Reactional Processes on Osmium–Polymeric Membranes for 5–Nitrobenzimidazole Reduction

Nechifor, Aurelia Cristina; Goran, Alexandru; Grosu, Vlad-Alexandru; Pîrțac, Andreia; Albu, Paul Constantin; Oprea, Ovidiu; Grosu, Alexandra Raluca; Pașcu, Dumitru; Păncescu, Florentina Mihaela; Nechifor, Gheorghe; Tanczos, Szidonia-Katalin; Bungău, Simona

doi:10.3390/membranes11080633

Cited by 8 publications

(37 citation statements)

References 63 publications

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“…The conversion (η %) of analytes calculated using the solution's concentration (2) or absorbance (3) [64,65] were:…”

Section: Carrying Out the Process Of Oxidation Or Reductionmentioning

confidence: 99%

“…The concentration of the solution of osmium tetroxide in tert-butyl alcohol was chosen at 0.6 g/L for the Os-PP1 membrane and 0.8 g/L for the Os-PP2 membrane. The concentrations of the solutions were chosen in order to be able to compare these composite membranes with the previously obtained and reported membrane, Os-PP0 [64]. The concentration of the solution of osmium tetroxide in tert-butyl alcohol was 0.4 g/L.…”

Section: The Preparation and Characterization Of The Composite Membrane Osmium-polypropylene Hollow Fiber (Os-pp) By In Situ Reduction Ofmentioning

confidence: 99%

“…These two arguments are the basis for determination of the process performance of composite membranes based on osmium nanoparticles-polypropylene hollow fibers Os-PP1 and Os-PP2 in the reduction reaction of p-nitrophenol from lower aliphatic alcohol solutions with molecular hydrogen. For the comparison of the results, a composite membrane of osmium nanoparticlespolypropylene hollow fibers Os-PP0 was tested, recently reported for reduction of 5nitrobenzimidazole [64].…”

Section: Reduction Of P-nitrophenol With Molecular Hydrogen With Osmium Nanoparticles-polypropylene Hollow Fibers Composite Membranesmentioning

confidence: 99%

“…The experiments performed for each type of composite membrane (Os-PP0, Os-PP1, and Os-PP2) for six hours showed that the evolution of hydrogenation was slow at the beginning of the operation interval, and the conversion value (η %) reached 75% (Os-PP0), 83% (Os-PP1), and 87% (Os-PP2) at six hours (Figure 14). For the comparison of the results, a composite membrane of osmium nanoparticlespolypropylene hollow fibers Os-PP0 was tested, recently reported for reduction of 5-nitrobenzimidazole [64].…”

Section: Reduction Of P-nitrophenol With Molecular Hydrogen With Osmium Nanoparticles-polypropylene Hollow Fibers Composite Membranesmentioning

confidence: 99%

“…After the oxidation process, the reaction compartment underwent three stages of tartar: with nitrogen gas to remove residual oxygen, with hydrogen (at least two hours to reduce any traces of osmium tetroxides), and then with nitrogen to remove residual hydrogen. The filtration characteristics of polypropylene hollow fiber membranes [56][57][58][59][60][61][62][63][64] ensured the complete retention of osmium nanoparticles in the reaction compartment which could be followed by established analytical techniques [74][75][76][77][78].…”

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Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes

et al. 2021

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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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“…The conversion (η %) of analytes calculated using the solution's concentration (2) or absorbance (3) [64,65] were:…”

Section: Carrying Out the Process Of Oxidation Or Reductionmentioning

confidence: 99%

Section: The Preparation and Characterization Of The Composite Membrane Osmium-polypropylene Hollow Fiber (Os-pp) By In Situ Reduction Ofmentioning

confidence: 99%

Section: Reduction Of P-nitrophenol With Molecular Hydrogen With Osmium Nanoparticles-polypropylene Hollow Fibers Composite Membranesmentioning

confidence: 99%

Section: Reduction Of P-nitrophenol With Molecular Hydrogen With Osmium Nanoparticles-polypropylene Hollow Fibers Composite Membranesmentioning

confidence: 99%

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confidence: 99%

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Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes

et al. 2021

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Emulsion Liquid Membranes Based on Os–NP/n–decanol or n–dodecanol Nanodispersions for p–Nitrophenol Reduction

Pîrțac,

Nechifor,

Tanczos

et al. 2024

Preprint

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Materials based on platinum metals with very good catalytic activity were tested in the reduction of p–nitrophenol (pNP) to p–aminophenol (pAP). The majority of presented catalytic materials are based on the adsorption of p–nitrophenol on the surface of the catalyst simultaneously with molecular hydrogen, coming from sodium borohydride in an aqueous medium, which reduces it. In the present paper, a catalytic material based on osmium dispersed in n–decanol or n–dodecanol is presented, which also works as an emulsion membrane, for the absorption of p–nitrophenol and molecular hydrogen at the n–alcohol aqueous solution interface. The hydrogenation of p–nitrophenol is carried out in a reaction and separation column in which the acid receiving phase emulsion is dispersed in the osmium nanodispersion, in n–alcohols. This emulsion circulates from the base of the column to its upper part in co-current or counter-current with the source phase consisting of p–nitrophenol and sodium borohydride. Experiments show that the circulation of counter-current phases is superior to that in co-current, and the emulsion based on n–decanol is more efficient than the one based on n–dodecanol. The increase in the pH difference between the source and receiving phases leads to the increase in the conversion of p–nitrophenol to p–aminophenol. The efficiency of separation of the reaction product in the receiving phase is lower than the conversion at the same operating time. The apparent catalytic rate constant (kapp) of the new catalytic material based on the emulsion membrane with nanodispersion of osmium nanoparticles (0.1×10−3 for n–dodecanol and 0.9×10−3 for n-decanol) is lower by an order of magnitude compared to those based on adsorption on catalysts from platinum metal group. The advantage of the tested membrane catalytic material is that it extracts p–aminophenol in the acid receiving phase. The paper proposes a mechanism of the studied reduction system.

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Green Synthesis of Hydrogel-Based Adsorbent Material for the Effective Removal of Diclofenac Sodium from Wastewater

Chelu

Popa

Moreno

et al. 2023

Gels

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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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Reactional Processes on Osmium–Polymeric Membranes for 5–Nitrobenzimidazole Reduction

Cited by 8 publications

References 63 publications

Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes

Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes

Emulsion Liquid Membranes Based on Os–NP/n–decanol or n–dodecanol Nanodispersions for p–Nitrophenol Reduction

Green Synthesis of Hydrogel-Based Adsorbent Material for the Effective Removal of Diclofenac Sodium from Wastewater

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