Solid complexes of carbon and sulphur—I. Sulphurised polymer carbons

Blayden, H. E.; Patrick, John W.

doi:10.1016/0008-6223(67)90030-9

Cited by 36 publications

(10 citation statements)

References 21 publications

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“…AC's existing atoms (e.g., sulfur, oxygen, hydrogen), functional groups, and unsaturated sites impact the effectiveness of sulfur impregnation (Puri and Hazra, 1971). At 600°C, impregnated sulfur can substitute onto existing functionalities, bond to unsaturated carbon atoms, or occupy activated sites due to carbon degradation during extended thermal treatment, as was shown using H 2 S, CS 2 , or SO 2 gases (Puri and Hazra, 1971;Blayden and Patrick, 1967). These reactions form organic sulfur on the AC surface.…”

Section: Sulfur Impregnation At 600°cmentioning

confidence: 99%

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Hsi

Rood

Rostam-Abadi

et al. 2013

Aerosol Air Qual. Res.

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The influences of sulfur, HNO 3 , and thermal treatments on the properties and Hg adsorption of activated carbon (AC) derived from bituminous coals were evaluated. These ACs were impregnated with either polysulfide or elemental sulfur at 120, 200, and 600°C. Additional ACs were treated with HNO 3 at 95°C to incorporate oxygen functionalities, and then subjected to temperature-programmed desorption to 950°C to remove surface oxygen groups and create nascent active sites on the AC surface. Polysulfide and elemental sulfur impregnation at < 200°C did not improve Hg 0 adsorption. However, improvement in HgCl 2 adsorption by up to 97% was observed. Elemental sulfur impregnation at 600°C enhanced Hg 0 and HgCl 2 adsorption by up to 42% and 404%, respectively, for ACs derived from a low-organic-sulfur coal. Improvements in Hg 0 adsorption for ACs from high-organic-sulfur coals were not observed after sulfur impregnation. HNO 3 and thermal treatments reduced Hg-active groups such as sulfur. Oxygen surface groups and the nascent carbon sites appeared to be more reactive towards other flue gas components than Hg, because HNO 3 and thermal treatments led to a reduction in Hg 0 and HgCl 2 adsorption. These results suggest that AC's physical and chemical properties after sulfur treatment influence Hg 0 adsorption, while HgCl 2 adsorption is mainly affected by AC's chemical characteristics.

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Section: Sulfur Impregnation At 600°cmentioning

confidence: 99%

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Hsi

Rood

Rostam-Abadi

et al. 2013

Aerosol Air Qual. Res.

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“…The reduction to elemental sulfur is an especially attractive alternative because the product is easy to handle and stock, and has a high commercial value . When heating different carbons with sulfur, hydrogen sulfide, carbon disulfide or sulfur dioxide, highly stable superficial C–S complexes have been observed that change the carbon's reactivity…”

Section: Introductionmentioning

confidence: 99%

Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons

Humeres

Moreira

2012

J of Physical Organic Chem

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Surface‐science studies of some reactions have allowed postulating the mechanisms using a variety of techniques. The surface chemistry of Group IV elements has been particularly studied recently because Si, Ge, and C are semiconductors, and the surface organic chemistry to functionalize these elements has seen immense progress in recent years. In this review article we describe the methodology used to study the mechanism of a solid–gas reaction, the reduction of SO2 on carbons, and the necessary conditions that allowed the measurement of the solid conversion and product distribution when the kinetics was chemically controlled and the reaction had reached the steady state. The reaction was first‐order with respect to SO2 and with respect to carbon and the stoichiometry was determined from the product distribution. The reaction proceeds through two thermally stable reaction intermediates bound to the surface, a six‐membered ring 1,3,2‐dioxathiolane and a five‐membered ring 1,2‐oxathietene 2‐oxide or γ‐sultine, both species being in equilibrium. The reaction was shown to be reversible. The primary product is an episulfide that, after a series of consecutive reactions of atomic sulfur, is able to free sulfur. The reactivity of the intermediates and the episulfide was studied for several reactions and consistent mechanisms were postulated from the X‐ray photoelectron spectroscopy and solid state nuclear magnetic resonance spectra. Aminolysis and the reaction with alkyl halides resulted on the insertion of the alkyl moiety in the episulfide primary product, while the thiolysis and photolytic alcoholysis resulted in the insertion of the alkyl moiety in the oxidized intermediates. Copyright © 2012 John Wiley & Sons, Ltd.

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“…When different carbons are heated in the presence of sulfur, H 2 S, CS 2 or SO 2 , surface complexes have been observed [4][5][6][7] that change the reactivity of the carbon [8]. Several mechanistic proposals have postulated that these surface complexes could act as intermediates, but without any experimental evidence [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

Humeres

Peruch

Moreira

et al. 2005

IJMS

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Abstract. The reduction of SO2 on different carbons in the presence of the nitrates and sulfides of sodium, potassium and calcium and potassium polysulfides was studied. The presence of salts increased the initial rate 2-5 fold for all of them and did not change the product distribution. The catalysis was not determined by the cation and there was no difference in the catalytic reactivity between nitrates and sulfides. The sulfur content of the activated carbon increased during the reaction on account of the stable reactive intermediates in the reduction of SO2. In the presence of NaNO3 or Na2S, the amount of sulfur incorporated was in the molar ratio Na:S = 3 Ã‚Â± 0.3, and the XPS spectra of the residual carbon showed an increase of ca. 9% of the non-oxidized form of sulfur in the intermediates. In the absence of salt, it is proposed that after the adsorption of SO2 on the carbon, a 1,3,2-dioxathiolane or 1,2-oxathietene 2-oxide are formed and that decompose to produce CO2 and atomic sulfur. The non-oxidized sulfur intermediate would be an episulfide 3, formed from the reaction of the atomic sulfur with the nearest double bond and followed by consecutive reactions of insertion of atomic sulfur to form a trisulfide. Extrusion of S2 from the trisulfide would regenerate the episulfide, establishing a sulfidedisulfide-trisulfide equilibrium that worked as a capture-release cycle of sulfur. In the presence of salt, the results are consistent with the assumption that the episulfide 3 reacts with the corresponding sulfide anion to form a disulfide anion, which upon reaction with atomic sulfur forms a trisulfide anion that decomposes releasing diatomic sulfur S2, transporting the sulfur and generating a thiolate that is part of the catalytic cycle

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Solid complexes of carbon and sulphur—I. Sulphurised polymer carbons

Cited by 36 publications

References 21 publications

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons

Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

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Solid complexes of carbon and sulphur—I. Sulphurised polymer carbons

Cited by 36 publications

References 21 publications

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Effects of Sulfur, Nitric Acid, and Thermal Treatments on the Properties and Mercury Adsorption of Activated Carbons from Bituminous Coals

Kinetics and mechanisms in flow systems: reduction of SO2 on carbons

Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

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Product

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Kinetics and mechanisms in flow systems: reduction of SO₂ on carbons