H2S Gas Concentration Research Articles

Construction of Ag2O/WO3-based hollow microsphere p-n heterojunction for continuous detection of ppb-level H2S gas sensor

Three-dimensional (3D) hierarchical hollow microsphere WO3 and Ag2O/WO3 heterojunction materials were prepared by a simple hydrothermal method for a highly sensitive continuous response H2S gas sensor. The results show that compared with the original WO3 (Ra/Rg=12.5, 10 ppm, 70℃), the sensor based on Ag2O/WO3 has excellent H2S sensing performance at 60℃. Including ultra-high sensitivity (Ra/Rg=207.12, 10 ppm), continuous detection of different concentrations of H2S gas (0.05–50 ppm), fast response capability (15 s), low detection limit (50 ppb), high selectivity and reliable stability. The study of gas sensing mechanism shows that the synthesized 3D hierarchical hollow microsphere structure provides more channels for gas diffusion and transmission. The dispersion of Ag2O nanoparticles (NPs) on the surface of WO3 provides more reactive sites for gas adsorption. At the same time, the charge transfer is promoted by constructing Ag2O/WO3 p-n heterojunction. Sulfurization of Ag2O improved the response value and selectivity to H2S gas. These factors together determine the superior performance of the prepared Ag2O/WO3 H2S-based sensor.

Preparation of ZnO Thick Films Activated with UV-LED for Efficient H2S Gas Sensing

In this work, ZnO thick films were synthesized via two simple and easy methods, mechanochemical synthesis and screen-printing deposition. The ZnO powders were obtained through milling at low temperature with milling times of 20, 40, and 60 min. The ZnO thick films were fabricated by depositing 10 cycles of ZnO inks onto glass substrates. The characterization of ZnO thick films revealed a thickness ranging from 4.9 to 5.4 µm with a surface roughness between 85 and 88 nm. The structural analysis confirmed a hexagonal wurtzite crystalline structure of ZnO, both in powders and in thick films, with a preferred orientation on the (002) and (101) planes. Nanostructures with sizes ranging from 36 to 46 nm were observed, exhibiting irregular agglomerated shapes, with an energy band found between 2.77 and 3.02 eV. A static experimental set up was fabricated for gas sensing tests with continuous UV-LED illumination. The ZnO thick films, well adhered to the glass substrate, demonstrated high sensitivity and selectivity to H2S gas under continuous UV-LED illumination at low operating temperatures ranging from 35 to 80 °C. The sensitivity was directly proportional, ranging from 3.93% to 22.40%, when detecting H2S gas concentrations from 25 to 600 ppm.

Achieving Room-Temperature ppb-Level H2S Detection in a Au-SnO2 Sensor with Low Voltage Enhancement Effect.

Although semiconductor metal oxide-based sensors are promising for gas sensing, low-power and room temperature operation (24 ± 1 °C) remains desirable for practical applications particularly considering the request of energy saving or net zero emission. In this study, we demonstrate a Au/SnO2-based ultrasensitive H2S gas sensor with a limit of detection (LOD) of 2 ppb, operating at very low voltages (0.05 to 0.5 V) at room temperature. The Au/SnO2-based sensor showed approximately 7 times higher response (the ratio of change in the current to initial current) of ∼270% and 4 times faster recovery (126 s) compared to the pure SnO2-based sensor when exposed to 500 ppb H2S gas concentration at 0.5 V operating voltage at relative humidity (RH) 17.5 ± 2.5%. The enhancement can be attributed to the catalytic characteristics of AuNPs, increasing the number of adsorbed oxygen species on sensing material surfaces. Additionally, AuNPs aid in forming flower-petal-like Au/SnO2 nanostructures, offering a larger surface area and more active sites for H2S sensing. Moreover, at low voltage (<1 V), the localized dipoles at the Au/SnO2 interface may further enhance the absorption of polar oxygen molecules and hence promote the reaction between H2S and oxygen species. This low-power, ultrasensitive H2S sensor outperforms high-powered alternatives, making it ideal for environmental, food safety, and healthcare applications.

Analysis of the Formation Mechanism of Hydrogen Sulfide in the 13# Coal Seam of Shaping Coal Mine.

In order to accurately predict the law of occurrence and migration of hydrogen sulfide (H2S) in the underground and effectively solve the problem of excessive concentration of H2S gas, laboratory experiments on the content of various forms of sulfur in coal, sulfur isotopes, thermal evolution history, and coal seam water samples were carried out by applying the theories of coal mine geology, microbiology, and analytical chemistry, and based on the experimental results, the cause of H2S gas was explored. Through the analysis of the geological conditions of the coal seam mined, it can be seen that the coal mine experienced the alternation of marine and continental phases in the process of coal formation and that there was no magma intrusion. The experimental results showed that iron sulfide in coal accounts for 73.25% of the total sulfur, indicating that the coal seam was rich in pyrite. The results of the isotope test showed that the sulfur isotopes in coal samples were all negative, indicating that the sulfur isotope fractionation in coal was large, the loss was serious, and the coal seam was greatly affected by seawater. According to the experimental results of vitrinite reflectance, it can be concluded that the highest temperature during the thermal evolution of the coal seam is 108.12 °C, which has not reached the temperature condition of sulfate thermochemical reduction. Comparing the concentration of acid ions in coal seam water and tap water, it was found that the concentration of SO42- in coal seam water is low, while the concentration of HCO3- is high. According to the experimental results and theoretical analysis, the H2S gas in the high-sulfur coal mine was caused by microbial sulfate reduction. Finally, the transformation path of sulfur in the coal seam was deduced and analyzed. The results showed that sulfur in coal is positively correlated with H2S gas concentration.

Efficient Cellulose/Nano‐silver Composite Sheet Derived from Pineapple Leaves for Hydrogen Sulfide Detection

AbstractPineapple leaves, a raw agricultural waste biomass material, were used to synthesize microcrystalline cellulose (MCC) through extraction, bleaching, and hydrolysis. Then, the MCC was mixed with different concentrations of silver nitrate solution to create a regenerated cellulose composite sheet loaded with silver nanoparticles (AgNPs) and used as a hydrogen sulfide (H2S) detector. The physicochemical properties of the cellulose composite sheet loaded with AgNPs before and after H2S exposure were analyzed using various advanced equipment. The H2S adsorption experiments revealed that the composite sheet underwent a visible change from yellow to brown upon exposure to H2S gas. The range for accurate prediction of the H2S concentration was 20–50 ppm. When temperature in the surroundings of the composite sheet was lower and the H2S gas concentration was higher, the color became darker (dark brown). The relative humidity conditions rarely impacted the sensitivity of color change in the cellulose composite sheet. The stability experiment showed that the cellulose composite sheet had exceptional stability at storage temperatures of 4 and 25 °C for 30 days. This composite sheet mixed with AgNPs has the potential to be used as a gas test strip to detect H2S, such as in food packaging.

Enhanced H2S gas sensing of Pd functionalized NiO thin films deposited by the magnetron sputtering process

This letter presents the H2S gas sensing results of Pd-decorated NiO (Pd/NiO) thin films deposited by the magnetron sputtering process. The presence of the Pd catalyst enhanced the H2S sensing capability of NiO thin films in terms of high response (Rg/Ra ratio ∼ 15) and relatively lower optimum operating temperature (Topt) at 250 °C for 100 ppm H2S gas concentration. Further, the Pd/NiO thin films also exhibited a fast response/recovery time of ∼65 s/29 s, low detection concentration (∼2 ppm), good stability, and high selectivity at Topt (i.e., at 250 °C) towards H2S gas. The significantly improved H2S gas sensing properties of the Pd/NiO thin films can be mainly attributed to the modulation of the potential barrier and an increase in the specific surface area for the target gas adsorptions. Thus, the current work offers the development of highly responsive Pd functionalized NiO thin films for H2S gas sensors, which ensures low power requirements.

Environmental health risk analysis of Hydrogen Sulfide (H2S) exposure to Jabon Sidoarjo landfill scavengers

Scavengers work every day by interacting with waste in landfill making them a group with a high risk of contracting diseases due to unhealthy working conditions and exposure to air pollutant gases, one of which is hydrogen sulfide gas (H2S). H2S gas can cause respiratory problems for scavengers such as coughing, flu, fever, headache, shortness of breath, sore throat, and sore nose. This study aims to analyze the environmental health risks analysis of hydrogen sulfide gas (H2S) exposure in Jabon Sidoarjo landfill scavengers. This research is a descriptive study with cross sectional design. The approach used is Environmental Health Risk Analysis. Measurement of H2S gas concentration was carried out in the scavenger work area. The research respondents were 46 scavengers who worked in old landfill. Data analysis using univariate analysis and risk analysis. The results for the concentration of H2S in the scavenger work area point 1 and point 2 were 0.00242 ppm and 0.00081 ppm. Analysis of the risk quotient (RQ) in real time, the next 10 years, and in real life, the result is 0.13; 0.25; 0.37. The results showed that the measurement of H2S gas concentrations in the scavenger work area was still below the provincial government's environmental quality standards. Risk quotient analysis (RQ) shows results below 1. This shows that scavengers are still safe from non-carcinogenic risks or the H2S gas produced is not at risk of causing health problems.

A Visual Color Response Test Paper for the Detection of Hydrogen Sulfide Gas in the Air.

Hydrogen sulfide (H2S) is widely found in oil and natural gas wells and industrial wastewater tanks. Owing to its high toxicity, the monitoring and detection of H2S in the air is essential. However, recent techniques for the quantitative detection of H2S gas suffer from limitations such as high cost, complicated operation, and insufficient sensitivity, preventing their practical application in industry. Thus, we have developed a portable test paper for real-time and inexpensive monitoring of H2S gas by color changes. The test paper had a significantly low H2S detection limit of 200 ppb, which is considered safe for humans. Moreover, the color of the test paper did not change noticeably when exposed to CO2, N2, O2, and air environments, indicating that the test paper is selective for H2S gas and can be stored for a long time. In addition, we fitted a color difference linear model between the color difference values (ΔE) and the concentrations of H2S gas. The establishment of the linear model substantiates that the test paper can provide accurate intensity information when detecting H2S gas leakage.

Effect of Au Doping on ZnO Nanoporous Structure for H2S Gas Sensing

This research mainly constitutes the fabrication of semiconductor gas sensors using high Power pulse magnetron sputtering (HiPIMS) technology to deposit ZnO thin films. As a doping substance, different thicknesses of gold plating is deposited on the surface of ZnO thin films. Various thicknesses of gold used in the study are 3.3 nm, 6.6 nm, 10 nm, 13.3 nm and 16.6 nm. The structural properties of thin films were identified by X-ray- diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). EDS analysis conveyed that gold particles filled the pores of nanoporous ZnO structures, which increased the films surface area and enhancing the gas sensing response. Various concentrations of H2S gas is used to test the gas sensing properties and the results proved the Au doped ZnO thin film sensor has enhanced sensing than the pure ZnO thin film sensor. 10 nm thickness doped Au has prime sensing properties with the operating temperature of 300 °C. Other sensing properties such as repeatability, selectivity and effect of humidity are tested and presented the data which shows the Au doping ZnO superiority over pure ZnO thin films.

Hydrogen sulfide measurement of combustion gaseous product using ultraviolet absorption spectroscopy

Measurement of hydrogen sulfide (H2S) in gaseous product can provide direct reference for high-temperature corrosion of industrial combustion equipment. Aiming at the interference effect of overlapping measurement of absorption spectrum for H2S and other combustion gas components in UV absorption spectroscopy, the simulation calculation of ultraviolet band absorption spectrum of the typical gaseous products of coal combustion were carried out. The cross interference effects of combustion gaseous products were analyzed in detail. Due to the SO2 and H2S gas under typical combustion condition have equivalent absorption strength in the 228 nm-233 nm band, the influence of SO2 on H2S concentration inversion must be emphatically considered, and the inversion algorithm of H2S gas concentration under the background interference of combustion gaseous products SO2 was put forward. In order to validate the measurement accuracy by the inversion algorithm, the measurement experiments of gas mixture of H2S and SO2 were carried out. The results show that the algorithm can effectively solve the problem of cross interference between the detection of H2S and SO2 in the combustion gaseous products by UV absorption spectroscopy. On this basis, the sampling, pre-treatment and H2S gas concentration measurement system for boiler flue gas near the wall was developed and applied to measure H2S concentration of flue gas near the wall in a 1000 MW ultra-supercritical coal-fired power generation boiler. The results can provide important references for combustion adjustment and high-temperature corrosion prevention of boiler.

Synthesis, characterizations, and hydrogen sulfide gas sensing application of BiOx (x = 1, 1.5) nanostructures

Hydrogen sulfide is one of the harmful gases that contribute to air pollution. Therefore, there is a need to develop high-response hydrogen sulfide (H₂S) gas sensors. Herein, the bismuth oxide nanostructured material was prepared using the hydrothermal chemical route. The prepared material was characterized using XRD, FESEM, TEM, XPS, EDS, and UV–visible spectroscopy techniques. The gas sensor device was fabricated using bismuth oxide nanomaterial, and gas sensing properties were investigated. The sensor exhibited the highest response of 22–92% towards H₂S gas at 250 °C for 10–100 ppm concentration range, respectively. The 92% response was recorded for 100 ppm H2S gas with rapid response and recovery times of 511 and 492 s, respectively. The sensor was tested at different operating temperatures and H2S gas concentrations. The sensor's selectivity, dynamic resistance response repeatability, and long-term (30 days) stability were studied. The nanostructured bismuth oxide can be a promising candidate for high-response H₂S sensor applications.

Hydrogen Sulfide Gas Detection in ppb Levels at Room Temperature with a Printed, Flexible, Disposable In2O3 NPs‐Based Sensor for IoT Food Packaging Applications

AbstractFlexible printed sensors are essential components for modern Internet of Things applications. They may twist and bend to fit any shape or surface. New potential applications emerge as these sensors’ sophistication and sensing efficiency improve. In this study, a printed sensor is prepared from indium oxide nanoparticles (In2O3 NPs)‐based nanocomposite for hydrogen sulfide (H2S) gas detection at ambient conditions. The as‐fabricated sensor has excellent capabilities, including sensitivity and selectivity to low gas concentrations than 100 ppb (&lt;100 ppb), anti‐humid property up to relative humidity (RH) ≈ 100%, high chemical stability in severe environments, good mechanical flexibility up to 50 bending cycles at 30° bending angle, and good thermomechanical stability between ‐40 °C ‐ 40 °C. Moreover, the sensor detects the low concentrations of H2S gas produced during the spoilage of organosulfur‐rich food (beef and fish) while remaining insensitive to humidity changes up to RH ≈ 100%, resulting in the fist‐of‐its‐type chemiresistive sensor for food packaging application. The sensors’ response to H2S gas is based on the contribution of the physical and chemical sensing mechanisms, which rely on the H2S molecules’ reactions on the sensor's surface with the adsorbed oxygen molecules and the sensing materials (copper acetate (CuAc) and In2O3 NPs), respectively.

Hydrogen sulfide gas sensing toward on-site monitoring of chilled meat spoilage based on ratio-type fluorescent probe

In this study, a fluorescence sensing platform for visual detection of hydrogen sulfide (H2S) based on ratiometric fluorescent substances was developed to real-time monitor meat spoilage. The copper nanoclusters (CuNCs) and nitrogen-doped carbon quantum dots (CNQDs) were used as dual emission fluorescence materials. The fluorescence ratio of the two wavelengths decreased in the sulphide concentration range of 0–3 μmolL(exp)−1, with a detection limit of 62.7 nmolL(exp)−1. In order to capture hydrogen sulfide gas in the air, the ratio fluorescent material is loaded on the paper base. By processing the RGB value of the photo under UV light, the detection limit of the sensor is 4.35 ppt in the range of 0 ∼ 45.2 ppt H2S gas concentration. This portable visual analysis greatly simplifies the steps of H2S gas detection while ensuring sensor stability and sensitivity. It also provides a new method for H2S detection during the meat storage process.

Risk Analysis of Exposure to NH3 And H2S Gas to Workers in The Small Industrial Environment of Magetan Regency in 2021

ABSTRACT Decomposition of fur, meat, and skin residues produces NH3 and H2S gases that may pose a risk to worker health. NH3 gas is a gas that has a characteristic pungent odor, is corrosive, and is highly toxic even in low concentrations. Exposure to H2S gas can cause bad effects on health because it is quickly absorbed by the lungs. This study aims to analyze and determine the risk of exposure to NH3 and H2S gases to workers' health in the Magetan Regency Small Industrial Environment (LIK). The design of this study is descriptive-quantitative, that is, a study that aims to describe or characterize an event that occurs in numerical and narrative form. The study used a cross-sectional temporal approach and an environmental health risk analysis (ARKL) approach. The sample consisted of 13 workers. Air samples were collected from a site where the leather tanning process was conducted in the unbundling phase. The data analysis method used is the risk analysis to determine the risk characterization of workers in the small industrial environment (LIK) Magetan. Based on ARKL guidelines, the level of risk is called "safe" when the RQ value is 1, and the level of risk is called "unsafe" when the RQ value is &gt; 1. The results show that the NH3 and H2S gas concentration is still below the NAV value based on the Minister of Manpower and Transmigration Order No. PER .05/MEN/X/2018, which is 25 ppm and 1 ppm, respectively. The ARKL calculation uses the minimum and maximum values for measuring NH3 and H2S gas concentrations with reference concentration (RfC) values of 0.5 mg/kg/day and 0.002 mg/kg/day. The RQ value for workers for NH3 and H2S gas concentrations RQ &lt; 1 is safe for workers.

Catalytic effect of Ag embedded with ZnO prepared by Co-sputtering on H2S gas sensing MEMS device

Ag doped ZnO thin films are deposited on a micro electromechanical systems (MEMS) device incorporating a microheater and sensing electrodes using a co-sputtering system. Structural properties and sensing properties were tested with pure Zn alongside with 0.15%, 0.3%, 0.5%, 1% and 2% Ag doping concentrations. The H2S gas sensing performance of the MEMS-based devices is evaluated for H2S concentrations in the range of 0.2–1.0 ppm and heating temperatures of 150–300 °C. The optimal sensing performance is obtained with a Ag concentration of 0.5% and a working temperature of 250 °C. For an H2S gas concentration of 1 ppm, the sensor achieves a sensing response of 16% and a response time of 3 s. The sensor additionally shows good selectivity for H2S gas compared to that for CO, NO2, NH3 and SO2, respectively. Finally, different response time phenomenon is explained due to the formation of Ag+ on doped ZnO surface.

Study on the Distribution Law of Coal Seam Gas and Hydrogen Sulfide Affected by Abandoned Oil Wells

This paper is devoted to solving the problem of how to comprehensively control coal seam gas and hydrogen sulfide in the mining face, distributed from the coal seam in abandoned oil wells in coal mining resource areas. The abandoned oil wells of Ma tan 30 and Ma tan 31 in the No. I0104105 working face of the Shuang Ma Coal Mine were taken as examples. Through parameter testing, gas composition analysis, field investigation at the source distribution, and the influence range of gas and hydrogen sulfide in coal seam in the affected range of the abandoned oil wells were studied. The results show that the coal-bearing strata in Shuang Ma coal field belong to the coal–oil coexistence strata, and the emission of H2S gas in the local area of the working face is mainly affected by closed and abandoned oil wells. Within the influence range of the abandoned oil wells, along the direction of the working face, the concentration of CH4 and H2S gas in the borehole increases as you move closer to the coal center, and the two sides of the oil well show a decreasing trend. In the affected area of the abandoned oil well, the distribution of the desorption gas content in coal seam along the center distance of the oil well presents a decreasing trend in power function, particularly the closer the working face is to the center of the oil well. The higher the concentration of CH4 and H2S, the lower the concentration when the working face moves further away from the oil well. The influence radius of CH4 and H2S gas on the coal seam in the affected area of Ma tan 31 abandoned oil well is over 300 m. The results provide a theoretical basis for further understanding the law of gas and hydrogen sulfide enrichment in the mining face and the design of treatment measures within the influence range of abandoned oil wells.

Hydrothermal synthesis of ZnO nanoflakes composed of fine nanoparticles for H2S gas sensing application

The ZnO has the potential to form a number of nanostructures with various morphologies that can influence the gas sensing properties. Herein, hydrogen sulphide (H2S) gas sensing properties of the ZnO powder with novel 2D nanoflake morphologies prepared using a hydrothermal technique is reported. The physicochemical properties of the ZnO were investigated by XRD, FESEM, TEM, EDS, elemental mapping, XPS, Raman, and UV–Visible spectroscopy. The ZnO powders were utilized to fabricate the gas sensors, and the sensor's responses were tested at various operating temperatures and gas concentrations. The sensor exhibited a high response towards H2S gas in the range of 10–100 ppm at 250 °C and the highest response of 94% for 100 ppm H2S gas concentration. The transient resistance response of the ZnO sensor was tested for 100–10 ppm H2S gas concentration. The sensor showed the excellent repeatability of the resistance response. The H2S sensing mechanism and stability of the ZnO sensor were studied.

Study of emitted gases from incinerator of Al-Sadr hospital in Najaf city

Abstract Medical waste incinerator of Al-Sadar hospital in Najaf city is one of the environmental pollution sources in the city due to reasons related to the quantity and quality of gases emitted from it, so this study aims to estimate environmental damage by determining the concentrations of some of these emitted gases. The study is concerned with determining the concentrations of six gases over five months (November 2013–March 2014), these gases were oxygen (O2), silane (SiH4), hydrogen (H2), sulfur dioxide (SO2), nitrogen dioxide (NO2), and hydrogen sulfide (H2S), in addition to studying some weather factors such as wind speed and temperature that affect on the concentrations of the gaseous pollutants. It is found that the study area suffers from pollution with SO2 gas, which is one of the main standard pollutants for assessing polluted areas, where the mean of gas concentration during the study period was 0.205 [ppm] and thus exceeded the permissible limits. Moreover, some of the studied gases (like NO2 and H2S) have concentration close to the upper limit of the standards, where NO2 gas concentration in December and January were 0.17 [ppm] and 0.2 [ppm], respectively, and H2S gas concentrations in February and March were 3.5 [ppm] and 4.4 [ppm], respectively, which poses a threat to public health and other elements of the environment, which confirms the existence of an air pollution problem that the study area and the nearby areas suffer from.

Removal of Gaseous Hydrogen Sulfide by a FeOCl/H2O2 Wet Oxidation System

The removal of gaseous hydrogen sulfide using FeOCl/H2O2 was studied. The effects of the FeOCl dosage, the H2O2 concentration, the reaction temperature, and the gas flow rate on the removal of H2S were investigated. The reaction products were analyzed, and the characterization of FeOCl was carried out by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy. Furthermore, radical quenching experiments were carried out using butylated hydroxytoluene, isopropanol, and benzoquinone. It was found that the H2S removal rate for a H2S gas concentration of 160 ppm reached 85.6% when bubbling through 100 mL of an aqueous solution containing FeOCl (1 g/L) and H2O2 (0.33 mol/L) at 293 K with a flow rate of 135 mL/min. Although the dissolution of chlorine in FeOCl was found to result in reduced catalytic performance, the activity was restored after soaking the catalyst in concentrated hydrochloric acid (37%) and subsequent calcination. The mechanism of H2S removal was also discussed, and it was found that this process was controlled by H2S diffusion. FeOCl was found to activate H2O2 and produce radicals, such as •OH and •O2–, resulting in the formation of a water film rich in radicals on the FeOCl surface. Following the diffusion of H2S into the water film, it underwent oxidation by radicals to produce SO42–. Overall, the catalyst and the product can be effectively separated.

Sensing Sub-ppm Concentration of H2S Gas at Room Temperature Using Silver-Doped SnO2 Nanocrystals

Sensing Sub-ppm Concentration of H2S Gas at Room Temperature Using Silver-Doped SnO2 Nanocrystals