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Pîrțac A, Nechifor AC, Tanczos SK, Oprea OC, Grosu AR, Matei C, Grosu VA, Vasile BȘ, Albu PC, Nechifor G. Emulsion Liquid Membranes Based on Os-NP/n-Decanol or n-Dodecanol Nanodispersions for p-Nitrophenol Reduction. Molecules 2024; 29:1842. [PMID: 38675662 PMCID: PMC11055161 DOI: 10.3390/molecules29081842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Membrane materials with osmium nanoparticles have been recently reported for bulk membranes and supported composite membrane systems. In the present paper, a catalytic material based on osmium dispersed in n-decanol (nD) or n-dodecanol (nDD) is presented, which also works as an emulsion membrane. The hydrogenation of p-nitrophenol (PNP) is carried out in a reaction and separation column in which an emulsion in the acid-receiving phase is dispersed in an osmium nanodispersion in n-alcohols. The variables of the PNP conversion process and p-aminophenol (PAP) transport are as follows: the nature of the membrane alcohol, the flow regime, the pH difference between the source and receiving phases and the number of operating cycles. The conversion results are in all cases better for nD than nDD. The counter-current flow regime is superior to the co-current flow. Increasing the pH difference between the source and receiving phases amplifies the process. The number of operating cycles is limited to five, after which the regeneration of the membrane dispersion is required. The apparent catalytic rate constant (kapp) of the new catalytic material based on the emulsion membrane with the nanodispersion of osmium nanoparticles (0.1 × 10-3 s-1 for n-dodecanol and 0.9 × 10-3 s-1 for n-decanol) is lower by an order of magnitude compared to those based on adsorption on catalysts from the platinum metal group. The advantage of the tested membrane catalytic material is that it extracts p-aminophenol in the acid-receiving phase.
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Affiliation(s)
- Andreia Pîrțac
- Analytical Chemistry and Environmental Engineering Department, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania; (A.P.); (A.C.N.); (A.R.G.)
| | - Aurelia Cristina Nechifor
- Analytical Chemistry and Environmental Engineering Department, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania; (A.P.); (A.C.N.); (A.R.G.)
| | - Szidonia-Katalin Tanczos
- Department of Bioengineering, University Sapientia of Miercurea-Ciuc, 500104 Miercurea-Ciuc, Romania;
| | - Ovidiu Cristian Oprea
- National Research Center for Micro and Nanomaterials, University POLITEHNICA of Bucharest, 060042 Bucharest, Romania; (O.C.O.); (B.Ș.V.)
- National Research Center for Food Safety, University POLITEHNICA of Bucharest, Splaiul Independentei 313, 060042 Bucharest, Romania
- Faculty of Chemical Engineering and Biotechnologies, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania
- Academy of Romanian Scientists, Ilfov Street 3, 050044 Bucharest, Romania
| | - Alexandra Raluca Grosu
- Analytical Chemistry and Environmental Engineering Department, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania; (A.P.); (A.C.N.); (A.R.G.)
| | - Cristian Matei
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania;
| | - Vlad-Alexandru Grosu
- Department of Electronic Technology and Reliability, Faculty of Electronics, Telecommunications and Information Technology, University POLITEHNICA of Bucharest, 061071 Bucharest, Romania
| | - Bogdan Ștefan Vasile
- National Research Center for Micro and Nanomaterials, University POLITEHNICA of Bucharest, 060042 Bucharest, Romania; (O.C.O.); (B.Ș.V.)
| | - Paul Constantin Albu
- Radioisotopes and Radiation Metrology Department (DRMR), IFIN Horia Hulubei, 023465 Măgurele, Romania;
| | - Gheorghe Nechifor
- Analytical Chemistry and Environmental Engineering Department, University POLITEHNICA of Bucharest, 1-7 Polizu St., 011061 Bucharest, Romania; (A.P.); (A.C.N.); (A.R.G.)
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Chelu M, Popa M, Calderon Moreno J, Leonties AR, Ozon EA, Pandele Cusu J, Surdu VA, Aricov L, Musuc AM. Green Synthesis of Hydrogel-Based Adsorbent Material for the Effective Removal of Diclofenac Sodium from Wastewater. Gels 2023; 9:454. [PMID: 37367125 DOI: 10.3390/gels9060454] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/20/2023] [Accepted: 05/29/2023] [Indexed: 06/28/2023] Open
Abstract
The removal of pharmaceutical contaminants from wastewater has gained considerable attention in recent years, particularly in the advancements of hydrogel-based adsorbents as a green solution for their ease of use, ease of modification, biodegradability, non-toxicity, environmental friendliness, and cost-effectiveness. This study focuses on the design of an efficient adsorbent hydrogel based on 1% chitosan, 40% polyethylene glycol 4000 (PEG4000), and 4% xanthan gum (referred to as CPX) for the removal of diclofenac sodium (DCF) from water. The interaction between positively charged chitosan and negatively charged xanthan gum and PEG4000 leads to strengthening of the hydrogel structure. The obtained CPX hydrogel, prepared by a green, simple, easy, low-cost, and ecological method, has a higher viscosity due to the three-dimensional polymer network and mechanical stability. The physical, chemical, rheological, and pharmacotechnical parameters of the synthesized hydrogel were determined. Swelling analysis demonstrated that the new synthetized hydrogel is not pH-dependent. The obtained adsorbent hydrogel reached the adsorption capacity (172.41 mg/g) at the highest adsorbent amount (200 mg) after 350 min. In addition, the adsorption kinetics were calculated using a pseudo first-order model and Langmuir and Freundlich isotherm parameters. The results demonstrate that CPX hydrogel can be used as an efficient option to remove DCF as a pharmaceutical contaminant from wastewater.
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Affiliation(s)
- Mariana Chelu
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Monica Popa
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Jose Calderon Moreno
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Anca Ruxandra Leonties
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Emma Adriana Ozon
- Department of Pharmaceutical Technology and Biopharmacy, Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020945 Bucharest, Romania
| | - Jeanina Pandele Cusu
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Vasile Adrian Surdu
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Ludmila Aricov
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
| | - Adina Magdalena Musuc
- "Ilie Murgulescu" Institute of Physical Chemistry, 202 Spl. Independentei, 060021 Bucharest, Romania
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Pașcu D, Nechifor AC, Grosu VA, Oprea OC, Tanczos SK, Man GT, Dumitru F, Grosu AR, Nechifor G. Hydrogen Sulphide Sequestration with Metallic Ions in Acidic Media Based on Chitosan/sEPDM/Polypropylene Composites Hollow Fiber Membranes System. MEMBRANES 2023; 13:350. [PMID: 36984736 PMCID: PMC10057485 DOI: 10.3390/membranes13030350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
This paper presents the preparation and characterization of composite membranes based on chitosan (Chi), sulfonated ethylene-propylene-diene terpolymer (sEPDM), and polypropylene (PPy), and designed to capture hydrogen sulfide. The Chi/sEPDM/PPy composite membranes were prepared through controlled evaporation of a toluene dispersion layer of Chi:sEPDM 1;1, w/w, deposited by immersion and under a slight vacuum (100 mmHg) on a PPy hollow fiber support. The composite membranes were characterized morphologically, structurally, and thermally, but also from the point of view of their performance in the process of hydrogen sulfide sequestration in an acidic media solution with metallic ion content (Cu2+, Cd2+, Pb2+, and/or Zn2+). The operational parameters of the pertraction were the pH, pM, matrix gas flow rate, and composition. The results of pertraction from synthetic gases mixture (nitrogen, methane, carbon dioxide) indicated an efficient removal of hydrogen sulfide through the prepared composite membranes, as well as its immobilization as sulfides. The sequestration and the recuperative separation, as sulfides from an acid medium, of the hydrogen sulfide reached up to 96%, decreasing in the order: CuS > PbS > CdS > ZnS.
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Affiliation(s)
- Dumitru Pașcu
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Aurelia Cristina Nechifor
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Vlad-Alexandru Grosu
- Department of Electronic Technology and Reliability, Faculty of Electronics, Telecommunications and Information Technology, University Politehnica of Bucharest, 061071 Bucharest, Romania
| | - Ovidiu Cristian Oprea
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Szidonia-Katalin Tanczos
- Department of Bioengineering, University Sapientia of Miercurea-Ciuc, 500104 Miercurea-Ciuc, Romania
| | - Geani Teodor Man
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Florina Dumitru
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Alexandra Raluca Grosu
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Gheorghe Nechifor
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
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Nechifor AC, Goran A, Tanczos SK, Păncescu FM, Oprea OC, Grosu AR, Matei C, Grosu VA, Vasile BȘ, Albu PC. Obtaining and Characterizing the Osmium Nanoparticles/ n-Decanol Bulk Membrane Used for the p-Nitrophenol Reduction and Separation System. MEMBRANES 2022; 12:1024. [PMID: 36295782 PMCID: PMC9609118 DOI: 10.3390/membranes12101024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Liquid membranes based on nanoparticles follow a continuous development, both from obtaining methods and characterization of techniques points of view. Lately, osmium nanoparticles have been deposited either on flat membranes, with the aim of initiating some reaction processes, or on hollow fiber membranes, with the aim of increasing the contact surface with the phases of the membrane system. This paper presents the obtainment and characterization of a liquid membrane based on osmium nanoparticles (Os-NP) dispersed in ndecanol (nDol) for the realization of a membrane system with a large contact surface between the phases, but without using a liquid membrane support. The dispersion of osmium nanoparticles in n-decanol is carried out by the method of reducing osmium tetroxide with 1-undecenoic acid (UDA). The resulting membrane was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy analysis (EDAX), thermoanalysis (TG, DSC), Fourier transform infra-red (FTIR) spectroscopy and dynamic light scattering (DLS). In order to increase the mass transfer surface, a design for the membrane system was realized with the dispersion of the membrane through the receiving phase and the dispersion of the source phase through the membrane (DBLM-dispersion bulk liquid membrane). The process performance was tested for the reduction of p-nitrophenol (pNP) from the source phase, using sodium tetra-borohydride (NaBH4), to p-aminophenol (pAP), which was transported and collected in the receiving phase. The obtained results show that membranes based on the dispersion of osmium nanoparticles in n-decanol can be used with an efficiency of over 90% for the reduction of p-nitrophenol and the separation of p-aminophenol.
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Affiliation(s)
- Aurelia Cristina Nechifor
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Alexandru Goran
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Szidonia-Katalin Tanczos
- Department of Bioengineering, University Sapientia of Miercurea-Ciuc, 500104 Miercurea-Ciuc, Romania
| | - Florentina Mihaela Păncescu
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Ovidiu-Cristian Oprea
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Alexandra Raluca Grosu
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Cristian Matei
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 011061 Bucharest, Romania
| | - Vlad-Alexandru Grosu
- Department of Electronic Technology and Reliability, Faculty of Electronics, Telecommunications and Information Technology, University Politehnica of Bucharest, 061071 Bucharest, Romania
| | - Bogdan Ștefan Vasile
- National Research Center for Micro and Nanomaterials, Politehnica University of Bucharest, 011061 Bucharest, Romania
| | - Paul Constantin Albu
- Radioisotopes and Radiation Metrology Department (DRMR), IFIN Horia Hulubei, 023465 Măgurele, Romania
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Simultaneous Release of Silver Ions and 10–Undecenoic Acid from Silver Iron–Oxide Nanoparticles Impregnated Membranes. MEMBRANES 2022; 12:membranes12060557. [PMID: 35736264 PMCID: PMC9227798 DOI: 10.3390/membranes12060557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/01/2022] [Accepted: 05/23/2022] [Indexed: 01/27/2023]
Abstract
The bio-medical benefits of silver ions and 10–undecenoic acid in various chemical-pharmaceutical preparations are indisputable, thus justifying numerous research studies on delayed and/or controlled release. This paper presents the effect of the polymer matrix in the simultaneous release of silver ions and 10–undecenoic acid in an aqueous medium of controlled pH and ionic strength. The study took into consideration polymeric matrices consisting of cellulose acetate (CA) and polysulfone (PSf), which were impregnated with oxide nanoparticles containing silver and 10–undecenoic acid. The studied oxide nanoparticles are nanoparticles of iron and silver oxides obtained by an accessible electrochemical method. The obtained results show that silver can be released, simultaneously with 10–undecenoic acid, from an impregnated polymeric membrane, at concentrations that ensure the biocidal and fungicidal capacity. Concentrations of active substances can be controlled by choosing the polymer matrix or, in some cases, by changing the pH of the target medium. In the studied case, higher concentrations of silver ions are released from the polysulfone matrix, while higher concentrations of 10–undecenoic acid are released from the cellulose acetate matrix. The results of the study show that a correlation can be established between the two released target substances, which is dependent on the solubility of the organic compound in the aqueous medium and the interaction of this compound with the silver ions. The ability of 10–undecenoic acid to interact with the silver ion, both through the carboxyl and alkene groups, contributes to the increase in the content of the silver ions transported in the aqueous medium.
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Albu PC, Ferencz (Dinu) A, Al-Ani HNA, Tanczos SK, Oprea O, Grosu VA, Nechifor G, Bungău SG, Grosu AR, Goran A, Nechifor AC. Osmium Recovery as Membrane Nanomaterials through 10-Undecenoic Acid Reduction Method. MEMBRANES 2021; 12:membranes12010051. [PMID: 35054577 PMCID: PMC8781728 DOI: 10.3390/membranes12010051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/22/2021] [Accepted: 12/28/2021] [Indexed: 12/19/2022]
Abstract
The recovery of osmium from residual osmium tetroxide (OsO4) is a necessity imposed by its high toxicity, but also by the technical-economic value of metallic osmium. An elegant and extremely useful method is the recovery of osmium as a membrane catalytic material, in the form of nanoparticles obtained on a polymeric support. The subject of the present study is the realization of a composite membrane in which the polymeric matrix is the polypropylene hollow fiber, and the active component consists of the osmium nanoparticles obtained by reducing an alcoholic solution of osmium tetroxides directly on the polymeric support. The method of reducing osmium tetroxide on the polymeric support is based on the use of 10-undecenoic acid (10-undecylenic acid) (UDA) as a reducing agent. The osmium tetroxide was solubilized in t-butanol and the reducing agent, 10-undecenoic acid (UDA), in i-propanol, t-butanol or n-decanol solution. The membranes containing osmium nanoparticles (Os-NP) were characterized morphologically by the following: scanning electron microscopy (SEM), high-resolution SEM (HR-SEM), structurally: energy-dispersive spectroscopy analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy. In terms of process performance, thermal gravimetric analysis was performed by differential scanning calorimetry (TGA, DSC) and in a redox reaction of an organic marker, p-nitrophenol (PNP) to p-aminophenol (PAP). The catalytic reduction reaction with sodium tetraborate solution of PNP to PAP yielded a constant catalytic rate between 2.04 × 10-4 mmol s-1 and 8.05 × 10-4 mmol s-1.
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Affiliation(s)
- Paul Constantin Albu
- Radioisotopes and Radiation Metrology Department (DRMR), IFIN Horia Hulubei, 023465 Măgurele, Romania; (P.C.A.); (A.C.N.)
| | - Andreea Ferencz (Dinu)
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania; (A.F.); (H.N.A.A.-A.); (G.N.); (A.R.G.); (A.G.)
| | - Hussam Nadum Abdalraheem Al-Ani
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania; (A.F.); (H.N.A.A.-A.); (G.N.); (A.R.G.); (A.G.)
- Chemical Industries Department, Institute of Technology, Middle Technical University, Al Zafaraniyah, Baghdad 10074, Iraq
| | - Szidonia-Katalin Tanczos
- Department of Bioengineering, University Sapientia of Miercurea-Ciuc, 500104 Miercurea-Ciuc, Romania
- Correspondence: (S.-K.T.); (V.-A.G.)
| | - Ovidiu Oprea
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, University Politehnica of Bucharest, 011061 Bucharest, Romania;
| | - Vlad-Alexandru Grosu
- Department of Electronic Technology and Reliability, Faculty of Electronics, Telecommunications and Information Technology, University Politehnica of Bucharest, 061071 Bucharest, Romania
- Correspondence: (S.-K.T.); (V.-A.G.)
| | - Gheorghe Nechifor
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania; (A.F.); (H.N.A.A.-A.); (G.N.); (A.R.G.); (A.G.)
| | - Simona Gabriela Bungău
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, 410028 Oradea, Romania;
| | - Alexandra Raluca Grosu
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania; (A.F.); (H.N.A.A.-A.); (G.N.); (A.R.G.); (A.G.)
| | - Alexandru Goran
- Analytical Chemistry and Environmental Engineering Department, University Politehnica of Bucharest, 011061 Bucharest, Romania; (A.F.); (H.N.A.A.-A.); (G.N.); (A.R.G.); (A.G.)
| | - Aurelia Cristina Nechifor
- Radioisotopes and Radiation Metrology Department (DRMR), IFIN Horia Hulubei, 023465 Măgurele, Romania; (P.C.A.); (A.C.N.)
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Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes. NANOMATERIALS 2021; 11:nano11102526. [PMID: 34684968 PMCID: PMC8537536 DOI: 10.3390/nano11102526] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 12/17/2022]
Abstract
Composite membranes play a very important role in the separation, concentration, and purification processes, but especially in membrane reactors and membrane bioreactors. The development of composite membranes has gained momentum especially through the involvement of various nanoparticles, polymeric, oxide, or metal, that have contributed to increasing their reactivity and selectivity. This paper presents the preparation and characterization of an active metal nanoparticle-support polymer type composite membrane, based on osmium nanoparticles obtained in situ on a polypropylene hollow fiber membrane. Osmium nanoparticles are generated from a solution of osmium tetroxide in tert-butyl alcohol by reduction with molecular hydrogen in a contactor with a polypropylene membrane. The composite osmium-polypropylene hollow fiber obtained membranes (Os-PPM) were characterized from the morphological and structural points of view: scanning electron microscopy (SEM), high resolution SEM (HR-SEM), energy dispersive spectroscopy analysis (EDAX), X-ray diffraction analysis (XRD), Fourier transform Infrared (FTIR) spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry (TGA, DSC). The process performance was tested in a redox process of p-nitrophenol and 10-undecylenic (10-undecenoic) acid, as a target substance of biological or biomedical interest, in solutions of lower aliphatic alcohols in a membrane contactor with a prepared composite membrane. The characteristics of osmium nanoparticles-polypropylene hollow fiber membranes open the way to biological and biotechnological applications. These membranes do not contaminate the working environment, operate at relatively low temperatures, provide a large contact area between reactants, allow successive oxidation and reduction operations in the same module, and help to recover the reaction mass by ultrafiltration. The results obtained show that the osmium-polypropylene composite membrane allows the reduction of p-nitrophenol or the oxidation of 10-undecylenic acid, the conversion depending on the concentration in the lower aliphatic alcohol, the nature of the lower aliphatic alcohol, and the oxidant or reducing flow through the membrane contactor.
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