Sphincter Of Oddi Pressure Research Articles

Modeling of Atmospheric Pollution in Urban and Rural Sites Using a Probabilistic and Objective Approach

Atmospheric pollution is affected by different individual pollutants (IP) and climatic factors (CF). In this work, the formulation of the Rasch model is proposed to get representative measures of atmospheric pollution in two urban locations, Badajoz and Cáceres, and one rural site, the Monfragüe Park (Southwest Spain). After applying the Rasch methodology, the ranking of all days was obtained according to their atmospheric pollution level and the influence on the environmental deterioration of each IP and CF (NO2, NO, SO2, O3, CO, benzene, PM10, precipitation, relative humidity, solar radiation, air temperature, and barometric pressure). The most influential items on atmospheric pollution are the O3 and the CF, mainly the lack of precipitation and those related to ozone generation (air temperature and solar radiation). Other IP exert a lower influence at both urban locations, being irrelevant at the Monfragüe Park. Unexpected behaviors of the CF or IP can be also analyzed.

Experimental study on the corrosion of a downhole string under flue gas injection conditions

AbstractFlue gas collection from steam generators and its utilization in enhanced oil recovery (EOR) can reduce CO2 emissions into the atmosphere and improve oil recovery efficiency. Under the environments of flue gas corrosion in oilfields, the effects of corrosion time, temperature, pressure, velocity, and concentrations of O2, SO2, H2O, and NaCl on corrosion rates of steels used for a downhole string were investigated through physical simulation experiments. The corrosion mechanisms were analyzed by component, and the morphology of the corrosion products tested by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). In the gas phase, the corrosion rates of X70, P110, and N80 notably increase with temperature and O2 concentration. The corrosion rates first increase rapidly with pressure from 1.0 to 3.0 MPa and then remain largely stable. Meanwhile, the corrosion rates of X70, P110, and N80 in the liquid phase first increase and then decrease with temperature and reach maximum values at 90°C. The corrosion rates of X70, P110, and N80 increase notably with velocity and the concentrations of O2, SO2, H2O, and NaCl. The corrosion rate of 13Cr is considerably lower than those of N80, P110, and X70, which shows good corrosion resistance performance. To reduce the flue gas corrosion of a downhole string, the relative humidity of the flue gas should be lower than 0.7, the temperature of the flue gas in the wellbore should avoid the range between 80 and 100°C, the excess air coefficient of the boiler should be kept at a reasonable value to reduce the O2 content in the flue gas, and the flue gas should not be coinjected into wellbores with brine. The injection of flue gas is technically feasible considering the corrosion of downhole string.

Effect mass independent isotope fractionation of sulfur (δ33S and δ36S) during photolysis SO2 in experiments with broadband light source

This paper presents the results of experimental studies to examine the behavior of mass-independent isotope effects of sulfur Δ33S and Δ36S during photochemical processes initiated by broadband ultraviolet radiation. Experiments were performed in a flow photochemical reactor using a high pressure mercury lamp which is a source of radiation of a wide range with a maximum radiation intensity in the wavelength range 270-330 nm and weaker in the range 190-250 nm. We present measurements of the temperature and SO2 pressure dependence of the sulfur isotope ratios in the elemental sulfur products. Based on a comparative analysis of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the character of the correlation dependences between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. Based on a comparison of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the character of the correlation dependencies between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. The results of our experiments allow the possibility that photochemical processes in the range 250-330 nm could play a significant role in the production of an isotope sulfur anomaly in the Archean atmosphere. The conditions in which radiation in the 250-330 nm region prevail over the radiation in the 190-220 nm region are consistent with the assumption that the level of solar radiation reaching the Earth’s surface in Archean was several orders of magnitude larger in the wavelength range 200-300 nm compared with the current level of radiation in this range.

Effect of Mass-Independent Isotope Fractionation of Sulfur (Δ33S and Δ36S) during SO2 Photolysis in Experiments with a Broadband Light Source

Abstract–This paper presents the results of experimental studies of the behavior of mass-independent isotope effects of sulfur Δ33S and Δ36S during photochemical processes initiated by a broadband ultraviolet radiation. Experiments were performed in a flow photochemical reactor using a high-pressure mercury lamp, which is a source of radiation of a wide range with maximum radiation intensity in the wavelength range of 270−330 nm and weaker intensity in the range of 190−250 nm. The temperature and SO2 pressure dependences of the sulfur isotope ratios in the elemental sulfur products are revealed. Based on a comparative analysis of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the correlation between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. Based on a comparison of our isotope data with data from previous experimental studies with xenon and hydrogen lamps, it was shown that the correlation between the values of δ34S, Δ33S and Δ36S in elemental sulfur depends on the relative spectral distribution of the radiation intensity. Our experiments suggest that photochemical processes in the range of 250−330 nm could play a significant role in the production of an isotope sulfur anomaly in the Archean atmosphere. The conditions in which 250− 330 nm radiation prevails over the 190−220 nm radiation are consistent with the assumption that the level of solar radiation reaching the Earth’s surface in Archean was several orders of magnitude higher in the wavelength range 200−300 nm compared with the current level of radiation in this range.

Experimental investigation of gas/slag/matte/tridymite equilibria in the Cu–Fe–O–S–Si system in controlled gas atmosphere at T = 1 200 °C and P(SO2) = 0.1 atm

AbstractThe effects of partial pressure of sulphur dioxide on the gas/slag/matte/tridymite equilibria in the Cu–Fe–O–S–Si system at 1 200 °C have been experimentally investigated and compared with the previous studies at various P(SO2). The experimental procedure includes equilibration of the sample and silica substrate at high temperature for the designated time, rapid quenching to preserve the equilibrium phases, followed by measuring the composition of the condensed phases with electron probe X-ray microanalysis. A set of graphs were constructed to present the compositions of slag and matte as a function of copper concentration in matte. The present study confirmed that the chemically dissolved copper and sulphur for the given Cu in matte are independent of the partial pressure of SO2. However, the experimentally measured liquidus (Fe/SiO2) are different for various P(SO2). The new data provide an important, accurate and reliable quantitative foundation for improvement of the thermodynamic databases for the chemical systems containing copper matte and slag. The present study is a part of a broader overall research program on the characterisation of the multi component (Cu–Fe–O–S–Si–Al–Ca–Mg), multi-phase (gas/slag/matte/metal/solids) systems with minor elements.

Reducing the competitive adsorption between SO2 and NO by Al2O3@TiO2 core-shell structure adsorbent

The Al2O3@TiO2 core-shell structure adsorbent was designed, prepared, and used to reduce the competitive adsorption between SO2 and NO. The result showed that γ-Al2O3 and anatase were obtained in this study, and Al2O3 was well wrapped by TiO2 to form the core-shell structure. The Al2O3@TiO2 core-shell structure adsorbent with the core-shell mole ratio of 1:1 showed the best capacity of simultaneous desulfurization and denitrification, and the capacity was much better than Al2O3, Al2O3 + TiO2, and TiO2. NOx is easier to get though the pore of the shell material because of the smaller molecular diameter of NOx comparing with SO2, and the special structure of the core-shell adsorbent can be used to change the partial pressure of NOx and SO2 on the surface of the core material, thereby reducing the competitive adsorption. NO and SO2 would be catalytically oxidized to NO2 and SO3 on the shell structure, then SO3 was adsorbed by the shell material, and NOx was adsorbed by the core. Al–O and Ti–O were the adsorption sites, and the product of chemisorption was nitrate and sulfate radical.

Experimental investigation of reaction kinetics of gas–liquid–solid Bunsen reaction in iodine–sulfur process

Iodine–sulfur (IS) cycle is the most promising thermochemical water-splitting process for nuclear hydrogen production. The Bunsen reaction, which produces sulfuric and hydriodic acid for the two decomposition reactions, plays a crucial role for the continuous stable operation of the IS cycle. Insufficient kinetics studies on Bunsen reaction, particularly under the gas–liquid–solid heterogeneous conditions, have caused difficulties for the design of Bunsen reactor, as well as the optimization and improvement of the efficiency of the process. In this work, the reaction kinetics of gas–liquid–solid Bunsen reaction denoted in the pressure drop of SO2 was experimentally investigated, and the effluences of the main factors, including the initial SO2 pressure, molar ratio of I2 to H2O, temperature, and stirring rate, were studied. In addition, a kinetics model for simulating the heterogeneous reaction was proposed and verified by the experimental data obtained under the three-phase Bunsen reaction conditions.

Total Pressure Dependence of Sulfur Mass‐Independent Fractionation by SO2Photolysis

AbstractSulfur Mass‐Independent Fractionation (S‐MIF) may provide a clue to understanding Earth's early atmosphere. We examined total pressure dependence of the S‐MIF produced by SO2photolysis. Isotopic self‐shielding is known to produce S‐MIF, which could be changed by both the partial pressure of SO2(pSO2) and by the total pressure (pTotal). Our experimental results show that both Δ33S and Δ36S values are constant when total pressure is below 10 kPa at constantpSO2, whereas they decrease as total pressure increases. The result suggests that pressure broadening of the SO2absorption line is responsible for the S‐MIF. The modeled high‐resolution isotopologue cross sections can reproduce our experimental results and its changes depending on bothpSO2andpTotal. Consequently, we conclude that the Archean Δ33S and Δ36S correlation can only be achieved when the total pressure of the Archean atmosphere was below 100 kPa, or it was produced in the upper atmosphere.

Thermodynamic Assessment of Slag–Matte–Metal Equilibria in the Cu-Fe-O-S-Si System

Equilibria among the slag, matte and metal phases in the Cu-Fe-O-S-Si system are critically assessed using thermodynamic modeling. The relationships among matte grade, temperature, partial pressure of SO2, Fe/SiO2 in the slag, and the copper concentration in the slag are described by the model, as well as the concentrations of other elements in all phases. A thermodynamic database is created, which can be used for understanding and improving the pyrometallurgical production of copper. An extensive experimental dataset includes the most recent results obtained by the equilibration/quenching/EPMA analysis technique. These data allow to distinguish the physical entrainment of the matte and solid phases in the slag from chemical solubility. As a result, it is possible to describe the copper solubility in the slag with high accuracy and establish the relationship between copper and sulfur in the slag. The thermodynamic database of the present study is consistent with previously reported thermodynamic evaluations of binary, ternary and quaternary subsystems. The slag phase is modeled using the two-sublattice modified quasichemical model in the quadruplet approximation. The matte and metal liquid phases are modeled as one solution using the single-sublattice modified quasichemical model in the pair approximation.

Importance of the Cu oxidation state for the SO2-poisoning of a Cu-SAPO-34 catalyst in the NH3-SCR reaction

Cu-exchanged zeolites of the CHA structure are state-of-the-art catalysts for selective catalytic reduction of NOx with NH3 in diesel aftertreatment systems. However, these catalysts deactivate in the presence of SO2, which is a constituent of diesel exhaust gas. In this article, the deactivation behavior and mechanisms of a Cu-SAPO-34 catalyst were studied with reactor tests and DFT calculations. Exposure of the catalyst to two different SO2 concentrations and durations, but with the same total SO2 exposure, calculated as the product of partial pressure of SO2 and exposure time, lead to the same degree of deactivation. Exposure of the Cu-SAPO-34 catalyst to SO2 in the presence and absence of NO and NH3 at different temperatures between 200–600 °C showed different trends for the deactivation. Below 400 °C, the S/Cu ratio on the catalyst increased with temperature in absence of NO and NH3, while it decreased with increasing temperature in the presence of NO and NH3. This is explained by the ability of NO and NH3 to reduce Cu(II) to Cu(I). DFT calculations show that SO2 adsorbs more strongly on Cu(I) than on Cu (II). Above 400 °C, the S/Cu ratio decreased with temperature irrespective of the presence of NO and NH3. In all cases, the S/Cu ratio is lower than 1. This is not compatible with extensive deposition of ammonium sulfate when co-feeding SO2, H2O and NH3. A more likely explanation for the deactivation is that SO2 is mainly related to the Cu sites. This is further corroborated by DFT calculations showing that SO2 and SO3, which is possibly formed by oxidation of SO2 over Cu sites, interact similar with Cu in Cu-SAPO-34 and Cu-SSZ-13.

Evaluation of Bunsen reaction at elevated temperature and high pressure in continuous co-current reactor in iodine-sulfur thermochemical process

Bunsen reaction is one of the three reaction steps of iodine-sulfur process. In present study, Bunsen reaction is carried out in co-current reactor to identify effect of different operating conditions on concentrations of Bunsen reaction product mixture. Bunsen reaction studies have been done in tubular reactor, which is made of tantalum tube and stainless steel jacket, in 50–80 °C temperature range, 2–6 bar (g) pressure range. Feed flow rates are varied for HIx (mixture of hydroiodic acid, water and iodine) 1.2 l/h - 3 l/h, SO2 0.02 g/s – 0.24 g/s and O2 0.008 g/s −0.016 g/s. It has been observed that, increasing SO2 feed flow rate and pressure results in increased mole fraction of HI in HIx phase and H2SO4 in sulfuric acid phase. Increase in temperature increased the mole fraction of HI in HIx phase but decreased the mole fraction of H2SO4 in sulfuric acid phase. Increase in feed I2/H2O ratio and HIx feed flow rate, decreased the mole fraction of HI in HIx phase. Higher pressure improved the conversion of Bunsen reactants to products.

Absorption behaviors of SO2 in HI acid for the iodine-sulfur thermochemical cycle

Bunsen reaction, which produces H2SO4 and HI acids from the reaction of I2, SO2 and H2O, is a crucial reaction for the iodine–sulfur thermochemical hydrogen production process. To study the reaction kinetics of Bunsen reaction by correlating SO2 pressure drop with reaction time, the physical absorption of SO2 in HI acid should be investigated. The absorption behaviors of SO2 in HI acid were firstly studied under various conditions, including different HI concentration, absorption temperature, and SO2 partial pressures. The results show that the absorption amount of SO2 in HI solution increases with both the pressure of the SO2 and HI acid concentration, while the effect of temperature on SO2 absorption in HI solution is complex. S and SO42− were detected in HI solutions after SO2 absorption, and iodine was found in some cases, especially under the conditions of high pressure or high temperature, indicating chemical absorption occurred, which leads to the disobeying of the physical absorption rules. It is thought that the redox reaction between HI and SO2 and the formed products are the main reasons of chemical absorption.

THz radiation generation via the interaction of two‐colour ultra‐short laser pulses with SO2 and NH3 gases

In this work, using a two‐dimensional particle‐in‐cell Monte Carlo collision computation method, terahertz (THz) radiation generation via the interaction of two‐colour, ultra‐short, high‐power laser pulses with the polyatomic molecular gases sulphur dioxide (SO2) and ammonia (NH3) is examined. The influence of SO2 and NH3 pressures and two‐colour laser pulse parameters, i.e., pulse shape, pulse duration, and beam waist, on the THz radiation generation is studied. It is shown that the THz signal generation from SO2 and NH3 increases with the background gas pressure. It is seen that the THz emission intensity for both gases at higher laser pulse durations is higher. Moreover, for these polyatomic gases, the plasma current density increases with increase in the laser pulse beam waist. A more powerful THz radiation intensity with a larger time to peak of the plasma current density is observed for SO2 compared to NH3. In addition, many THz signals with small intensities are observed for both polyatomic gases. It is seen that for both SO2 and NH3 the generated THz spectral intensity is higher at higher gas pressures.

Apparent kinetics of the Bunsen reaction in I2/HI solution for the iodine–sulfur hydrogen production process

Massive hydrogen production featuring high efficiency, CO2 free, and cost effectiveness is a crucial challenge for the hydrogen economy. Nuclear hydrogen production through thermochemical iodine–sulfur (IS) process is a potential candidate for this purpose. Chemical reaction kinetics data are indispensable for developing a high-performance reactor as well as the scaling up of the process. The apparent kinetics of the reaction under simulated recycling conditions of IS closed cycle operation was studied by initial rate method. The effects of key parameters, including agitation speed, SO2 partial pressure, I2 concentration, and reaction temperature, on reaction rate, were systematically investigated by measuring the variation in SO2 pressure with reaction time. Initial rate analysis method indicated that the Bunsen reaction rates were 0.23 ± 0.01 and 0.77 ± 0.01 order with respect to SO2 pressure and I2 concentration. The apparent activation energy was 5.86 ± 0.21 kJ/mol. Based on these results, an exponential rate expression of the Bunsen reaction was established. In addition, a simplified method for calculation of kinetics parameters was proposed and compared with conventional techniques. Experimental results provide theoretical basis for design and development of Bunsen reactors and for elucidating the reaction process.

Sulfur isotope fractionation by broadband UV radiation to optically thin SO2 under reducing atmosphere

Photochemical mechanisms of Sulfur Mass-Independent Fractionation (S-MIF) are still poorly understood. Previous laboratory experiments have indicated that the S-MIF depends largely on the spectrum of the incident light source and the partial pressure of SO2, though the basic character of the Archean S-MIF (ΔS36/ΔS33=∼−1) has never been reproduced. We have conducted new photochemical experiments at low pSO2 (1–10 Pa) conditions under the presence of CO and found a reasonable mechanism to reproduce the Δ36S/Δ33S slope about −1. As previously suggested (Ono et al., 2013), the low pSO2 is key to studying the self-shielding effect within a range of realistic atmospheric conditions. Also, reducing conditions are critical for simulating the O2-poor atmosphere, whereas photolysis of pure SO2 provides excess O atoms that significantly change the overall chemistry. Our experimental results confirmed that significant S-MIF (ΔS36/ΔS33=−2.4) can be produced by self-shielding in the SO2 photolysis band (185–220 nm), even if the SO2 column density is as low as 1016 molecules cm−2. Thus, photolysis within a volcanic plume of ∼0.1 ppm SO2 is capable of producing a large S-MIF signature. The isotopic fractionations originating from the different absorption cross sections of SO2 isotopologues (i.e. wavelength dependent effect; without self-shielding) are only minor (potentially up to +4‰ for Δ33S). Under reducing conditions, however, another S-MIF signal with Δ36S/Δ33S ratio of ∼+0.7 is produced due to collision-induced intersystem crossing (ISC) from singlet to triplet states of SO2 (Whitehill et al., 2013), and should also be transferred into the final product that is responsible for changing the Δ36S/Δ33S slope. Based on a photochemical model of the S–O–C system with the two S-MIF-yielding reactions, the largest S-MIF observed in the late Archean Mt. McRae Fm. (ΔS33=+9.4‰, ΔS36=−7.5‰) can be reproduced by solar UV irradiation of a SO2 column of ∼6.4×1016 molecules cm−2 with a sufficiently high concentration of reducing gasses (∼2% CO or CH4) where the ISC-derived MIF contributes ∼3% through the photoexcitation channel initiated in the 240–340 nm region. Our work shows that a photochemical model considering the two major S-MIF-yielding reactions (SO2+hν→SO+O and SO21+M→SO23+M) can explain the behavior of the S-MIF observed in laboratory experiments. The combination of the two effects is more important under reducing condition and should be considered to interpret the geological record.

Efficient SO2 Capture through Multiple Chalcogen Bonds, Sulfur‐Centered Hydrogen Bonds and S•••π Interactions: A Computational Study

AbstractThe non‐toxic, environment friendly, biodegradable properties and cost effectiveness of active pharmaceutical ingredients (APIs) allow them to be used as green‐solvents for several applications. The presence of multiple binding sites in the APIs has an additional advantage for the flue gas capture. Herein we report a detailed analysis of efficient SO2 capture by the anions associated with APIs through several strong and weak non‐covalent interactions. The DFT studies and Langmuir adsorption model suggest that the APIs based anions are highly efficient alternatives for SO2 capture at low as well as high partial pressures (0.01 – 0.1 MPa) of SO2. The absorption capacity can be achieved as much as 5.8 mol SO2/mol APIs; the best absorption capacity till reported. Our computational results suggest that for the efficient SO2 capture, the enthalpy of absorption (ΔH) should be −65 to −50 kJ.mol−1; below this range absorption capacity reduces drastically. This study also emphasizes the importance of weak interactions (S•••π and C−H•••O and C−H•••S hydrogen bonds) together with the strong chalcogen bonds to be considered in designing new absorbing materials for SO2 capture.

New experimental data for absorption of SO2 into DMA solution

Removal of SO2 and its accurate prediction from the flue gases emitted from various chemical industries in a techno‐econo‐enviro manner is of great importance. The experiments were conducted in a bubble column to study the absorption of SO2 into dimethyl amine (DMA) solution from simulated gas stream as absorption of SO2 in DMA solution yields an ionic liquid. The effects of DMA concentration, initial SO2 concentration, absorbent temperature, and the initial pH value of absorbent on SO2 removal were investigated by using DMA solution. The experimental results showed that the SO2 saturation uptake increased with increase in absorbent concentration. The maximum removal efficiency of approximately 100% was observed at 9.32 mol/dm3 DMA solution, temperature of 303 K and initial DMA solution pH 11. The mass transfer coefficient based on the liquid phase increases with increasing partial pressure of SO2 in inlet gas stream. The lethal air pollutant SO2 is an acidic gas emitted from combustion of fossil fuel. The removal of SO2 from flue gas streams was investigated through absorption by using an organic solvent DMA. Absorption of SO2 into DMA gives di‐methyl ammonium N,N‐dimethyl amidosulfinate an ionic liquid. The absorption of SO2 using DMA has dual benefits in terms of resource generation as ionic liquid production resulting in omission of absorbent regeneration step and SO2 emission control from waste gas stream. The value of kLa increases with increasing partial pressure of SO2 in inlet gas stream. The DMA showed an excellent performance on SO2 absorption. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1298–1304, 2016

Study of Bunsen reaction in agitated reactor operating in counter current mode for iodine-sulphur thermo-chemical process

The iodine-sulphur (IS) thermo-chemical process is being studied as a potential process for production of hydrogen by water splitting. It consists of three chemical reactions: 1) Bunsen reaction, which is the acid production step, 2) sulphuric acid decomposition to produce oxygen; 3) hydrogen iodide decomposition to produce hydrogen. In this work, a detailed parametric study of the Bunsen reaction is presented, which was carried out in agitated reactor (ABR) in counter current mode of operation. Experiments have been carried out in the reactor at different temperatures by varying the sulphur dioxide (SO2) flow rate and partial pressure of SO2. Bunsen reaction rate and SO2 conversion are calculated experimentally from feed rate and scrubbing rate of SO2. It has been observed that the reaction rate and SO2 conversion increase with increase in SO2 flow, increase in SO2 partial pressure and decrease in temperature. 'Tanks-in-series' model, one of the non-ideal reactor models, has been proposed to describe the ABR reaction system. The model has been validated with experimental results. This approach can be useful for the design and scaling up of the agitated reactor.

Biliary manometry in patients with common bile duct stones and juxtapapilary duodenal diverticulum

Objective To explore the impact of juxtapapilary duodenal diverticulum on the formation of choledocholithiasis and biliary manometry after surgery. Methods The clinical data of 97 patients with common bile duct stones who successfully underwent ERCP and biliary manometry treatment from May 2011 to March 2014 were retrospectively analyzed. Ninty-seven common bile duct stone patients were divided to two groups, that is, 52 cases of juxta-papilary duodenal diverticulum (experimental group) and 45 cases without juxta-papilary duodenal diverticulum (control group). The biliary manometric results before and after EST of both groups were compared. Results The basal pressure of sphincter Oddi of the experimental group before EST[(84.8±26.1)mmHg]was higher than that of the control group before EST[(75.5±14.6)mmHg](P 0.05). The biliary manometry was performed in 81 patients after one month and it was found that the basal pressure of sphincter Oddi of experimental group was still higher than that of the control group[(34.8±17.1) mmHg VS (29.6±15.3)mmHg, P<0.05]. The biliary pressure of common bile of the experimental group was higher than that of the control group[(19.9±11.2)mmHg VS (17.1±13.1)mmHg, P<0.05]. Conclusion The existence of juxtapapilary duodenal diverticulum increases the pressure of common bile duct and Oddi sphincter and leads to CBD stones. Key words: Biliary manometry; Juxta-papilary duodenal diverticulum; Cholangiopancreatography, endoscopic retrograde; Choledocholithiasis; Sphincter of Oddi pressure; Common bile duct pressure

Absorption of SO2 in different electrolyte solutions, seawater and brine

A systematic study of the SO2 solubility of binary systems (SO2+water+1 electrolyte) and of the complex mixtures seawater and brine was performed. The experimental setup allowed a comprehensive description of the equilibrium state by a UV spectroscopic measurement of the partial pressure of SO2 in the gas phase and the concentration of sulfur compounds in the liquid phase. The influence of main ions present in the brine (e.g., Na+, Cl−, K+, Mg2+, Ca2+, HCO3−) was studied at 298 and 323K. The experiments revealed considerable deviations of already existing models from experimental data mainly at higher temperatures. A thermodynamic model based on caloric data and a Pitzer and a Sechenov approach for the calculation of activity coefficients was fitted to experimental data. This work demonstrates that fitting selected Pitzer parameters improves the model performance very much. The new model provides a reliable prediction of SO2 solubility over the entire investigated range of temperature and concentrations.