Pub Date : 2024-10-30DOI: 10.1016/j.clay.2024.107587
Andrea Bernasconi , Nicoletta Marinoni , Lucia Mancini , Marco Voltolini , Fernando Francescon , Rinaldo Sartori , Alessandro Pavese
A combination of technological properties, mineralogical composition and three-dimension (3D) imaging is proposed to get insights into sanitary-ware ceramic bodies of the Vitreous-China technology as a function of the different clay raw materials used in the formulation of slip. Particular attention is paid to the effects induced along the production chain, during casting, after drying (dried body) and after firing (fired body).
The different combinations of China and ball clays lead to different casting behaviour, in first instance, and to different mechanical strength, then, due to variations in the particle size distribution rather than in the mineralogical composition. In particular, the finer the particle size, the finer the pore size and, in addition, the better the mechanical properties (with a maximum of 4.7 MPa), due to a better packing. However, fine particle size distribution worsens the slip's behaviour into moulds, impacting negatively on productivity, with a 17 % reduction of casting thickness.
Upon firing process, such differences are mitigated by the body densification and result in more similar pores' distributions, though the importance of the mineralogical composition is revealed. In fact, differences in mineralogical phases' contents and in kaolinite HI index guide the comprehension of high temperature phase evolution and technological properties like the fired body thermal expansion, foremost via residual quartz.
These results are important for a plastic raw materials's selection within the ceramic sanitary-ware process.
通过将技术特性、矿物学成分和三维成像相结合，可以深入了解中国玻璃工艺的卫生洁具陶瓷坯体与配制滑料时所使用的不同粘土原料之间的关系。首先，中国粘土和球粘土的不同组合会导致不同的铸造行为，然后，由于粒度分布的变化而不是矿物成分的变化，会导致不同的机械强度。特别是，粒度越细，孔径越细，此外，由于更好的填料，机械性能越好（最大为 4.7 兆帕）。在烧制过程中，这种差异会因为坯体致密化而得到缓解，并产生更相似的孔隙分布，但矿物成分的重要性也会显现出来。事实上，矿物相含量和高岭石 HI 指数的差异有助于理解高温相演变和技术特性，如烧成体的热膨胀，主要是通过残留石英。
{"title":"Effects of different China and ball clays on traditional ceramic process: A multi-methodological approach","authors":"Andrea Bernasconi , Nicoletta Marinoni , Lucia Mancini , Marco Voltolini , Fernando Francescon , Rinaldo Sartori , Alessandro Pavese","doi":"10.1016/j.clay.2024.107587","DOIUrl":"10.1016/j.clay.2024.107587","url":null,"abstract":"<div><div>A combination of technological properties, mineralogical composition and three-dimension (3D) imaging is proposed to get insights into sanitary-ware ceramic bodies of the Vitreous-China technology as a function of the different clay raw materials used in the formulation of slip. Particular attention is paid to the effects induced along the production chain, during casting, after drying (dried body) and after firing (fired body).</div><div>The different combinations of China and ball clays lead to different casting behaviour, in first instance, and to different mechanical strength, then, due to variations in the particle size distribution rather than in the mineralogical composition. In particular, the finer the particle size, the finer the pore size and, in addition, the better the mechanical properties (with a maximum of 4.7 MPa), due to a better packing. However, fine particle size distribution worsens the slip's behaviour into moulds, impacting negatively on productivity, with a 17 % reduction of casting thickness.</div><div>Upon firing process, such differences are mitigated by the body densification and result in more similar pores' distributions, though the importance of the mineralogical composition is revealed. In fact, differences in mineralogical phases' contents and in kaolinite HI index guide the comprehension of high temperature phase evolution and technological properties like the fired body thermal expansion, foremost via residual quartz.</div><div>These results are important for a plastic raw materials's selection within the ceramic sanitary-ware process.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107587"},"PeriodicalIF":5.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552243","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 : 2024-10-29DOI: 10.1016/j.clay.2024.107606
Lucas Nao Horiuchi , Raquel de Melo Barbosa , Joyce Batista Azevedo , Fátima Garcia-Villen , César Viseras , Rosana Lopes Lima Fialho
The widespread use of plastics in seedling production, due to their convenience and cost-effectiveness, poses significant environmental challenges, including pollution and high resource consumption. To address these issues, a sustainable hybrid bio-composite was developed using bio-polybutylene succinate (PBS) combined with canabrava fibers (Cana) (up to 30 wt%), lignin (Lig), montmorillonite (MMT), and sepiolite (SEP). This bio-composite, featuring a negative carbon footprint and fully biodegradable components, offers a promising alternative to polypropylene packaging in seedling production, enhancing environmental sustainability and promoting the valorization of waste materials like Cana and Lig. The bio-composites were synthesized via melt blending in an extruder, and their mechanical, thermal, and morphological properties were evaluated. The melt flow rate could be effectively managed by adjusting the combination of Cana, Lig, and clays, achieving values comparable to polypropylene (EP440L). Notable enhancements in mechanical properties were observed relative to neat PBS, with increases in Young's modulus (up to 353 %), yield stress (up to 198 %), flexural modulus (up to 390 %), and flexural strength (up to 160 %). These improvements are mainly attributed to the high Cana fiber content and the hybrid effects of clays, particularly SEP. However, reductions in impact resistance and elongation were noted compared to neat PBS and EP440L, likely due to limited fiber-polymer interactions and increased compactness as observed in SEM analysis. FT-IR analysis indicated strong interactions between clays and PBS, evidenced by a shoulder at 1602–1608 cm−1. XRD analysis suggested the exfoliation of MMT, as indicated by the absence of the (001) plane reflection, although the high content of Cana may have mitigated some mechanical benefits. DSC analysis revealed increased crystallinity with the incorporation of Cana, Lig, and clays, likely driven by nucleation effects. The presence of SEP was associated with a secondary melting peak, indicating effective dispersion and interfacial crystal formation. Enhanced thermal stability was demonstrated by a higher temperature at 90 % mass loss compared to neat PBS. These findings suggest the bio-composite is a sustainable alternative for reducing plastic waste in seedling production.
{"title":"Eco-friendly composite materials of polybutylene succinate with clay minerals, lignin and canabrava fiber","authors":"Lucas Nao Horiuchi , Raquel de Melo Barbosa , Joyce Batista Azevedo , Fátima Garcia-Villen , César Viseras , Rosana Lopes Lima Fialho","doi":"10.1016/j.clay.2024.107606","DOIUrl":"10.1016/j.clay.2024.107606","url":null,"abstract":"<div><div>The widespread use of plastics in seedling production, due to their convenience and cost-effectiveness, poses significant environmental challenges, including pollution and high resource consumption. To address these issues, a sustainable hybrid bio-composite was developed using bio-polybutylene succinate (PBS) combined with canabrava fibers (Cana) (up to 30 wt%), lignin (Lig), montmorillonite (MMT), and sepiolite (SEP). This bio-composite, featuring a negative carbon footprint and fully biodegradable components, offers a promising alternative to polypropylene packaging in seedling production, enhancing environmental sustainability and promoting the valorization of waste materials like Cana and Lig. The bio-composites were synthesized via melt blending in an extruder, and their mechanical, thermal, and morphological properties were evaluated. The melt flow rate could be effectively managed by adjusting the combination of Cana, Lig, and clays, achieving values comparable to polypropylene (EP440L). Notable enhancements in mechanical properties were observed relative to neat PBS, with increases in Young's modulus (up to 353 %), yield stress (up to 198 %), flexural modulus (up to 390 %), and flexural strength (up to 160 %). These improvements are mainly attributed to the high Cana fiber content and the hybrid effects of clays, particularly SEP. However, reductions in impact resistance and elongation were noted compared to neat PBS and EP440L, likely due to limited fiber-polymer interactions and increased compactness as observed in SEM analysis. FT-IR analysis indicated strong interactions between clays and PBS, evidenced by a shoulder at 1602–1608 cm<sup>−1</sup>. XRD analysis suggested the exfoliation of MMT, as indicated by the absence of the (001) plane reflection, although the high content of Cana may have mitigated some mechanical benefits. DSC analysis revealed increased crystallinity with the incorporation of Cana, Lig, and clays, likely driven by nucleation effects. The presence of SEP was associated with a secondary melting peak, indicating effective dispersion and interfacial crystal formation. Enhanced thermal stability was demonstrated by a higher temperature at 90 % mass loss compared to neat PBS. These findings suggest the bio-composite is a sustainable alternative for reducing plastic waste in seedling production.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107606"},"PeriodicalIF":5.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531197","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 : 2024-10-26DOI: 10.1016/j.clay.2024.107608
Ji-Hee Lee , Hyeon-Ju Ryu , N. Sanoj Rejinold , J. Yoon Choi , Yun-Ze Long , Goeun Choi , Jin-Ho Choy
Ethylene vinyl acetate copolymer (EVA) micro-composites having both anionic and cationic clays were made using a solution-blending technology. Anionic clay (layered double hydroxide; LDH) and Cationic clay (Fluoro-mica; ME) were functionalized with hydrophobic molecules such as stearate (SA) and cetyltrimethylammonium (CTA) for improving the compatibility with hydrophobic EVA. The SA intercalated MgAl-LDH (SA-LDH) and CTA intercalated ME (CTA-ME) were prepared by co-precipitation and ion-exchange methods, then blended into EVA matrix together along with intumescent flame retardant (IFR) by solution blending forming final EVA micro-composite. The impact of organoclays on the flame retardancy of EVA micro-composites were tested by a cone calorimeter test and vertical flammability with UL-94 test method. As per XRD for EVA micro-composites, the (00l) peaks of organoclays vanished, indicating their exfoliation in EVA matrix. The thermo-mechanical characteristics for EVA micro-composites improved further than EVA containing IFR only. EVA composite containing 30 wt% IFR, 1 wt% LDH and 4 wt% ME (L1M4-I30-EVA) passed the UL-94 test with V-0 rating, lowering the peak heat release rate from 2107.7 kW/m2 of intact EVA to 213.1 kW/m2. The observed char morphology revealed that organoclays were effective in forming rigid tight char layers. The synergy between organoclays and the IFR in the current EVA micro-composite is crucial for improving char formation and enhancing flame-retardant performance.
采用溶液混合技术制成了具有阴离子和阳离子粘土的乙烯-醋酸乙烯共聚物（EVA）微复合材料。阴离子粘土（层状双氢氧化物；LDH）和阳离子粘土（氟云母；ME）被硬脂酸盐（SA）和十六烷基三甲基铵（CTA）等疏水分子功能化，以改善与疏水 EVA 的相容性。通过共沉淀和离子交换方法制备了 SA 插层 MgAl-LDH（SA-LDH）和 CTA 插层 ME（CTA-ME），然后通过溶液共混将其与膨胀型阻燃剂（IFR）一起混入 EVA 基体中，形成最终的 EVA 微型复合材料。有机粘土对 EVA 微复合材料阻燃性能的影响采用锥形量热计测试，垂直可燃性采用 UL-94 测试方法。根据 EVA 微复合材料的 XRD，有机黏土的（00l）峰消失，表明它们在 EVA 基体中剥离。与仅含 IFR 的 EVA 相比，EVA 微复合材料的热机械特性得到了进一步改善。含有 30 wt% IFR、1 wt% LDH 和 4 wt% ME 的 EVA 复合材料（L1M4-I30-EVA）通过了 UL-94 V-0 级测试，峰值热释放率从完整 EVA 的 2107.7 kW/m2 降至 213.1 kW/m2。从观察到的焦炭形态可以看出，有机黏土能有效地形成坚硬致密的焦炭层。目前 EVA 微复合材料中有机黏土和 IFR 的协同作用对于改善炭的形成和提高阻燃性能至关重要。
{"title":"Nano-enhanced thermo-mechanical properties of ethylene vinyl acetate with intumescent agent and organoclays","authors":"Ji-Hee Lee , Hyeon-Ju Ryu , N. Sanoj Rejinold , J. Yoon Choi , Yun-Ze Long , Goeun Choi , Jin-Ho Choy","doi":"10.1016/j.clay.2024.107608","DOIUrl":"10.1016/j.clay.2024.107608","url":null,"abstract":"<div><div>Ethylene vinyl acetate copolymer (EVA) micro-composites having both anionic and cationic clays were made using a solution-blending technology. Anionic clay (layered double hydroxide; LDH) and Cationic clay (Fluoro-mica; ME) were functionalized with hydrophobic molecules such as stearate (SA) and cetyltrimethylammonium (CTA) for improving the compatibility with hydrophobic EVA. The SA intercalated MgAl-LDH (SA-LDH) and CTA intercalated ME (CTA-ME) were prepared by co-precipitation and ion-exchange methods, then blended into EVA matrix together along with intumescent flame retardant (IFR) by solution blending forming final EVA micro-composite. The impact of organoclays on the flame retardancy of EVA micro-composites were tested by a cone calorimeter test and vertical flammability with UL-94 test method. As per XRD for EVA micro-composites, the (00<em>l</em>) peaks of organoclays vanished, indicating their exfoliation in EVA matrix. The thermo-mechanical characteristics for EVA micro-composites improved further than EVA containing IFR only. EVA composite containing 30 wt% IFR, 1 wt% LDH and 4 wt% ME (L1M4-I30-EVA) passed the UL-94 test with V-0 rating, lowering the peak heat release rate from 2107.7 kW/m<sup>2</sup> of intact EVA to 213.1 kW/m<sup>2</sup>. The observed char morphology revealed that organoclays were effective in forming rigid tight char layers. The synergy between organoclays and the IFR in the current EVA micro-composite is crucial for improving char formation and enhancing flame-retardant performance.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107608"},"PeriodicalIF":5.3,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531195","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 : 2024-10-23DOI: 10.1016/j.clay.2024.107603
Cristina Maria Belfiore, Serena Parisi, Salvatore Menta, Paolo Mazzoleni
This paper explores the use of waste materials as substitutes in ceramic paste formulations. Building on previous research which has laid the groundwork for the use of volcanic ash as temper in ceramic tile manufacture, investigation is here extended to a broader spectrum of waste-based ceramic pastes. Specifically, five different mixtures have been manufactured through the hand-made technique by using Etna volcanic ash and/or tile processing residues (chamotte), mixed with clay in variable proportions. Physical-mechanical tests including flexural strength, water absorption, resistance to thermal shock, deep abrasion and impact, have been performed and results compared with those of reference tiles. Notably, ceramic pastes combining clay with chamotte or clay with chamotte and fine volcanic ash, show better performance. This is certainly due to the good physical-mechanical properties of chamotte which binds well with the clayey groundmass so reducing shrinkage / cracking and improving the overall quality of ceramic products. Conversely, volcanic ash does not show a high degree of union with the clayey matrix, particularly when occurring in larger grain size. However, when present in fine clasts and in combination with chamotte, the resulting products display good physical-mechanical characteristics.
This study highlights once again the potential of waste materials in ceramic manufacturing, paving the way for a more sustainable and resource-efficient industry.
{"title":"Use of volcanic ash and chamotte as substitute temper in the production of ceramic tiles","authors":"Cristina Maria Belfiore, Serena Parisi, Salvatore Menta, Paolo Mazzoleni","doi":"10.1016/j.clay.2024.107603","DOIUrl":"10.1016/j.clay.2024.107603","url":null,"abstract":"<div><div>This paper explores the use of waste materials as substitutes in ceramic paste formulations. Building on previous research which has laid the groundwork for the use of volcanic ash as temper in ceramic tile manufacture, investigation is here extended to a broader spectrum of waste-based ceramic pastes. Specifically, five different mixtures have been manufactured through the hand-made technique by using Etna volcanic ash and/or tile processing residues (chamotte), mixed with clay in variable proportions. Physical-mechanical tests including flexural strength, water absorption, resistance to thermal shock, deep abrasion and impact, have been performed and results compared with those of reference tiles. Notably, ceramic pastes combining clay with chamotte or clay with chamotte and fine volcanic ash, show better performance. This is certainly due to the good physical-mechanical properties of chamotte which binds well with the clayey groundmass so reducing shrinkage / cracking and improving the overall quality of ceramic products. Conversely, volcanic ash does not show a high degree of union with the clayey matrix, particularly when occurring in larger grain size. However, when present in fine clasts and in combination with chamotte, the resulting products display good physical-mechanical characteristics.</div><div>This study highlights once again the potential of waste materials in ceramic manufacturing, paving the way for a more sustainable and resource-efficient industry.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107603"},"PeriodicalIF":5.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531189","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 : 2024-10-23DOI: 10.1016/j.clay.2024.107607
Alberto Mannu , Matteo Poddighe , Marzia Mureddu , Simona Castia , Gabriele Mulas , Fabrizio Murgia , Maria Enrica Di Pietro , Andrea Mele , Sebastiano Garroni
Waste Cooking Oils (WCOs) are generated worldwide through industrial food processing and household use, posing environmental concerns upon disposal. Bentonites often showed to be effective in removing minor contaminants in vegetable oil refining. The present research focused on the processing of raw WCOs using four bentonites, two commercials and two obtained by ball milling of the latest. The different bentonites (hydrophobic and hydrophilic) were characterized before and after ball milling (BM) procedure, including an exhaustive analyses of crystal structure, morphology and surface area via x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N2-physisorption technique. Optimization of BM processing in terms of milling time was achieved within 60 min. The milled powders were then tested as adsorbents for recycling WCOs with different degrees of decomposition (expressed in terms of free fatty acids, FFAs, content). Employing a design of experiments approach, the impact of five parameters (FFAs content, temperature, specific surface area, stirring, BM time) on the resulting pour point (PP), taken as a quality benchmark for recycled oil, was assessed. Quantitative multivariate statistical analysis revealed temperature's negligible role and identified the significant impact of two characteristics of the bentonite (specific superficial area and ball milling time), as well as the relevant role of the stirring during the treatment. At the end, hydrophilic bentonite resulted able to improve the PP of waste oils with a low content of free fatty acids of about 10 °C.
{"title":"Impact of morphology of hydrophilic and hydrophobic bentonites on improving the pour point in the recycling of waste cooking oils","authors":"Alberto Mannu , Matteo Poddighe , Marzia Mureddu , Simona Castia , Gabriele Mulas , Fabrizio Murgia , Maria Enrica Di Pietro , Andrea Mele , Sebastiano Garroni","doi":"10.1016/j.clay.2024.107607","DOIUrl":"10.1016/j.clay.2024.107607","url":null,"abstract":"<div><div>Waste Cooking Oils (WCOs) are generated worldwide through industrial food processing and household use, posing environmental concerns upon disposal. Bentonites often showed to be effective in removing minor contaminants in vegetable oil refining. The present research focused on the processing of raw WCOs using four bentonites, two commercials and two obtained by ball milling of the latest. The different bentonites (hydrophobic and hydrophilic) were characterized before and after ball milling (BM) procedure, including an exhaustive analyses of crystal structure, morphology and surface area via x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N<sub>2</sub>-physisorption technique. Optimization of BM processing in terms of milling time was achieved within 60 min. The milled powders were then tested as adsorbents for recycling WCOs with different degrees of decomposition (expressed in terms of free fatty acids, FFAs, content). Employing a design of experiments approach, the impact of five parameters (FFAs content, temperature, specific surface area, stirring, BM time) on the resulting pour point (PP), taken as a quality benchmark for recycled oil, was assessed. Quantitative multivariate statistical analysis revealed temperature's negligible role and identified the significant impact of two characteristics of the bentonite (specific superficial area and ball milling time), as well as the relevant role of the stirring during the treatment. At the end, hydrophilic bentonite resulted able to improve the PP of waste oils with a low content of free fatty acids of about 10 °C.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107607"},"PeriodicalIF":5.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531194","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 : 2024-10-23DOI: 10.1016/j.clay.2024.107605
F. Diba , A.R. Goodarzi , S. Sobhanardakani , M. Cheraghi , B. Lorestani
This study investigated the effectiveness and underlying mechanisms of purging solutions enhanced by intermittent power in improving electrokinetic (EK) restoration of clay soils even under high levels of heavy metals (HM). In so doing, the artificially contaminated specimens containing a wide range of copper (Cu) were prepared and then subjected to a series of EK tests with various electrolytes and electric regimes. Macro and micro scale examinations revealed that under the unenhanced EK condition (i.e., continuous current without agents), the formation of non-conducting solid phases and/or the clogged fabric in the samples with the high dosages (> 250 mg/kg) of HM could dramatically impede the metal separation from the soil. Hence, increasing the remediation time would not be very effective in facilitating the decontamination process. It was observed that the EDTA-ameliorated treatment accompanied by pentetic acid and acetic acid can mitigate the metal precipitation/encapsulation effects induced by EK actions, resulting in improved rate of HM removal. In this case; however, a high portion of these enhancers would be required to ensure the stable mobility of ions and to achieve successful recovery. Such a limitation has been shown to be overcome by incorporating pulsed power (PP) at an optimal frequency. In fact, as evidenced by SEM-EDX and XRD analyses, the integration of chemical agents with PP could simultaneously retain the solubilized Cu species in the soil mass and modify the matrix tortuosity (i.e., the establishment of well-linked pores), two features that have been found to play essential roles in providing for favorable activity of HM ions during the EK operation. The corresponding refinements in the binary system would cause an almost 8 folds increase in the removal efficiency and a shorter (up to 30 %) time of treatment compared to conventional EK.
本研究调查了间歇性电源增强的净化溶液在改善粘土的电动力（EK）修复（即使在重金属（HM）含量较高的情况下）方面的有效性和基本机制。为此，我们制备了含有多种铜（Cu）的人工污染试样，然后用不同的电解质和电机制进行了一系列电动力测试。宏观和微观检测结果表明，在未增强的电解池条件下（即无药剂的持续电流），高剂量（250 毫克/千克）HM 样品中形成的非导电固相和/或堵塞的织物会极大地阻碍金属从土壤中分离出来。因此，延长修复时间并不能有效促进去污过程。据观察，乙二胺四乙酸（EDTA）与戊乙酸和乙酸的混合处理可减轻 EK 作用引起的金属沉淀/包裹效应，从而提高 HM 的去除率。不过，在这种情况下，需要大量使用这些增强剂，以确保离子的稳定流动性，并实现成功回收。事实证明，在最佳频率下加入脉冲电源 (PP) 可以克服这种限制。事实上，SEM-EDX 和 XRD 分析表明，将化学制剂与 PP 结合使用，可同时将溶解的铜离子保留在土体中，并改变基质的曲折性（即建立连接良好的孔隙），这两个特征已被发现在 EK 运行期间为 HM 离子提供有利活性方面发挥了重要作用。与传统的 EK 相比，二元系统的相应改进将使去除效率提高近 8 倍，处理时间缩短（最多 30%）。
{"title":"An enhanced electrokinetic system for remediation of Cu-polluted clay soils by integrating purging solutions and intermittent power","authors":"F. Diba , A.R. Goodarzi , S. Sobhanardakani , M. Cheraghi , B. Lorestani","doi":"10.1016/j.clay.2024.107605","DOIUrl":"10.1016/j.clay.2024.107605","url":null,"abstract":"<div><div>This study investigated the effectiveness and underlying mechanisms of purging solutions enhanced by intermittent power in improving electrokinetic (EK) restoration of clay soils even under high levels of heavy metals (HM). In so doing, the artificially contaminated specimens containing a wide range of copper (Cu) were prepared and then subjected to a series of EK tests with various electrolytes and electric regimes. Macro and micro scale examinations revealed that under the unenhanced EK condition (i.e., continuous current without agents), the formation of non-conducting solid phases and/or the clogged fabric in the samples with the high dosages (> 250 mg/kg) of HM could dramatically impede the metal separation from the soil. Hence, increasing the remediation time would not be very effective in facilitating the decontamination process. It was observed that the EDTA-ameliorated treatment accompanied by pentetic acid and acetic acid can mitigate the metal precipitation/encapsulation effects induced by EK actions, resulting in improved rate of HM removal. In this case; however, a high portion of these enhancers would be required to ensure the stable mobility of ions and to achieve successful recovery. Such a limitation has been shown to be overcome by incorporating pulsed power (PP) at an optimal frequency. In fact, as evidenced by SEM-EDX and XRD analyses, the integration of chemical agents with PP could simultaneously retain the solubilized Cu species in the soil mass and modify the matrix tortuosity (i.e., the establishment of well-linked pores), two features that have been found to play essential roles in providing for favorable activity of HM ions during the EK operation. The corresponding refinements in the binary system would cause an almost 8 folds increase in the removal efficiency and a shorter (up to 30 %) time of treatment compared to conventional EK.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107605"},"PeriodicalIF":5.3,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531196","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 : 2024-10-21DOI: 10.1016/j.clay.2024.107597
Jinmiao Chen , Yuxi Mo , Xiangyan Zhang , Shaohua Zhang , Aihua Cui , Xueqin Wang , Jiwei Li
In this study, chitosan/polyethylene oxide fibrous membranes (CS/PEO) with varying halloysite nanotubes (HNTs) contents were prepared by solution-blow spinning. The HNTs-CS/PEO membranes with a 12 wt% HNTs content exhibited excellent hydrophilicity, air permeability, and flexibility. The in vitro hemostasis time of the 12 % HNTs-CS/PEO was 217 s, and it was observed to form a stable thrombus. Moreover, the antibacterial efficacy of 12 % HNTs-CS/PEO against Escherichia coli and Staphylococcus aureus was 90.05 % and 69.86 %, respectively. Furthermore, the in vitro cytotoxicity study demonstrated the nontoxic nature of the 12 % HNTs-CS/PEO. The solution-blow spinning HNTs-CS/PEO fibrous membrane can potentially prevent the risk of distal thrombosis caused by separating individual HNTs and offer the advantages of a simple preparation and application process. This study presents a novel first-aid hemostatic dressing and offers a novel approach to loading inorganic nanoparticles onto fibers.
{"title":"Solution-blow spinning halloysite nanotube loaded chitosan-polyethylene oxide fibrous membrane as hemostatic dressings","authors":"Jinmiao Chen , Yuxi Mo , Xiangyan Zhang , Shaohua Zhang , Aihua Cui , Xueqin Wang , Jiwei Li","doi":"10.1016/j.clay.2024.107597","DOIUrl":"10.1016/j.clay.2024.107597","url":null,"abstract":"<div><div>In this study, chitosan/polyethylene oxide fibrous membranes (CS/PEO) with varying halloysite nanotubes (HNTs) contents were prepared by solution-blow spinning. The HNTs-CS/PEO membranes with a 12 wt% HNTs content exhibited excellent hydrophilicity, air permeability, and flexibility. The in vitro hemostasis time of the 12 % HNTs-CS/PEO was 217 s, and it was observed to form a stable thrombus. Moreover, the antibacterial efficacy of 12 % HNTs-CS/PEO against <em>Escherichia coli</em> and <em>Staphylococcus aureus</em> was 90.05 % and 69.86 %, respectively. Furthermore, the in vitro cytotoxicity study demonstrated the nontoxic nature of the 12 % HNTs-CS/PEO. The solution-blow spinning HNTs-CS/PEO fibrous membrane can potentially prevent the risk of distal thrombosis caused by separating individual HNTs and offer the advantages of a simple preparation and application process. This study presents a novel first-aid hemostatic dressing and offers a novel approach to loading inorganic nanoparticles onto fibers.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107597"},"PeriodicalIF":5.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531191","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}
Oily wastewater discharge causes severe environmental pollution and resource waste, requiring the development of low-cost adsorbents with good hydrophobicity. This study presents the preparation and use of a novel highly hydrophobic adsorbent based on natural vermiculite clay minerals to separate free/emulsified oil-water mixtures. Vermiculite was first activated with sulfuric acid and potassium hydroxide to increase its adsorption capacity and surface area. The sample was then modified with cetyltrimethylammonium bromide (CTAB) to change the wetting properties from hydrophilic to hydrophobic and increase oil adsorption. XRD, XRF, FESEM, BET, FTIR, and zeta potential analyses were carried out to determine changes in texture, morphology, and chemical composition of vermiculite affected by acid, base and acid-base activation. According to the results, the acid-base activation process was selected for vermiculite treatment before CTAB modification, which demonstrated a high oil adsorption selectivity (1910.6 %) compared to raw vermiculite (44.14 %). Effect of CTAB concentration on vermiculite's wetting properties was studied. The results confirmed that the acid-base activated sample modified at 0.9 mmol.L−1 near the critical micelle concentration of CTAB exhibited highly hydrophobic properties (water contact angle of 148° ± 1°). For oil-in-water emulsions, the treated adsorbent demonstrated a high oil removal efficiency of 96 ± 2 %. Additionally, a packed layer of highly hydrophobic vermiculite was applied for free heavy/light oil-water mixture and water-in-oil emulsion separation. The performance test for separation of free oil-water mixture and water-in-oil emulsion showed high separation efficiency (all above 90 %). The reusability of highly hydrophobic vermiculite as well as the effect of oil type, the thickness of the adsorbent layer, and the height of the water phase on separation performance were also investigated.
{"title":"Organoclays from acid-base activated vermiculites for oil-water mixture separations","authors":"Faezeh Hajizadeh , Reza Norouzbeigi , Elmira Velayi","doi":"10.1016/j.clay.2024.107600","DOIUrl":"10.1016/j.clay.2024.107600","url":null,"abstract":"<div><div>Oily wastewater discharge causes severe environmental pollution and resource waste, requiring the development of low-cost adsorbents with good hydrophobicity. This study presents the preparation and use of a novel highly hydrophobic adsorbent based on natural vermiculite clay minerals to separate free/emulsified oil-water mixtures. Vermiculite was first activated with sulfuric acid and potassium hydroxide to increase its adsorption capacity and surface area. The sample was then modified with cetyltrimethylammonium bromide (CTAB) to change the wetting properties from hydrophilic to hydrophobic and increase oil adsorption. XRD, XRF, FESEM, BET, FTIR, and zeta potential analyses were carried out to determine changes in texture, morphology, and chemical composition of vermiculite affected by acid, base and acid-base activation. According to the results, the acid-base activation process was selected for vermiculite treatment before CTAB modification, which demonstrated a high oil adsorption selectivity (1910.6 %) compared to raw vermiculite (44.14 %). Effect of CTAB concentration on vermiculite's wetting properties was studied. The results confirmed that the acid-base activated sample modified at 0.9 mmol.L<sup>−1</sup> near the critical micelle concentration of CTAB exhibited highly hydrophobic properties (water contact angle of 148° ± 1°). For oil-in-water emulsions, the treated adsorbent demonstrated a high oil removal efficiency of 96 ± 2 %. Additionally, a packed layer of highly hydrophobic vermiculite was applied for free heavy/light oil-water mixture and water-in-oil emulsion separation. The performance test for separation of free oil-water mixture and water-in-oil emulsion showed high separation efficiency (all above 90 %). The reusability of highly hydrophobic vermiculite as well as the effect of oil type, the thickness of the adsorbent layer, and the height of the water phase on separation performance were also investigated.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107600"},"PeriodicalIF":5.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531190","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 : 2024-10-20DOI: 10.1016/j.clay.2024.107602
Xinying Su , Weihong Chai , Ziyang Zhang , Zhenlin Tang , Meihuan Gao , Yingge Li , Zhishuang Han , Xinmeng Lv , Jing He , Haidi Li , Zaihang Zheng
Aimed at settling the adverse effect of halogen−/phosphorus-containing flame retardants on the human health and ecological environment, a hydromagnesite (HM)-based flame retardant was prepared via sequential modification of polydopamine (PDA) and layered double hydroxide (LDH), which was expected to enhance the flame retardancy of silicone rubber (SR). The preparation feasibility for HM@PDA@LDH were confirmed by a series of characterizations in view of chemical composition, surface morphology, wettability and thermal degradation. The flame retardancy of 20 parts of HM@PDA@LDH per one hundred of silicone rubber (SR/20 phr HM@PDA@LDH) was upgraded with limiting oxygen index (LOI) of 30.5 %, Underwriters Laboratories-1894 Vertical burning-0 (UL-94 V-0) rating and peak heat release rate (PHRR) reduction of 59.6 % in comparison with neat SR. Besides, the possible mechanism was proposed by investigating the combustion residues of SR composites. Along with durable flame retardancy and maintained mechanical strength, the good balance among comprehensive properties of SR composites was gained. Thus, this paper proposed a valuable strategy for overcoming the contradiction between flame retardancy and environmental pollution, which was feasible for the real-world application of SR materials.
为了解决含卤/磷阻燃剂对人类健康和生态环境的不利影响，通过对多巴胺（PDA）和层状双氢氧化物（LDH）进行连续改性，制备了一种水镁石（HM）基阻燃剂，有望提高硅橡胶（SR）的阻燃性。从化学成分、表面形貌、润湿性和热降解等方面进行的一系列表征证实了 HM@PDA@LDH 制备的可行性。与纯硅橡胶相比，每 100 份硅橡胶中含有 20 份 HM@PDA@LDH （SR/20 phr HM@PDA@LDH）时的阻燃性能得到提升，极限氧指数（LOI）为 30.5%，达到美国保险商实验室-1894 垂直燃烧-0（UL-94 V-0）等级，峰值热释放率（PHRR）降低了 59.6%。此外，还通过研究 SR 复合材料的燃烧残留物提出了可能的机理。在持久阻燃和保持机械强度的同时，SR 复合材料还获得了良好的综合性能平衡。因此，本文为克服阻燃性与环境污染之间的矛盾提出了一种有价值的策略，这对于 SR 材料在现实世界中的应用是可行的。
{"title":"Preparation of environmentally-benign, hydrophobic, phosphorus-/halogen-free, mono-component and hydromagnesite-based flame retardant for intensifying the fire safety of silicone rubber","authors":"Xinying Su , Weihong Chai , Ziyang Zhang , Zhenlin Tang , Meihuan Gao , Yingge Li , Zhishuang Han , Xinmeng Lv , Jing He , Haidi Li , Zaihang Zheng","doi":"10.1016/j.clay.2024.107602","DOIUrl":"10.1016/j.clay.2024.107602","url":null,"abstract":"<div><div>Aimed at settling the adverse effect of halogen−/phosphorus-containing flame retardants on the human health and ecological environment, a hydromagnesite (HM)-based flame retardant was prepared via sequential modification of polydopamine (PDA) and layered double hydroxide (LDH), which was expected to enhance the flame retardancy of silicone rubber (SR). The preparation feasibility for HM@PDA@LDH were confirmed by a series of characterizations in view of chemical composition, surface morphology, wettability and thermal degradation. The flame retardancy of 20 parts of HM@PDA@LDH per one hundred of silicone rubber (SR/20 phr HM@PDA@LDH) was upgraded with limiting oxygen index (LOI) of 30.5 %, Underwriters Laboratories-1894 Vertical burning-0 (UL-94 V-0) rating and peak heat release rate (PHRR) reduction of 59.6 % in comparison with neat SR. Besides, the possible mechanism was proposed by investigating the combustion residues of SR composites. Along with durable flame retardancy and maintained mechanical strength, the good balance among comprehensive properties of SR composites was gained. Thus, this paper proposed a valuable strategy for overcoming the contradiction between flame retardancy and environmental pollution, which was feasible for the real-world application of SR materials.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107602"},"PeriodicalIF":5.3,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531201","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 : 2024-10-20DOI: 10.1016/j.clay.2024.107601
M. Milojević-Rakić , N. Gavrilov , A. Janošević Ležaić , S. Uskoković-Marković , B. Nedić Vasiljević , D. Bajuk-Bogdanović
Organic dyes from industrial wastewater pollute water tables. Here proposed solution for environmental control relies on pristine red soil for adsorption and oxidative degradation of methylene blue. Soil analysis comprised XRD, spectroscopic (FTIR and Raman) and microscopic (SEM/EDS) techniques, while spectrophotometry was applied for dye quantification. The dominant soil mineral is kaolinite while Fe homogeneous distribution is witnessed in the α- and γ-FeO(OH) form. Dye adsorption was monitored for both soil and kaolinite, with rising removal under basic conditions due to methylene blue transformation. Theoretical modelling enabled insight into dye orientation over goethite crystallographic planes and estimation of binding energy. Soil/Fenton reagent achieved a substantial 93 % dye removal. An optimal oxidant concentration in the Fenton system was 10 mM. We confirmed the excellent performance of pristine red soil samples as naturally occurring adsorbents and catalysts in Fenton oxidation of environmental pollutants.
{"title":"Complementary: Green catalysis over red soil for pollutant removal","authors":"M. Milojević-Rakić , N. Gavrilov , A. Janošević Ležaić , S. Uskoković-Marković , B. Nedić Vasiljević , D. Bajuk-Bogdanović","doi":"10.1016/j.clay.2024.107601","DOIUrl":"10.1016/j.clay.2024.107601","url":null,"abstract":"<div><div>Organic dyes from industrial wastewater pollute water tables. Here proposed solution for environmental control relies on pristine red soil for adsorption and oxidative degradation of methylene blue. Soil analysis comprised XRD, spectroscopic (FTIR and Raman) and microscopic (SEM/EDS) techniques, while spectrophotometry was applied for dye quantification. The dominant soil mineral is kaolinite while Fe homogeneous distribution is witnessed in the α- and γ-FeO(OH) form. Dye adsorption was monitored for both soil and kaolinite, with rising removal under basic conditions due to methylene blue transformation. Theoretical modelling enabled insight into dye orientation over goethite crystallographic planes and estimation of binding energy. Soil/Fenton reagent achieved a substantial 93 % dye removal. An optimal oxidant concentration in the Fenton system was 10 mM. We confirmed the excellent performance of pristine red soil samples as naturally occurring adsorbents and catalysts in Fenton oxidation of environmental pollutants.</div></div>","PeriodicalId":245,"journal":{"name":"Applied Clay Science","volume":"262 ","pages":"Article 107601"},"PeriodicalIF":5.3,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531200","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}
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