Carbon Monoxide Gas Concentration Research Articles

RGO/CuCl-Based Flexible Gas Sensor for High-Concentration Carbon Monoxide Gas Detection at Room Temperature.

Carbon monoxide (CO) gas sensors are widely used, especially for environmental monitoring in confined spaces such as the landscape of mining cave ruins in mining parks, which is essential for ensuring the health and safety of tourists and staff. In this paper, a flexible CO gas sensor based on polyimide, interdigital electrodes, and reduced graphene oxide (RGO)/cuprous chloride (CuCl) composite film is designed and manufactured for reliable room temperature detection of high-concentration CO gas. The structure size of RGO/CuCl gas-sensitive film is 5 × 5 mm. The RGO with a 62.65% C-C bond is prepared by the thermal reduction method. The test results show that the sensor has a high response in the range of 400-2000 ppm CO gas concentration, and the maximum response is 1.56. The linear correlation coefficient of the sensor is 0.981, which indicates that the sensor has good output response characteristics. The response time of the sensor for 400 ppm CO gas is 332 s, which indicates that the sensor has a fast response rate. Furthermore, compared with other gases, the sensor shows higher gas selectivity for CO gas. This sensor has the characteristics of small size and easy attachment; therefore, it can be installed on the shoulder or helmet of tourists' safety suits, providing personalized real-time warning prompts for tourists' physical health status.

Hard-Target Reflection Laser Spectroscopy of Carbon Monoxide Gas Concentration for the Early Detection of Spontaneous Combustion of Coal.

We report on the hard-target reflection spectroscopy of carbon monoxide (CO) gas based on the technique of infrared tunable diode laser absorption spectroscopy aiming at developing a low-cost yet sensitive sensor for the early detection of spontaneous coal combustion. A narrow-band distributed feedback laser emitting around 2333.7 nm is used to monitor CO gas molecules contained in a 5 cm gas cell. The light diffusely backscattered from the surface of a lump of coal placed at the end of a 50 cm light path is detected with a photodiode in the coaxial transmitter/receiver setup. From the variation of the detected signal profile with the CO partial pressure in the cell, the detection limit of the current system is estimated to be about 30 parts per million per meter (ppm·m), which meets the sensitivity required for monitoring the self-heating of coal in mines, silos, or stockpiles.

Effectiveness of Pregnane Glycoside Compound Extracts from Sansevieria Trifasciata Laurentii and Sansevieria Trifasciata Plants in Reducing Carbon Monoxide Gas

This study aimed to evaluate the effectiveness of pregnane glycoside compound extracts obtained from the Sansevieria trifasciata Laurentii plant in reducing carbon monoxide (CO) emissions. The extraction method uses solvent extraction techniques with organic solvents to isolate active compounds from the plant. After extraction, the pregnane glycoside compound was tested at various concentrations to determine its effectiveness in reducing CO gas concentrations. Tests were carried out using tools that allow real-time gas monitoring. The results of this study show that the pregnane glycoside compound extract from the Sansevieria trifasciata Laurentii and Sansevieria trifasciata plants can reduce carbon monoxide gas with significant effectiveness. This research contributes to the development of natural solutions for reducing air pollution caused by CO gas and can develop plant-based air treatment technology.

DEVELOPMENT OF A PORTABLE MOTOR VEHICLE EMISSION TEST SYSTEM BASED ON ARDUINO WITH ANDROID INTERFACE

This study takes a comprehensive approach by proposing the design of an innovative emission test tool for motorized vehicles. The primary objective of this tool's design is to establish an alternative emission testing apparatus based on Arduino AT-Mega 2560, proficient in capturing vehicle exhaust emissions. The underlying methodology involves an in-depth investigation of various components, including the MQ2 and MQ7 sensors, microcontrollers, and supplementary sensors. This meticulous observational process aims to unravel the fundamental principles that govern the functionality of these components. Subsequently, the study advances to the prototyping phase, manifesting in the creation of an Android-based emission test system. This system capitalizes on the integration of Arduino programming and App Inventor technology. The integrated system is devised to facilitate sensor data acquisition. The empirical results of the tests indicate that the developed tool effectively measures hydrocarbon gas and carbon monoxide gas concentrations, yielding readings of 6.31% and 3.73%, respectively, under engine conditions ranging from 1500 to 3000 rpm with error in regions 1.4% and 5.1% compared to a commercial instrument. However, during the testing phase, certain challenges surfaced. Notably, the presence of water particles within the tool, coupled with the generation of heat due to the accommodated exhaust gases, increased the temperature within the tool's enclosure. Consequently, the sensors' temperature escalated, resulting in erratic sensor behavior and unstable readings. Nonetheless, a significant advantage of the proposed tool lies in its real-time data visualization capability, which is particularly accessible through Android smartphones. This feature enhances the immediacy of test results, facilitating prompt analysis and decision-making. In conclusion, this study lays the groundwork for an innovative emission testing tool that demonstrates promise in addressing the air quality degradation stemming from vehicular emissions.

CO-based early warning threshold for coal spontaneous combustion

Few studies have been involved in the CO-based early warning threshold, although carbon monoxide (CO) is a vital gas indicator for predicting coal spontaneous combustion. In this paper, based on the dependency relationship between CO concentration and coal temperature, a novel approach is proposed to determine the critical value of CO. Firstly, the low-temperature oxidation characteristics of coal samples were investigated through a temperature-programmed system, and the critical temperature of coal samples was analyzed. Furthermore, the functional relationship between CO emissions and coal temperature was investigated based on on-site measurements. Accordingly, the critical value of CO corresponding to the critical temperature was determined. Finally, the migration and generation behavior of CO was studied by combining with air seepage, component transport, thermal transfer, and exothermic reaction. The results show that when the coal temperature in goaf reaches the critical temperature of 53 °C, the CO concentration will reach 110.84 ppm. This concentration is the critical value of CO. The numerical simulation analysis of CO gas migration in goaf shows that when CO concentration reaches the critical value, the CO gas concentration in the corner of the upper corner, the return air flow, and extraction pipeline are 10.69 ppm, 7.91 ppm and 67.26 ppm, respectively. This concentration is the critical value of CO at the corresponding position. The approach established can meet the requirements of identification of spontaneous combustion potential of coal, and ensure the safety of mine production.

Ni-MOF-74 film coated optical microfiber CO sensor cascaded with spiral fiber grating temperature compensator

Metal-organic framework (MOF) material is a good carbon monoxide (CO) storage material. This paper proposed a composite optical fiber structure based on spiral fiber grating (SFG) and tapered microfiber (TMF), which can realize the simultaneous sensing of CO concentration and temperature by coating different functional films. The refractive index (RI) of Ni-MOF-74 coated on tapered microfiber can be changed by absorbing CO molecules. The thermal expansion of Ultraviolet (UV) glue will change the period of the spiral fiber grating. Based on the above mechanism, the research shows that the CO sensitivity of the optical microfiber can reach 64.11 pm/ppm, and the temperature sensitivity is −30.1 pm/°C. The temperature sensitivity of the spiral fiber grating can reach 294 pm/°C, which can effectively compensate for the temperature sensitivity of the microfiber. This composite structure has a good application prospect in accurate CO gas concentration measurement.

CVD-fabricated Co3O4-Co3S4 heterojunction for ultra-sensitive detection of CO in SF6 discharge decomposition products

SF6-insulated electrical equipment will produce CO gas when it fails. Therefore, effective detection of CO gas can determine whether SF6-insulated electrical equipment is operating normally. In this paper, the p-Co3O4/n-Co3S4 heterojunction was fabricated by two-phase hydrothermal and chemical vapour deposition (CVD) methods for CO detection. The gas sensitivity of the p-Co3O4/n-Co3S4 heterojunction to CO in both the air and SF6 background was studied for the first time. The results show that the best operating temperature of the sensor is 200°C in both air and SF6 environment. The sensor showed a better response in the SF6 background than in the air background, but the recovery time was longer in the air background. At the same time, the sensor has good selectivity for CO in both environments, resistance to moisture, and long-term stability. In addition, it is proven by first principles that the adsorption performance of the p-Co3O4/n-Co3S4 heterojunction on CO is better than that of the p-Co3O4 and n-Co3S4, and the interaction between p-Co3O4/n-Co3S4 heterojunction and CO is further described by differential charge density and state density curves. The designed and constructed carbon monoxide detection system can realise the effective detection and alarm of carbon monoxide gas concentration.

Sensitive carbon monoxide detection based on laser absorption spectroscopy with hollow‐core antiresonant fiber

AbstractA carbon monoxide (CO) sensing system based on hollow‐core antiresonant fiber (HC‐ARF) is developed using tunable diode laser absorption spectroscopy (TDLAS) technology. A HC‐ARF with length of 75 cm is applied as light transmission passage and gas chamber. Compared with conventional multipass cell, HC‐ARF has the advantages of compact volume, low cost, steady transmission, and simple optical alignment. Two techniques of direct absorption spectroscopy (DAS) and wavelength modulation spectroscopy (WMS) were used respectively. In DAS, the minimum detection limit (MDL) was 12251.04 ppm. In WMS, the modulation depth of this HC‐ARF based CO‐TDLAS sensor was optimized to be 0.13 cm−1 and the R‐squared numeric of the linear relationship between the peak of the 2 f signal and the gas concentration was 0.99, indicating that the system has a nice linear responsiveness to the CO gas concentration. Finally, the MDL of the sensor was calculated to be 196.33 ppm.

Argyrophilic nucleolar organizer regions as a promising biomarker for the detection of brain hypoxia levels caused by different doses of carbon monoxide poisoning.

The purpose of the study is to investigate whether there is any relationship between mean argyrophilic nucleolar organizing regions (AgNOR) number and total AgNOR area/total nuclear area (TAA/TNA) ratio and the levels of brain hypoxia after exposure to different acute doses of carbon monoxide (CO) gas. Each experimental group was exposed to CO gas (concentrations of 1,000, 3,000 and 5,000 ppm). Then, the rats were anesthetized, and blood samples were taken from the right jugular vein for carboxyhemoglobin levels detection. The rats were sacrificed on seventh day. AgNOR staining was applied to brain tissues. TAA/TNA and mean AgNOR number were detected for each nucleus. Significant differences were detected among all groups for TAA/TNA ratio, mean AgNOR number and carboxyhemoglobin level. According to a double comparison of groups, the differences between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 5,000 ppm were significant for TAA/TNA ratio. When mean AgNOR number was considered, significant differences were detected between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 3,000 ppm. AgNOR proteins may be used for early detection of the duration, intensity, and damage of brain injury caused by CO poisoning. Thus, effective treatment strategies can be developed for the prevention of hypoxic conditions.

Measuring the concentrations of carbon monoxide gas in the departments of Salah al-Din General company of Industry and Minerals

The CO gas concentration Was measured in the company of Salah aldin general of industry and minerals during six months by once in every month during the period of study from (October 2012) to( March 2013) . the results of statistical analysis showed that the increase concentration of (CO) significantly compare with control in all month study. The highest recorded value of (CO)gas pollution is (8.222ppm) at significantly level (p≤0.05) in the cycle breakers electric plant were the lower value in plastic packaging plant recorded values ranging (2.111ppm) at significantly level (p≤0.05).

High Performance of Carbon Monoxide Gas Sensor Based on a Novel PEDOT:PSS/PPA Nanocomposite.

In this work, the carbon monoxide (CO) detection property of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/poly(p-anisidine) (PEDOT:PSS/PPA) nanocomposite was systematically investigated at room temperature. The PEDOT:PSS/PPA nanocomposite was synthesized by the cost-effective “in situ chemical oxidation polymerization” technique. The electric, optical, spectroscopic, and structural properties of the as-prepared nanomaterials were analyzed with I–V, UV–vis, Raman, Fourier transform infrared (FTIR), and X-ray diffraction (XRD) spectroscopies. Topological investigations of materials were conducted by atomic force microscopy (AFM). The gas-sensing performance of the PEDOT:PSS/PPA and PEDOT:PSS nanocomposites toward CO gas in the concentration range of 50–300 ppm at room temperature was explored, and their performances were compared. The PEDOT:PSS/PPA sensor shows a perfectly linear response to different concentrations (50–300 ppm) of CO gas (R2 = 0.9885), and the response time and recovery time of the CO gas sensor (100 ppm) can be about 58 and 61 s, respectively, showing high sensitivity to CO gas and rapid response recovery with outstanding stability. Thus, the PEDOT:PSS/PPA-based sensors, with their impressive sensing performance, may give assurance for future high-performance CO-sensing applications.

The Effectiveness Of Substances In Growth Regulators On Growth Of Root Cutting Of Mother-In Law’s Tongue Leaves (Sansevieria trifasciata)

Air pollution is often a major problem in industrial cities because it causes various respiratory diseases. Mother-in law’s tongue (Sansevieria trifasciata) is an ornamental plant that has many benefits. One of them is to help reducing the concentration of carbon monoxide gas in the air. In addition, this plant is easily propagated by cutting. The purpose of this study was to determine the effectiveness of natural and synthetic growth regulators (ZPT) with various doses on root growth of three materials from plant cuttings. This study used a completely randomized design (CRD) with three factors and three replications. The first factor was the type of ZPT, among others, shallot filtrate and Rootone-F. The second factor is the forth ZPT concentration. They are 25%, 50%, 75% and 100%. The third factor is the origin of the plant cuttings. If the collected data has a significant effect it would be further tested by using DMRT (Duncan Multiple Range Test) at a level of 5%. The results showed that the difference in ZPT had a significant effect on root length, but did not affect significantly the number of roots, fresh weight and dry weight. The treatment interaction had a very significant effect on the root length of Sansivera. The interaction with the highest value was found in the interaction of treatment with PGR type Rootone-F with a concentration of 100% with the cuttings originating from the middle of the plant, while the lowest was in the interaction between PGR type and onion filtrate with a concentration of 25% with the cuttings originating from the tip of the plant.

Carbon monoxide gas sensor based on an α-Fe2O3/reduced graphene oxide quantum dots composite film integrated Michelson interferometer

A carbon monoxide (CO) sensor based on a Michelson interferometer combined with α-Fe2O3/reduced graphene oxide quantum dots (rGOQDs) composite film is proposed and fabricated. First, a waist-enlarged taper is formed between the single-mode fiber (SMF) and the no-core fiber (NCF), then the other end of the NCF is spliced with a section of thin-core fiber (TCF). The end of the TCF is coated with a layer of silver film to enhance the reflection. Thus, a Michelson interferometer comprising SMF–NCF–TCF is formed. The α-Fe2O3/rGOQDs composite film is deposited on the outside surface of the TCF. The specific adsorption of CO by the composite film leads to a change in the sensor’s effective refractive index, realizing the detection of CO. The results show that the interference intensity of the monitoring valley decreases with increase in the concentration of CO. The sensitivity of the sensor is 0.057 dBm ppm−1, the detection limit of the sensor is 105 ppb and the response time and recovery time are 70 s and 100 s, respectively. The sensor has the advantages of high sensitivity, high selectivity and simple structure, and it is expected to be used for the detection of low concentrations of CO gas.

Influence of zinc on the multifunctional properties of ferrites [formula omitted] (M = Cu, Mg, Ni, x = 0, 0.35)

We study the magnetic and gas sensing properties of M1-xZnxFe2O4 where M = Cu, Mg, Ni, and x = 0, 0.35, focussing on the influence of zinc on their application as a soft magnetic material and a sensor as well. Ferrites are synthesized by thermal decomposition of the glyoxylate precursor obtained from the redox reaction between metal nitrate and ethylene glycol. The phase formation and microstructure were investigated using X-ray diffraction and electron microscopic methods. X-ray diffraction analysis confirmed the cation redistribution in the spinel lattice due to zinc doping. The porous structure was studied using nitrogen adsorption-desorption isotherms and confirmed the role of zinc on the surface structure. The magnetic properties of the ferrites under the influence of zinc were measured using a vibration sample magnetometer. The oxidation state of cations and oxygen vacancies in the spinel structure has been examined using X-ray photoelectron spectroscopy (XPS) which confirmed a strong interplay between the oxidation state of cations, adsorbed oxygen level, and electrical conductivity. The n-type semiconducting property has been correlated to the adsorbed oxygen abundance and its interaction with gas molecules. The study revealed enhanced soft magnetic properties of ferrite due to zinc doping. In addition, this study presents a stable and sensitive material for detecting a low concentration of carbon monoxide gas.

A Fundamental Study on Estimating the Concentration of Carbon Monoxide (CO) By Fabric-Based Colorimetric Analysis Using an Optical RGB Color Sensor

We propose a sensitive colorimetric sensing system for estimating the concentration of Carbon Monoxide (CO) using an optical RGB color sensor. Tasteless and odorless hazardous gas, such as carbon monoxide (CO), can be life-threatening, even at prolonged exposure at low concentrations. Early detection of these gases under low concentration conditions is a difficult problem. Thus, studying environmental health, monitoring of air quality, and the safety of people from harmful gas exposures have motivated increasing efforts to develop low cost and high-performance various sensors[1-2]. A detection method using the visual and optical device is relatively easy to apply because they are widely used and cheaper than in the past. This method can effectively detect harmful substances with reactive dyes. Potassium disulfide dye is suitable as a reactive dye because it has a property of discoloration in response to CO. Therefore, we used this to detect the optical response of the fabric discoloration process and perform quantitative gas concentration estimation. The chemical reaction of CO gas and disulfide potassium dyes is as shown in Formula 1, and the fabric exposed to the reaction turns black. The discoloration information for the fabric was collected from chambers that can control the gas concentration, and the concentration of CO gas considered in the experiment is 0-600 ppm. The time to reach full discoloration was recorded according to each gas concentration condition, and an RGB sensor was used to detect discoloration information. We used Moving-median filtering to remove noise caused by sensor characteristics of the collected data. To estimate the gas concentration, a curve fitting model using a least-squares method was applied. This method of converting to a power law scale and then use poly fitted to fit a linear curve to data. In the process of discoloration, we observed the difference in the discoloration progression rate according to the gas level and time. Also, under each gas concentration condition, the spending times from 20% progression to 80% progression in the whole discoloration process have a significant difference. These characteristics were applied to approach algorithms for estimate concentrations. Results show that the spending time to discolor from 20 % to 80 % progression at 200, 400, and 600 ppm was 275, 163.8 and 151.4 seconds, respectively in Figure 1. In the low concentration section, a significant time difference was observed compared to the high concentration section. The time characteristics of each section were extracted and applied to the concentration estimation algorithm. Except for outliers, the actual measurement data applied to the estimation algorithm, the concentration estimated were about 95%, 77% and 72% accuracy at 200, 400 and 600 ppm. As a result, we could estimate the concentration of CO gas by analyzing some of the discolored sections. This result is since the response time of discoloration varies depending on the gas concentration level. As future work, the gas concentration estimation method in this study could be improved by machine learning and data processing methods. The early detect system on dyed fabric color by gases exposes can be applied to for the next generation of the smart industrial safety system and intelligent clothing.AcknowledgementThis study has been conducted with the support of the Korea Institute of Industrial Technology.

Highly Sensitive Room Temperature CO Gas Sensor Based on MWCNT-PDDA Composite

In this work, a resistive sensor based on multiwalled carbon nanotube (MWCNT) - poly(diallyldi- methylammonium chloride) solution (PDDA) composite is proposed for highly sensitive carbon monoxide (CO) detection at room temperature. The surface of MWCNTs is functionalized with PDDA, and the functionalization is investigated by Fourier transform infrared and Raman spectroscopy. The MWCNT-PDDA composite is used as a sensing material with deposited interdigitated electrodes (IDE) of silver (Ag) on glass substrates. The resistance of the sensors changes due to charge transfer from CO to the positively charged quaternary ammonium group present on PDDA. The developed sensors are able to detect very low concentrations of CO gas ranging from 1 to 20 ppm with high sensitivity and limit of detection (LOD) of 127 ppb. The interference of other gases and volatile organic compounds is investigated, and the results are presented. The influence of humidity and temperature on the sensors is also explored. The stability and repeatability of the sensors are examined, and the sensors are almost stable for 2 months with excellent reproducibility. The sensors also follow the Langmuir adsorption/desorption model. The sensors have shown excellent potential for rapid CO gas sensing, and it can be used in wearable electronics applications.

Plasma sprayed copper oxide sensor for selective sensing of carbon monoxide

This investigation deals with a carbon monoxide (CO) sensing of copper oxide (CuO) coating obtained using plasma spraying of CuO powder. CO sensing measurements were undertaken using a dynamic flow gas sensing set up that operated in the temperature range of 100–350 °C. The coating showed a maximum sensor response at 150 °C. Therefore, effect of variation of CO gas concentration (500-5 ppm) on the sensor response was studied at 150 °C. Coating exhibited reproducible CO sensing characteristics along with good stability of baseline resistance. To understand the stability aspect, time dependent sensor response at various concentrations were analysed using a reversible sensing model following the Langmuir-Hinshelwood mechanism. To ascertain the selectivity of response towards CO, sensing measurements were performed at 150 °C in the presence of other gases like nitrogen dioxide (NO2), iso-butane (i-C4H10), and methane (CH4) in addition to CO. The plausible reasons for selective CO sensing are also discussed. To the best of authors’ knowledge, this is the first report presenting the CO sensing capability of plasma sprayed CuO coating.

Highly sensitive CO sensor based on Al-doped-ZnO nanorods-coated resonant microcantilevers

A highly sensitive (at the picogram order) Al-doped-ZnO nanorods (AZNRs)-coated resonant microcantilever (MC) for carbon monoxide (CO) gas sensing, operable at ambient temperature and under humid condition was synthesized. The ZnO nanorods were grown on the MC surface by using the hydrothermal method and doped by aluminum (Al). The sensitivities of un-doped and AZNRs for various CO gas concentrations were investigated by measuring the changes in the resonant frequencies and the Q-factor analysis of the vibrating MCs. The mechanisms of the remarkable enhancement of the sensitivity of the AZNRs-coated-microcantilever to CO were thoroughly investigated and discussed on the basis of energy gap between the highest occupied molecular orbital-lowest occupied molecular orbital of AZNRs and CO, active surface area of AZNRs, and the interaction of water vapor on AZNRs surface with CO.

Modeling the CO gas response of PEDOT:PSS/Fe(salen) thin film for a gas sensor

Abstract. A thin film carbon monoxide (CO) gas sensor based on PEDOT:PSS/Fe (salen) has been developed using the spin coating technique on several glass pieces with interdigitated Au electrodes. The change in electrical resistance of the sensors with various content of dopants was measured in different CO gas concentrations and temperatures. It is found that Fe (salen) as a dopant can significantly improve the performance of PEDOT:PSS based gas sensors. Least square support vector regression (LSSVM) method was applied to predict the gas response characteristics of the films for different testing conditions. Modeling results show a satisfactory agreement with experimental findings.

Improvement of the carbon monoxide gas sensing properties of polyaniline in the presence of gold nanoparticles at room temperature

In the present work, the influence of gold (Au) nanoparticles on carbon monoxide gas sensing performance of polyaniline (PAni) at room temperature was comprehensively studied. The Au/PAni nanocomposites were synthesized by the ultrasound mixing of emeraldine salt polyaniline and different amounts of Au nanoparticles colloidal solution. The analyses of field emission scanning electron microscope in conjunction with energy-dispersive X-ray spectroscopy indicated that the surface of PAni fibers was well decorated with Au nanoparticles due to the electrostatic interaction and hydrogen bonding. Then, the gas sensing performance of all sensors was investigated toward various concentrations of carbon monoxide gas ranging from 200 to 6000 ppm at room temperature. The results indicated that the 2.5 %Au/PAni sensor possesses high response(14 %–1000 ppm), low detection limit(33 ppm), the acceptable response time(180 s), wide dynamic range(200−6000 ppm) and good selectivity owing to catalytic properties of Au nanoparticles. Thus, the one-dimensional nanostructure might give a promise for high-performance sensing applications.