scholarly journals Investigation and Optimization of a Line-Locked Quartz Enhanced Spectrophone for Rapid Carbon Dioxide Measurement

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5225
Author(s):  
Hui Zhang ◽  
Wenling Jin ◽  
Mengpeng Hu ◽  
Mai Hu ◽  
Jingqiu Liang ◽  
...  

We have developed a rapid quartz enhanced spectrophone for carbon dioxide (CO2) measurement, in which the laser wavelength was tightly locked to a CO2 absorption line and a custom quartz tuning fork (QTF) operating at 12.5 kHz was employed. The intrinsic QTF oscillation-limited response time, as well as the optimal feedback interval, was experimentally investigated. By tightly locking the laser to the R(16) transition of CO2, we obtained a stable laser operation with its center wavelength variation kept within 0.0002 cm−1, merely three times the laser linewidth. The reported CO2 sensor achieved a detection limit of 7 ppm, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 4.7 × 10−9 W·cm−1·Hz−1/2, at a response time of 0.5 s. The detection limit can be further improved to 0.45 ppm at an integration time of 270 s, illustrating a good system stability. This spectrophone enables the realization of compact and fast-response gas sensors for many scenarios, where CO2 concentration from sub-ppm to hundreds of thousands of ppm is expected.

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4187 ◽  
Author(s):  
Shunda Qiao ◽  
Yanchen Qu ◽  
Yufei Ma ◽  
Ying He ◽  
Yao Wang ◽  
...  

A photoacoustic spectroscopy (PAS) based carbon dioxide (CO2) sensor with a fixed wavelength quantum cascade laser (FW-QCL) was demonstrated. The emission wavelength of the FW-QCL at 4.42 μm in the mid-infrared spectral region matched a fundamental CO2 absorption line. Amplitude modulation of the laser intensity was used to match the resonant photoacoustic (PA) cell. The noise from the background was reduced with the correlation demodulation technique. The experimental results showed that the sensor had excellent signal stability and a concentration linear response. When the integration time was 1 s, a 1σ minimum detection limit (MDL) of 2.84 parts per million (ppm) for CO2 detection was achieved. The long-term stability of the sensor was evaluated by means of an Allan deviation analysis. With an integration time of ~100 s, the MDL was improved to 1 ppm. This sensor was also used to measure the CO2 concentration from some common emission sources, such as cigarette smoking, automobile exhaust, and the combustion of some carbon-containing materials, which confirmed the stability and robustness of the reported FW-QCL based CO2-PAS sensor system.


2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Arash Esmaeili ◽  
◽  
Zhibang Liu ◽  
Yang Xiang ◽  
Jimmy Yun ◽  
...  

A high pressure carbon dioxide (CO2) absorption from a specific gas in a conventional column has been evaluated by the Aspen HYSYS simulator using a wide range of single absorbents and blended solutions to estimate the outlet CO2 concentration, absorption efficiency and CO2 loading to choose the most proper solution in terms of CO2 capture for environmental concerns. The property package (Acid Gas-Chemical Solvent) which is compatible with all applied solutions for the simulation in this study, estimates the properties based on an electrolyte non-random two-liquid (E- NRTL) model for electrolyte thermodynamics and Peng-Robinson equation of state for the vapor and liquid hydrocarbon phases. Among all the investigated single amines as well as blended solutions, piperazine (PZ) and the mixture of piperazine and monoethanolamine (MEA) have been found as the most effective absorbents respectively for CO2 absorption with high reactivity based on the simulated operational conditions.


2020 ◽  
Vol 44 (41) ◽  
pp. 17849-17853
Author(s):  
Yanxia Qiao ◽  
Rui Zhang ◽  
Fangyuan He ◽  
Wenli Hu ◽  
Xiaowei Cao ◽  
...  

A glucose sensor based on conductive Ni-MOF nanosheet arrays/CC exhibits a fast response time, a low detection limit, a high sensitivity, and it can also be applied for the detection of glucose in human serum samples.


RSC Advances ◽  
2016 ◽  
Vol 6 (81) ◽  
pp. 77854-77862 ◽  
Author(s):  
Zeinab F. Akl ◽  
Tamer Awad Ali

Potentiometric screen-printed electrodes were constructed for Th(iv) determination in water samples. The optimized electrodes exhibited fast response time, wide linear range, low detection limit and high selectivity towards Th(iv) ions.


RSC Advances ◽  
2017 ◽  
Vol 7 (53) ◽  
pp. 33419-33425 ◽  
Author(s):  
Li Sun ◽  
Wencheng Fang ◽  
Ying Yang ◽  
Hui Yu ◽  
Tingting Wang ◽  
...  

Porous single-crystal In2O3 nanosheet was well-designed and prepared through calcination after liquid reflux, then exhibited a distinguished response, fast response time to NOx with good selectivity and low detection limit at room temperature.


2018 ◽  
Vol 12 (4) ◽  
pp. 4088-4097
Author(s):  
S. Ma’mun ◽  
Hallvard F. Svendsen ◽  
I. M. Bendiyasa

Global emission of carbon dioxide (CO2), a major contributor to the climate change, has increased annually and it reached over 37 Gt in 2017. An effort to reduce the emission, therefore, needs to be conducted, e.g. post-combustion capture by use of amine-based absorption. The objective of this study is to evaluate the kinetic and mass transfer parameters in a CO2 absorption process using monoethanolamine (MEA), 2-(methylamino)ethanol (MMEA), and 2-(ethylamino)ethanol (EMEA) as absorbents. The experiments were conducted in a bubble reactor at atmospheric pressure and 40 °C with 10-vol% CO2 flowrate of 5 NL/men. The CO2 concentration leaving the reactor was measured by an IR CO2 analyzer. The results obtained from this experiment were the overall absorption rates consisting of both chemical reaction and mass transfer. Analysis result shows that the reaction between CO2 and amines takes place fast, therefore the mass transfer of CO2 from the gas into the liquid through the gas film would control the overall absorption rate.


2014 ◽  
Vol 12 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Cecylia Wardak

AbstractA new solid contact Zn2+ polyvinylchloride membrane sensor with 2-(2-Hydroxy-1-naphthylazo)-1,3,4 -thiadiazole as an ionophore has been prepared. For the electrode construction, ionic liquids, alkylmethylimidazolium chlorides are used as transducer media and as a lipophilic ionic membrane component. The addition of ionic liquid to the membrane phase was found to reduce membrane resistance and determine the potential of an internal reference Ag/AgCl electrode. The electrode with the membrane composition: ionophore: PVC: o-NPOE: ionic liquid in the percentage ratio of (wt.) 1:30:66:3, respectively, exhibited the best performance, having a slope of 29.8 mV decade−1 in the concentration range 3×10−7–1×10−1 M. The detection limit is 6.9×10−8 M. It has a fast response time of 5–7 s and exhibits stable and reproducible potential. It has a fast response time of 5–7 s and exhibits stable and reproducible potential, which does not depend on pH in the range 3.8–8.0. The proposed sensor shows a good and satisfactory selectivity towards Zn2+ ion in comparison with other cations including alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for direct determination of zinc ions in tap water and as an indicator electrode in potentiometric titration of Zn2+ ions with EDTA.


2017 ◽  
Vol 41 (15) ◽  
pp. 7517-7523 ◽  
Author(s):  
Wencheng Fang ◽  
Ying Yang ◽  
Hui Yu ◽  
Xiangting Dong ◽  
Ruihong Wang ◽  
...  

An In2O3 nanorod-decorated reduced graphene oxide composite has been successfully synthesized, and this composite shows a good response, fast response time to NOx with good selectivity and low detection limit at room temperature.


2020 ◽  
Vol 8 (25) ◽  
pp. 5411-5415 ◽  
Author(s):  
Yanxia Qiao ◽  
Qian Liu ◽  
Siyu Lu ◽  
Guang Chen ◽  
Shuyan Gao ◽  
...  

A glucose sensor based on a conductive Ni-MOF as an electrocatalyst exhibits a fast response time, low detection limit, and high sensitivity, and it can also be applied for the detection of glucose in blood serum samples.


2021 ◽  
Vol 287 ◽  
pp. 02007
Author(s):  
Nur Farhana Ajua Mustafa ◽  
Azmi Mohd Shariff ◽  
WeeHorng Tay ◽  
Siti Munirah Mhd Yusof

This paper presented the effect of CO2 concentration in the gas feed to the CO2 absorption performance using a green solvent, potassium carbonate promoted with glycine (PCGLY). Recently, the performance of this solvent (with precipitates) was hindered by its poor mass transfer performance due to the blockage in packings and piping. Therefore, this study focused to study the CO2 absorption performance of non-precipitating potassium carbonate promoted with glycine. This green solvent contains aqueous blend of 15wt% potassium carbonate and 3 wt% glycine. The absorption performance of the solvent was obtained by demonstrated a few experimental works using a bench scale packed absorption column. The packing type was Sulzer metal gauze and the column consisted of six sampling point which located equidistance along the packing.The effect of CO2 concentration at the gas feed was assessed in term of its CO2 removal efficiency and concentration profile along the packing. The study shows the decreasing trend of CO2 removal as CO2 inlet concentration in the gas feed increases. The reason of this behavior is due to the limited reactant of liquid phase to absorb high CO2 concentration in gas phase. The main outcome of this study demonstrated the efficient absorption which can absorb up to 79.24 % of CO2 from natural gas using non-precipitated PCGLY.


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