Jafar Sufian, Mohammad Babaakbari Sari, Filippo Marchelli, Luca Fiori, Armen Avanes, S. Moradi
Chlorella vulgaris is an inexpensive microalga that could be employed for environmental remediation, but further investigations are needed to assess its suitability and optimal treatment methodology. With this aim in mind, this study focused on the raw biomass and the biochar and hydrochar obtained from it, analyzing their physicochemical properties and testing them to capture cadmium from an aqueous environment. The adsorption/absorption tests assessed the effect of adsorbent dosage, pH, Cd concentration, and contact time, and the results were analyzed through a structural equation model. Biochar and hydrochar performed similarly and better than the raw biomass, with the highest Cd removal observed at an adsorbent dosage of 0.8 g L−1, an initial concentration of Cd solution of 30 mg L−1, a pH of 6, and a contact time of 30 min. The adsorption isotherm data for Cd could be well-described by the Langmuir and Temkin models. The results from the structural equation modeling revealed that the variables material type, dosage, and concentration all contributed to Cd removal in water, with time mediating these effects.
{"title":"An Analysis of the Factors Influencing Cadmium Removal in Aquatic Environments by Chlorella vulgaris-Derived Solids","authors":"Jafar Sufian, Mohammad Babaakbari Sari, Filippo Marchelli, Luca Fiori, Armen Avanes, S. Moradi","doi":"10.3390/c10010002","DOIUrl":"https://doi.org/10.3390/c10010002","url":null,"abstract":"Chlorella vulgaris is an inexpensive microalga that could be employed for environmental remediation, but further investigations are needed to assess its suitability and optimal treatment methodology. With this aim in mind, this study focused on the raw biomass and the biochar and hydrochar obtained from it, analyzing their physicochemical properties and testing them to capture cadmium from an aqueous environment. The adsorption/absorption tests assessed the effect of adsorbent dosage, pH, Cd concentration, and contact time, and the results were analyzed through a structural equation model. Biochar and hydrochar performed similarly and better than the raw biomass, with the highest Cd removal observed at an adsorbent dosage of 0.8 g L−1, an initial concentration of Cd solution of 30 mg L−1, a pH of 6, and a contact time of 30 min. The adsorption isotherm data for Cd could be well-described by the Langmuir and Temkin models. The results from the structural equation modeling revealed that the variables material type, dosage, and concentration all contributed to Cd removal in water, with time mediating these effects.","PeriodicalId":503899,"journal":{"name":"C","volume":"18 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139158149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sirine Zallouz, Bénédicte Réty, J. Le Meins, Mame Youssou Ndiaye, P. Fioux, Camélia Matei Ghimbeu
Although transition metal sulfides have prodigious potential for use as electrode materials because of their low electronegativities, their large volume changes inhibit broad application. Moreover, there is only limited knowledge of the ageing processes of these materials at the nanoscale. Herein, nano-C/FeS2 materials were prepared via one-pot syntheses from green biodegradable carbon precursors, followed by activation and sulfidation. The increased activation/sulfidation time led to an increase in the size of the nanoparticles (7 to 17 nm) and their aggregation, as well as in an increase in the specific surface area. The materials were then used as electrodes in 2-electrode symmetric supercapacitors with 2 M KOH. The activation process resulted in improved capacitance (60 F g−1 at 0.1 A g−1) and rate capability (36%) depending on the composite porosity, conductivity, and size of the FeS2 particles. The ageing of the FeS2 nanoparticles was investigated under air, and a progressive transformation of the nano-FeS2 into hydrated iron hydroxy sulfate with a significant morphological modification was observed, resulting in drastic decreases in the capacitance (70%) and retention. In contrast, the ageing of nano-FeS2 during cycling led to the formation of a supplementary iron oxyhydroxide phase, which contributed to the enhanced capacitance (57%) and long-term cycling (132% up to 10,000 cycles) of the device.
尽管过渡金属硫化物因其电负性低而在用作电极材料方面具有巨大潜力，但其巨大的体积变化阻碍了其广泛应用。此外，人们对这些材料在纳米尺度上的老化过程了解有限。在本文中，纳米碳/FeS2 材料是通过绿色可生物降解碳前体的一锅合成法制备的，然后进行活化和硫化。活化/硫化时间的延长导致纳米颗粒的尺寸（7 至 17 纳米）增大、聚集以及比表面积的增加。这些材料随后被用作 2 M KOH 的双电极对称超级电容器的电极。活化过程提高了电容（0.1 A g-1 时为 60 F g-1）和速率能力（36%），这取决于复合孔隙率、电导率和 FeS2 颗粒的大小。在空气中对纳米 FeS2 颗粒的老化进行了研究，结果发现纳米 FeS2 逐渐转变为水合羟基硫酸铁，形态发生了显著变化，导致电容（70%）和保持率急剧下降。与此相反，在循环过程中，纳米铁二氧化物的老化导致形成了羟基氢氧化铁补充相，从而提高了器件的电容（57%）和长期循环能力（132%，高达 10,000 次循环）。
{"title":"FeS2 Nanoparticles in S-Doped Carbon: Ageing Effects on Performance as a Supercapacitor Electrode","authors":"Sirine Zallouz, Bénédicte Réty, J. Le Meins, Mame Youssou Ndiaye, P. Fioux, Camélia Matei Ghimbeu","doi":"10.3390/c9040112","DOIUrl":"https://doi.org/10.3390/c9040112","url":null,"abstract":"Although transition metal sulfides have prodigious potential for use as electrode materials because of their low electronegativities, their large volume changes inhibit broad application. Moreover, there is only limited knowledge of the ageing processes of these materials at the nanoscale. Herein, nano-C/FeS2 materials were prepared via one-pot syntheses from green biodegradable carbon precursors, followed by activation and sulfidation. The increased activation/sulfidation time led to an increase in the size of the nanoparticles (7 to 17 nm) and their aggregation, as well as in an increase in the specific surface area. The materials were then used as electrodes in 2-electrode symmetric supercapacitors with 2 M KOH. The activation process resulted in improved capacitance (60 F g−1 at 0.1 A g−1) and rate capability (36%) depending on the composite porosity, conductivity, and size of the FeS2 particles. The ageing of the FeS2 nanoparticles was investigated under air, and a progressive transformation of the nano-FeS2 into hydrated iron hydroxy sulfate with a significant morphological modification was observed, resulting in drastic decreases in the capacitance (70%) and retention. In contrast, the ageing of nano-FeS2 during cycling led to the formation of a supplementary iron oxyhydroxide phase, which contributed to the enhanced capacitance (57%) and long-term cycling (132% up to 10,000 cycles) of the device.","PeriodicalId":503899,"journal":{"name":"C","volume":"113 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139265710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Niki Loura, E. Gkartzou, A. Trompeta, G. Konstantopoulos, P. Klonos, A. Kyritsis, C. Charitidis
In the present study, a series of carbon-based nanocomposites based on recycled thermoplastic polyurethane (TPU) matrix and MWCNT fillers synthesized in a laboratory environment were prepared at various loadings and assessed in terms of their functional thermal, dielectric, and rheological properties, as well as their ohmic heating capability, for self-healing applications in extrusion-based 3D printing technologies. The synthesis of nanomaterials focused on the production of two different types of carbon nanotubes (CNTs) via the chemical vapor deposition (CVD) method. A comparative assessment and benchmarking were conducted with nanocomposite filaments obtained from commercial nanomaterials and masterbatches with MWCNTs. For all the polymer nanocomposites, samples were prepared at additive contents up to 15 wt.% and filament feedstock was produced via the melt-extrusion process for 3D printing; these were previously characterized by rheological tests. The measurements of thermal and electrical conductivity resulted in a selected composition with promising ohmic heating capability. As a preliminary assessment of the self-healing ability of the above samples, artificial cracks were introduced on the surface of the samples and SEM analysis took place at the crack location before and after applying voltage as a measure of the effectiveness of the material remelting due to the Joule effect. Results indicate a promising material response with a partial restoration of artificial cracks.
在本研究中，我们在实验室环境中合成了一系列基于回收热塑性聚氨酯（TPU）基体和 MWCNT 填料的碳基纳米复合材料，这些复合材料具有不同的负载量，并评估了它们在挤出式 3D 打印技术中自愈合应用的功能性热、介电和流变特性以及欧姆加热能力。纳米材料的合成侧重于通过化学气相沉积（CVD）方法生产两种不同类型的碳纳米管（CNT）。使用商用纳米材料和含有 MWCNTs 的母料制成的纳米复合丝进行了比较评估和基准测试。所有聚合物纳米复合材料的样品都是在添加剂含量高达 15 wt.% 的条件下制备的，长丝原料是通过熔融挤压工艺生产的，用于 3D 打印；这些样品之前都通过流变测试进行了表征。热导率和电导率的测量结果表明，所选成分具有良好的欧姆加热能力。作为对上述样品自愈能力的初步评估，在样品表面引入了人工裂缝，并在施加电压前后对裂缝位置进行了扫描电镜分析，以衡量焦耳效应导致的材料重熔的有效性。结果表明，材料反应良好，人工裂纹部分恢复。
{"title":"Development of CNT-Based Nanocomposites with Ohmic Heating Capability towards Self-Healing Applications in Extrusion-Based 3D Printing Technologies","authors":"Niki Loura, E. Gkartzou, A. Trompeta, G. Konstantopoulos, P. Klonos, A. Kyritsis, C. Charitidis","doi":"10.3390/c9040111","DOIUrl":"https://doi.org/10.3390/c9040111","url":null,"abstract":"In the present study, a series of carbon-based nanocomposites based on recycled thermoplastic polyurethane (TPU) matrix and MWCNT fillers synthesized in a laboratory environment were prepared at various loadings and assessed in terms of their functional thermal, dielectric, and rheological properties, as well as their ohmic heating capability, for self-healing applications in extrusion-based 3D printing technologies. The synthesis of nanomaterials focused on the production of two different types of carbon nanotubes (CNTs) via the chemical vapor deposition (CVD) method. A comparative assessment and benchmarking were conducted with nanocomposite filaments obtained from commercial nanomaterials and masterbatches with MWCNTs. For all the polymer nanocomposites, samples were prepared at additive contents up to 15 wt.% and filament feedstock was produced via the melt-extrusion process for 3D printing; these were previously characterized by rheological tests. The measurements of thermal and electrical conductivity resulted in a selected composition with promising ohmic heating capability. As a preliminary assessment of the self-healing ability of the above samples, artificial cracks were introduced on the surface of the samples and SEM analysis took place at the crack location before and after applying voltage as a measure of the effectiveness of the material remelting due to the Joule effect. Results indicate a promising material response with a partial restoration of artificial cracks.","PeriodicalId":503899,"journal":{"name":"C","volume":"52 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139263116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
José Moreira de Sousa, W. Brandão, Weverson Lucas Aguiar Paula Silva, L. A. Ribeiro Júnior, Douglas Soares Galvão, M. L. Pereira Júnior
A novel 2D carbon allotrope, pentagraphyne (PG-yne), was introduced in a recent theoretical study. This unique structure is derived from pentagraphene by incorporating acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Given its intriguing electronic and structural properties, it is imperative to investigate the mechanical characteristics and thermal responses of PG-yne in both monolayer and nanotube configurations, which encompass different chiralities and diameters. We conducted fully atomistic reactive molecular dynamics (MD) simulations employing the ReaxFF potential to address these aspects. Our findings reveal that Young’s modulus of PG-yne monolayers stands at approximately 51 GPa at room temperature. In contrast, for the studied nanotubes, regardless of their chirality, it hovers around 45 GPa. Furthermore, our observations indicate that PG-yne-based systems feature an extensive and relatively flat plastic region before reaching the point of total fracture, irrespective of their topology. Regarding their thermal properties, we identified a melting point at approximately 3600 K, accompanied by a phase transition around 1100 K.
{"title":"Nanomechanical Behavior of Pentagraphyne-Based Single-Layer and Nanotubes through Reactive Classical Molecular Dynamics","authors":"José Moreira de Sousa, W. Brandão, Weverson Lucas Aguiar Paula Silva, L. A. Ribeiro Júnior, Douglas Soares Galvão, M. L. Pereira Júnior","doi":"10.3390/c9040110","DOIUrl":"https://doi.org/10.3390/c9040110","url":null,"abstract":"A novel 2D carbon allotrope, pentagraphyne (PG-yne), was introduced in a recent theoretical study. This unique structure is derived from pentagraphene by incorporating acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Given its intriguing electronic and structural properties, it is imperative to investigate the mechanical characteristics and thermal responses of PG-yne in both monolayer and nanotube configurations, which encompass different chiralities and diameters. We conducted fully atomistic reactive molecular dynamics (MD) simulations employing the ReaxFF potential to address these aspects. Our findings reveal that Young’s modulus of PG-yne monolayers stands at approximately 51 GPa at room temperature. In contrast, for the studied nanotubes, regardless of their chirality, it hovers around 45 GPa. Furthermore, our observations indicate that PG-yne-based systems feature an extensive and relatively flat plastic region before reaching the point of total fracture, irrespective of their topology. Regarding their thermal properties, we identified a melting point at approximately 3600 K, accompanied by a phase transition around 1100 K.","PeriodicalId":503899,"journal":{"name":"C","volume":"96 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139370269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：