Different Concentrations Of CO2 Research Articles

Cobalt Impregnation on Titania Photocatalysts Enhances Vis Phenol Photodegradation.

One of the main challenges of photocatalysis is to find a stable and effective photocatalyst, that is active and effective under sunlight. Here, we discuss the photocatalytic degradation of phenol as a model pollutant in aqueous solution using NUV-Vis (>366 nm) and UV (254 nm) in the presence of TiO2-P25 impregnated with different concentrations of Co (0.1%, 0.3%, 0.5%, and 1%). The modification of the surface of the photocatalyst was performed by wet impregnation, and the obtained solids were characterized using X-ray diffraction, XPS, SEM, EDS, TEM, N2 physisorption, Raman and UV-Vis DRS, which revealed the structural and morphological stability of the modified material. BET isotherms are type IV, with slit-shaped pores formed by nonrigid aggregate particles and no pore networks and a small H3 loop near the maximum relative pressure. The doped samples show increased crystallite sizes and a lower band gap, extending visible light harvesting. All prepared catalysts showed band gaps in the interval 2.3-2.5 eV. The photocatalytic degradation of aqueous phenol over TiO2-P25 and Co(X%)/TiO2 was monitored using UV-Vis spectrophotometry: Co(0.1%)/TiO2 being the most effective with NUV-Vis irradiation. TOC analysis showed ca. 96% TOC removal with NUV-Vis radiation, while only 23% removal under UV radiation.

Determination of Co2+ ions in blood samples: A multi-way sensing based on NH2-rich carbon quantum dots

Multiple forms of detecting Co2+ are reported in this work to quantify these ions in real blood plasma samples. Carbon Quantum Dots (CQDs) were used as a fluorescent nanoprobe. The CQDs were obtained from a bottom-up approach using a hydrothermal method and choline chloride and branched poly(ethyleneimine) as precursor molecules. Several spectroscopic and structural characterizations were performed. The efficient fluorescence quenching of CQDs related to the Co2+ ion was used for the detection of the analyte, generating a sensing strategy with a limit of detection (LOD) of 0.98 μmol L−1. Furthermore, the interaction between the Co2+ ion with the CQDs resulted in the color change of the solution from colorless to pale yellow. Thus, a colorimetric Co2+ sensor was also developed, since there was an absorption band at 315 nm attributed to the formation of the complex CQD + Co2+. The colorimetric method showed an excellent sensitivity to Co2+, with a LOD of 3.01 μmol L−1. In addition, Principal Component Analysis (PCA) together with Linear Discriminant Analysis (LDA) were used successfully to distinguish different concentrations of Co2+ and different interfering ions present in the solution. Finally, a real sample of blood plasma was properly treated and doped with different concentrations of Co2+, which was successfully quantified via fluorescent method. Therefore, the CQDs obtained in this work are a powerful and versatile Co2+ detection tool.

An environmentally friendly green synthesis of Co2+ and Mn2+ ion doped ZnO nanoparticles to improve solar cell efficiency

Global warming is a threat to human health in the context of increasing organic or inorganic pollutants, which are produced by various products. The “Green synthesis” method effectively eliminates toxic and/or harmful effects that arise due to the wet-chemical synthesis process. Different concentrations of Co2+ and Mn2+ ion doped ZnO-nanoparticles (NPs) were designed at a low temperature, about 70 °C by utilizing an eco-friendly sustainable method with dandelion leaf (DL) extract as a solvent and these biosynthesized NPs were annealed to grow the crystallinity enhancement. The confirmation of NPs crystal phase, phase purity, and grain size was performed by XRD, showing the hexagonal-Wurtzite phase structure. SEM and TEM images of the NPs demonstrated sub-100 nm spherical-shaped particles. Fourier transform infrared displays characteristics band about ∼523 cm–1 which corresponds to Zn–O tetrahedron asymmetric stretching vibrations. Both UV-Visible and luminescence studies confirmed the adjacent band edge emission of ZnO and successive incorporation of Co2+ and Mn2+ ion-doped ZnO host. For improving power conversion efficiency, the polycrystalline silicon solar cells (PSSCs), different layers of Co2+ and Mn2+ ion-doped ZnO-NPs coated on bare PSSCs are promising strategies. Additionally, solar cell efficiency decreases with further coating of NPs layers and/or thickness. Optimum solar cell efficiency was observed for 5 at% Mn2+ ion-doped ZnO-NPs with three layers. Finally, Radish and Cress plants are grown, using the biosynthesized ZnO-NPs supernatant from DL extract, which showed high environmental biocompatibility.

A controllable cobalt-doping improve electrocatalytic activity of ZnO basal plane for oxygen evolution reaction: A first-principles calculation study

To design highly efficient, low-cost, and good stable electrocatalysts for the oxygen evolution reaction (OER) which is the key to the water-splitting, we doped ZnO with different concentrations of Co based on density functional theory calculations. The precise Co concentrations control from 0 % to 100 % can be achieved by cation exchange reaction in the experiment. The introduction of Co can modulate the electronic structure of ZnO, as the concentration of Co increases, the band gap greatly decreases, the system tunes from the semiconductor to the metal, and the electric conductivity is significantly improved, favoring the OER. The introduction of Co induces charge arrangement, the electrons gradually concentrate on the active site, and the bindings between the oxygen-containing intermediate and the surface are greatly improved, therefore, the potential of the OER decreases, the rate-determining step changes from the first step in pure ZnO to the third step in Co exchanged ZnO. Additionally, Co0.5Zn0.5O exhibits the favorite OER activity with the overpotential of 0.4 V. These interesting findings may simulate experimental validations and facilitate the development of more efficient OER catalysts.

System for performance evaluation and calibration of low-cost gas sensors applied to air quality monitoring

The increasing emissions of air pollutants have been a current issue and with great interest by regulatory agencies, industries, and society in general as they represent a threat to health and to the environment. The monitoring using low-cost atmospheric sensors has been an emerging alternative with great prospect of use to complement the data obtained by traditional air quality monitoring stations. However, the data obtained by these low-cost sensors are still questionable and can often be unreliable. The objective of this work was to build a system for calibration and evaluation of performance parameters of low-cost monitor comparing their results to reference analyzers. In this sense, three low-cost sensors for CO, O3 and SO2 of a monitor were calibrated and evaluated against the performance parameters defined by baseline drift, linearity, precision, bias, accuracy, response time, interference of pollutant gases and long-term drift. There was no significant deviation from baseline drift for any sensor. All sensors showed a linear profile (R2ADJ ∼1), good precision (>95%), and a response time of less than 2 min. After calibration, satisfactory accuracy (>89%) and bias (close to zero) data were obtained. The SO2 sensor showed signal disturbances in the presence of different concentrations of CO. Long-term drift suggests a calibration periodicity of less than 60 days. To use these sensors to monitor air quality, prior calibration is necessary, and the determination of performance parameters is suggested.

Exposure of insects and host plants to different concentrations of CO2 affects the performance of Mahanarva spectabilis (Hemiptera: Cercopidae) in successive insect generations.

The performance of three successive generations of Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) fed on four forages exposed to environments with different CO2 concentrations was evaluated. In the first bioassay, we utilized the following scenarios: A) plants and insects were kept at high and constant CO2 (700 ppm) and B) the insects were kept at CO2 700 ppm and fed on plants from the greenhouse (average of 390 ppm). In the second bioassay, we utilized the following scenarios: C) plants and insects were kept in a greenhouse and D) the insects were kept in the greenhouse and fed on plants kept at CO2 700 ppm. The survival and duration of the nymphal and adult stages and the number of eggs/female of M. spectabilis were evaluated. It was only possible to evaluate the cumulative effects of the increase of CO2 on three successive generations of M. spectabilis kept in a greenhouse, due to the reduced survival of the insects in the first generation in the laboratory. A greater direct than indirect effect of the CO2 level on the performance of M. spectabilis was observed. Furthermore, it should be considered that the effect of CO2 elevation on the survival, periods of development, and fecundity, when taken together, can significantly impact the population dynamics of M. spectabilis in future climate scenarios.

A Europium-Based Optical Sensor for the Detection of Carbon Dioxide and Its Application for a Fermentation Reaction

A new europium-based complex, K[Eu(hfa)4] with hfa = hexafluoroacetylacetonate is synthesized and its structure confirmed via X-ray crystallography. The structure unravels an anionic octa-coordinate complex, K[Eu(hfa)4], as opposed to the neutral hexacoordinate complex Eu(hfa)3 routinely/ubiquitously presumed to be the case in the literature. The complex displayed pH-dependent, “on–off” emission changes in solution and exhibited a pKa of 6.13 ± 0.06 in ethylene glycol. In solution, the sensor complex exhibited drastic variation in emission intensity corresponding to changes in the concentration of CO2 gas purged. Based on multiple purge cycles of N2 and CO2, the emission intensity changes can be correlated to the concentration of CO2 in the solution. The sensor’s ability to quantify the CO2 presence is based on emission variations of the 5D0 → 7F2 line in the Eu(III) complex at 618 nm. The sensor exhibits a linear response to CO2 concentrations in the range of 0–25% (0–8.50 mM or 0–189.95 mmHg). Based on calibration data, the limit of detection (LOD) is determined to be 0.57% (0.19 mM or 4.33 mmHg) in solution. The I100/I0 ratio is determined to be 80.29 ± 3.79. The percent change in intensity from purging N2 to 100% CO2 is 7911.16%. Over the course of seven cycles of purging different concentrations of CO2, there is essentially no deviation in the emission intensity of the sensor in solution, indicating stability and reversibility. In addition to the analytical characterization of the sensor, the mechanism of CO2 sensing is investigated using cyclic voltammetry, IR, and Raman spectroscopy. These data indicate the reduction of europium(III) to europium(II) in an alkaline medium and suggest changes in the hfa ligand chemistry (association/dissociation and protonation) due to CO2 purging. The potential use of the sensor complex for real-life applications is herein evaluated via a well-known fermentation reaction. The CO2 generated during yeast’s anaerobic respiration in sucrose media is quantified using the sensor complex and a calibrated, commercial CO2 probe; both exhibit similar CO2 concentration values, validating the calibration curve and the viability of the complex as a bona fide sensor. Based on the data collected, a highly stable, brightly red-emissive Eu(III) complex with the ability to differentiate concentrations of CO2 in solution is hereby developed and characterized with benefits for various CO2 sensing applications.

Management of Pulse Beetle in Green Gram Seed Using Modified Atmosphere

The experiment was conducted at Seed Research and Technology Center, PJTSAU, Rajendranagar, Hyderabad, Telangana State, India during June, 2019 under laboratory conditions using modified atmosphere with elevated levels of CO2 in two varieties of green gram namely LGG-460 and LGG-407. The study indicated that biological parameters of the test insect and the seed quality parameters were highly influenced by different levels of CO2 and storage intervals and varied between the two accessions of green gram. Emergence of adults decreased with increased concentrations of CO2. Among the two accessions, LGG-460 had least adult emergence with comparatively less insect damage than LGG-407. Higher concentrations of CO2 (45%) significantly reduced the per cent insect infestation and weight loss of both the accessions. The efficacy of different concentrations of CO2 on seed infestation and population build up revealed that exposing the bruchid infested green gram seed to 45% and higher concentrations of CO2 not only checked seed infestation but also checked the progeny production of the pest even after prolonged periods of storage up to 2 MAS. The green gram seeds stored in CO2 rich atmosphere also maintained seed quality with high germination percentage and seedling vigor up to 2 MAS. Two months storage period was effective for control of insect infestation and weight loss. Among the 2 accessions, seedling vigour I and II were found to be high in LGG 460 even at 6 months storage interval.

Pt-O-Cu anchored on Fe2O3 boosting electrochemical water-gas shift reaction for highly efficient H2 generation

Electrochemical water–gas shift (EWGS) reaction is an emerging technology with energy-saving and environmental-friendly advantages to produce high-purity hydrogen form the waste gas containing CO. However, it remains a significant challenge to design superior activity and highly durable EWGS electrocatalysts, particularly with low content of noble metals. Herein, a series of Pt-xCu/Fe2O3 (x = 0, 2, 5) catalysts are synthesized by the complexation precipitation method to construct coupling sites between Pt and CuOx, aiming to optimize the adsorption of CO and the activation of OH–. The obtained 2.5Pt-2Cu/Fe2O3 catalyst presents a unique Pt-O-Cu structure, delivering a much lowest onset potential, high specific activity, and excellent mass activity (1.5 A·mgPt-1) at 0.73 V (vs. RHE), which is over 15 and 3 times that of commercial Pt/C (20%) and unmodified Pt/Fe2O3 catalyst, respectively. Meanwhile, the in-situ X-ray absorption results demonstrate that the facilitated interaction among the Pt-O-Cu structure promotes the high durability of the 2.5Pt-2Cu/Fe2O3 catalyst and the operability at high potential. More importantly, the moderate binding of CO and moderate activation of OH* are suggested for boosting the reactivity in the CO electro-oxidation reaction. In particular, the fabricated Pt||2.5Pt-2Cu/Fe2O3, employed in coupling the HER and CO electro-oxide reaction, shows a remarkable hydrogen production of about 98 mmolH2·h−1·mgPt−1 at 0.8 V (vs. RHE). This work also definitely confirms the possibility of the catalyst being applied to produce hydrogen under practical conditions with different concentrations of CO, even being applied in the purification of trace CO in a hydrogen-rich atmosphere.

Rate constant determination in the reaction of gold ion with carbonyl using single-atom chemistry in gas phase

The reactions of single gold ion Au+ with CO and H2O molecules in gas phase were studied by experiment and calculation. A reaction tube was connected to the end of the jet to destroy the supersonic state of the molecular beam and enhance the collisions between the laser-sputtered metal ions with gas molecules, so as to ensure the equilibrium reaction conditions. The ionic products were analyzed by a time-of-flight mass spectrometer. The collision temperature in reaction tube was calibrated to 409 K by the reaction of Au+ ion and H2O molecules. The contents of ionic products Au(CO)+ and Au(CO)2+ in the reaction of Au+ with CO molecules were monitored under different concentrations of CO in precursor gas. The combination reaction rate constants of single Au + ion sequentially with two CO molecules were determined to be k1 = 1.1 (2) × 10−12 cm3s−1 and k2 = 4.5 (5) × 10−10 cm3s−1. The geometric structures and binding energies of the ionic products, as well as the pathway and rate constants of the reactions were predicted by a high-level ab initial calculation. The binding mode of Au+ and CO and the formation of molecular orbital were discussed.

Microfluidic Device with Room Temperature Ionic Liquids for Detecting Low Concentrations of CO2

In this work we report the use of a gas sensor that can be used in inline configuration for applications like organ-on-a-chip. The key element of the device is a microfluidic channel with a thickness of 140 μm and width of 500 μm. This microfluidic channel is sandwiched between a top and bottom substrate, each substrate containing microelectrodes making this a non-planar interdigitated microelectrode (NP-IμE) configuration. Room temperature ionic liquids (RTILs) are used as electrolyte in the microfluidic channel. Due to the dimensions of the microfluidic channel only low volume of RTILs are required as electrolyte. RTILs can be tuned to selectively capture specific gases. This in addition to other favourable properties such as wide electrochemical window, thermal stability and negligible vapor pressure makes it a good candidate as the selective electrolyte in electrochemical gas sensor. The use of NP-IμE makes the electric field penetrate through the channel. This allows us to register the perturbations in signal caused by absorption of CO2 from the entire cross-section of the channel, thereby increasing the sensitivity of the device (as compared to a planar architecture). 1-ethyl-3-methylimidazolium 2-cyanopyrolide ([EMIM][2-CNpyr]) was used as the RTIL, as it has been shown to be a good sorbent of CO2 with high capacity at low partial pressures due to its chemical affinity. The RTILs exposed to different concentrations of CO2 was injected into the microfluidic channel. Cyclic Voltammetry (CV), Differential pulse voltammetry (DPV) and Electrochemical impedance spectroscopy (EIS) experiments were done using our microfluidic device. During the CV and DPV experiments, RTIL exposed to CO2 shows a reduction peak (of CO2). This along with the changes in EIS spectrum (Nyquist plot) can be used to detect the presence of CO2. We used CO2 as a test gas to analyse the sensitivity of our microfluidic device combined with RTIL. In future we will be using this same setup to sense biomarker gases and other toxic gases by changing the RTIL and tuning its affinity towards the target analytes.

Study on Photoacoustic Spectroscopy Detection of CO in Gas Insulation Equipment

The related regulations for electric power industry stipulate that CO gas is an important component to be detected when analyzing the gas composition of SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> equipment. In this study, based on the photoacoustic spectroscopy technology, the quantitative gas detection of CO is carried out. First, in order to avoid the cross-interference effects of other component gases on photoacoustic spectroscopy detection of CO, the characteristic absorption spectrum of CO in 4291.5 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> (whose wavelength is 2330.2 nm) is determined. Second, the nonresonant photoacoustic cell is optimized in this study. After that, designing and building a trace gas photoacoustic spectroscopy detection platform around the developed photoacoustic cell, using the built detection platform to perform photoacoustic spectroscopy detection of the concentration of CO, and obtaining photoacoustic signals of different concentrations of CO, the photoacoustic signals increase linearly as the concentration increases. With SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> as the background gas, the lower detection limit of CO gas reaches 20.5 ppm, and with N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> as the background gas, it reaches 5.6 ppm. After all, the influence mechanism of the background gas on the photoacoustic signal is studied, and based on the influence mechanism, the lower detection limit of CO with the background gas of different mixing ratios of SF <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is predicted. The verified experiment is basically consistent with the predicted results, which proves the accuracy of the forecast. This study provides guidance for the engineering application of CO photoacoustic spectroscopy detection in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> equipment.

The Endogenous Metabolic Response of Tribolium castaneum under a High Concentration of CO2

High carbon dioxide concentrations can effectively control most storage pests. To estimate the toxicity effect of high concentrations of CO2, four different concentrations of CO2 (25% CO2, 50% CO2, 75% CO2, and 95% CO2) were used to treat Tribolium castaneum, and the biochemical (carbohydrate content and gene expression level) and physiological (mortality, pupation, eclosion rate, and weight) features of insects submitted to different treatments with CO2 were evaluated. The T. castaneum mortality rate was 50% in approximately 2 days when exposed to a treatment with 95% CO2. When the CO2 concentration exceeded 75%, the pupation rate and eclosion rate of T. castaneum seriously declined. Higher than 25% CO2 concentrations resulted in a lower weight and shrunken body size of T. castaneum. It was further found that different CO2 concentration treatments all influenced the levels of the three carbohydrate contents in T. castaneum. In addition, according to the detection of trehalose metabolism pathway-related genes, T. castaneum mainly responds to stress factors via high expression of TPS, TRE1-2, and TRE1-3. Our results enrich the evaluation of the toxicity effect of CO2 treatment on grain storage pests, providing a basis for further improving the method of regulating grain storage to control insect pests.

Synergistic promoting effect of increasing aquatic ammonium and CO2 on Microcystis aeruginosa

Owing to climate change and intensive agricultural development, freshwater bodies have been affected by increases in both CO2 levels and chemically-reduced forms of N. However, little is known about how these changes affect cyanobacterial growth and blooms. This study explored a range of light conditions (30, 80, 130, or 200 μmol photons/m2/s) wherein Microcystis aeruginosa, a widespread bloom-forming species, was exposed to different concentrations of CO2 (400 parts per million (ppm) and 1000 ppm) in a medium containing NH4+ or NO3－. The interactive effects of N sources and CO2 levels on the C/N metabolic balance and energy balance were examined to assess changes in the growth of M. aeruginosa. When the light intensity was 80 μmol photons/m2/s, elevated CO2 could reduce intracellular reactive oxygen species (ROS) in NH4+-grown M. aeruginosa. Meanwhile, cell density and chlorophyll a (Chl a) increased with increasing CO2 levels, and the increase in Chl a was significantly greater in NH4+-grown M. aeruginosa than in NO3－-grown M. aeruginosa. Under light conditions of 200 μmol photons/m2/s, elevated CO2 concentration caused NO3－-grown M. aeruginosa to be affected by a large amount of ROS, and the growth of NO3－-grown M. aeruginosa was finally suppressed. However, NH4+-grown M. aeruginosa had a smaller amount of ROS and showed improved growth as CO2 was elevated. This difference can be attributed to the faster metabolic pathways in the NH4+ environment, which manifested in a lower accumulation of 2-oxoglutarate and fatty acids as CO2 was elevated. These findings suggest that the simultaneous increase in ammonium and CO2 in aquatic ecosystems confers cyanobacteria with greater advantages than the combination of nitrate and CO2, which may aggravate cyanobacterial blooms.

Synthesis of Co3O4@TiO2 catalysts for oxygen evolution and oxygen reduction reactions

The electrospinning method combined with high temperature thermal annealing was used to prepare TiO 2 fibers modified with different concentrations of Co 3 O 4 . Field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), desktop scanning electron microscope (TM3030)-energy spectrometer (SwiftED3000), thermal analyzer (TGA), X-ray diffractometer (XRD), X-ray photoelectron energy Spectral analyzer (XPS), Brunauer–Emmett–Teller (BET) (BET) were used to study the influence of different cobalt oxide concentrations on the morphology of mesoporous TiO 2 fibers. Cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and continuous cycle method were used to evaluate the fiber's oxygen evolution reaction (OER) and oxygen reduction (ORR) reactivity. It was found that the fiber with a molar ratio of Co to Ti of 1:10 showed the best performance for both OER and ORR reactions in alkaline solution. The fiber showed an overpotential of 382 mV at a current density of 10 mA cm −2 , a Tafel slope of 58 mV·dec −1 , and a half-wave potential change of only 10 mV after 4000 CV cycles. It has an onset potential of 0.83 V (vs RHE) in the ORR reaction. The OER/ORR overpotential gap (E) of 0.85 V is significantly lower than commercial platinum/carbon and bulk TiO 2 analogs. Obviously, this catalytic activity stems from the synergy between Co 3 O 4 and TiO 2 fibers. In addition, the higher specific surface area and the presence of disordered mesopores provide a higher charge carrier density during the electrocatalytic process, which improves the reaction activity. • TiO 2 was adopted in present research to replace carbon as a catalyst support substrate. • The Co 3 O 4 @TiO 2 nanofiber possess an unique mesoporous structure, which provides more active sites for the reaction, and makes good catalytic performance for the reaction through the synergistic of TiO 2 and Co 3 O 4 . • The Co 3 O 4 @TiO 2 nanofibers show good catalytic performance for both the OERand ORR.

Understanding the Increasing Trend of Sensor Signal with Decreasing Oxygen Partial Pressure by a Sensing-Reaction Model Based on O2- Species.

Although the increasing trend of sensor signal with decreasing oxygen partial pressure was observed quite early, the underlying mechanism is still elusive, which is a hindrance to accurate gas detection under varying oxygen partial pressure. In this work, a sensing model based on previous experimental and theoretical results is proposed, in which the O2- species is determined to be the main oxygen species because O- species has not been observed by direct spectroscopic studies. On this basis, combined with the band bending of SnO2 at different oxygen partial pressures, the functional relationship between the surface electron concentration, oxygen partial pressure, and reducing gas concentration is established, which includes three forms corresponding to the depletion layer, accumulation layer, and flat band. In the depletion layer case, the variation of the sensor resistance to different concentrations of CO and oxygen can be well fitted with our function model. Besides, this model predicts that the response of sensors will no longer maintain the increasing trend in an extremely hypoxic atmosphere but will decrease and approach 1 with the background oxygen content further going down to 0.

Carbon Dioxide Chemically Responsive Switchable Gas Valves with Protonation-Induced Liquid Gating Self-Adaptive Systems.

Carbon dioxide (CO2 ) capture and storage technologies are promising to limit CO2 emission from anthropogenic activities, to achieve carbon neutrality goals. CO2 capture requires one to separate CO2 from other gases, and therefore a gas flow system that exhibits discernible gating behaviors for CO2 would be very useful. Here we propose a self-adaptive CO2 gas valve composed of chemically responsive liquid gating systems. The transmembrane critical pressures of the liquid gate vary upon the presence of CO2 , due to the superamphiphiles assembled by poly(propylene glycol) bis(2-aminopropyl ether) and oleic acid in gating liquids that are protonated specifically by CO2 . It is shown that the valve can perform self-adaptive regulation for specific gases and different concentrations of CO2 . This protonation-induced liquid gating mechanism opens a potential platform for applications of CO2 separators, detectors, sensors and beyond.

Carbon Dioxide Chemically Responsive Switchable Gas Valves with Protonation‐Induced Liquid Gating Self‐Adaptive Systems

AbstractCarbon dioxide (CO2) capture and storage technologies are promising to limit CO2 emission from anthropogenic activities, to achieve carbon neutrality goals. CO2 capture requires one to separate CO2 from other gases, and therefore a gas flow system that exhibits discernible gating behaviors for CO2 would be very useful. Here we propose a self‐adaptive CO2 gas valve composed of chemically responsive liquid gating systems. The transmembrane critical pressures of the liquid gate vary upon the presence of CO2, due to the superamphiphiles assembled by poly(propylene glycol) bis(2‐aminopropyl ether) and oleic acid in gating liquids that are protonated specifically by CO2. It is shown that the valve can perform self‐adaptive regulation for specific gases and different concentrations of CO2. This protonation‐induced liquid gating mechanism opens a potential platform for applications of CO2 separators, detectors, sensors and beyond.

Amine-Functionalized Mesoporous Silica Adsorbent for CO2 Capture in Confined-Fluidized Bed: Study of the Breakthrough Adsorption Curves as a Function of Several Operating Variables

Carbon capture, utilization, and storage (CCUS) is one of the key promising technologies that can reduce GHG emissions from those industries that generate CO2 as part of their production processes. Compared to other effective CO2 capture methods, the adsorption technique offers the possibility of reducing the costs of the process by setting solid sorbent with a high capacity of adsorption and easy regeneration and, also, controlling the performance of gas-solid contactor. In this work, an amine-functionalized mesoporous sorbent was used to capture CO2 emissions in a confined-fluidized bed. The adoption of a confined environment allows the establishment of a homogeneous expansion regime for the sorbent and allows to improve the exchange of matter and heat between gas and solid phase. The results illustrate how the different concentration of the solution adopted during the functionalization affects the adsorption capacity. That, measured as mg of CO2 per g of sorbent, was determined by breakthrough curves from continuous adsorption tests using different concentrations of CO2 in air. Mesoporous silica functionalized with a concentration of 20% of APTES proves to be the best viable option in terms of cost and ease of preparation, low temperature of regeneration, and effective use for CO2 capture.

Monitoring of ambient carbon monoxide concentrations based on wavelength modulation direct absorption spectroscopy

Wavelength modulation-direct absorption spectroscopy (WM-DAS) has the advantages of both direct absorption spectroscopy (DAS) measurable absorptivity function and wavelength modulation spectrum (WMS) with high signal-to-noise ratio (SNR). In this paper, the WM-DAS spectrum is used to measure the absorptivity of 4300.7 cm&lt;sup&gt;–1&lt;/sup&gt; line of CO molecule and the detection limit is as low as 4 × 10&lt;sup&gt;–7&lt;/sup&gt; (200 s) at 0.5 m optical path, room temperature and low pressure. Then, through combining the WM-DAS spectrum with a 120 m long optical path Herriott cell, at room temperature and atmospheric pressure, the standard deviation of the fitting residual error of the absorptivity function is reduced down to ~5.1 × 10&lt;sup&gt;–5&lt;/sup&gt; (1 s). Finally, different concentrations of CO are continuously monitored by long-path WM-DAS measurement system, and compared with the results obtained from the cavity ring-down spectroscopy (CRDS). The experimental results show that the measurement results from the long-path WM-DAS and CRDS method are the same. The detection limit of CO concentration in long-path WM-DAS system is as low as 0.9 ppb (200 s), and the WM-DAS system is simple and the measurement speed is much faster than CRDS. At the same time, the long-path WM-DAS system is used to continuously monitor the atmospheric trace CO concentration and trend for one month, and the measured results are highly consistent with those from the China Environmental Monitoring Station.