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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

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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

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In vitro degradation and cytotoxicity response of biobased nanoparticles prepared by thiol-ene polymerization in miniemulsion

arXiv

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arXiv 2024年

作者： Hoelscher, Fernanda Cardoso, Priscila B. Candiotto, Graziâni Guindani, Camila Feuser, Paulo Araújo, Pedro H.H. Sayer, Claudia Department of Chemical Engineering and Food Engineering Federal University of Santa Catarina EQA UFSC C.P. 476 SC FlorianópolisCEP 88040-900 Brazil Institute of Chemistry Federal University of Rio de Janeiro IQ/UFRJ RJ Rio de JaneiroCEP 21941-909 Brazil Chemical Engineering Program COPPE Federal University of Rio de Janeiro PEQ COPPE UFRJ RJ Rio de JaneiroCEP 21941-972 Brazil

Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the degradation of poly(thioether-ester) (PTEe) nanoparticles in aqueous media. The α,ω-diene diester derived from vegetable oil, 1,3-propylene diundeca-10-polenoate (Pd10e) was used as monomer in the solvent-free synthesis of Pd10e-based nanoparticles (A-PTEe nanoparticles) via thiol-ene miniemulsion polymerization. The theoretical partition coefficients of A-PTEe and a PTEe based on dianhydro-D-glucityl diundec-10-enoate (DGU) (B-PTEe nanoparticles) were calculated using density functional theory (DFT), in order to compare their degradation behavior. The results showed that A-PTEe is more hydrophilic than B-PTEe, thus indicating the possible faster degradation of the former. The experimental degradation studies showed that, in fact, A-PTEe nanoparticles are faster degraded than B-PTEe, presenting substantial molecular weight decrease, which confirms the theoretical results. The effects of degradation could be observed in the chemical composition and thermal properties of the polymer. Considering its applicability potential as a biomaterial due to its fast degradation behavior, the cytotoxicity of A-PTEe nanoparticles and its degradation products were evaluated. In vitro assays confirmed the biocompatibility of A-PTEe nanoparticles and its degradation products when exposed on fibroblasts and red blood cells. These results suggest A-PTEe nanoparticles can be promising candidates as biobased nanocarriers for biomedical applications. © 2024, CC BY.

关键词： Nanoparticles

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Forcing mass transfer approach in multicomponent miscible mixtures using the lattice Boltzmann method

arXiv

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arXiv 2025年

作者： Lourenço, Ramon G.C. Constantino, Pedro H. Tavares, Frederico W. Chemical Engineering Program PEQ/COPPE Federal University of Rio de Janeiro PO Box 68502 RJ Rio de Janeiro21941-972 Brazil Federal University of Rio de Janeiro P.O. Box 68542 RJ Rio de Janeiro21941-909 Brazil Program in Engineering of Chemical and Biochemical Processes EPQB Federal University of Rio de Janeiro P.O. Box 68542 RJ Rio de Janeiro21941-909 Brazil

While the lattice Boltzmann method (LBM) has proven robust in areas like general fluid dynamics, heat transfer, and multiphase modeling, its application to mass transfer has been limited. Current modeling strategies often oversimplify the complexities required for accurate and realistic mass transfer simulations in multicomponent miscible mixtures involving external forces. We propose a forcing approach within the explicit velocity-difference LBM framework to address these limitations. Our approach recovers the macroscopic mass conservation equations, the Navier-Stokes equation with external forcing term, and the full Maxwell-Stefan equation for ideal mixtures at low Knudsen numbers. A novel boundary scheme for impermeable solid walls is also suggested to ensure proper mass conservation while effectively managing the spatial interpolations required for multicomponent mixtures with varying molecular masses. We demonstrated the physical consistency and accuracy of the proposed forcing approach through simulations of the ultracentrifuge separation of uranium isotopes and the Loschmidt tube with gravitational effects. Our approach encompasses advanced modeling of species dynamics influenced by force fields, such as those encountered in geological CO$_2$ sequestration in aquifers and oil reservoirs under gravitational fields. © 2025, CC BY-NC-ND.

关键词： Petroleum reservoir evaluation

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Development and Large-Scale Validation of A Highly Accurate SARS-COV-2 Serological Test Using Regular Test Strips for Autonomous and Affordable Finger-Prick Sample Collection, Transportation, and Storage

Research Square

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Research Square 2021年

作者： Alvim, Renata G.F. Lima, Tulio M. Rodrigues, Danielle A.S. Marsili, Federico F. Bozza, Vicente B.T. Higa, Luiza M. Monteiro, Fabio L. Abreu, Daniel P.B. Leitão, Isabela C. Carvalho, Renato S. Galliez, Rafael M. Castineiras, Terezinha M.P.P. Travassos, Leonardo H. Nobrega, Alberto Tanuri, Amilcar Ferreira, Orlando C. Castilho, Leda R. Vale, André M. Federal University of Rio de Janeiro UFRJ Brazil COPPE Chemical Engineering Program Cell Culture Engineering Lab School of Chemistry EPQB Program Institute of Biophysics Carlos Chagas Filho Program in Immunobiology Brazil Institute of Microbiology Immunology Dept. Institute of Chemistry Biochemistry Program Biology Institute Genetics Dept. Molecular Virology Lab. School of Pharmacy Pharmaceutical Biotechnology Dept. Medical School Infectious and Parasitic Disease Dept

Accurate serological tests are essential tools to allow adequate monitoring and control of COVID-19 spread. Production of a low-cost and high-quality recombinant viral antigen can enable the development of reliable and affordable serological assays, which are urgently needed to facilitate epidemiological surveillance studies in low-income economies. Trimeric SARS-COV-2 spike (S) protein was produced in serum-free, suspension-adapted HEK293 cells. Highly purified S protein was used to develop an ELISA, named S-ufrj test. It was standardized to work with different types of samples: (i) plasma or serum from venous blood samples;(ii) eluates from dried blood spots (DBS) obtained by collecting blood drops from a finger prick. We developed a cost-effective, scalable technology to produce S protein based on its stable expression in HEK293 cells. Using this recombinant antigen, we presented a workflow for test development in the setting of a pandemic, starting from limited amounts of samples up to reaching final validation with hundreds of samples. Test specificity was determined to be 98.6%, whereas sensitivity was 95% for samples collected 11 or more days after symptoms onset. A ROC analysis allowed optimizing the cut-off and confirming the high accuracy of the test. Endpoint titers were shown to correlate with virus neutralization assessed as PRNT90. There was excellent agreement between plasma and DBS samples, significantly simplifying sample collection, storing, and shipping. An overall cost estimate revealed that the final retail price could be in the range of one US dollar. The S-ufrj assay developed herein meets the quality requirements of high sensitivity and specificity. The low cost and the use of mailable DBS samples allow for serological surveillance and follow-up of SARS-CoV-2 vaccination of populations regardless of geographical and socio-economic aspects. We hope the detailed guidelines for the development of an affordable and accurate anti-spike SARS-COV-2

关键词： COVID-19

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Synthetic Cells: From Simple Bio-Inspired Modules to Sophisticated Integrated Systems

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Angewandte Chemie 2021年第16期134卷

作者： Dr. Camila Guindani Dr. Lucas Caire da Silva Dr. Shoupeng Cao Tsvetomir Ivanov Prof. Dr. Katharina Landfester Chemical Engineering Program COPPE Federal University of Rio de Janeiro PEQ/COPPE/UFRJ CEP 21941-972 Rio de Janeiro RJ Brazil Department of Physical Chemistry of Polymers Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany

Bottom-up synthetic biology is the science of building systems that mimic the structure and function of living cells from scratch. To do this, researchers combine tools from chemistry, materials science, and biochemistry to develop functional and structural building blocks to construct synthetic cell-like systems. The many strategies and materials that have been developed in recent decades have enabled scientists to engineer synthetic cells and organelles that mimic the essential functions and behaviors of natural cells. Examples include synthetic cells that can synthesize their own ATP using light, maintain metabolic reactions through enzymatic networks, perform gene replication, and even grow and divide. In this Review, we discuss recent developments in the design and construction of synthetic cells and organelles using the bottom-up approach. Our goal is to present representative synthetic cells of increasing complexity as well as strategies for solving distinct challenges in bottom-up synthetic biology.

关键词： artificial cells artificial organelles cell mimics microreactors synthetic biology

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Stable and highly active zero-valent iron-nickel nanofilaments/silica for the hexavalent chromium reduction

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Environmental Nanotechnology, Monitoring and Management 2020年 14卷

作者： Silva-Calpa, Leydi de R. Correia, Thiago O.F. Netto-Ferreira, José C. Kuriyama, Sergio N. Letichevsky, Sonia de Avillez, Roberto R. Nanotechnology Engineering Program – COPPE Federal University of Rio de Janeiro – UFRJ Cidade Universitária Rio de Janeiro 21941-594 RJ Brazil Department of Materials and Chemical Engineering Pontifical Catholic University of Rio de Janeiro PUC-Rio Rio de Janeiro RJ Brazil Federal Rural University of Rio de Janeiro UFRRJ Seropédica 23890-000 RJ Brazil Instituto Nacional de Metrologia Qualidade e Tecnologia INMETRO Duque de Caxias 25520-020 RJ Brazil Innovation Institute for Green Chemistry Senai-FIRJAN Rio de Janeiro 20271-030 RJ Brazil

Zero-valent iron nanoparticles, active in the reductive depletion of heavy metals, are prone to oxidation unless stored in an appropriate medium such as inert gas, vacuum, or solvent, which involves extra costs. Ideally, these nanoparticles should remain unoxidized. This paper describes the procedure to obtain zero-valent iron-nickel nanofilaments supported on amorphous silica, stable to oxidation. The materials are characterized by X-ray diffraction, scanning electron microscopy, chemical composition, and nitrogen physisorption. The reduction rate coefficient of hexavalent to trivalent chromium was 7.37 min⁻¹. After 12 months of storage, the material still yielded a reaction rate coefficient of 2.73 min⁻¹. These are excellent values compared to literature. Both the enhancement in the chromium reduction and the stability of the nanoparticles can potentially reduce the costs in a treatment of water contaminated by hexavalent chromium on a large-scale. © 2020 Elsevier B.V.

关键词： Chromium (VI) Depletion kinetics Effluent remediation Fe-Ni Nanoparticles

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Front Cover Image, Volume 42, Issue 6

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Medicinal Research Reviews 2022年第6期42卷

作者： Luana Xavier Soares Gomes Moura Fé Eliane Pereira Cipolatti Martina Costa Cerqueira Pinto Suema Branco Fábio César Sousa Nogueira Gisela Maria Dellamora Ortiz Anderson de Sá Pinheiro Evelin Andrade Manoel Departamento de Biotecnologia Farmacêutica Faculdade de Farmácia Centro de Ciências da Saúde (CCS) Universidade Federal do Rio de Janeiro (UFRJ)—Cidade Universitária Rio de Janeiro Rio de Janeiro Brazil Departamento de Engenharia Química Instituto de Tecnologia Universidade Federal Rural do Rio de Janeiro (UFRRJ) Seropédica Rio de Janeiro Brazil Departamento de Bioquímica Instituto de Química Centro de Tecnologia (CT) Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Rio de Janeiro Brazil Chemical Engineering Program Instituto Alberto Luiz Coimbra de Pós-graduação e Pesquisa de Engenharia (COPPE) Centro de Tecnologia (CT) Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Rio de Janeiro Brazil Biofísica Ambiental Instituto de Biofísica Carlos Chagas Filho Centro de Ciências da Saúde (CCS) Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Rio de Janeiro Brazil Departamento de Fármacos e Medicamentos Faculdade de Farmácia Centro de Ciências da Saúde (CCS) Universidade Federal do Rio de Janeiro (UFRJ)—Cidade Universitária Rio de Janeiro Rio de Janeiro Brazil

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Modelling of a dividing-wall distillation column and comparisonwith conventional 2-columns distillation system using EMSO software 22

Modelling of a dividing-wall distillation column and compari...

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22nd International Congress of chemical and Process engineering, CHISA 2016 and 19th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction, PRES 2016

作者： Henrique, J.P. Sousa, R. Secchi, A.R. Ravagnani, M.A.S.S. Costa, C.B.B. Federal University of São Carlos Chemical Engineering Graduate Program São Carlos - SP Brazil Federal University of São Carlos Chemical Engineering Department São Carlos - SP Brazil Federal University of Rio de Janeiro Chemical Engineering Program - PEQ/COPPE Rio de Janeiro RJ Brazil State University of Maringá Chemical Engineering Department Maringá PR Brazil

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Oxygen Permeability of Nanocomposite-Based Polyolefin Films

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Macromolecular Symposia 2016年第1期368卷 19-23页

作者： Fujiyama-Novak, Jane H. Rufino, Vivianne Amaral, Rafael A. Habert, A. Claudio Borges, Cristiano P. Mano, Bárbara Chemical Engineering Program/COPPE/UFRJ Federal University of Rio de Janeiro Rio de Janeiro Brazil Interdisciplinary Department Federal University of Rio Grande do Sul RS Brazil BRASKEM S.A. Polo Petroquímico do Sul Triunfo RS Brazil

Polyethylene and polypropylene are vastly employed for packaging due to their high versatility and low cost. However, their films are permeable at different degree to small molecules like gases and the use of additives improves the barrier properties. Therefore, the aim of this work is to investigate the effect of organically modified montmorillonite on oxygen transport properties of PE and PP films. Nanocomposites were prepared by means of polymer dissolution in organic solvent and subsequent nanoparticle addition at 3, 5 and 10% (w/w). Scanning electron microscopy images of the films indicate the presence of microcavities and some agglomerated nanoclay. On the other hand, X-rays diffraction analysis shows clay in well-dispersed state independent of polyolefin type. Enhancement of oxygen barrier is achieved, but this property is dependent on the nanoclay content, polyolefin type and film morphology. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： Polypropylenes

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PH effect on the dissolution behavior of the microspheres containing strontium ranelate 26

PH effect on the dissolution behavior of the microspheres co...

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26th Symposium and Annual Meeting of the International Society for Ceramics in Medicine, ISCM 2014

作者： Moreira, Ana Paula Duarte Sader, Marcia Soares De Almeida Soares, Gloria Dulce Leão, Maria Helena Rocha Miguez Technology Program in Chemical and Biochemical Processes Federal University of Rio de Janeiro-UFRJ Rio de JaneiroRJ21941-972 Brazil Program of the Metallurgical and Materials Engineering/COPPE/Polytechnic School Federal University of Rio de Janeiro-UFRJ Brazil

ISBN: (纸本)9783038352822

Strontium is known for efficient actions on bone formation and resorption. Strontium ranelate (SrR) is a commercial drug which maintains this balance during bone turnover, reducing the risks of vertebral fractures in the patients. Calcium phosphate bioceramics associated with alginate matrices containing strontium (Sr) could improve bone regeneration due to gradual Sr release. In this report, the strontium ranelate was incorporated on microspheres of alginate (ALG)/β-tricalcium phosphate in a single route of the production. Energy dispersive spectroscopy showed that strontium was incorporated on the surface of the microspheres produced. The dissolution behaviour into a buffer solution at pH 4.0 and at 7.4 was evaluated, measuring Sr content on the microspheres after in vitro assays by atomic absorption spectrometry. Dissolution tests showed a rapid strontium release in both assays, however, it was more pronounced at pH 4.0. Fourier transform infrared spectra indicated the presence of a new precipitated phase at pH 7.4 up after 14 days. Scanning electron microscopy of the microspheres submitted to in vitro revealed that the microspheres at pH 4.0 buffer underwent erosion up to 7 days, while the ones in pH 7.4 buffer, eroded in 48h. This behaviour is due to the high swelling rate of the microspheres in neutral pH. The solubility of the microspheres favors its use as a great material for a local strontium release and remodeling bone. © (2015) Trans Tech Publications, Switzerland.

关键词： Scanning electron microscopy

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