检索结果-内蒙古大学图书馆

Production and characterization of polymeric nanocomposite foams based on starch and cellulose nanofibers from oil palm mesocarp fiber

引用

Applied Nanoscience (Switzerland) 2025年第2期15卷 1-11页

作者： Souza, Mariana Costa Gonçalves, Ana Paula Bispo da Silva Oliveira, Emanoel Igor dos Santos, Juscivaldo Passos Lazzari, Lídia Kunz Zattera, Ademir José José, Nadia Mamede Chemical Engineering Graduate Program Polytechnic School Federal University of Bahia Bahia Salvador Brazil Department of Education Federal Institute of Education Science and Technology Feira de Santana Bahia Brazil Postgraduate Program in Process Engineering and Technologies University of Caxias Do Sul Rio Grande Do Sul Caxias Do Sul Brazil

The demand for sustainable and eco-friendly materials has promoted studies over the years to explore different polymeric materials that meet requirements such as biodegradability and sustainability. In this context, biopolymer materials based on cellulose nanoparticles and starch from different botanical sources have been investigated, aiming to achieve satisfactory performance. The present study aims to develop and characterize cassava starch foams based on density, scanning electron microscopy (SEM), and three-point flexure tests, and to evaluate the effect of cellulose nanofibers obtained from palm mesocarp fibers using the ultrafine friction grinding method after different processing times, characterized by X-ray diffractometry (XRD), microscopy, and chemical composition, as a reinforcing filler. The chemical composition and scanning electron microscopy revealed the effectiveness of the cellulose isolation process, with the analysis of the chemical composition revealing a cellulose content of 55.70% in the fibers after pulping and bleaching, in addition to changes in the visual characteristics of the material after the process aimed at isolating the cellulose. After grinding, XRD showed an increase in crystallinity (76.1% at the maximum grinding time), along with typical microscopy images of cellulose nanofibers. The analysis of the obtained nanocomposites provided insights into the role of these nanostructures in the thermo-expanded starch matrix, indicating that the nanofibers promoted changes such as an increase in mechanical properties and crystallinity, which contributed to improving overall mechanical performance. A 67.48% increase in flexural strength was achieved for the formulation with cellulose nanofibers that underwent 150 min of grinding, without causing major variations in density. © King Abdulaziz City for Science and Technology 2025.

关键词： Starch

来源：评论

学校读者我要写书评

暂无评论

Investigating CO_(2) electro-reduction mechanisms:DFT insight into earth-abundant Mn diimine catalysts for CO_(2) conversions over hydrogen evolution reaction,feasibility,and selectivity considerations

引用

Frontiers of chemical Science and engineering 2024年第12期18卷 117-129页

作者： Murugesan Panneerselvam Marcelo Albuquerque Iuri Soter Viana Segtovich Frederico W.Tavares Luciano T.Costa MolMod-CS-Institute of Chemistry Fluminense Federal UniversityValonginho CampusCentroNiteroi 24020-14Rio de JaneiroBrazil Chemical Engineering Program(PEQ/COPPE) Federal University of Rio de Janeiro(UFRJ)Moniz AragaoRio de Janeiro21941-594RJBrazil Institute of Physics Fluminense Federal UniversityPraia Vermelha CampusGragoataNiteroiRio de JaneiroBrazil Chemical and Biochemical Process Engineering School of ChemistryFederal University of Rio de JaneiroRio de Janeiro 21941Brazil

This study investigates the detailed mechanism of CO_(2) conversion to CO using the manganese(I) diimine electrocatalyst [Mn(pyrox)(CO)3Br], synthesized by Christoph Steinlechner and coworkers. Employing density functional theory calculations, we thoroughly explore the electrocatalytic pathway of CO_(2) reduction alongside the competing hydrogen evolution reaction. Our analysis reveals the significant role of diimine nitrogen coordination in enhancing the electron density of the Mn center, thereby favoring both CO_(2) reduction and hydrogen evolution reaction thermodynamically. Furthermore, we observe that triethanolamine (TEOA) stabilizes transition states, aiding in CO_(2) fixation and reduction. The critical steps influencing the reaction rate involve breaking the MnC(O)–OH bond during CO_(2) reduction and cleaving the MnH–H–TEOA bond in the hydrogen evolution reaction. We explain the preference for CO_(2) conversion to CO over H_(2) evolution due to the higher energy barrier in forming the Mn-H_(2) species during H_(2) production. Our findings suggest the potential for tuning the electron density of the Mn center to enhance reactivity and selectivity in CO_(2) reduction. Additionally, we analyze potential competing reactions, focusing on electrocatalytic processes for CO_(2) reduction and evaluating “protonation-first” and “reduction-first” pathways through density functional theory calculations of redox potentials and Gibbs free energies. This analysis indicates the predominance of the “reduction-first” pathway in CO production, especially under high applied potential conditions. Moreover, our research highlights the selectivity of [Mn(pyrox)(CO)3Br] toward CO production over HCOO– and H_(2) formation, proposing avenues for future research to expand upon these findings by using larger basis sets and exploring additional functionalized ligands.

关键词： manganese carbonyl complex CO_(2)reduction reaction hydrogen evolution reaction selectivity density functional theory studies

来源：评论

学校读者我要写书评

暂无评论

Bacterial Cellulose Films for Biodegradable Packaging with Essential Oils

引用

Macromolecular Symposia 2024年第6期413卷

作者： Teixeira, Stefani Regina Zibetti Garcia, Michele Cristina Formolo Silva, Denise Abati Kasper Kurek, Ana Paula Schneider, AndréaLima dosSantos Pezzin, Ana Paula Testa Postgraduate Program in Process Engineering University of the Joinville Region – UNIVILLE SC Joinville89219-710 Brazil Department of Chemical Engineering University of the Joinville Region – UNIVILLE SC Joinville89219-710 Brazil

Petrochemical polymers provide most packaging materials in the food industry and cause environmental problems due to their non-biodegradability. Developing biodegradable polymers with additives is a strategy, and bacterial cellulose (BC) presents favorable properties for this application. This work aims to evaluate the effect of essential oils (EOs) of clove, cinnamon, basil, and oregano as additives in BC matrix for application in food packaging. BC membranes are synthesized by the bacteria Komagataeibacter hansenii and incorporated into EOs using ethanol as a solvent. The membranes are characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), antibacterial activity, and soil biodegradation. Furthermore, the samples are also tested for their antifungal potential on the surface of bread slices. FTIR analyses confirm the incorporation of EOs into BC membranes. TGA analysis indicates a slight increase in thermal stability for the incorporated samples. All samples show antibacterial potential, except BC, incorporated with the essential basil oil. The fungal analysis is performed by visually evaluating the appearance of filamentous fungi on the surface of the bread pieces. Soil biodegradation tests demonstrate mass loss for all membranes. © 2024 Wiley-VCH GmbH.

关键词： Cellulose

来源：评论

学校读者我要写书评

暂无评论

Bacterial Cellulose Membranes Incorporated with Lipase for Oil Degradation

引用

Macromolecular Symposia 2024年第6期413卷

作者： Silveira, Victória Fonseca da Silva, Victória Mendes Junior, Sandro Rogério Kumineck Garcia, Michele Cristina Formolo Pezzin, Ana Paula Testa de Oliveira, Therezinha Maria Novais Schneider, Andrea Lima dos Santos Postgraduate Program in Health and Environment University of Joinville Region – UNIVILLE Santa Catarina Joinville89219-710 Brazil Department of Chemical Engineering University of Joinville Region – UNIVILLE Santa Catarina Joinville89219-710 Brazil Postgraduate Program in Process Engineering University of Joinville Region – UNIVILLE Santa Catarina Joinville89219-710 Brazil

The immobilization of enzymes increases their stability and allows their reuse, and bacterial cellulose (BC) is a material that can be used in this technique. This work aims to produce an enzymatic product to degrade oils and fats using BC as a matrix. Komagataeibacter hansenii bacteria produce BC membranes, and lipase is immobilized on the membranes by ex situ method. Then, the surface of the membranes is modified with zein, a hydrophobic corn protein. The membranes are characterized by TGA, FTIR, scanning electron microscopy (SEM) analysis and oil degradation test. TGA demonstrates higher stability for the membranes with lipase and zein. The FTIR spectrum of pure BC membrane and zein-modified membrane are very similar because of the high zein coating. SEM analysis shows that zein-modified membranes with lipase present smaller amounts of pores. Finally, using soy oil, lipase degrades oil even after immobilization during the degradation test. © 2024 Wiley-VCH GmbH.

关键词： Nafion membranes

来源：评论

学校读者我要写书评

暂无评论

Biosorption of chromium by live and dead cells of Bacillus nitratireducens isolated from textile effluent

引用

Chemosphere 2024年 359卷 142389页

作者： Imron, Muhammad Fauzul Setiawan, Wahyu Putranto, Trisnadi Widyaleksono Catur Abdullah, Siti Rozaimah Sheikh Kurniawan, Setyo Budi Study Program of Environmental Engineering Department of Biology Faculty of Science and Technology Universitas Airlangga Campus C UNAIR Jalan Mulyorejo Surabaya60115 Indonesia Department of Water Management Faculty of Civil Engineering and Geosciences Delft University of Technology Stevinweg 1 CN Delft2628 Netherlands Study Program of Environmental Science Postgraduate Program Sriwijaya University Palembang30139 Indonesia Department of Chemical and Process Engineering Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia UKM Bangi Selangor 43600 Malaysia

Bacillus nitratireducens was isolated from textile effluent and showed high tolerance to chromium (Cr), reaching up to a 1000 mg/L MIC value. This research was aimed at utilizing biosorbents from live and dead cells of B. nitratireducens to remove Cr from an aqueous solution. A batch biosorption test was performed, and mechanisms analysis was approached by an adsorption-desorption test, SEM-EDS, and FTIR analysis. Cr removal by dead cells in 25, 50, and 100 mg/L of Cr were 58.99 ± 0.7%, 69.8 ± 0.2%, and 82.87 ± 0.11%, respectively, while that by live cells was 73.08 ± 1.9%, 80.27 ± 6.33%, and 86.17 ± 1.93%, respectively. Live cells showed significantly higher Cr removal and adsorption capacities as compared to dead cells. In all concentrations, absorption contributed more than adsorption to the Cr removal by both live and dead cells. Absorption of Cr was subjected to occur due to passive mechanisms in dead cells while involving some active mechanisms in live cells. SEM-EDS confirmed the detection of Cr on the cell surface, while FTIR revealed the shifting of some peaks after the biosorption test, suggesting interactions between Cr and functional groups. Further TEM analysis is suggested to be conducted as a future approach to reveal the inner structure of cells and confirm the involvement of absorption mechanisms. © 2024 Elsevier Ltd

关键词： Heavy metals

来源：评论

学校读者我要写书评

暂无评论

Development of Bacterial Cellulose Membranes Incorporated with Plant Extracts

引用

Macromolecular Symposia 2022年第1期406卷

作者： Neves, Eduarda Zeni Kumineck Junior, Sandro Rogério Katrucha, Graziéli Paulino Silveira, Victória Fonseca Silveira, Márcia Luciane Lange Pezzin, Ana Paula Testa Schneider, Andréa Lima dos Santos Garcia, Michele Cristina Formolo Apati, Giannini Pasiznick Department of Chemical Engineering University of the Joinville Region – UNIVILLE SC Joinville89219-710 Brazil Postgraduate Program in Process Engineering University of the Joinville Region – UNIVILLE SC Joinville89219-710 Brazil Postgraduate Program in Environment and Health University of the Joinville Region – UNIVILLE SC Joinville89219-710 Brazil

A new generation of functional healing membranes has been researched to avoid infection and improve wound healing, combining wound moisture maintenance properties, exudate removal, antimicrobial activity, and the absence of side effects. Thus, this work aims to synthesize wound dressing membranes of bacterial cellulose (BC) incorporated with different plant extracts with antimicrobial properties. The BC membranes are synthesized by the bacterium Komagataeibacter hansenii and are associated with the extracts through the ex situ incorporation technique. The barbatimão extract presents the most significant total phenolic content and antimicrobial activity of the extracts researched. The determination of tannins and flavonoids confirms the extracts’ incorporation into the samples’ structure. The thermogravimetric analysis of the membranes incorporated with the extracts shows a reduction in the thermal stability relative to BC. The results show a good final extract for developing healing membranes with antimicrobial properties. © 2022 Wiley-VCH GmbH.

关键词： Membranes

来源：评论

学校读者我要写书评

暂无评论

Effect of Lyophilized Peach Incorporation on Yam Cookies Quality: Oxidative Stability, Nutritional Potential and Antioxidant Properties

SSRN

引用

SSRN 2024年

作者： Carpes, Solange Teresinha Souza da Silva, Letícia Perin, Ellen Cristina Fontoura, Bruno Henrique Pereira, Edimir Andrade de Camargo, Robson Rosa Bianchin, Mirelli de Oliveira, Jonas Cardoso Citadin, Idemir Department of Chemistry Postgraduate Program in Chemical and Biochemical Process Technology Federal Technological University of Paraná campus Pato Branco PO Box 571 PR Pato BrancoCEP 85503-390 Brazil Department of Agronomy Postgraduate Program in Agronomy Federal Technological University of Paraná campus Pato Branco PO Box 571 PR Pato BrancoCEP 85503-390 Brazil Department of Chemistry Postgraduate Program in Chemical State University of Maringá Av. Colombo 5790 - Zona 7 PR Maringá87020-900 Brazil Department of Food Engineering Federal Technological University of Paraná campus Francisco Beltrão Linha Santa Bárbara s/n PR Francisco Beltrão85601-970 Brazil

This study aimed to increase oxidative stability and enhance yam flour cookies' nutritional and antioxidant properties by incorporating lyophilized peach (LP). The cookies were subjected to two storage conditions: one with exposure to light and one in darkness for 60 days at room temperature. Four formulations were tested: a control (F1), F2 and F3 with 10% and 20% LP, respectively, and F4 with a synthetic antioxidant (SA). The cookies were a good source of protein and fiber. The incorporation of LP into yam cookies exhibited a strong antioxidative effect. Besides, the F3 shows oxidative stability comparable to the SA (F4), measured by TBARS values, under both storage conditions. However, light exposure influenced the retention of phenolics with antioxidant activity, with higher levels observed in cookies stored in darkness. The LP effectively inhibited oxidative processes, demonstrating its potential as an alternative to SA for improving the oxidative stability of yam cookies. © 2024, The Authors. All rights reserved.

关键词： Fruits

来源：评论

学校读者我要写书评

暂无评论

Evaluation of the use of pullulan films with the addition of organophilic clay in the post-harvest conservation of guavas

引用

Food Chemistry 2025年 491卷

作者： V.R.L. Oliveira E.F.C. Sérvulo Veronica Calado Postgraduate Program in Chemical and Biochemical Process Engineering Technology Center – School of Chemistry Universidade Federal do Rio de Janeiro Avenida Athos da Silveira Ramos Cidade Universitária Rio de Janeiro 21941-909 Brazil

Biopolymeric coatings are essential in food preservation, distribution, and marketing, offering a sustainable approach for postharvest quality maintenance. This study developed pullulan-based coatings (2 % w / v ) reinforced with organically modified clay (CTAB-Mt) at varying concentrations to improve barrier and mechanical properties. The formulation containing 10 % CTAB-Mt (P2BO10) showed significant enhancements in water vapor resistance and mechanical strength. Guavas coated with P2BO10 exhibited a reduced respiration rate, contributing to better retention of nutritional quality. Mechanical analysis revealed a 90 % increase in elasticity and over 75 % reduction in solubility, indicating improved resistance to moisture and environmental stress. Physicochemical and physiological evaluations confirmed that P2BO10 effectively preserved the quality of ‘Pedro Sato’ guavas during 15 days of storage at 14 ± 2 °C and 80 ± 2 % RH. The coating extended shelf life while maintaining key quality attributes, demonstrating its potential as an eco-friendly solution for postharvest fruit preservation.

关键词： Biopolymer Guava Organically modified clay Package Pullulan

来源：评论

学校读者我要写书评

暂无评论

Phenomenological modeling of polyols, citric acid and bio-oil concurrent production by Yarrowia lipolytica from glycerol

引用

Cleaner chemical engineering 2023年 5卷

作者： Ana Luiza B.M.A. Campos Felipe V. do Nascimento Argimiro R. Secchi Maria Alice Z. Coelho Chemical and Biochemical Process Engineering Program EPQB/EQ Universidade Federal do Rio de Janeiro PO Box 68502 ZIP 21941-972 Rio de Janeiro Brazil Biochemical Processes Technology Department Chemistry Institute Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil

biochemical routes have shown to be an interesting alternative for the reuse of glycerol, largely generated as a co-product in biodiesel production reaction. Previous works from the research group have demonstrated that glycerol can be efficiently assimilated by Yarrowia lipolytica to produce erythritol, mannitol, citric acid and bio-oil. To better understand the metabolic pathways involved, this work proposes a mathematical model to describe the observed phenomenon. This is the first computational work to model polyol's production and to address the simultaneous formation of four products by Yarrowia lipolytica . Particle Swarm Optimization and Interior Point Optimization were employed together to find the global optima. The developed model proved to be significantly promising and capable of satisfactorily predict the system's behavior in more than one experimental condition. Not only products’ concurrent formation was accurately described, but also polyols’ modeling was successfully performed, reaching R² values greater than 0.93.

关键词： Yarrowia lipolytica Erythritol Mannitol Biodiesel Particle swarm optimization Interior point optimization

来源：评论

学校读者我要写书评

暂无评论

Palygorskite and Solvatochromic Dye in Solid-State Colorimetric Devices for Rapid Assessment of the Amount of Water in Ethanol Fuel

SSRN

引用

SSRN 2022年

作者： de Souza, Cristiane Gimenes dos Santos, Rafael Cavalcante Bertolino, Luiz Carlos de Andrade, Débora França Spinelli, Luciana d'Avila, Luiz Antonio Graduate Program in Nanotechnology Engineering COPPE Federal University of Rio de Janeiro Cidade Universitária Rio de JaneiroCEP 21941-909 Brazil Program in Chemical and Biochemical Process Engineering School of Chemistry Federal University of Rio de Janeiro Cidade Universitária Rio de JaneiroCEP 21941-909 Brazil Mineral Technology Center CETEM Cidade Universitária Rio de JaneiroCEP 21941-908 Brazil Institute of Chemistry Federal University of Rio de Janeiro Cidade Universitária Rio de JaneiroCEP 21941-908 Brazil

This study presents the results of a novel method developed for quantitative determination of water in ethanol fuel based on a colorimetric device composed of the solvatochromic dye methylene blue adsorbed on palygorskite, with filter paper as a support. The quantitative analysis was based on digital images taken of the prepared support, in which hydrous ethanol interacted with the colorimetric devices, giving different colors according to the level of water in the fuel. The digital images were acquired using a novel system consisting of a photo chamber and compartments for liquid or solid samples coupled to a smartphone. The digital images were processed by image processing software (ImageJ v.1.52n) installed on an external laptop, which enabled analyses using RGB and/or HSB. The method was partially validated and compared to the reference method ( Karl Fischer ASTM E203/16 ) for determining water in ethanol fuel. The proposed method showed good linearity, with coefficients of determination 0.9613, 0.9431, and 0.8835 for R, G, and S, respectively. The limits of detection of the channels R, G, and S were 0.329%, 0.306%, and 0.557% m/m, respectively;the limits of quantification for the same channels were 0.998%, 0.927%, and 1.688% m/m, respectively. The accuracy of the method (recovery) was between 98% and 110%. Precision, assessed by relative standard deviation, was 0.56%, 0.92%, and 2.05%, respectively, for R, G, and S. The paired t-test showed that there was no significant difference (with 95% confidence) between the proposed and reference methods. R was selected as the best channel for analyzing water in ethanol fuel as it had the best validation parameters. The proposed method, based on a novel colorimetric device, was found to be a good alternative to the reference method for the determination of water in ethanol fuel as it is quick, simple, effective, and could be used in the field for quality control. © 2022, The Authors. All rights reserved.

关键词： Ethanol

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：