Proposed mechanisms for the removal of nitrate from water by platinum catalysts supported on polyaniline and polypyrrole

García-Fernández, Mariano; Pastor-Blas, M. Mercedes; Epron, Florence; Sepúlveda-Escribano, A.

doi:10.1016/j.apcatb.2017.11.064

Cited by 48 publications

(14 citation statements)

References 30 publications

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“…To prepare the supported platinum catalysts, the hybrid titania/polymer materials were impregnated with hexachloroplatinic acid (H 2 PtCl 6 ) in a first step. As a result, a chloroplatinum complex anchors to the N functionalities of the polymeric chain, as it has been previously reported . During the formation of the coordination compound, Pt 4+ from H 2 PtCl 6 is partially reduced to Pt 2+ .…”

Section: Resultssupporting

confidence: 56%

“…As a result, a chloroplatinum complex anchors to the N functionalities of the polymeric chain, as it has been previously reported. 67 During the formation of the coordination compound, Pt 4+ from H 2 PtCl 6 is partially reduced to Pt 2+ . The reduction of platinum ion is produced by the electrons coming from the polymeric chain through the N functionality (Scheme 3a-b).This is more evident in the composite with PANI, where only Pt 2+ is detected after the impregnation of the material with H 2 PtCl 6 ( Figure 8a), and this is accompanied by an increase in the amount of N + functionalities (Figure 5a).…”

Section: Materials Characterizationmentioning

confidence: 99%

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confidence: 99%

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Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

et al. 2019

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Materials able to produce the reduction of nitrate from water without the need of a metal catalyst and with avoiding the use of gaseous hydrogen have been developed by combining the synergistic properties of titania and two conducting polymers. Polymerization of aniline and pyrrol on titanium dioxide in the presence of two different oxidants/dopants (iron trichloride or potassium persulfate) has been evaluated. The resulting hybrid materials have good thermal stability imparted by the titania counterpart, and a considerable conductivity provided by the conducting polymers. The capability of the hybrid materials of reducing aqueous nitrate has been assessed and compared to the catalytic hydrogenation of nitrate using a platinum catalyst supported on these hybrid synthesized materials. The mechanism of nitrate abatement implies adsorption of nitrate on the polymer by ion exchange with the dopant anion, followed by the reduction of nitrate. The electron transfer from titania to the conducting polymer in the hybrid material favors the reductive ability of the polymer, in such a way that nitrate is selectively reduced with a very low production of undesirable side products. The obtained results show that the activity and selectivity of the catalytic reduction of nitrate with dihydrogen in the presence of a platinum catalyst supported on the hybrid materials are considerably lower than those of the metal-free nanocomposites.

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Section: Resultssupporting

confidence: 56%

Section: Materials Characterizationmentioning

confidence: 99%

mentioning

confidence: 99%

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Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

et al. 2019

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“…The anchoring of Mo-containing active species onto a suitable organic "support" might retain their high selectivity while endowing an extra catalytic performance derived from the organic "support". Notably, polyaniline (PAN) has recently received particular interest in catalytic applications as a heterogeneous organic support owing to its facile synthesis, air-stable performance, good dispersion of active species, and the pseudo-homogeneous character in organic solvents [20,[37][38][39][40][41][42][43][44]. In our group, we found that the functionalized PANs exhibited promising catalytic performance towards the dehydration of fructose into furans [45][46][47].…”

Section: Introductionmentioning

confidence: 94%

One-Pot Synthesis of 2,5-Diformylfuran from Fructose by Bifunctional Polyaniline-Supported Heteropolyacid Hybrid Catalysts

Liu

Dai

et al. 2019

Catalysts

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We report the preparation of bifunctional hybrid catalysts by supporting H3PMo12O40 (PMo12) heteropolyacid (HPA) on polyaniline (PAN) or formyl-functionalized PAN (F-PAN) for the “one-pot” and “one-step” synthesis of 2,5-diformylfuran (DFF) from fructose via 5-hydroxymethylfurfural (HMF) intermediate. We show that the PMo12 HPA is the main active species for both fructose dehydration and HMF oxidation owing to its Brønsted acidic and redox characters. However, the anchoring of PMo12 on PAN reduces the Brønsted acidity by acid–base interaction between protons in HPA and quinoid diimine structure in PAN, thereby reducing the dehydration performance. We demonstrate that the catalytic dehydration performance of the hybrid catalyst could be strengthened by grafting formyl groups on PAN before HPA anchoring. The highest DFF yield of 76.7% is obtained by conducting the “one-pot” reaction over the 40-PMo12/F3-PAN catalyst at 413 K for 7 h in air, wherein the side-reactions of fructose or HMF degradation and HMF rehydration have been significantly reduced. This hybrid catalyst is reusable without significant activity loss, highlighting the designing of stable inorganic–organic hybrid catalysts for producing valuable hexose-derived platform chemicals.

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“…PPy has been directly polymerized on activated carbon surfaces to effectively remove anions from water [8,20]. PPy has mainly been used to treat water to remove NO 3 − [21,22], F − [23,24], and SO 4 2− [9,25]. Polymerization of Py can equally occur at the α and β positions, so PPy grows in three dimensions during polymerization [26,27].…”

Section: Introductionmentioning

confidence: 99%

Effect of Sodium Benzenesulfonate on SO₄²⁻ Removal from Water by Polypyrrole‐Modified Activated Carbon

Zhang

Wang

Yang

et al. 2021

Advances in Materials Science and Engineering

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Sodium benzenesulfonate was doped into polypyrrole-modified granular activated carbon (pyrrole-FeCl3·(6H2O)-sodium benzenesulfonate-granular activated carbon; PFB-GAC) with the goal of improving the modified GAC’s ability to adsorb sulfate from aqueous solutions. At a GAC dosage of 2.5 g and a pyrrole concentration of 1 mol L−1, the adsorption capacity of PFB-GAC prepared using a pyrrole:FeCl3·(6H2O):sodium benzenesulfonate ratio of 1000 : 1500 : 1 reached 23.05 mg g−1, which was eight times higher than that for GAC and two times higher than that for polypyrrole-modified GAC without sodium benzenesulfonate. Adsorption was favored under acidic conditions and high initial sulfate concentrations. Doping with sodium benzenesulfonate facilitated polymerization to give polypyrrole. Sodium benzenesulfonate introduced more imino groups to the polypyrrole coating, and the N+ sites improved ion exchange of Cl− and SO42− and increased the adsorption capacity of sulfate. Adsorption to the PFB-GAC followed pseudo-second-order kinetics. The adsorption isotherm conformed to the Langmuir model, and adsorption was exothermic. Regeneration using a weak alkali (NH3·H2O), which released OH− slowly, caused less damage to the polypyrrole than using a strong alkali (NaOH) as the regeneration reagent. NH3·H2O at a concentration of 12 mol L−1 (with the same OH− concentration as 2 mol L−1 NaOH) released 85% of the sorbed sulfate in the first adsorption-desorption cycle, and the adsorption capacity remained >6 mg g−1after five adsorption-desorption cycles.

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Proposed mechanisms for the removal of nitrate from water by platinum catalysts supported on polyaniline and polypyrrole

Cited by 48 publications

References 30 publications

Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

One-Pot Synthesis of 2,5-Diformylfuran from Fructose by Bifunctional Polyaniline-Supported Heteropolyacid Hybrid Catalysts

Effect of Sodium Benzenesulfonate on SO₄²⁻ Removal from Water by Polypyrrole‐Modified Activated Carbon

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Proposed mechanisms for the removal of nitrate from water by platinum catalysts supported on polyaniline and polypyrrole

Cited by 48 publications

References 30 publications

Conducting Polymer–TiO2Hybrid Materials: Application in the Removal of Nitrates from Water

Conducting Polymer–TiO2Hybrid Materials: Application in the Removal of Nitrates from Water

One-Pot Synthesis of 2,5-Diformylfuran from Fructose by Bifunctional Polyaniline-Supported Heteropolyacid Hybrid Catalysts

Effect of Sodium Benzenesulfonate on SO42− Removal from Water by Polypyrrole‐Modified Activated Carbon

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Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

Conducting Polymer–TiO₂Hybrid Materials: Application in the Removal of Nitrates from Water

Effect of Sodium Benzenesulfonate on SO₄²⁻ Removal from Water by Polypyrrole‐Modified Activated Carbon