Sorption Of Sulfur Dioxide Research Articles

Efficacy and sorption of sulfur dioxide as a fumigant for control of navel orangeworm (Amyelois transitella) on stored pistachios

Sulfur dioxide (SO2) fumigation was evaluated for postharvest control of navel orangeworm (NOW), Amyelois transitella, on stored pistachios in a laboratory study. Sorption of SO2 on pistachios were measured at 5, 15, and 25 °C. Because of rapid sorption of SO2 on pistachios after SO2 injection, 3 h short fumigations were used to determine effective treatments against NOW eggs, larvae, and pupae. SO2 fumigation was effective against all of the life stages tested. However, large larvae in infested pistachios were most tolerant and eggs were most susceptible to SO2 fumigation. Smaller larvae were more susceptible to SO2 fumigation than larger larvae. Complete controls of eggs, larvae, and pupae were achieved in 3 h fumigations with 0.2, 2.0, and 1.0% SO2, respectively. Large SO2 fumigation trials each with 4.5 kg pistachios were conducted in a 19.8L chamber and complete control of 6th instar larvae were achieved in 3 h fumigation with about 1.6–1.8% SO2 at ambient temperatures of 18–21 °C. The results showed that SO2 fumigation has potential to control NOW on stored pistachios as well as to control other postharvest pests on stored products.

Evaluation of factors affecting the sorption of sulfur dioxide by FIBAN fibrous anion exchangers

The sorption of sulfur dioxide from the air by the fibrous anion exchangers containing amino groups of different structure and basicity has been comparatively investigated. The most effective sorbents of sulfur dioxide are the anion exchangers with ternary amino groups, which have a high exchange capacity (more than 5 meq/g) and additionally contain secondary amino groups. The anion exchangers with high-base amino groups absorb sulfur dioxide at low relative humidity (30 %) but have low dynamic sorption capicity (up to 1.3 meq/g). The anion exchangers with primary and secondary amino groups absorb sulfur dioxide at high relative humidity (more than 54 %) if their cation exchange capacity is several times less than the anion exchange capacity.

Peculiarities of sulfur dioxide sorption from air by weak base anion exchangers

Peculiarities of sulfur dioxide sorption from air by weak base anion exchangers

SO 2 sorption properties of fly ash zeolites.

In the presented study, the sulfur dioxide sorption properties of fly ash zeolite X were investigated. Sorption tests were performed on fly ash zeolite samples that were not prepared specially for sorption, in addition to dried samples and samples in the presence of water vapor. The samples saturated with water vapor showed the highest sorption capacity. The sorption capacity of the samples additionally dried prior to the sorption experiment was higher than that of the samples that were not specially prepared for the sorption test. Regeneration tests indicated relatively good regeneration properties. The obtained results were described with the use of Langmuir, Sips, and Dubinin–Astakhov models, with the Dubinin–Astakhov model providing the best fit.

The influence of binders for the pelletization of fly ash zeolites on sulfur dioxide sorption properties

AbstractFly ash zeolites are economically and ecologically attractive alternatives to synthetic and natural zeolites. Their use as sulfur dioxide sorbents is one of the possible applications of these materials. During the process of fly ash zeolite synthesis, a light powder is formed, which is not acceptable in practical applications due to technical problems, such as a marked drop in pressure, diffusion limits, hydraulic resistance, clogging in the packed beds and the possibility of losing a bed. It is therefore necessary to perform a pelletization process. Thickening of the material during pelletization influences sorption capacity negatively due to diffusing limitations, while the lack of an additional binder may result in a material of low mechanical durability. In this study, pressure pelletization experiments with fly ash zeolite were performed. Binders were selected on the basis of economic considerations as well as their potential to exert a positive influence on the sorption properties of the produced pellets. Cyclic sorption experiments were conducted (on sulfur dioxide) in which one zeolite powder sample was subjected to pelletization without a binder and another sample was subjected to the process with selected binders added. The results of the experiments were then analysed to ascertain the influence of the pelletization process on sulfur dioxide sorption capacity.

Synthesis of zeolites from fly ash with the use of modified two-step hydrothermal method and preliminary SO2 sorption tests

Synthesis of zeolites from fly ash is an ecologically justified process aimed at the transformation of energy sector waste – fly ash into microcrystalline zeolites of broad possible application field. In this study, the synthesis of zeolites from fly ash by using a modified two-step synthesis was presented. The aim of such a planned experiment was to use the waste solutions from previous synthesis, in such a way that minimalization of negative influence of post-synthesis wastes on environment was possible. Received materials were tested for its sulfur dioxide sorption capacity, indicating its future possible application to capture SO2 from exhaust gases.

Ni-Carbon Mineral Sorbent - Catalyst of Sulfur Dioxide Sorption

The morphology and structure of Ni-carbon mineral sorbent-catalysts on the basis of local mineral raw material were studied by methods of thermoprogrammed desorption and electron microscopy. The specific<br />surface, filamentary carbon diameter sizes and sorption characteristics of sulfur dioxide adsorption were determined. It was shown that the adsorption capacity of carboncontaining sorbents is influenced by: nature of metals of varying valence, specific surface and density of patterns. Physical and chemical sorption of sulfur dioxide was shown experimentally.

CHEMISORPTION OF SULFUR DIOXIDE BY POLYETHYLENE POLYAMINE IMPREGNATED FIBROUS MATERIALS. 2. THE STUDY OF WATER VAPOR INFLUENCE ON PREADSORBTION SO2 CHEMISORPTION BY FIBROUS MATE RIALS

Sulfur dioxide sorption by artificial and synthetic fibers as well as needlepunched nonwoven fibrous materials (IVHS-PEPA) impregnated with polyethylene polyamine (PEPA) under static and dynamic conditions has been investigated. It was found that when the vapor H2O and SO2 were present together the adsorption on the surface of the initial fiber had the competitive character, wherein the polar water molecules through hydrogen bonds to block the active sites of the fibers resulting in reduced absorption of sulfur dioxide in comparison with dry samples, throughout the range of values of the relative water vapor pressure ( р/рs = 0÷0,92). It was found that the process of chemisorption of SO2 IVHS-PEPA occurs only in the presence of «free» water. It is shown that the import-substituting IVHS-PEPA based lavsan fibers are not inferior to the protective characteristics of the best foreign fibrous chemisorbents brand VION.

Investigation of the pore blockage of a Brazilian dolomite during the sulfation reaction

The influence of the temperature and reaction time on the sulfation process of a dolomite is investigated in this paper. The sulfation effectiveness was evaluated and correlated with changes in the physical characteristics of a Brazilian dolomite during the reactive process. Calcination and sulfation experiments were performed under isothermal conditions for dolomite samples with average particle sizes of 545μm at temperatures of 750°C, 850°C and 950°C at different times of sulfation. Thermogravimetric tests were applied to establish the reactivity variation of the dolomite in function of the time in the sulfation reaction and evaluate the methodology of the samples preparation. Porosimetry tests were performed to study the pore blockage of dolomite during the sulfation reaction. The highest values of BET surface area were 25.55m2/g, 29.55m2/g and 12.62m2/g for calcined samples and after their sulfation processes, conversions of 51.5%, 61.9% and 42.8% were obtained at 750°C, 850°C and 950°C, respectively. Considering the process as a whole, the best fit was provided by a first-order exponential decay equation. Moreover, the results have shown that it is possible to quantify the decreasing in the dolomite reactivity for sulfur dioxide sorption and understand the changes in the behavior of the sulfation process of limestones when applied to technologies, as fluidized bed combustor, in which sulfur dioxide is present.

Guanidinium-based ionic liquids for sulfur dioxide sorption

Three guanidinium-based ionic liquids (GBILs) including [1,1,3,3-tetramethylguanidinium][phenol] ([TMG][PHE]), [1,1,3,3-tetramethylguanidinium][2,2,2-trifluoroethanol] ([TMG][TE]) and [1,1,3,3-tetramethylguanidinium][imidazole] ([TMG][IM]) were synthesized and their absorption and desorption of sulfur dioxide were investigated, respectively. The saturated molar ratio of SO 2 to GBILs varied from 2.24 to 3.16 at 40 °C with high absorption rate. The absorption mechanism might be that SO 2 reacts with the –NH 2 group on the cation and then a new –SO 2H group is formed. The new GBILs could absorb SO 2 by both physical and chemical interactions while physical absorption does play an important role at the experimental conditions under investigation.

Development of a Countercurrent Multistage Fluidized-Bed Reactor and Mathematical Modeling for Prediction of Removal Efficiency of Sulfur Dioxide from Flue Gases

A bubbling countercurrent multistage fluidized-bed reactor for the sorption of sulfur dioxide by hydrated lime particles was simulated employing a two-phase model, with the bubble phase assumed to ...

Removal of hazardous gaseous pollutants from industrial flue gases by a novel multi-stage fluidized bed desulfurizer

Sulfur dioxide and other sulfur compounds are generated as primary pollutants from the major industries such as sulfuric acid plants, cupper smelters, catalytic cracking units, etc. and cause acid rain. To remove the SO 2 from waste flue gas a three-stage counter-current multi-stage fluidized bed adsorber was developed as desulfurization equipment and operated in continuous bubbling fluidization regime for the two-phase system. This paper represents the desulfurization of gas mixtures by chemical sorption of sulfur dioxide on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of the multi-stage fluidized bed reactor are of high mass transfer and high gas–solid residence time that can enhance the removal of acid gas at low temperature by dry method. Experiments were carried out in the bubbling fluidization regime supported by visual observation. The effects of the operating parameters such as sorbent (lime) flow rate, superficial gas velocity, and the weir height on SO 2 removal efficiency in the multistage fluidized bed are reported. The results have indicated that the removal efficiency of the sulfur dioxide was found to be 65% at high solid flow rate (2.0 kg/h) corresponding to lower gas velocity (0.265 m/s), wier height of 70 mm and SO 2 concentration of 500 ppm at room temperature.

Issue topics

Sorption of sulfur dioxide by carbonaceous adsorbents in the presence of water vapor and oxygen results in the formation of sulfuric acid. The retention capacity of sulfur dioxide in this manner is much greater than that of physical adsorption. This article reports the experimental results on the sulfuric acid loading in coal reject-derived char. It is shown that both temperature and concentrations of sulfur dioxide and water vapor have significant effect on the sulfuric acid loading rate. Compared with the commercial-activated carbon, the coal reject char has lower sorption capacity but higher initial rate owing to the catalytic effect of oxides present in the char.

Sulfur dioxide adsorption isotherms and breakthrough analysis on molecular sieve 5A zeolite

In this study sulfur dioxide adsorption and rate were investigated on molecular sieve 5A zeolite in a packed bed system at 473 K. The experimental adsorption isotherms were compared with Langmuir, Freundlich, and Dubinin-Radushkevitch-Kaganer (DRK) adsorption isotherm models. The simple Langmuir and the Freundlich models provided a better description of sulfur dioxide sorption on molecular sieve 5A zeolite, so that a selective surface adsorption mechanism for adsorption of sulfur dioxide on molecular sieve 5A zeolite can be suggested. The breakthrough behavior for sulfur dioxide adsorption on molecular sieve 5A was also investigated in this study. The experimental breakthrough curves were compared with deactivation models proposed by Orbey et al., and the recent models of Suyadal et al. and Yas¸yerli et al. The deactivation models were found to give good agreement with the experimental results.

Sulfur Dioxide Sorption Properties and Thermal Stability of Hydrophobic Zeolites

Adsorption isotherms of SO{sub 2} in air on hydrophobic dealuminated Y (DAY) zeolite and silicalite at SO{sub 2} partial pressures ranging from 0.5 to 5 kPa were measured by the gravimetric method. The SO{sub 2} sorption isotherms on these two zeolites at different temperatures (25--100 C) can be correlated by the langmuir equation at low SO{sub 2} pressures (< 2 kPa) and by the Freundlich equation in the whole SO{sub 2} pressure range studied. The sorption capacity of SO{sub 2} on silicalite is larger than that of the DAY zeolite. Selective surface adsorption rather than the pore-filling mechanism was observed on adsorption equilibrium in these two zeolites. The SO{sub 2} sorption and desorption kinetic data obtained on these two zeolites show the dominant role of the reaction of SO{sub 2} on the zeolite surface in the SO{sub 2} sorption or desorption process. The simple Langmuir adsorption kinetic model provides a good description of SO{sub 2} sorption and desorption kinetics on these two zeolites at low SO{sub 2} partial pressures. The thermal stability of these two zeolites was studied by comparing the pore texture, crystalline structure, and SO{sub 2} adsorption ability of the fresh samples with those of the thermally treatedmore » samples at 550 or 850 C under various caustic conditions. It was found that these two zeolites are thermally and chemically stable under the studied conditions.« less

Sorption and transport of sulfur dioxide in polysulfone

The sorption and transport of sulfur dioxide (SO[sub 2]) in polymers is important in areas such as food packaging, polymer degradation, and sensors and monitoring devices. Another possible application is in pollution control for exhaust gases from power plants. Polysulfone is a polymer that is widely used for commercial gas separations with membranes. The authors have investigated the sorption and transport of SO[sub 2] in a commercially available Bisphenol A polysulfone near room temperature. The results were interpreted using the dual-mode sorption model with partial immobilization. Although similar data on other polymers have been published in the literature, they are not aware of any studies of sorption and transport of SO[sub 2] in polysulfone.

Retention of sulfur dioxide as sulfuric acid by activated coal reject char

Sorption of sulfur dioxide by carbonaceous adsorbents in the presence of water vapor and oxygen results in the formation of sulfuric acid. The retention capacity of sulfur dioxide in this manner is much greater than that of physical adsorption. This article reports the experimental results on the sulfuric acid loading in coal reject-derived char. It is shown that both temperature and concentrations of sulfur dioxide and water vapor have significant effect on the sulfuric acid loading rate. Compared with the commercial-activated carbon, the coal reject char has lower sorption capacity but higher initial rate owing to the catalytic effect of oxides present in the char.

Characterization of sulfur retained by soils exposed to sulfur dioxide

Abstract Soils have substantial capacity for sorption of sulfur dioxide (SO2) but little is known about the nature of the sorbed S. Three surface soils varying in pH, organic matter, CaCO3 equivalent and surface area were exposed to air containing 5% SO2 and subsequently analyzed by ten different procedures to characterize the sorbed S. Most of the sulfur retained by soils after exposure to SO2 could be recovered as CaCl2‐extractable S, Ca(H2PO4)2‐extractable S, or S released as H2S by hydriodic acid (HI). Only small amounts of sulfur could be recovered as tetrachloromercurate (TCM)‐extractable S, S released as SO2 by HCl, or S released as H2S by HCl + Zn, HCl + Sn, or Raney Ni and NaOH. However, large amounts of S released as SO2 by HCl were recovered from the air‐dry Webster and the moist Storden soils indicating that SO2 sorption is influenced by organic matter in air‐dry soils and by CaCO3 in moist soils.

Sorption and transport of sulfur dioxide in polycarbonate-polyarylate blends

Blends of polycarbonate and polyarylate were prepared and characterized by differential scanning calorimetry and a dynamic mechanic measurements techni two glass transition temperatures suggesting immiscibility. Sorption and transport measurements were made at 25 °C and up to approximately atmospheri All the obtained data are described well with the dual sorption dual-mobility models developed for a gas-glassy-polymer system. The sorption and transp correlated with blend composition. The diffusion coefficient data are interpreted in terms of the partial immobilization model.

Kinetics of sulphur dioxide sorption by single pellets of activated carbon

As an example for separation processes that involve physical adsorption and catalytic conversion a mathematical model for the sorption of sulphur dioxide by activated carbon is proposed. This takes into account the film diffusion and intraparticle diffusion of the reactants, the surface adsorption, the catalytic surface reaction and the deactivation of the catalyst by non-desorbed reaction products. The parameters included in the model to describe transfer processes and reaction kinetics are evaluated by comparing the numerical results of computer simulation with experimental data. The evaluation of the dimensionless groups describing heat and mass transfer resistances and characteristic diffusion and reaction time reveals that the model can be simplified in order the reduce computation time. The results of the single-pellet experiments are combined with the conservation equation of fixed-bed reactors, thus yielding the breakthrough curve.