Large and Highly Selective and Permeable CHA Zeolite Membranes

Large (100 cm2 membrane area) tubular chabazite (CHA) zeolite membranes (450 nm thick) were experimentally evaluated for the separation of CO2/CH4 in an industrial laboratory. An industrially relevant feed flow rate of 250 Ndm3/min was used. The feed pressure and temperature were varied in the ranges of 5–18 bar and 292–318 K, respectively. For a CO2/CH4 feed with a molar ratio of 1:1, the experimental CO2/CH4 selectivity was high at 205, and the CO2 permeance arrived at 52 × 10–7 mol/(m2·s·Pa) at 5 bar and 292 K. As far as we know, there is no report in the literature on large CHA membranes with such high permeability and selectivity. A high CO2/CH4 selectivity was also observed for a 1:4 CO2/CH4 feed. However, as indicated by mathematical modeling, concentration polarization was still an issue for membrane performance, especially at high operating pressures, even though the flow rate of the feed was relatively high. Without concentration polarization, the theoretical CO2/CH4 selectivity was 41% higher than the experimental value for a 1:1 CO2/CH4 feed at 18 bar. The corresponding CO2 permeance without concentration polarization was 23% higher than the experimentally observed value, reaching 34 × 10–7 mol/(m2·s·Pa). CHA membrane processes for the removal of CO2 from CH4 were designed, and the electricity consumption and module cost of the process were also estimated. All of the results in this study indicate a great potential of the large CHA membranes for biogas and natural gas upgrading; however, concentration polarization should be minimized in industrial processes

Influence of Zn(II) on the Adsorption of Arsenate onto Ferrihydrite

Addition of iron oxide to arsenic-contaminated soil has been proposed as a means of reducing the mobility of arsenic in the soil. Arsenic and zinc are common coexisting contaminants in soils. The presence of zinc therefore may affect the adsorption properties of arsenic on iron oxide, and may thus affect its mobility in the soil. The influence of Zn­(II) on the adsorption of arsenate ions on iron oxide was studied. Batch adsorption experiments indicated that Zn­(II) increased the arsenate removal from a solution by ferrihydrite at pH 8. However, ATR-FTIR spectroscopy showed that no adsorption of arsenate on a ferrihydrite film occurred at pD 8 in the presence of Zn­(II). Precipitation of zinc hydroxide carbonate followed by arsenate adorption onto the precipitate was found to be a plausible mechanism explaining the arsenate removal from a solution in the presence of Zn­(II) at pH/pD 8. The previously suggested mechanisms attributing the enhanced removal of arsenate from solution in the presence of Zn­(II) to additional adsorption on iron oxides could not be verified under the experimental conditions studied. It was also shown that at pH/pD 4, the presence of Zn­(II) in the system did not significantly affect the adsorption of arsenate on ferrihydrite

Adsorption of CO₂, CH₄, and H₂O in Zeolite ZSM‑5 Studied Using In Situ ATR-FTIR Spectroscopy

Biogas and natural gas are interesting fuels with high H/C ratio. However, these gases frequently contain carbon dioxide and water which lowers the heat value of the gas and may induce corrosion. Therefore, the development of more efficient processes, such as membrane processes and improved adsorbents, for the separation of carbon dioxide and water from biogas and natural gas is of great importance. Zeolite ZSM-5 membranes are promising for this separation which is controlled by the adsorption and diffusion of the different species in the zeolite. Multicomponent adsorption data are therefore required for development of new membrane and adsorption processes. In the present work, the adsorption of water, carbon dioxide, and methane in a Na-ZSM-5 zeolite film at various temperatures was studied by in situ Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy for the first time. Adsorption isotherms were retrieved from the experimental data and the Langmuir model fitted the isotherms very well. Limiting heat of adsorption was determined from the Henrýs law regime and the values determined agreed well with previously reported data. A few experiments were conducted with multicomponent mixtures and the experimentally determined amounts adsorbed were compared with values predicted by the Ideal Adsorbed Solution Theory (IAST). It was found that for the binary mixture of carbon dioxide and methane there was good agreement between the experimental values and those predicted by the IAST. However, when water was also introduced, the IAST could not fully capture the adsorption behavior of the multicomponent mixture, probably because the adsorbed phase is not ideal. These findings are in line with previous reports for adsorption in zeolites. The multicomponent adsorption behavior of this system will be further investigated in forthcoming work

Additional file 1 of Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

Additional file 1: Sysmex XN10 machine cell counting.docx: Information regarding Sysmex XN10 machine cell counting and the term functional sensitivity

Additional file 2 of Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

Additional file 2: Intraventricular Hemorrhage Score (IVHS).docx: Information regarding IVHS calculation

Additional file 4 of Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

Additional file 4: Computed tomography (CT)-related predictors of change between pair samples.PNG: Table with univariate mixed model linear regression analyses. The results of p < .01 are bolded. CT parameters appear most correlated with changes in erythrocytes, but not with direction of change. IVH volume, sediment depth, catheter distance, and IVHS are defined in the methods section. Δ: pair-wise difference, including absolute and relative derivatives. IVHS: intraventricular hemorrhage score. IVH: intraventricular hemorrhage

Additional file 3 of Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

Additional file 3: Correlation of paired sample differences and cell types.PNG: Scatter plots comparing the granulocyte Δ with the erythrocyte Δ and the granulocyte Δ with the monocyte Δ, respectively. Granulocytes and monocytes exhibit a stronger correlation (R2 = 0,624) vs. granulocytes and erythrocytes (R2 = 0,346) suggesting that a greater concordance is seen for cells of similar types. Δ: pair-wise difference

Measurement of lactate in pleural fluid rapidly identify infection and guide therapy

Measurements of pleural fluid biomarkers for rapid identification of complicated parapneumonic effusion (CPPE) are crucial for optimal management. Previous studies for biomarker evaluation were however based on pleura culture, not modern DNA technique. Lactate has not been thoroughly studied earlier as a potential biomarker in this regard. To evaluate whether the routine biomarkers pH, glucose, lactate dehydrogenase (LDH) measured in pleural fluid in a microbiological well characterised cohort could differentiate simple parapneumonic effusion (SPPE) from CPPE and if pleural fluid lactate could be of additional use in this discrimination. Pleural fluid prospectively collected from adult patients (n = 112) with PPE admitted to the Departments of Infectious Diseases (DIDs) at four Stockholm County hospitals were characterised microbiologically with bacterial culture and 16S rDNA sequencing, and biochemically with pH, glucose, LDH and lactate. Forty and seventy two patients were categorised as SPPE/CPPE. The median values between SPPE/CPPE differed significantly for all biomarkers with varying overlap. Receiver operating characteristics (ROC) curves showed the area under the curve (AUC) for pH 0.905 (CI 0.847–0.963), glucose 0.861 (CI 0.79–0.932), LDH 0.917 (CI 0.860–0.974) and lactate 0.927 (CI 0.877–0.977), corresponding to best cut-off levels and sensitivity/specificity for pH of 7.255, 0.819/0.9, glucose 5.35 mmol/L, 0.847/0.775, LDH 9.8 µcat/L, 0.905/0.825 and lactate 4.9 mmol/L, 0.875/0.85. To distinguish between SPPE/CPPE, pH and LDH performed well, but optimal cut-off values differed from earlier established recommendations. Pleura lactate had the largest AUC of the investigated biomarkers and may be used in the analyses of PPE-staging.</p

Additional file 1 of Bacterial co-infections in community-acquired pneumonia caused by SARS-CoV-2, influenza virus and respiratory syncytial virus

Additional file 1: Figure S1. Flowchart of health care episodes included in the study. Table S1. ICD-10 codes for specific comorbidities. Table S2. Definition of positive microbiological tests. Figure S2. Bacterial co-infection testing practices over time in SARS-CoV-2 patients. Figure S3. Detected bacterial co-pathogens in LRT and blood cultures in SARS-CoV-2, influenza and RSV