The potential mechanism of potassium promoting effect in the removal of COS over K/NiAlO mixed oxides

Zhao, Shunzheng; Tang, Xiaolong; Miao, He; Yi, Honghong; Gao, Feifei; Wang, Jiangen; Huang, Yonghai; Yang, Zhongyu

doi:10.1016/j.seppur.2017.10.032

Cited by 23 publications

(8 citation statements)

References 33 publications

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“…According to the previous studies, , COS can combine with OH – groups on the surface of the catalyst to form HSCO 2 – , which could be further decomposed into H 2 S and CO 2 . In addition, the gaseous water adsorbed on the metal oxide surface will partially supplement the hydroxyl (OH – groups) consumed in the COS hydrolysis process to form HSCO 2 – .…”

Section: Resultsmentioning

confidence: 97%

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Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Zhang

et al. 2021

Ind. Eng. Chem. Res.

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A new method for delaying or avoiding catalyst poisoning in COS catalytic hydrolysis was found by using one of the existing gas components in blast furnace flue gas: CO. In this work, wood-based activated carbon (AC) catalysts were prepared, and the experimental results of COS catalytic hydrolysis showed that 10% Ni/AC could completely hydrolyze COS in a N2 atmosphere within 380 min, while there was no obvious deactivation within 1200 min in a CO atmosphere. The corresponding characterization showed that the oxidation process of H2S to sulfate (SO4 2–) was inhibited, and it was easier to desorb from the catalyst surface in a CO atmosphere. Obvious electron transfer occurred on the catalyst surface, and the enrichment and conversion of sulfate (SO4 2–) on the catalyst surface were inhibited. The excellent durability in CO can be attributed to the inhibition of sulfate formation by the presence of CO and the supplement of hydroxyl consumed on the catalyst surface by the presence of H2O, which is the key factor to inhibit the poisoning or deactivation of the catalyst in COS hydrolysis.

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Section: Resultsmentioning

confidence: 97%

“…So far, hydrolysis catalysts are based on alkaline earth metal oxides, , activated carbon, , and hydrotalcite-like compounds. In a previous study, modified AC catalysts at low temperatures (<80 °C) showed high hydrolysis efficiencies .…”

Section: Introductionmentioning

confidence: 99%

Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Zhang

et al. 2021

Ind. Eng. Chem. Res.

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“…The highest peak intensity was observed for K 0.2 Ti 0.5 Al, indicating that this sample had the strongest CO 2 affinity, which further proved its highest basicity. 33 During the temperature-programmed desorption, bicarbonate signals disappeared by 200 °C, and traces of carbonates were detected up to 300 °C. Based on the thermal properties of the adsorbates formed upon CO 2 adsorption, the basicity, especially weak and moderate basicity, was improved remarkably by K/Na-doping as expected.…”

Section: Resultsmentioning

confidence: 99%

Contribution of Na/K Doping to the Activity and Mechanism of Low-Temperature COS Hydrolysis over TiO₂-Al₂O₃ Based Catalyst in Blast Furnace Gas

Liu

Shen

et al. 2022

ACS Omega

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As an organic sulfur pollutant generated in blast furnace gas, carbonyl sulfide (COS) has attracted more attention due to its negative effects on the environment and economy. The TiO 2 -Al 2 O 3 composite metal oxide (Ti 0.5 Al) with uniformly dispersed particles was prepared by the co-precipitation method. And on this basis, a series of Na/K-doped catalysts were prepared separately. The activity evaluation results showed that the introduction of Na/K significantly improved the low-temperature COS hydrolysis activity, which exhibited a COS conversion of 98% and H 2 S yield of 95% at 75 °C with 24,000 h –1 . And K showed a better promoting effect than Na. Brunauer–Emmett–Teller (BET) results revealed the increased mesopore proportion of Na/K-modified catalysts. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that Na and K formed prismatic and nanorod-like structures, respectively. More weakly basic sites with enhanced intensity and decreased O ads /O lat content contributed to the excellent catalytic activity, as certified by the results of CO 2 temperature-programmed desorption (CO 2 -TPD) and X-ray photoelectron spectroscopy (XPS). It was also proposed that the decrease of weakly basic sites ultimately deactivated catalyst activity. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) showed that the introduction of Na/K enhanced the dissociation of H 2 O, and the generated abundant hydroxyl groups promoted the adsorption of COS and formed surface transition species, such as HSCO 2 – and HCO 3 – .

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“…Promotion with potassium determined a dramatic improvement in activity. 31 Modification of the catalyst with the appropriate amount of KOH and K 2 CO 3 allowed outstanding performances when compared to the undoped samples, while KCl and KNO 3 were found not suitable for this application, as they decrease the desulfurization efficiency. In particular, they suggested that K 2 CO 3 is decomposed on the catalyst surface in K 2 O; it enhances the catalytic activity because of its electron donation, which can improve the Lewis basicity of Ni atoms.…”

Section: Low-temperature Cos Hydrolysismentioning

confidence: 97%

“…The characterization analyses demonstrated that Al doping of the HTO determined the presence of abundant surface basic sites; moreover, in Ni3Al-HTO, there was a striking reduction of Ni 2+ by Al doping in NiO, which suggested a large amount of oxygen vacancies. Promotion with potassium determined a dramatic improvement in activity . Modification of the catalyst with the appropriate amount of KOH and K 2 CO 3 allowed outstanding performances when compared to the undoped samples, while KCl and KNO 3 were found not suitable for this application, as they decrease the desulfurization efficiency.…”

Section: Low-temperature Cos Hydrolysismentioning

confidence: 99%

Recent Solutions for Efficient Carbonyl Sulfide Hydrolysis: A Review

Renda

Barba

Palma

2022

Ind. Eng. Chem. Res.

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Carbonyl sulfide (molecular formula COS) is the most abundant organic sulfur compound present in the atmosphere, and its removal to satisfy the worldwide limitations on emissions of injurious substances is one of the challenging issues in the desulfurization technologies scenario. The hydrolysis of carbonyl sulfide can be addressed as a new frontier in the removal of sulfur compounds. The interest toward this process arose significantly in the past 20 years, mainly because of the new regulations on harmful gases emissions and because of the exploitation of fossil fuels with higher sulfur content. According to the current literature, COS hydrolysis can be performed as low-temperature and high-temperature processes, giving rise to the establishment of different mechanisms and phenomena. Through a detailed analysis of the recent advances in the field, low-temperature hydrolysis was identified as the most promising alternative for the industrial scenario. To overcome the kinetic limitations, the modification of alumina-based catalysts having enhanced porous structures with electron-donating substituents (such as alkaline and alkaline-earth metals) was found particularly effective, since hydrolysis has been identified as a base-catalyzed reaction. In addition, in this process, hydrotalcite and hydrotalcite-like materials find a satisfactory application. Due to the strongly limited kinetics, the adsorption of the components of the reaction mixtures is controlling, and therefore, the most credited reaction mechanism is described through a Langmuir–Hinshelwood model. Despite the strong appeal of the process, industrial applications still involve mainly high-temperature hydrolysis; indeed, most of the recent patents report operating temperatures in the range of 100–300 °C.

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The potential mechanism of potassium promoting effect in the removal of COS over K/NiAlO mixed oxides

Cited by 23 publications

References 33 publications

Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Contribution of Na/K Doping to the Activity and Mechanism of Low-Temperature COS Hydrolysis over TiO₂-Al₂O₃ Based Catalyst in Blast Furnace Gas

Recent Solutions for Efficient Carbonyl Sulfide Hydrolysis: A Review

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The potential mechanism of potassium promoting effect in the removal of COS over K/NiAlO mixed oxides

Cited by 23 publications

References 33 publications

Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Inhibition of CO in Blast Furnace Flue Gas on Poisoning and Deactivation of a Ni/Activated Carbon Catalyst in COS Hydrolysis

Contribution of Na/K Doping to the Activity and Mechanism of Low-Temperature COS Hydrolysis over TiO2-Al2O3 Based Catalyst in Blast Furnace Gas

Recent Solutions for Efficient Carbonyl Sulfide Hydrolysis: A Review

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Contribution of Na/K Doping to the Activity and Mechanism of Low-Temperature COS Hydrolysis over TiO₂-Al₂O₃ Based Catalyst in Blast Furnace Gas