Oxidation Of Ammonium Sulfite Research Articles

Electrophoretic Deposition of Nanoparticles as Electrocatalysts for Electrolysis in the Solar Sulfur Ammonia Hydrogen Production

Cobalt ferrite nanoparticles were deposited using electrophoretic deposition from two different bath chemistries, 90 vol.% water and 10 vol.% isopropanol with hexadecyltrimethlyammonium bromide (CTAB) and 100 % ethanol. The deposits were tested for electrocatalytic activity for the oxidation of ammonium sulfite to ammonium sulfate as part of a solar sulfur ammonia thermochemical cycle to produce hydrogen.

Generation of Reactive Oxygen Species by Surface Discharge Plasma for Enhancing the Oxidation of Ammonium Sulfite

Surface discharge plasma was used to activate air to produce reactive oxygen species (ROS) for promoting the oxidation of ammonium sulfite by air forced oxidation method. The effect of applied voltage and the air speed in discharge reactor on the generation of ozone as well as the oxidation kinetic of ammonium sulfite were analyzed and discussed. The ozone concentration increased with the discharge voltage, but decreased with the air speed, and a maximum mass of generated ozone was obtained at air speed of 15 m/s. Compared with air forced oxidation, the oxidation kinetic constant of ammonium sulfite by ROS injection had an increase by 2.67-fold, and the oxidation of ammonium sulfite followed a pseudo zero order kinetics. An increase in air speed accelerated the oxidation of ammonium sulfite, and the oxidation kinetic constant of ammonium sulfite was increased by 5-fold when the air speed increased by 2-fold.

Oxidation of ammonium sulfite by oxygen in a microporous tube-in-tube microchannel reactor

Abstract The homogeneous catalytic oxidation of ammonium sulfite in a microporous tube-in-tube microchannel reactor (MTMCR) was studied in this paper. It was found that the oxidation rate of ammonium sulfite in the MTMCR is 360 times higher than that in a packing column and could be further boosted about 4–6 times by the Co 2+ catalyst. The effects of different operating parameters on the oxidation of ammonium sulfite were investigated. Experimental results indicated that the oxidation ratio of ammonium sulfite increased with the increase of the oxygen volumetric flow rate, but decreased with the increase of the liquid volumetric flow rate and sulfite concentration, and a smaller micropore size and annular channel width resulted in a higher oxidation ratio of ammonium sulfite. The oxidation ratio reached 80% under the optimum operating conditions in the catalytic oxidation process. This study reveals that the MTMCR is a potential intensification device for the oxidation process of ammonium sulfite.

Oxidation of ammonium sulfite by a multi-needle-to-plate gas phase pulsed corona discharge reactor

The oxidation of ammonium sulfite in the ammonia-based flue gas desulfurization (FGD) process was investigated in a multi-needle-to-plate gas phase pulsed corona discharge reactor in this paper. The effect of several parameters, including capacitance and peak pulse voltage of discharge system, electrode gap and bubbling gas flow rate on the oxidation rate of ammonium sulfite was reviewed. The oxidation rate of ammonium sulfite could reach 47.2% at the capacitance, the peak pulse voltage, electrode gap and bubbling gas flow rate equal to 2 nF, −24.6 k V, 35 mm and 4 L min−1 within treatment time of 40 min The experimental results indicate that the gas phase pulsed discharge system with a multi-needle-to-plate electrode can oxide the ammonium sulfite. The oxidation rate increased with the applied capacitance and peak pulse voltage and decreased with the electrode gap. As the bubbling gas flow rate increased, the oxidation rate increased first and then tended to reach a stationary value. These results would be important for the process optimization of the (NH4)2SO3 to (NH4)2SO4 oxidation.

Oxidation of ammonium sulfite in aqueous solutions using ozone technology

How to deal with unstable ammonium sulfite, the byproduct of flue gas desulfuration by ammonia absorption methods, has been a difficult problem in recent years. Oxidation of ammonium sulfite in aqueous solutions using ozone produced by a surface discharge system was investigated in the paper. The oxidation efficiency of ammonium sulfite by ozone and traditional air aeration were compared, and the factors including ozone concentration, gas flow rate, initial concentration of ammonium sulfite solution and reaction temperature were discussed. The results show that the oxidation efficiency of ammonium sulfite by ozone technology reached nearly 100% under the optimum conditions, which had a significant increase compared with that by air aeration.

A pilot investigation on oxidation of ammonium sulfite by streamer corona plasma

Abstract For ammonia flue gas desulfurization (FGD), the sulfite to sulfate oxidation is very critical for industrial applications. This paper reports a novel corona plasma-induced oxidation technique to convert concentrated ammonium sulfites to sulfates in an aqueous solution. The streamer corona plasmas are generated with a dc superimposed ac power source. Ammonium sulfite solution is sprayed in a reactor by using two-phase nozzles. When the sulfite concentration is around 1–3 mol L −1 , the oxidation efficiency after one-cycle processing is in the range of 20–60%. Multiple-cycle treatments can be used to improve the oxidation efficiency. The energy consumption is around 20 Wh mol −1 . Based on the present investigations, we anticipate that an industrial plasma-assisted ammonium FGD can be applied in industries.

Oxidation of Ammonium Sulfite in Aqueous Solutions with Streamer Plasmas

A streamer corona plasma induced oxidation technique, which used the so called AC/DC power supply to convert high concentration ammonium sulfite to sulfate, was reported. The results showed that the sulfite oxidation rate was significantly higher than that in the forced air oxidation process. Research on how to use streamer discharge plasmas to oxidize high concentration ammonium sulfite in the liquid phase has obtained remarkable progress. On the basis of the experiment results, the following conclusions could be arrived: (1) In contrast to the plasma-induced oxidation, the spontaneous oxidations made negligible contributions to convert sulfite to sulfate. (2) When the initial sulfite concentration was within 1–3 mol·L −1, plasma induced one-cycle oxidation efficiency was in the range of 20%–60%. The oxidation rate was faster than that at concentration less than 1 mol·L −1. To make the technique industrially applicable, the plasma induced oxidation process should be performed under the initial concentration more than 1 mol·L −1. (3) With the increase of the power density, the molar energy consumption of ammonium sulfite oxidation increased faster than the oxidation efficiency did, which indicated that radical-radical termination reactions dominated the process.