null,"abstract":"<div><div>Acid sites of clay minerals are active to catalyze numerous organic reactions. Previous studies had focused on the types and strength of these sites by correlating them with acid, pillaring or heat treatments, but the relation of acid sites with clay mineral morphology is not well understood. In this study, the synthesis of samples having similar chemical composition and structure, but different morphology characteristics was realized. The surface of samples was characterized by low-pressure argon adsorption at 77 K. The acid sites were probed by thermal desorption of 2-phenylethylamine. Three sites of different acid strength were identified. Whereas the assignment of these sites to basal and edge surfaces remains debatable, the method of thermal desorption of 2-phenylethylamine could clearly distinguish different sites related to homogenous and heterogeneous surfaces.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107714"},"PeriodicalIF":5.3,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
NiO as an appealing electrode material has been used for supercapacitors due to its high theoretical capacity and easy availability, but intrinsically low electrical conductivity and insufficient redox active sites restrict its further applications. In this work, a novel oxalate-derived NiO@NiAl-layered double hydroxide (LDH) with 3D core-shell structure (denoted as NiOOA@LDH) was prepared via hydrothermal calcination method, where the oxalate-derived porous C-doping NiO (NiOOA) grown on nickel foam (NF) was constructed using NiC2O4 as a sacrificial template and carbon source. The deposition of the ultrathin NiAl-LDH nanosheets on the NiOOA was conducive to forming robust adhesion between the core and the shell, which promoted effective electron/ion transfer and structure stability. Benefiting from the unique 3D core-shell structure and complementary compositional features, the NiOOA@LDH gave a high specific charge of 1347.0C g−1 at 1 A g−1, prominent rate performance (68.5 % retention at 15 A g−1) and cycle stability (91.1 % retention at 5 A g−1 after 5000 cycles). Furthermore, the as-assembled NiOOA@LDH//activated carbon (AC) device achieved a high energy density of 45.6 Wh kg−1 at a power density of 557.8 W kg−1 and an outstanding cycle stability (93.1 % retention at 5 A g−1 after 10,000 cycles).
{"title":"Oxalate-derived NiO@NiAl-layered double hydroxide core-shell material for supercapacitors","authors":"Hong-Li Yue, Hong-Yan Zeng, Wei Yan, Chao-Wei Luo, Zi-Feng Tian, Kai-Wen Xu","doi":"10.1016/j.clay.2025.107715","DOIUrl":"10.1016/j.clay.2025.107715","url":null,"abstract":"<div><div>NiO as an appealing electrode material has been used for supercapacitors due to its high theoretical capacity and easy availability, but intrinsically low electrical conductivity and insufficient redox active sites restrict its further applications. In this work, a novel oxalate-derived NiO@NiAl-layered double hydroxide (LDH) with 3D core-shell structure (denoted as NiO<sub>OA</sub>@LDH) was prepared via hydrothermal calcination method, where the oxalate-derived porous C-doping NiO (NiO<sub>OA</sub>) grown on nickel foam (NF) was constructed using NiC<sub>2</sub>O<sub>4</sub> as a sacrificial template and carbon source. The deposition of the ultrathin NiAl-LDH nanosheets on the NiO<sub>OA</sub> was conducive to forming robust adhesion between the core and the shell, which promoted effective electron/ion transfer and structure stability. Benefiting from the unique 3D core-shell structure and complementary compositional features, the NiO<sub>OA</sub>@LDH gave a high specific charge of 1347.0C g<sup>−1</sup> at 1 A g<sup>−1</sup>, prominent rate performance (68.5 % retention at 15 A g<sup>−1</sup>) and cycle stability (91.1 % retention at 5 A g<sup>−1</sup> after 5000 cycles). Furthermore, the as-assembled NiO<sub>OA</sub>@LDH//activated carbon (AC) device achieved a high energy density of 45.6 Wh kg<sup>−1</sup> at a power density of 557.8 W kg<sup>−1</sup> and an outstanding cycle stability (93.1 % retention at 5 A g<sup>−1</sup> after 10,000 cycles).</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107715"},"PeriodicalIF":5.3,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-27DOI: 10.1016/j.clay.2025.107711
Jing Zhang , Hao Zhang , Leibo Ji , Mingyi Huang , Qinfu Liu , JiaXing Li , XiaoYu Ding , Xi Xu
Natural halloysite have attracted great attention owing to their unique hollow tube and strong adsorption capacity. Nevertheless, the straightforward utilization of halloysite without further processing cannot fully discover its potential will lead to the waste of resources. In this study, an environmentally friendly method for the simultaneous separation of silica and aluminum from natural 7 Å halloysite via the aluminum thermal reduction method upon 700 °C under the system of aluminum powder and NaCl in N2 atmosphere was developed, concurrently occurs with the structural transformation from the raw hollow tubular halloysite to AIN whiskers and monocrystalline silicon droplet tips was observed. The formation of AlN whiskers can be concluded as three steps: (1) the reduction of Si4+ in SiO tetrahedron into Si0 atoms; (2) the separation of silicon and aluminum in the 1:1 meta-halloysite layer and the Si0 atoms transportation to the end of whisker rod to form the monocrystalline silicon microsphere; (3) the formation of AlN whiskers by the replacement of the remaining oxygen atoms in the aluminum‑oxygen octahedra. This in-situ replacement of oxygen atoms by nitrogen atoms in the AlO octahedron of tubular meta-halloysite plays a pivotal role in decreasing the reaction temperature. This work provides a novel idea and opens up a new technical route to prepare aluminum nitride and monocrystalline silicon with green efficiency and low cost.
{"title":"Instant formation of AlN whiskers and monocrystalline silicon with the separation of silicon and aluminum elements from 7 Å halloysite during thermite reduction","authors":"Jing Zhang , Hao Zhang , Leibo Ji , Mingyi Huang , Qinfu Liu , JiaXing Li , XiaoYu Ding , Xi Xu","doi":"10.1016/j.clay.2025.107711","DOIUrl":"10.1016/j.clay.2025.107711","url":null,"abstract":"<div><div>Natural halloysite have attracted great attention owing to their unique hollow tube and strong adsorption capacity. Nevertheless, the straightforward utilization of halloysite without further processing cannot fully discover its potential will lead to the waste of resources. In this study, an environmentally friendly method for the simultaneous separation of silica and aluminum from natural 7 Å halloysite via the aluminum thermal reduction method upon 700 °C under the system of aluminum powder and NaCl in N<sub>2</sub> atmosphere was developed, concurrently occurs with the structural transformation from the raw hollow tubular halloysite to AIN whiskers and monocrystalline silicon droplet tips was observed. The formation of AlN whiskers can be concluded as three steps: (1) the reduction of Si<sup>4+</sup> in Si<img>O tetrahedron into Si<sup>0</sup> atoms; (2) the separation of silicon and aluminum in the 1:1 meta-halloysite layer and the Si<sup>0</sup> atoms transportation to the end of whisker rod to form the monocrystalline silicon microsphere; (3) the formation of AlN whiskers by the replacement of the remaining oxygen atoms in the aluminum‑oxygen octahedra. This in-situ replacement of oxygen atoms by nitrogen atoms in the Al<img>O octahedron of tubular meta-halloysite plays a pivotal role in decreasing the reaction temperature. This work provides a novel idea and opens up a new technical route to prepare aluminum nitride and monocrystalline silicon with green efficiency and low cost.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107711"},"PeriodicalIF":5.3,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oral drug delivery systems (ODDSs) offer numerous advantages, such as convenient administration, high patient adherence, and cost-effectiveness. However, challenges like enzyme barriers and first-pass metabolism limit their effectiveness, and traditional methods often lack features for controlled release and targeted delivery, tending to cause severe systemic toxic side effects. Recent advancements in drug delivery have introduced alternative delivery vehicles. Montmorillonite (Mt), an FDA-approved biocompatible nanomaterial, stands out due to its high specific surface area, ideal adsorption capacity and cation exchange properties. This review explores preparation, modification, and application of Mt-based micro- and nanocomposites (MNCs) for ODDSs. Drugs encapsulated in Mt-based MNCs are shielded from the gastrointestinal environment, facilitating delayed and targeted drug release and enhancing drug bioavailability. The paper provides insights into the rational selection of Mt-based MNCs for advanced ODDSs, highlighting their potential to overcome limitations of traditional drug delivery systems.
{"title":"Montmorillonite-enhanced micro- and nanocomposites for targeted and controlled oral drug delivery systems","authors":"Zhenping Xiao , Xuemin Gu , Ji Huang , Liangzhe Liu , Siying Yuan , Peng Jiang , Yangrong Zhang , Yingshan Zhao , Shijie Wei , Qi Tao , Dongzhi Hou","doi":"10.1016/j.clay.2025.107713","DOIUrl":"10.1016/j.clay.2025.107713","url":null,"abstract":"<div><div>Oral drug delivery systems (ODDSs) offer numerous advantages, such as convenient administration, high patient adherence, and cost-effectiveness. However, challenges like enzyme barriers and first-pass metabolism limit their effectiveness, and traditional methods often lack features for controlled release and targeted delivery, tending to cause severe systemic toxic side effects. Recent advancements in drug delivery have introduced alternative delivery vehicles. Montmorillonite (Mt), an FDA-approved biocompatible nanomaterial, stands out due to its high specific surface area, ideal adsorption capacity and cation exchange properties. This review explores preparation, modification, and application of Mt-based micro- and nanocomposites (MNCs) for ODDSs. Drugs encapsulated in Mt-based MNCs are shielded from the gastrointestinal environment, facilitating delayed and targeted drug release and enhancing drug bioavailability. The paper provides insights into the rational selection of Mt-based MNCs for advanced ODDSs, highlighting their potential to overcome limitations of traditional drug delivery systems.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107713"},"PeriodicalIF":5.3,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TiO2 coating of a building envelope is expected to contribute to the mitigation of the heat-island effect because of the photoinduced cooling effect. However, the limited water adsorbability and retentivity of the TiO2 thin film can require successive sprinkling of water onto a building to achieve the sufficient cooling effect. In this study, a thin film consisting of a mixture of TiO2 and saponite was prepared through a sol–gel method. The high water retentivity of saponite was found to enhance the photoinduced cooling effect of the TiO2-based thin film. The photoinduced temporal change in the water adsorbability and retentivity of the highly hydrophilic composite was successfully monitored by using a hydrophilic xanthene dye adsorbed onto the coating as a probe. The effect of environmental humidity on the photoinduced cooling effect was also investigated. We found that higher humidity in the surrounding environment triggered stronger photoinduced cooling effects of the composite film. Especially during summer in Japan, when humidity is high, the TiO2–saponite composite film did not require intentional water sprinkling to achieve cooling effects.
{"title":"Photoinduced cooling effect of water-retentive composite of TiO2 and saponite","authors":"Yosuke Kageshima , Koharu Yagawa , Katsuya Teshima , Hiromasa Nishikiori","doi":"10.1016/j.clay.2025.107712","DOIUrl":"10.1016/j.clay.2025.107712","url":null,"abstract":"<div><div>TiO<sub>2</sub> coating of a building envelope is expected to contribute to the mitigation of the heat-island effect because of the photoinduced cooling effect. However, the limited water adsorbability and retentivity of the TiO<sub>2</sub> thin film can require successive sprinkling of water onto a building to achieve the sufficient cooling effect. In this study, a thin film consisting of a mixture of TiO<sub>2</sub> and saponite was prepared through a sol–gel method. The high water retentivity of saponite was found to enhance the photoinduced cooling effect of the TiO<sub>2</sub>-based thin film. The photoinduced temporal change in the water adsorbability and retentivity of the highly hydrophilic composite was successfully monitored by using a hydrophilic xanthene dye adsorbed onto the coating as a probe. The effect of environmental humidity on the photoinduced cooling effect was also investigated. We found that higher humidity in the surrounding environment triggered stronger photoinduced cooling effects of the composite film. Especially during summer in Japan, when humidity is high, the TiO<sub>2</sub>–saponite composite film did not require intentional water sprinkling to achieve cooling effects.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107712"},"PeriodicalIF":5.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-24DOI: 10.1016/j.clay.2025.107710
Emilia García-Romero , Eva Manchado , Mercedes Suárez
Kaolinite and smectite coexist in variable proportions along the Tamame de Sayago deposit in Zamora, Spain, suggesting a close genetic relationship. Kaolinite is formed through the weathering of the Variscan granite, while smectite is subsequently derived from kaolinite through a superimposed hydrothermal process that contributes to Si and Mg content. The transformation of smectites into kaolinite has been widely investigated, however, the reverse transformation of kaolinite into smectite is rarely documented. In this study, a group of representative samples from the deposit were studied via analytical electron microscopy and high-resolution transmission electron microscopy to determine the crystal chemistry of particles and explain the genetic relationship between the two clay minerals. The results showed that the crystal chemistry of particles varied, both among the particles of a sample and at different points within single particles. Chemical composition varied progressively from compositions of kaolinite to kaolinite/smectite and ultimately montmorillonite, with most particles displaying intermediate compositions. SiO2 and MgO contents increased progressively from kaolinite to montmorillonite through intermediate compositions. The morphologies and compositions of particles suggest the predominance of a solid-state transformation of kaolinite to smectite via interstratified kaolinite-smectite in areas less affected by hydrothermal fluids. Point analyses revealed the existence of domains with different compositions within single pseudohexagonal particles, suggesting the existence of areas with different degrees of transformation in single particles. In areas closer to faults, through which Si and Mg could circulate, dissolution-crystallisation was likely the main process responsible for smectite neoformation. Occasionally, epitaxial smectite growth was observed along the edges of kaolinite crystals. The simultaneous operation but different intensities of three processes solid-state transformation, epitaxy, and dissolution-precipitation generated particles with a complex crystal chemistry related to the existence of interstratified phases.
{"title":"Kaolinite to smectite transformation: A crystal chemistry study by analytical electron microscopy","authors":"Emilia García-Romero , Eva Manchado , Mercedes Suárez","doi":"10.1016/j.clay.2025.107710","DOIUrl":"10.1016/j.clay.2025.107710","url":null,"abstract":"<div><div>Kaolinite and smectite coexist in variable proportions along the Tamame de Sayago deposit in Zamora, Spain, suggesting a close genetic relationship. Kaolinite is formed through the weathering of the Variscan granite, while smectite is subsequently derived from kaolinite through a superimposed hydrothermal process that contributes to Si and Mg content. The transformation of smectites into kaolinite has been widely investigated, however, the reverse transformation of kaolinite into smectite is rarely documented. In this study, a group of representative samples from the deposit were studied via analytical electron microscopy and high-resolution transmission electron microscopy to determine the crystal chemistry of particles and explain the genetic relationship between the two clay minerals. The results showed that the crystal chemistry of particles varied, both among the particles of a sample and at different points within single particles. Chemical composition varied progressively from compositions of kaolinite to kaolinite/smectite and ultimately montmorillonite, with most particles displaying intermediate compositions. SiO<sub>2</sub> and MgO contents increased progressively from kaolinite to montmorillonite through intermediate compositions. The morphologies and compositions of particles suggest the predominance of a solid-state transformation of kaolinite to smectite via interstratified kaolinite-smectite in areas less affected by hydrothermal fluids. Point analyses revealed the existence of domains with different compositions within single pseudohexagonal particles, suggesting the existence of areas with different degrees of transformation in single particles. In areas closer to faults, through which Si and Mg could circulate, dissolution-crystallisation was likely the main process responsible for smectite neoformation. Occasionally, epitaxial smectite growth was observed along the edges of kaolinite crystals. The simultaneous operation but different intensities of three processes solid-state transformation, epitaxy, and dissolution-precipitation generated particles with a complex crystal chemistry related to the existence of interstratified phases.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107710"},"PeriodicalIF":5.3,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-20DOI: 10.1016/j.clay.2025.107707
Alejandro Jiménez , Raquel Trujillano , Antonio Gil , Vicente Rives , Miguel Ángel Vicente
An exhaustive bibliographical review of one of the most peculiar Layered Double Hydroxides, LDH, namely hydrocalumite and hydrocalumite–type compounds, has been carried out. The main differences that make hydrocalumite a special and interesting LDH are described, as well as the main methods of synthesis. A comprehensive comparison is also made with respect to MgAl–carbonate hydrotalcite with a Mg/Al molar ratio of 2. Thermal behavior of hydrocalumite is also different than that of other LDH, leading to the formation of attractive Mixed Metallic Oxides, MMO. Thus, the applications of hydrocalumite, hydrocalumite–type compounds and the derived MMO in environmental remediation and heterogeneous catalysis and photocatalysis are presented. Hydrocalumite, contrary to hydrotalcite, is not currently commercialized on an industrial scale, probably because its preparation is more complicated. Considering the excellent properties of hydrocalumite and the price, abundance and biocompatibility of its components, the scaling of its production should be a key challenge to take advantage in its industrial application.
{"title":"Hydrocalumite and hydrocalumite-type compounds: A special type of layered double hydroxides","authors":"Alejandro Jiménez , Raquel Trujillano , Antonio Gil , Vicente Rives , Miguel Ángel Vicente","doi":"10.1016/j.clay.2025.107707","DOIUrl":"10.1016/j.clay.2025.107707","url":null,"abstract":"<div><div>An exhaustive bibliographical review of one of the most peculiar Layered Double Hydroxides, LDH, namely hydrocalumite and hydrocalumite–type compounds, has been carried out. The main differences that make hydrocalumite a special and interesting LDH are described, as well as the main methods of synthesis. A comprehensive comparison is also made with respect to MgAl–carbonate hydrotalcite with a Mg/Al molar ratio of 2. Thermal behavior of hydrocalumite is also different than that of other LDH, leading to the formation of attractive Mixed Metallic Oxides, MMO. Thus, the applications of hydrocalumite, hydrocalumite–type compounds and the derived MMO in environmental remediation and heterogeneous catalysis and photocatalysis are presented. Hydrocalumite, contrary to hydrotalcite, is not currently commercialized on an industrial scale, probably because its preparation is more complicated. Considering the excellent properties of hydrocalumite and the price, abundance and biocompatibility of its components, the scaling of its production should be a key challenge to take advantage in its industrial application.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"267 ","pages":"Article 107707"},"PeriodicalIF":5.3,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143101107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号