Kinetics of the self-fouling oxidation of hydrogen sulfide on activated carbon

The method of obtaining a chemical adsorbent of ammonia and hydrogen sulfide is proposed to be modified to improve sorption characteristics. The dependence of the kinetics of the process was studied - crystallization of solutions of copper (II) sulfate with a concentration of 2.19 mol/dm3 and 2.38 mol/dm3 depending on the method of preparation of the impregnating solution: thermal with heating to a temperature of 80 - 90 °C, using ultrasonic oscillations with a frequency of 22 kHz and an intensity of 3.5 W/cm2, and the dependence of the studied thermal method with the additional introduction of 0.01% surfactants into the solution with nonionic, anionic and cationogenic properties. Crystallization of copper sulfate was performed using a probe video microscopy system. The formation of smaller crystals is observed upon cooling of the solutions subjected to ultrasound. The introduction of surfactants did not affect the size of the crystals of copper (II) sulfate. The dependence of the physicochemical properties of a solution of copper (II) sulfate at a concentration of 1.17 mol/dm3 and 2.26 mol/dm3 on the introduction of 0.01% surfactant and a change in the temperature of the solution was studied. It was found that the introduction of a surfactant can effectively reduce the surface tension of the solution at a temperature of 80 °C and reduce the contact angle of the solution of activated carbon granules. Impregnating solutions of copper (II) sulfate are prepared using the above methods and samples of a chemical adsorbent of ammonia and hydrogen sulfide are made by impregnating granular activated carbon with the obtained solutions. It is proved that the use of surfactants and ultrasonic vibrations during the preparation of an impregnating solution allows to increase the amount of active form of copper on the surface of the carrier during impregnation, which helps to increase the dynamic capacity of chemisorbents.

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Kinetics of the Oxidation of Hydrogen Sulfide by Atmospheric Oxygen in an Aqueous Medium

Journal of Atmospheric Science Research ◽

10.30564/jasr.v4i3.3465 ◽

2021 ◽

Vol 4 (3) ◽

Author(s):

Deepak Singh Rathore ◽

Vimlesh Kumar Meena ◽

Chandra Pal Singh Chandel ◽

Krishna Swarup Gupta

Keyword(s):

Hydrogen Sulfide ◽

Reaction Rate ◽

Dissociation Constants ◽

Atmospheric Oxygen ◽

Total Concentration ◽

Order Rate Constant ◽

Order Conditions ◽

Rate Law ◽

Oxidation Of Hydrogen ◽

Kinetics Of

Hydrogen sulfide is an important acid rain precursor and this led us to investigate the kinetics of its oxidation in aqueous phase by atmospheric oxygen. The kinetics was followed by measuring the depletion of oxygen in a reactor. The reaction was studied under pseudo order conditions with [H2S] in excess. The kinetics followed the rate law: -d[O2]/dt = k[S][O2]t (A) Where [S] represents the total concentration of hydrogen sulfide, [O2]t is the concentration of oxygen at time t and k is the second order rate constant. The equilibria (B - C) govern the dissolution of H2S; the sulfide ion in water forms different species: H2S K1 HS- + H+ (B) HS- K2 S2- + H+ (C) Where K1 and K2 are first and second dissociation constants of H2S. Although, H2S is present as undissociated H2S, HS- and S2- ions, nature of [H+ ] dependence of reaction rate required only HS- to be reactive and dominant. The rate law (A) on including [H+ ] dependence became Equation (D). -d[O2]/dt = k1K1[H+ ][S][O2]t / ([H+ ] 2 + K1[H+ ] + K1K2) (D) Our results indicate anthropogenic VOCs such as acetanilide, benzene, ethanol, aniline, toluene, benzamide, o-xylene, m-xylene, p-xylene and anisole to have no significant effect on the reaction rate and any observed small effect is within the uncertainty of the rate measurements.

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