•In situ DRIFT spectroscopy was employed to monitor the dust surface.•XRF, XRD and ICP-MS analyses were used for the chemical characterization of dusts.•Particles Size and the Ca/Si ratio could ...determine water adsorption onto dust.•At ambient relative humidity, natural mineral samples are always covered with water.
The adsorption of water molecules on natural mineral dusts was investigated employing in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The natural dust samples originated from North and West Africa, Saudi Arabia and Gobi desert regions. Furthermore, the hygroscopicity of commercially available Arizona Test Dusts (ATDs) and Icelandic volcanic ash were examined. N2 sorption measurements, X-ray fluorescence and diffraction (XRF and XRD), as well as Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analyses were performed to determine the physicochemical properties of the particles. The water adsorption experiments were conducted in an optical cell, at room temperature under the relative humidity (RH) range of 1.9–95%. Results were simulated using a modified three-parameter Brunauer-Emmett-Teller (BET) equation. Water monolayer (ML) was formed in the RH range of 15–25%, while additional water layers were formed at higher RH. Besides, the standard adsorption enthalpies of water onto natural mineral dust samples were determined. A thorough comparison of two commercially available ATD samples indicated that size distribution and/or porosity should play a key role in particle hygroscopicity. Regarding the natural mineral particles, Ca/Si ratios, and to a lesser extent Al/Si, Na/Si, Mg/Si ratios, were found to impact the minimum RH level required for water monolayer formation. These results suggest that the hygroscopic properties of investigated African dusts are quite similar over the whole investigated RH range. Furthermore, one of the major conclusions is that under most atmospheric relative humidity conditions, natural mineral samples are always covered with at least one layer of adsorbed water.
The present study combines nonthermal plasma (NTP) and thermal catalysis to exploit the synergism for direct conversion of CO2 to CH3OH using H2. Series of catalyst, that is, CuO/QW, NiO/QW, ...Fe2O3/QW, NiO/Fe2O3/QW, CuO/Fe2O3/QW have been tested for CO2 conversion and CH3OH selectivity. And it was observed that 5 wt% CuO/Fe2O3/QW exhibited better CO2 conversion and CH3OH selectivity as compared to other catalysts. With 5 wt% CuO/Fe2O3/QW, at 200°C and 2‐W NTP input power (100 ml/min feed flow and 1:3 ratio of CO2 and H2) about 16.7% CO2 conversion and 32.7% CH3OH selectivity have been reached. Indeed, the highest of 9.32 mmol h−1 gcat−1 of CH3OH space‐time yield is obtained over CuO/Fe2O3/QW, which is about two times higher than the reported value in the literature (4.41 mmol h−1 gcat−1 of CH3OH using Cu/ZnO/Al2O3, 30°C, feed flow 40 ml/min, and 30‐W input power).
The direct conversion of CO2 to CH3OH using H2 on a bifunctional catalytic system (CuO/Fe2O3/QW and NiO/Fe2O3/QW) has been explored. A synergistic effect is observed between the plasma and thermal catalytic process. About 16.7% CO2 conversion and 32% of CH3OH selectivity have been reached with 2‐W input power at 200°C. Indeed, the highest of 9.32 mmol h−1 gcat−1 of CH3OH space‐time yield is obtained over CuO/Fe2O3/QW, which is about two times higher than the reported value in the literature.
Abstract
The present study combines nonthermal plasma (NTP) and thermal catalysis to exploit the synergism for direct conversion of CO
2
to CH
3
OH using H
2
. Series of catalyst, that is, CuO/QW, ...NiO/QW, Fe
2
O
3
/QW, NiO/Fe
2
O
3
/QW, CuO/Fe
2
O
3
/QW have been tested for CO
2
conversion and CH
3
OH selectivity. And it was observed that 5 wt% CuO/Fe
2
O
3
/QW exhibited better CO
2
conversion and CH
3
OH selectivity as compared to other catalysts. With 5 wt% CuO/Fe
2
O
3
/QW, at 200°C and 2‐W NTP input power (100 ml/min feed flow and 1:3 ratio of CO
2
and H
2
) about 16.7% CO
2
conversion and 32.7% CH
3
OH selectivity have been reached. Indeed, the highest of 9.32 mmol h
−1
gcat
−1
of CH
3
OH space‐time yield is obtained over CuO/Fe
2
O
3
/QW, which is about two times higher than the reported value in the literature (4.41 mmol h
−1
gcat
−1
of CH
3
OH using Cu/ZnO/Al
2
O
3
, 30°C, feed flow 40 ml/min, and 30‐W input power).
IntroductionFailure of early identification of sepsis in the emergency department (ED) leads to significant delays in antibiotic administration which adversely affects patient outcomes.AimThe primary ...objective of our Quality Improvement (QI) project was to reduce the door-to-antibiotic time (DTAT) by 30% from the preintervention in patients with suspected sepsis. Secondary objectives were to increase the blood culture collection rate by 30% from preintervention, investigate the predictors of improving DTAT and study the effect of these interventions on 24-hour in-hospital mortality.MethodsThis QI project was conducted in the ED of a tertiary care teaching hospital of North India; the ED receives approximately 400 patients per day. Adult patients with suspected sepsis presenting to our ED were included in the study, between January 2019 and December 2020. The study was divided into three phases; preintervention phase (100 patients), intervention phase (100 patients) and postintervention phase (93 patients). DTAT and blood cultures prior to antibiotic administration was recorded for all patients. Blood culture yield and 24-hour in-hospital mortality were also recorded using standard data templates. Change ideas planned by the Sepsis QI Team were implemented after conducting plan-do-study-act cycles.ResultsThe median DTAT reduced from 155 min in preintervention phase to 78 min in postintervention phase. Drawing of blood cultures prior to antibiotic administration improved by 67%. Application of novel screening tool at triage was found to be an independent predictor of reduced DTAT.ConclusionOur QI project identified the existing lacunae in implementation of the sepsis bundle which were dealt with in a stepwise manner. The sepsis screening tool and on-site training improved care of patients with sepsis. A similar approach can be used to deal with complex quality issues in other high-volume low-resource settings.
In the present studies, the synthesis of pure ZnO nanoparticles and Mg and S-doped ZnO particles were carried out using a non-aqueous sol–gel method. The synthesized nanoparticles (NPs) are ...characterized using XRD, FESEM, EDX, FTIR, UV–Vis-DRS, XPS, PL, and BET surface area analysis. X-ray diffraction (XRD) techniques were used to examine the crystallization of ZnO, Mg-ZnO, and S-ZnO samples. The Mg-ZnO and S-ZnO samples exhibit significant
c
-axis compression and smaller crystallite sizes as compared to undoped ZnO. The optical band gap of Mg-ZnO and S-ZnO NPs were found to be 2.93 eV and 2.32 eV, respectively, which are lower than that of ZnO NPs (3.05 eV). The S-doped ZnO resulted in the homogenous distribution of sulfur ions in the ZnO lattice crystal. XPS analysis revealed that the doped S element was mostly S
4+
and S
6+
. A systematic evaluation has been conducted to assess the influence of several operational parameters, including doped/undoped stoichiometry, solution pH, catalyst dosage, and radical trapping experiment, on the photocatalytic degradation of Rhodamine 6G (Rh 6G) dye. Furthermore, we investigated the photocatalytic degradation activity of ZnO, Mg-ZnO, and S-ZnO samples with aquoues solution of 5 ppm Rhodamine 6G (Rh 6G) at room temperature. Results indicated that pure ZnO nanoparticles have the highest photocatalytic degradation rate constant (0.00344 min
−1
), compared to the samples Mg-ZnO (0.00104 min
−1
) and S-ZnO (0.00108 min
−1
) with Rh 6G dye in presence of visible light emitting diode (Vis-LED) source at room temperature. The enhanced visible light photocatalytic activities of pure ZnO NPs were attributed to their superior surface properties (18.30 m
2
/g) and effective electron–hole separation.
Graphical Abstract
The hydrogenation of CO2 to CH3OH on the binary mixed metal oxides of CuO–Fe2O3 under nonthermal plasma discharge has been reported in this study. The catalysts are synthesized using the sol–gel ...route and characterized by XRD, FTIR, SEM, and XPS techniques. The impact of CuO mixing with Fe2O3 on CO2 conversion and CH3OH yield has been investigated. Herein, we have compared two distinct techniques, namely thermal and plasma catalytic processes. The overall outcome shows that the CO2 conversion and CH3OH production increase with an increase in CuO mixing with Fe2O3. The synthesized catalyst does not show significant CO2 conversion and CH3OH formation in the thermal catalytic process (100–250 °C). Interestingly, when plasma discharge is combined with thermal heating, CO2 conversion and CH3OH production significantly improve. The plasma discharges in the CO2/H2 gas stream, at low temperatures (<200 °C), reduce Cu+2 to Cu+1 and Fe+3 to Fe+2, which could probably enhance the CO2 conversion and CH3OH production. Among the catalysts prepared, 15% CuO–Fe2O3 exhibited the best catalytic activity with 13.2% CO2 conversion, 7.3% CH3OH yield, and a space–time yield of 13 mmolCH3OH/h gcat, with 4.67 kJ/L of specific input energy (SIE). The CH3OH space–time yield is 2.9-fold higher than that of the commercial catalyst Cu/ZnO/Al2O3, which is operated at 30 °C with 45.45 kJ/L SIE.
The hydrogenation of CO
to CH
OH on the binary mixed metal oxides of CuO-Fe
O
under nonthermal plasma discharge has been reported in this study. The catalysts are synthesized using the sol-gel route ...and characterized by XRD, FTIR, SEM, and XPS techniques. The impact of CuO mixing with Fe
O
on CO
conversion and CH
OH yield has been investigated. Herein, we have compared two distinct techniques, namely thermal and plasma catalytic processes. The overall outcome shows that the CO
conversion and CH
OH production increase with an increase in CuO mixing with Fe
O
. The synthesized catalyst does not show significant CO
conversion and CH
OH formation in the thermal catalytic process (100-250 °C). Interestingly, when plasma discharge is combined with thermal heating, CO
conversion and CH
OH production significantly improve. The plasma discharges in the CO
/H
gas stream, at low temperatures (<200 °C), reduce Cu
to Cu
and Fe
to Fe
, which could probably enhance the CO
conversion and CH
OH production. Among the catalysts prepared, 15% CuO-Fe
O
exhibited the best catalytic activity with 13.2% CO
conversion, 7.3% CH
OH yield, and a space-time yield of 13 mmol
/h g
, with 4.67 kJ/L of specific input energy (SIE). The CH
OH space-time yield is 2.9-fold higher than that of the commercial catalyst Cu/ZnO/Al
O
, which is operated at 30 °C with 45.45 kJ/L SIE.
The conversion of CO
to CH
OH over binary mixed metal oxides of NiO-Fe
O
is investigated in the study. A series of catalysts,
, NiO, Fe
O
, 5% NiO-Fe
O
(5NF), 10% NiO-Fe
O
(10NF), and 15% NiO-Fe
O
...(15NF), was tested for CO
conversion and CH
OH selectivity performance. The results show that binary mixed metal oxides are more active in comparison to pure metal oxides. Moreover, increasing NiO mixing leads to the agglomeration of NiO particles. At 200 °C, around 1.5%, 2%, and 3.2% CO
conversion is achieved for 5NF, 10NF, and 15NF, respectively. Interestingly, when cold plasma was ignited at 200 °C, around 5.4%, 6.2%, and 10.2% CO
conversion was achieved for the 5NF, 10NF, and 15NF catalysts, respectively. 15NF exhibited the highest CO
conversion, but produced only CH
. Plasma coupling with the catalyst led to an increase in the CH
OH yield, and around an 5.8-fold enhancement was achieved with 10NF at 200 °C compared to thermal catalysis. We showed that the combination of plasma and thermal heating brings about significant changes to the catalyst morphology, which significantly improved the catalytic activity. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization revealed that plasma treatment leads to the formation of a mixture of spinel compounds (NiO-Fe
O
, NiFe
O
, and Fe
O
).
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