| 1. |
- Ashour, Radwa M., et al.
(författare)
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Preparation and characterization of magnetic iron oxide nanoparticles functionalized by L-cysteine : Adsorption and desorption behavior for rare earth metal ions
- 2016
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier. - 2213-3437. ; 4:3, s. 3114-3121
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Tidskriftsartikel (refereegranskat)abstract
- In this work, magnetic iron oxide nanoparticles functionalized with L-cysteine (Cys-Fe3O4 NPs) was synthesized and fully characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infra-red (FTIR), thermogravimetric analysis (TGA) and zeta potential measurements. The synthesized Cys-Fe(3)O(4)NPs has been evaluated as a highly adsorbent for the adsorption of a mixture of four rare earths RE3+ ions (La3+, Nd3+, Gd3+ and Y3+) from digested monazite solutions. The influence of various factors on the adsorption efficiency such as, the contact time, sample pH, temperature, and concentration of the stripping solution were investigated. The results indicate that Cys-Fe3O4 NPs achieve high removal efficiency 96.7, 99.3, 96.5 and 87% for La3+, Nd3+, Gd3+ and Y3+ ions, respectively, at pH = 6 within 15 min, and the adsorbent affinity for metal ions was found to be in order of Nd3+ > La3+ > Gd3+ > Y3+ ions. Using the Langmuir model, a maximum adsorption capacity of La3+, Nd3+, Gd3+ and Y3+ at room temperature was found to be 71.5, 145.5, 64.5 and 13.6 mg g (1), respectively. The Langmuir isotherm and pseudo-second order model fitted much better than the other isotherms and kinetic models. The obtained results for the thermodynamic parameters confirmed the spontaneous and endothermic nature of the process. Moreover, the desorption was carried out with 0.1 M nitric acid solutions. In addition, Cys-Fe3O4 NPs can be used as a highly efficient adsorbent for the adsorption of La3+, Nd3+, Gd3+ and Y3+ ions from digested monazite solutions.
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| 2. |
- Ashour, Radwa M., et al.
(författare)
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Rare Earth Ions Adsorption onto Graphene Oxide Nanosheets
- 2017
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Ingår i: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 35:2, s. 91-103
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Tidskriftsartikel (refereegranskat)abstract
- Graphene oxide (GO) was synthesized and used as a coagulant of rare earth elements (REEs) from aqueous solution. Stability and adsorption capacities were exhibited for target REEs such as La(III), Nd(III), Gd(III), and Y(III). The parameters influencing the adsorption capacity of the target species including contact time, pH, initial concentration, and temperature were optimized. The adsorption kinetics and thermodynamics were studied. The method showed quantitative recovery (99%) upon desorption using HNO3 acid (0.1 M) after a short contact time (15 min).
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| 3. |
- Abdel-Khalek, Ahmed A., et al.
(författare)
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Chemical Studies on Uranium Extraction from Concentrated Phosphoric Acid by Using PC88A and DBBP Mixture.
- 2011
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer. - 0236-5731 .- 1588-2780. ; 290, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- Liquid–liquid extraction of U (VI) from concentrated phosphoric acid by using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester (PC88A) and di-butyl butyl phosphonate (DBBP) has been investigated. The effect of different factors affecting the extraction process (PC88A concentration, DBBP concentration, shaking time, aqueous/organic phase ratio, phosphoric acid concentration and effect of diluents) have been investigated. The obtained data of temperature on the extraction showed that the enthalpy change is −17.15 kJ mol−1. Uranium was extracted from the strip liquor by using di (2-ethylhexyl) phosphoric acid and tri-octyl phosphine oxide mixture and finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 365 °C.
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| 4. |
- Abdel-Magied, Ahmed F., et al.
(författare)
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Synthesis and characterization of chiral phosphirane derivatives of [(μ-H)4Ru4(CO)12] and their application in the hydrogenation of an α,β-unsaturated carboxylic acid
- 2017
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Ingår i: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X. ; 849-850, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- Ruthenium clusters containing the chiral binaphthyl-derived mono-phosphiranes [(S)-([1,1'-binaphthalen]-2-yl)phosphirane] (S)-1a, [(R)-(2'-methoxy-1,1'-binaphthyl-2-yl)phosphirane] (R)-1b, and the diphosphirane [2,2'-di(phosphiran-1-yl)-1,1'-binaphthalene] (S)-1c have been synthesized and characterized. The clusters are [(μ-H)4Ru4(CO)11((S)-1a)] (S)-2, [(μ-H)4Ru4(CO)11((R)-1b)] (R)-3, 1,1-[(μ-H)4Ru4(CO)10((S)-1c)] (S)-4, [(μ-H)4Ru4(CO)11((S)-binaphthyl-P(s)(H)Et)] (S,S p)-5, [(μ-H)4Ru4(CO)11((S)-binaphthyl-P(R)(H)Et)] (S,R p)-6, [(μ-H)4Ru4(CO)11((R)-binaphthyl-P(s)(H)Et)] (R,S p)-7, [(μ-H)4Ru4(CO)11((R)-binaphthyl-P(R)(H)Et)] (R,R p)-8 and the phosphinidene-capped triruthenium cluster [(μ-H)2Ru3(CO)9(PEt)] 9. Clusters 5-8 are formed via hydrogenation and opening of the phosphirane ring in clusters (S)-2 and (R)-3. The phosphirane-substituted clusters were found to be able to catalyze the hydrogenation of trans-2-methyl-2-butenoic acid (tiglic acid), but no enantioselectivity could be detected. The molecular structures of (S)-4, (R,S p)-7 and 9 have been determined and are presented.
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| 5. |
- Abdel-Magied, Ahmed F., et al.
(författare)
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Asymmetric hydrogenation of an α-unsaturated carboxylic acid catalyzed by intact chiral transition metal carbonyl clusters-diastereomeric control of enantioselectivity
- 2020
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 49:14, s. 4244-4256
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Tidskriftsartikel (refereegranskat)abstract
- Twenty clusters of the general formula [(μ-H)2Ru3(μ3-S)(CO)7(μ-P-P∗)] (P-P∗ = chiral diphosphine of the ferrocene-based Walphos or Josiphos families) have been synthesised and characterised. The clusters have been tested as catalysts for asymmetric hydrogenation of tiglic acid [trans-2-methyl-2-butenoic acid]. The observed enantioselectivities and conversion rates strongly support catalysis by intact Ru3 clusters. A catalytic mechanism involving an active Ru3 catalyst generated by CO loss from [(μ-H)2Ru3(μ3-S)(CO)7(μ-P-P∗)] has been investigated by DFT calculations.
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| 6. |
- Abdel-Magied, Ahmed F., et al.
(författare)
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Chemical and Photochemical Water Oxidation Mediated by an Efficient Single-Site Ruthenium Catalyst
- 2016
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 9:24, s. 3448-3456
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Tidskriftsartikel (refereegranskat)abstract
- Water oxidation is a fundamental step in artificial photosynthesis for solar fuels production. In this study, we report a single-site Ru-based water oxidation catalyst, housing a dicarboxylate-benzimidazole ligand, that mediates both chemical and light-driven oxidation of water efficiently under neutral conditions. The importance of the incorporation of the negatively charged ligand framework is manifested in the low redox potentials of the developed complex, which allows water oxidation to be driven by the mild one-electron oxidant [Ru(bpy)(3)](3+) (bpy = 2,2'-bipyridine). Furthermore, combined experimental and DFT studies provide insight into the mechanistic details of the catalytic cycle.
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| 7. |
- Abdel-Magied, Ahmed F., et al.
(författare)
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Substituent Effects in Molecular Ruthenium Water Oxidation Catalysts Based on Amide Ligands
- 2017
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Ingår i: ChemCatChem. - : Wiley. - 1867-3880 .- 1867-3899. ; 9:9, s. 1583-1587
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Tidskriftsartikel (refereegranskat)abstract
- The production of clean and sustainable energy is considered as one of the most urgent issues for our society. Mastering the oxidation of water to dioxygen is essential for the production of solar fuels. A study of the influence of the substituents on the catalytic activity of a series of mononuclear Ru complexes (2a-e) based on a tetradentate ligand framework is presented. At neutral pH, using [Ru(bpy)(3)](PF6)(3) (bpy=2,2'-bipyridine) as the terminal oxidant, a good correlation between the turnover frequency (TOF) and the Hammett sigma(meta) parameters was obtained. Additionally, a general pathway for the deactivation of Ru-based catalysts 2a-e during the catalytic oxidation of water through poisoning by carbon monoxide was demonstrated. These results highlight the importance of ligand design for fine-tuning the catalytic activity of water oxidation catalysts.
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| 8. |
- Abdel-Magied, Ahmed F., et al.
(författare)
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Synthesis, Characterization and Catalytic Activity Studies of Rhenium Carbonyl Complexes Containing Chiral Diphosphines of the Josiphos and Walphos Families
- 2015
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Ingår i: Journal of Cluster Science. - : Springer Science and Business Media LLC. - 1040-7278 .- 1572-8862. ; 26:4, s. 1231-1252
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Tidskriftsartikel (refereegranskat)abstract
- Ten rhenium carbonyl complexes-[Re(H)(CO)(3)(1a)], [Re-3(mu-H)(3)(CO)(10) (1a)], [Re-2(CO)(9)(2a)], [Re-2(CO)(8)(2a)], [Re-2(CO)(9)(2b)], [{Re-2(CO)(9)}(2)(2b)], [Re-2 (CO)(8)(2b)], [Re-2(CO)(8)(1b)], [Re-2(mu-H)(2)(CO)(6)(2b)] and [Re-3(mu-H)(3)(CO)(11)(2b)]-containing different bidentate chiral phosphine ligands of the Josiphos (1a, 1b) and Walphos (2a, 2b) families have been synthesized and fully characterized (1a: (R)-1-{(S-P)-2-[Bis[3,5-bis(trifluoromethyl) phenyl] phosphino] ferrocenyl} ethyldi(3,5-xylyl) phosphine, 1b: (R)-1-{(S-P)-2-[Di(2-furyl) phosphino] ferrocenyl} ethyldi-tert-butylphosphine, 2a: (R)-1-{(R-P)-2-[2-[Bis(4-methoxy-3,5-dimethylphenyl) phosphino] phenyl] ferrocenyl} ethylbis[3,5-bis(trifluoromethyl) phenyl] phosphine and 2b: (R)-1-{(R-P)-2-[2( Diphenylphosphino) phenyl] ferrocenyl} ethyldicyclohexylphosphine). The phosphine-substituted clusters were tested for hydrogenation of tiglic acid [trans-2-methyl-2-butenoic acid]. The catalytic reactions gave reasonable conversion rates (15-88 %) under relatively mild conditions but relatively moderate enantiomeric excesses (8-57 %) were observed. The crystal structures of [ReH(CO)(3)(1a)], [Re-2 (CO)(9)(2a)], [{Re-2(CO)(9)}(2)(2b)] and [Re-2(mu-H)(2)(CO)(6)(2b)] are presented.
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| 9. |
- Arafa, Wael A. A., et al.
(författare)
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ULTRASOUND-MEDIATED THREE-COMPONENT REACTION ON-WATER PROTOCOL FOR THE SYNTHESIS OF NOVEL MONO- AND BIS-1,3-THIAZIN-4-ONE DERIVATIVES
- 2017
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Ingår i: Heterocycles. - 0385-5414 .- 1881-0942. ; 94:8, s. 1439-1455
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Tidskriftsartikel (refereegranskat)abstract
- Green synthetic and catalyst-free strategy towards the synthesis of novel mono- and bis-1,3-thiazin-4-one scaffolds through a one pot, reaction of carbon disulfide, monoacetylenic esters and amines under ultrasonication has been reported. The merits of this protocol comprise no need for tedious workup steps and afforded the desired products in excellent yields make this synthetic protocol more efficient and worthy of further attentiveness. Moreover, the method exhibited excellent score in a number of green metrics.
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| 10. |
- Das, Biswanath, et al.
(författare)
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Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework
- 2016
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Ingår i: Dalton Transactions. - : ROYAL SOC CHEMISTRY. - 1477-9226 .- 1477-9234. ; 45:34, s. 13289-13293
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of two molecular iron complexes, a dinuclear iron(III,III) complex and a nonanuclear iron complex, based on the di-nucleating ligand 2,2-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)(3)](3+).
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| 11. |
- F. Abdel-Magied, Ahmed, et al.
(författare)
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Magnetic metal-organic frameworks for efficient removal of cadmium(II), and lead(II) from aqueous solution
- 2022
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier BV. - 2213-2929 .- 2213-3437. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Efficient and convenient methods for the removal of toxic heavy metal ions especially Cd(II) and Pb(II) from aqueous solutions is of great importance due to their serious threat to public health and the ecological system. In this study, two magnetic metal-organic frameworks (namely: Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2) were synthesized, fully characterized, and applied for the adsorption of Cd(II) and Pb(II) from aqueous solutions. The adsorption efficiencies for the prepared nanocomposites are strongly dependent on the pH of the aqueous solution. The maximum adsorption capacities of Fe3O4@UiO-66–NH2, and Fe3O4@ZIF-8 at pH 6.0 were calculated to be 714.3 mg·g−, and 370 mg·g−1 for Cd(II), respectively, and 833.3 mg·g−1, and 666.7 mg·g−1 for Pb(II), respectively. The adsorption process follows a pseudo-second-order model and fit the Langmuir isotherm model. Moreover, the thermodynamic studies revealed that the adsorption process is endothermic, and spontaneous in nature. A plausible adsorption mechanism was discussed in detail. The magnetic adsorbents: Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2 showed excellent reusability, maintaining the same efficiency for at least four consecutive cycles. These results reveal the potential use of magnetic Fe3O4@ZIF-8, and Fe3O4@UiO-66–NH2 as efficient adsorbents in removing Cd(II) and Pb(II) from aqueous solutions.
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| 12. |
- Iqbal, M. Naeem, et al.
(författare)
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Mesoporous Ruthenium Oxide : A Heterogeneous Catalyst for Water Oxidation
- 2017
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 5:11, s. 9651-9656
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Tidskriftsartikel (refereegranskat)abstract
- Herein we report the synthesis of mesoporous ruthenium oxide (MP-RuO2) using a template-based approach. The catalytic efficiency of the prepared MP-RuO2 was compared to commercially available ruthenium oxide nanoparticles (C-RuO2) as heterogeneous catalysts for water oxidation. The results demonstrated superior performance of MP-RuO2 for oxygen evolution compared to the C-RuO2 with respect to recyclability, amount of generated oxygen, and stability over several catalytic runs.
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| 13. |
- Rahaman, Ahibur, et al.
(författare)
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Chalcogenide-capped triiron clusters [Fe3(CO)9(μ3-E)2], [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) as proton-reduction catalysts
- 2019
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Ingår i: Journal of Organometallic Chemistry. - : Elsevier BV. - 0022-328X. ; 880, s. 213-222
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Tidskriftsartikel (refereegranskat)abstract
- Chalcogenide-capped triiron clusters [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe3(CO)9(μ3-E)2] are unaffected by strong acids. Mono-capped [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] react with HBF4.Et2O but changes in IR spectra are attributed to BF3 binding to the face-capping carbonyl, while bicapped [Fe3(CO)7(μ3-E)2(μ-dppm)] are protonated but in a process that is not catalytically important. DFT calculations are presented to support these protonation studies. Cyclic voltammetry shows that [Fe3(CO)9(μ3-Se)2] exhibits two reduction waves, and upon addition of strong acids, proton-reduction occurs at a range of potentials. Mono-chalcogenide clusters [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] (E = S, Se) exhibit proton-reduction at ca. -1.85 (E = S) and -1.62 V (E = Se) in the presence of p-toluene sulfonic acid (p-TsOH). Bicapped [Fe3(CO)7(μ3-E)2(μ-dppm)] undergo quasi-reversible reductions at -1.55 (E = S) and -1.45 V (E = Se) and reduce p-TsOH to hydrogen but protonated species do not appear to be catalytically important. Current uptake is seen at the first reduction potential in each case, showing that [Fe3(CO)7(μ3-E)2(μ-dppm)]- are catalytically active but a far greater response is seen at ca. -1.9 V being tentatively associated with reduction of [H2Fe3(CO)7(μ3-E)2(μ-dppm)]+. In general, selenide clusters are reduced at slightly lower potentials than sulfide analogues and show slightly higher current uptake under comparable conditions.
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| 14. |
- Rahaman, Ahibur, et al.
(författare)
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Phosphine addition to the sigma,pi-thienyl complex [Fe-2(CO)(6)(mu-Th)(mu-PTh2)] (Th = C4H3S): Carbonyl substitution and migratory carbonyl insertion to give the thienyl-acyl complexes [Fe-2(CO)(4)(diphosphine)(mu-O=C-Th)(mu-PTh2)]
- 2015
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Ingår i: Inorganica Chimica Acta. - : Elsevier BV. - 0020-1693. ; 430, s. 208-215
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Tidskriftsartikel (refereegranskat)abstract
- The reactivity of the sigma,pi-thienyl complex [Fe-2(CO)(6)(mu-Th)(mu-PTh2)] (1) towards a range of phosphines has been studied. With PR3 (R = Ph, Th) carbonyl substitution affords [Fe-2(CO)(5)(PR3)(mu-Th)(mu-PTh2)] (2ab) as the major product, with smaller amounts of the thienylacyl complexes [Fe-2(CO)(5)(PR3)(mu-O=C-Th)(mu-PTh2)] (3ab) resulting from a migratory carbonyl insertion into the thienyl ligand. With diphosphines, thienylacyl complexes are the major products in all cases. With dppm, [Fe-2(CO)(4)(mu-dppm)(mu-O=C-Th)(mu-PTh2)] (4) results in which the diphosphine bridges the ironiron bond, while with other diphosphines the chelate complexes [Fe-2(CO)(4)(kappa(2)-diphosphine)(mu-O=C-Th)(mu-PTh2)] (59) are isolated, as established through crystallographic studies on [Fe-2(CO)(4)(kappa(2)-dppe)(mu-O=C-Th)(mu-PTh2)] (5) and [Fe-2(CO)(4)(kappa(2)-dppb)(mu-O=C-Th)(mu-PTh2)] (9), both of which show that the diphosphine binds selectively to the oxygen-bound metal centre with phosphorus atoms lying trans to the metalmetal bond and mu-PTh2 bridge. With 1,2-bis(diphenylphosphino)benzene (dppb), [Fe-2(CO)(5){mu,kappa(2)-C6H4PPh(C6H4)PPh2}(mu-PTh2)] (10) is isolated in low yields and results from cyclometalation of a phenyl ring and putative elimination of thiophene. In a separate experiment, it has been shown that heating 9 results in the slow formation of 10. (C) 2015 Elsevier B.V. All rights reserved.
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| 15. |
- Shatskiy, Andrey, et al.
(författare)
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Catalyst-solvent interactions in a dinuclear Ru-based water oxidation catalyst
- 2016
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 45:47, s. 19024-19033
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic water oxidation represents a key process in conversion of solar energy into fuels and can be facilitated by the use of molecular transition metal-based catalysts. A novel straightforward approach for covalent linking of the catalytic units to other moieties is demonstrated by preparation of a dinuclear complex containing two [Ru(pdc)(pic)(3)]-derived units (pdc = 2,6-pyridinedicarboxylate, pic = 4-picoline). The activity of this complex towards chemical and photochemical oxidation of water was evaluated and a detailed insight is given into the interactions between the catalyst and acetonitrile, a common co-solvent employed to increase solubility of water oxidation catalysts. The solvent-induced transformations were studied by electrochemical and spectroscopic techniques and the relevant quantitative parameters were extracted.
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