SO2 Gas Concentration Research Articles

Development of broadband ultraviolet pulsed laser using Ce:LiCAF crystal to determine SO\(_2\) gas concentration by differential absorption spectroscopy

Earth’s atmosphere is a mixture of many gases which include pollutants such as SO2, NO2, NO, and O3 that have absorption in the ultraviolet (UV) wavelength region. Therefore, the development of broadband UV laser sources that are useful in a differential absorption spectroscopy (DOAS) system for environmental research is necessary. In this research, we present the DOAS system using the Ce:LiCAF laser for determining SO2 gas concentration in the atmosphere. The Ce:LiCAF laser has a full width at half maximum of 2 nm with a wavelength range from 286 to 291 nm and a peak wavelength of 288.5 nm. The results show that the DOAS system accurately determines the gas concentration with a measurement error of 6 %. This result can serve as the basis for developing practical DOAS systems with the ability to monitor a wide range of gasses and survey many other types of pollutants.

Numerical modelling of Cz-β-Ga2O3 crystal growth in reactive atmosphere

The present study focuses on computer modeling of Cz- β-Ga2O3 crystal growth while also addressing the issue of minimizing Ir crucible oxidation. To accomplish this objective, a comprehensive framework was developed that combines thermodynamic equilibrium calculations with a CFD numerical model. This integrated approach is designed to simulate the impact of SO2 gas concentration in the chamber atmosphere. The primary goal of this numerical model is to assess deviations from the stoichiometric ratio in the Ga2O3 melt by examining the processes taking place at the free surface of the melt and their effects on its stoichiometry. These processes include the dissociation of the Ga2O3 melt into Ga and O ions, as well as the evaporation of volatile species from the melt surface.Simulations were conducted for both 2-inch and 4-inch crystals, with varying concentrations of SO2 and CO2 in an Ar atmosphere, facilitating a direct comparison between the two gases. The study's findings indicate that the optimal concentration of SO2 in the atmosphere should be approximately 40%, whereas for CO2, the optimal concentration is around 9%. Significantly reduced concentrations of both SO2 and CO2 were achieved by increasing the free melt surface area. Notably, the atmosphere with a SO2 concentration exhibited a substantial 30% reduction in the O concentration surrounding the crucible, underlining the advantages of using SO2 as a viable alternative to CO2.

Zinc-aluminum layered double hydroxide and double oxide for room-temperature oxidation of sulfur dioxide gas

Sulfur dioxide (SO2) gas at trace levels challenges the consumption of fuel gases and cleaning of flue gases originating from diverse anthropogenic sources. We have demonstrated Zn–Al layered double hydroxide (LDH) and layered double oxide (LDO) as low-cost and effective adsorbents in removing lowly concentrated SO2 gas at room temperature. Water in the adsorbent bed significantly improved the performance, where the maximum adsorption capacity of 38.0 mg g−1 was achieved for LDO. Based on the spectroscopic findings, the adsorbed gas molecules were oxidized to surface-bound sulfate/bisulfate species, showing complete mineralization of SO2 molecules. By employing an inexpensive NaOH–H2O2 solution-based regeneration strategy, we successfully regenerated the spent LDO, significantly restoring its gas uptake capacity. The regenerated oxide exhibited an increased gas uptake capacity ranging from 38.0 to 98.5 mg g−1, highlighting the practicality and economic feasibility of our approach. LDH/LDO materials are promising regenerable adsorbents for removing low concentrations of SO2 gas in ambient conditions.

Digital colorimetric sensing for real‐time gas monitoring for smart green energy system

AbstractIn this study, we demonstrate that a digital colorimetric sensor platform can transform a conventional energy system, such as gas‐insulated switchgear (GIS) into a smart green energy system. Our sensor platform consists of a colorimetric sensor film (CSF), an array of silicon photodiodes, and a low‐power‐driven fiber optical photodiode with a wireless communication protocol integrated into an information network. The photodiode measures the transmitted light of the color‐variable CSF when exposed to sulfur dioxide (SO2) gas, a decomposition by‐product of the sulfur hexafluoride (SF6) gas in GIS. We report the electrical photocurrent measurement through the CSF can measure the concentration of SO2 gas via remote and real‐time monitoring and shows a comparable behavior to UV–Vis absorption measurement. The limit of detection of the sensor, 0.78 ppm is sufficient to analyze the GIS insulation deterioration allowing green energy systems.image

Low-Cost Instrument to Monitor Sulphur Dioxide Emissions Based on The DOAS Method

Various techniques to measure SO2 concentration based on Differential Optical Absorption Spectroscopy (DOAS) have been widely developed and applied for various measurements. However, most of the applications are still relatively expensive. Some efforts have been made to reduce the cost by using Ultraviolet Light Emitting Diodes (LEDs) as light sources, showing promising results. Further reductions can be possibly made by providing an alternative to replace high spectral resolution spectrometers widely used in DOAS applications since those spectrometers are commercially expensive. This paper studies the feasibility of a DOAS instrument using a low-cost spectrometer and UV-LEDs as light sources. The resolution of the spectrometer is 0.7 nm. With this resolution, it is expected that the instrument hardly captures narrow band structures of SO2 optical absorption in the spectral range between 280 nm and 320 nm when measuring SO2 gas concentration lower than the limits of SO2 emissions regulated by the Indonesian government. To compensate for this drawback, narrow and broad bands of optical absorption structures are considered in the data analysis to achieve a detection limit far below the regulated limits. To capture the broadband structures, four UV-LEDs are used to cover spectral absorption from 250 nm to 320 nm. The instrument was calibrated using eight different standard concentrations of SO2. The correlation between the readings and the standard concentrations is high, indicated by the Pearson correlation coefficient of 0.9999. It was also found that the lowest concentration the instrument can distinguish from blank samples or the Limit of Detection is 16 ppm. However, the instrument can precisely measure concentrations higher than or equal to 25 ppm with a standard deviation of less than 10% of the mean concentration measured from five measurements. This is far below the required legal limits, below 229 ppm. After the calibration, the DOAS instrument was used to measure SO2 sampled from the emission of burning coals. To compare, a commercial SO2 sensor was used to measure the same gas. The results indicate that the difference in the readings between the two instruments is around 6% of the concentration.

A Biomass-Based Colorimetric Sulfur Dioxide Gas Sensor for Smart Packaging

Sulfur dioxide (SO2) gas, which can effectively prohibit the growth of pathogenic microorganisms, has been internationally used in commercial food packaging to maintain high-quality food and reduce the incidence of foodborne illnesses. However, the current mainstream methods for SO2 detection are either large and expensive instruments or synthesized chemical-based labels, which are not suitable for large-scale gas detection in food packaging. Recently, we discovered that petunia dye (PD), which is extracted from natural petunia flowers, demonstrates a highly sensitive colorimetric response to SO2 gas with its total color difference (ΔE) modulation reaching up to 74.8 and detection limit down to 1.52 ppm. To apply the extracted petunia dye in smart packaging for real-time gas sensing and food-quality prediction, a flexible and freestanding PD-based SO2 detection label is prepared by incorporating PD in biopolymers and assembling the films through a layer-by-layer approach. The developed label is utilized to predict grapes' quality and safety by monitoring the embedded SO2 gas concentration. The developed colorimetric SO2 detection label could potentially be used as an intelligent gas sensor for food status prediction in daily life, food storage, and supply chains.

Correlation method of compensating the zero temperature-drift of four-electrode low-range electrochemical NO2 and SO2 gas concentration sensors

Correlation method of compensating the zero temperature-drift of four-electrode low-range electrochemical NO2 and SO2 gas concentration sensors

Experimental Study on Desulfurization of Zinc Oxide

Sulfur dioxide can be eliminated by zinc oxide dust. The process conditions for the direct absorption of sulfur dioxide by the slurry were discussed in this paper. The influence of the variables like the ratio of liquid to liquid, the ratio of liquid to gas, the concentration of SO2 gas, and the gas velocity on the desulfurization efficiency were investigated. The desulfurization effect of using high-efficiency atomizing nozzle is better than that of vortex nozzle. As the solid content of zinc oxide slurry reaches above 45%, the rate of increase of desulfurization efficiency becomes lower, and even a decreasing trend appears at the later stage.

Structural, Optical and Electrical Properties of ATO Nanoparticles Synthesized by Combustion Method

Antimony doped tin oxide (ATO) nanoparticles (1,2 and 3 wt%) were green synthesized by combustion method using Terminalia bellirica (T. Bellirica) seed extract as a fuel, stannous chloride and antimony trichloride as precursor. The microstructural, optical and electrical properties of synthesized ATO nanoparticles were investigated using XRD, SEM, FTIR, UV–Vis and computer-controlled impedance analyser. XRD analysis of green synthesized ATO nanoparticles exhibit tetragonal structure. SEM investigation shows granular structure of nanoparticles. FTIR studies confirm the formation of ATO nanoparticles. The optical band gap was found using diffused reflectance spectral studies. AC conductivity is studied as function of frequency using impedance analyzer. The improved microstructural, optical and electrical properties of 2 wt% ATO nanoparticles was used for SO2 gas sensing application by pellet technique. SO2 gas sensing studies were carried out using pellet of 2 wt% ATO nanoparticles and sensing response of 16% was obtained for 3.2 ppm of SO2 gas concentration.

Analisis Parameter Sulfur Dioksida dari Aktivitas Transportasi di Sekitar Industri Pertambangan Nikel

Ambient air pollution outside the outdoor environment comes from moving sources, namely exhaust fumes from incompletely burned vehicles such as motorcycles, gasoline cars, diesel cars, Morosi District is an industrial area that accommodates several large companies engaged in energy and mineral purification, so that these companies will accommodate human resources. In this case, of course, many workers use motorized vehicles to optimize working time. The mobility of workers is a contribution to air pollution, especially air resulting from the use of motorized vehicles known as Sulfur Dioxide (SO2). Efforts to monitor the amount of SO2 need to be carried out considering the impact that will arise in the future.The measurement of SO2 concentration was carried out using a measurement procedure method that refers to SNI 19-7117.10-2005, using Impingger. In the morning, afternoon and evening measurements the concentration of SO2 gas reached 50.60 g/m³, 41.80 60 g/m³, and in the afternoon 72.10 g/m the concentration of SO2 was still safe for life and the environment because it did not exceed the quality standard. which is 150 ug/m³.

Ordering Transitions of Liquid Crystals Triggered by Metal Oxide-catalyzed Reactions of Sulfur Oxide Species

Liquid crystals (LCs), when supported on reactive surfaces, undergo changes in ordering that can propagate over distances of micrometers, thus providing a general and facile mechanism to amplify atomic-scale transformations on surfaces into the optical scale. While reactions on organic and metal substrates have been coupled to LC-ordering transitions, metal oxide substrates, which offer unique catalytic activities for reactions involving atmospherically important chemical species such as oxidized sulfur species, have not been explored. Here, we investigate this opportunity by designing LCs that contain 4'-cyanobiphenyl-4-carboxylic acid (CBCA) and respond to surface reactions triggered by parts-per-billion concentrations of SO2 gas on anatase (101) substrates. We used electronic structure calculations to predict that the carboxylic acid group of CBCA binds strongly to anatase (101) in a perpendicular orientation, a prediction that we validated in experiments in which CBCA (0.005 mol %) was doped into an LC (4'-n-pentyl-4-biphenylcarbonitrile). Both experiment and computational modeling further demonstrated that SO3-like species, produced by a surface-catalyzed reaction of SO2 with H2O on anatase (101), displace CBCA from the anatase surface, resulting in an orientational transition of the LC. Experiments also reveal the LC response to be highly selective to SO2 over other atmospheric chemical species (including H2O, NH3, H2S, and NO2), in agreement with our computational predictions for anatase (101) surfaces. Overall, we establish that the catalytic activities of metal oxide surfaces offer the basis of a new class of substrates that trigger LCs to undergo ordering transitions in response to chemical species of relevance to atmospheric chemistry.

Double-Layered NiO/SnO2 Sensor for Improved SO2 Gas Sensing with MEMS Microheater Device

Micro Electro mechanical systems (MEMS) sensor is fabricated for testing low concentration gas sensing of sulphur dioxide (SO2) with sensing layers of single layer tin oxide (SnO2) and double layered heterojunction structure of nickel oxide and tin oxide (NiO/SnO2). NiO and SnO2 structures are deposited with RF sputtering and the elemental composition were identified with structural properties such as X-ray diffraction (XRD), Scanning electron microscope (SEM) and Energy Dispersive X-ray Analysis (EDX) analysis. Sensing results proved that NiO/SnO2 double layered sensor had better sensing characteristics than single layered SnO2 sensor due to the formation of p-n junctions. At 400 ppb of SO2 gas concentration, NiO/SnO2 sensor has maximum sensing response of 20% is recorded and at 2000 ppb, 30% sensing response is recoded. The optimal temperature of the sensor is 250 °C (∼63 mW). Selectivity of the sensor is tested with 5 different gases such as VOC, pyruvate, CO, NH3, SO2 and the sensor has high and better response with SO2 gas.

Humidity-Responsive Photonic Crystals with pH and SO2 Gas Detection Ability Based on Cholesteric Liquid Crystalline Networks.

Dynamic photonic crystals with tunable structural colors have been a hot topic in the research of anticounterfeiting devices, decoration, and detection. In this work, we prepared cholesteric liquid crystalline network (CLCN)-based photonic crystals that present humidity- and SO2 gas-responsive behaviors. The covalently cross-linked CLCN film presents humidity-responsive color changes due to the swelling/deswelling of the matrix under different humidity conditions. When treating the CLCN film with SO2 gas, the carboxylic salt converted to the acid and the film was not able to respond to the humidity change anymore. The mechanism of the SO2 gas-gated humidity responsiveness of the CLCN film was characterized. It was found that the acidic gas caused changes of pH, resulting in the conversion of the salt to acid and alteration of the surface property. The influence of concentration of SO2 gas and pH on humidity responsiveness of the CLCN film was investigated. We hope that this method provides inspirations for the design and fabrication of visualized pH and acidic gas detectors.

Development of automated fumigation chamber for treatment of grapes with SO2 and CO2

AbstractThe export of grapes from one country to another is dependent on the grape's quality that should pass the strict phytosanitary requirements of the importing country. There is a requirement of fumigation of grapes with CO2 and SO2 at specified concentrations for a certain period besides the other pack‐house protocols and export standards. This study was focused to develop and establish an electronically controlled model fumigation chamber for the treatment of grapes in the grapes‐producing region. The gas injection and evacuation systems are electronically operated, and the fumigant concentration can be varied according to the requirement. Heaters of 2 kW are fitted inside the chamber to maintain the treatment temperature above 16°C for grapes fumigation. The fumigation chamber was found leak‐proof during pressurized helium leak testing. The CO2 and SO2 gas concentrations can be maintained between 600 and 60,000 ± 100 ppmv and 10 and 10,000 ± 2 ppmv, respectively, for 1–90 min (1% is equivalent to 10,000 ppmv). The fumigation of grapes with 6% CO2 for 30 min followed by fumigation with 1% SO2 for 30 min ensured 100% mortality of the adult fruit fly (Drosophilla melanogaster). This chamber may also be used for the fumigation treatment of other fruits, vegetables, nuts, and so on, as per the time and concentration of gases required for the 100% mortality of target pest. Nevertheless, the protocol for such treatments should be developed for other fruits, and the effect of the gases on the quality of the products should be studied.Practical ApplicationsThe developed automated fumigation chamber for treatment of grapes with CO2 and SO2 is an effective measure for disinfesting the grapes from invasive pests like Drosophilla suzukii, spiders, and so on. This would help in overcoming phytosanitary measures put in place by many grapes importing countries like New Zealand, Australia, and so on. These countries offer huge market potential for export of Indian grapes, and if the trade barriers are overcome, it would lead to earning huge foreign exchange. Furthermore, the developed automated fumigation chamber can be used as an integral part of horticultural pack houses both for domestic as well as international trade as it would eliminate most of the adult field pests at preliminary stages before pack‐house operation.

Uji Kandungan Gas Sulfur Dioksida (SO2) pada Udara Ambien Akibat Adanya Pembakaran Batubara PLTU Nii Tanasa, Sulawesi Tenggara

Along with the high demand for electrical energy consumption by the Indonesian people, it will also affect the increase in the construction of power plants in various regions. PLTU Nii Tanasa is one of the power plants located in the Lalonggasumeeto District, Konawe Regency, Southeast Sulawesi. This PLTU uses coal as the main raw material in producing electrical energy. This study analyzed the SO2 content in the exhaust gas of PLTU Nii Tanasa. Based on the results of the study, the concentration of SO2 gas in Nii Tanasa Village was 99.31 g/Nm3. The temperature conditions at the time of sampling were 30ºC and the wind speed was 3.7 km/hour. Meanwhile, point 2 is located in Rapambinopaka Village, the distance from the pollutant source is ± 1 km, the concentration of SO2 gas is 147.69 g/Nm3. The temperature at the time of sampling was 25ºC and the wind speed was 3.7 km/hour. The increase in upper respiratory infection disease that occurs every year is not caused by air pollution, especially SO2 parameters.

Reduction Process for Sulfur Chemical Looping Combustion with Fe <sub>2</sub>O <sub>3</sub> Oxygen Carriers

Chemical looping combustion (CLC) is a new energy-saving and energy-efficient combustion technology. In this study, the possible products of CLC were analyzed by determining the equilibrium constants of competitive reactions of sulfur and oxygen carriers (OCs) at different temperatures. The effects of reaction temperature, sulfur partial pressure, and sulfur dioxide partial pressure on the distribution of solid products were evaluated by computing the dominant region diagram. The gaseous and solid products produced by the reduction reaction of sulfur and OCs at different temperatures were simulated using Aspen Plus. The feasibility of sulfur chemical chain combustion was verified through experiments. Research findings indicated that almost all sulfur reacted with OCs to produce SO2 and metal oxide. In addition, a low sulfur equilibrium partial pressure was beneficial to the generation of metal oxide, whereas a high sulfur equilibrium partial pressure was beneficial to the generation of metal sulfide. Under the conditions of a S/Fe2O3 molar ratio of 1:6, a carrier gas flow rate of 300 ml/min, a sulfur gasification temperature of 500 ℃, and an OC reduction temperature of 900 ℃, sulfur CLC was the best. This study laid a foundation for the practical application of sulfur chemical chain combustion to produce high concentrations of SO2 gas and demonstrated the great development potential in the CLC acid-making industry.

Sulfur dioxide sensing properties of MOF-derived ZnFe2O4 functionalized with reduced graphene oxide at room temperature

In this paper, ZnFe2O4 nanorods were prepared using Zn/Fe metal organic framework (MOF) as precursors, and ZnFe2O4/reduced graphene oxide (rGO) was prepared by hydrothermal method. The morphology and composition of the ZnFe2O4/rGO nanocomposite were characterized, and the results showed that the MOF-derived ZnFe2O4 nanorods are uniformly modified on the surface of rGO. The ZnFe2O4/rGO nanocomposite exhibits better SO2 gas sensing performance than the single ZnFe2O4 nanorods at room temperature. The sensing characteristics of single ZnFe2O4 film sensor, single rGO film sensor and ZnFe2O4/rGO composite film sensor at SO2 gas concentration (1 × 10−6–100 × 10−6) were tested. The response of ZnFe2O4/rGO composite sensor can reach 18.32% at room temperature. Compared with single ZnFe2O4 and rGO film sensors, the ZnFe2O4/rGO composite sensor has better transient response, good sensitivity and selectivity. In this work, the improvement of the sensor performance is not only due to the p–n heterostructure between ZnFe2O4 nanorods and rGO nanosheets, but also to the excellent electrical properties of rGO. It provides a new idea for the detection of SO2 at room temperature.

Jet absorption and desulfurization technology of sulfur waste gas in the acrylonitrile apparatus

Considering the sulfuric acid-containing gas (such as H2S and SO2) in the waste gas of the Shanghai Petrochemical Acrylonitrile Apparatus, an injection, absorption, and desulfurization technology is developed for the pilot test of sulfur-containing waste gas in the acrylonitrile apparatus, under the operating conditions of the apparatus and the characteristics of the waste gas. A single hydraulic jet swirl core tube is adopted to study the effects of H2S gas concentration, SO2 gas concentration, NaOH absorption concentration, and intake air amount on desulfurization efficiency. Results show that under the smooth operation of the apparatus, the absorption efficiency of H2S gas and SO2 gas can continuously reach 85 % and 70 % respectively. The absorption efficiency is increased with the increased concentrations of H2S gas and SO2 gas as well as the increase of the liquid volume of the absorption liquid. However, the absorption efficiency decreased as the amount of air intake increases. The findings can serve as valuable reference for the use of injection, absorption, and desulfurization technology in engineering applications.

APPLICATION OF LAND SURFACE TEMPERATURE DERIVED FROM ASTER TIR TO IDENTIFY VOLCANIC GAS EMISSION AROUND BANDUNG BASIN

Gas emission in volcanic areas is one of the features that can be used for geothermal exploration and to monitor volcanic activity. Volcanic gases are usually emitted in permeable zones in geothermal fields. The use of thermal infrared radiometers (TIR) onboard of advanced spaceborne thermal emission and reflection radiometers (ASTER) aims to detect thermal anomalies at the ground surface related to gas emissions from permeable zones. The study area is located around Bandung Basin, West Java (Indonesia), particularly the Papandayan and Domas craters. This area was chosen because of the easily detected land surface temperature (LST) following emissivity and vegetation corrections (Tcveg). The ASTER TIR images used in this study were acquired by direct night and day observation, including observations made using visible to near-infrared radiometers (VNIR). Field measurements of volcanic gases composed of SO2 and CO2 were performed at three different zones for each of the craters. The measured SO2 concentration was found to be constant over time, but CO2 concentration showed some variation in the craters. We obtained results suggesting that SO2 gas measurements and Tcveg are highly correlated. At Papandayan crater, the SO2 gas concentration was 334.34 ppm and the Tcveg temperature was 35.67 °C, results that are considered highly anomalous. The same correlation was also found at Domas crater, which showed an increased SO2 gas concentration of 35.39 ppm located at a high-anomaly Tcveg of 30.65 °C. Therefore, the ASTER TIR images have potential to identify volcanic gases as related to high Tcveg.

Application of bag filter in integrated technology of dry desulfurization and dust collection

A new technical route is explored to realize the integrated design of dry gas desulfurization and dust collection, combining dry duct injection technology with bag filter technology. Sodium bicarbonate (NaHCO3) was used as desulfurizer, outside and inside filtration bag filters were used as the main body of the reaction device. A series of experiments were carried out, and the temperature, NaHCO3 particle size, inlet SO2 concentration, sodium to sulphur ratio and dust concentration were evaluated. The results showed that the desulfurization reaction was mainly composed of two parts: the NaHCO3 injection section of duct and the filtration of bag filter. The desulfurization efficiency of the inside filtration was better than that of the outside filtration, and collection efficiency was maintained above 99.9%. From 130°C to 150°C, the desulfurization efficiency of both inside and outside filtration bag filter increased with temperature increased, but the efficiency decreased at the temperatures of 150°C∼200°C because of the thermal decomposition reaction of sodium bicarbonate. After adding 1000mg·m−3 dust, the desulfurization efficiency of both the inside filtration and outside filtration bag filters increased by 10%, and the trend of desulfurization efficiency with temperature was the same as that before adding dust. It was found that the desulfurization reaction was better with the NaHCO3 particles size was smaller, and the inlet SO2 gas concentration had little effect on the desulfurization efficiency.