Improving the detection capability and efficiency of SARS-CoV-2 RNA specimens by the specimen turn-around process with multi-department cooperation.

Objective: Improving the detection capability and efficiency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA specimens is very important for the prevention and control of the outbreak of Coronavirus disease 2019 (COVID-19). In this study, we evaluated the detection capability and efficiency of two outbreaks of COVID-19 before and after the process re-engineering in April and July 2022. Methods: This retrospective cross-sectional study involved 359,845 SARS-CoV-2 RNA specimens 2 weeks before and 2 weeks after the two outbreaks of COVID-19 in April and July. The number, transportation time and detection time of specimens, and the number of reports of more than 24 h were analyzed by SPSS software. Results: While 16.84% of people chose nasopharyngeal swabs (NPS) specimens, 83.16% chose oropharyngeal swabs (OPS) specimens to detect SARS-CoV-2 RNA. There were significant upward trends in the percentage of 10 sample pooling (P-10) from April before process re-engineering to July after process re-engineering (p < 0.001). Compared with April, the number of specimens in July increased significantly not only 2 weeks before but also 2 weeks after the outbreak of COVID-19, with an increase of 35.46 and 93.94%, respectively. After the process re-engineering, the number of reports more than 24 h in the 2 weeks before and after the outbreak of COVID-19 in July was significantly lower than that in April before process re-engineering (0% vs. 0.06% and 0 vs. 0.89%, both p < 0.001). Conclusion: The present study shows that strengthening the cooperation of multi-departments in process re-engineering, especially using the P-10 strategy and whole process informatization can improve the detection capability and efficiency of SARS-CoV-2 RNA specimens.

Correlating micro/meso pore evolution and chemical structure variation in a mild thermal treatment of a subbituminite.

This work investigates the evolution of micro/meso pores during a mild thermal treatment of subbituminous coal based on the observation of coal structure changes with the gradual detachment of organic matter from the coal. Pores in coal can be described as super-micropores (d < 1 nm), micropores (1 nm < d < 2 nm) and mesopores (2 nm < d < 50 nm). The decomposition of the carboxyl group at 200 °C decreases the super-micropore volume. A mild and sustained reaction takes place at 300 °C to gradually change the aromaticity and CH2/CH3 ratio of the treated coal. The amount of micropore structure sharply decreases in the early stages of heating, while the amount of mesopore structure continuously decreases during the whole process. A dramatic reaction takes place at 400 °C to sharply change the aromaticity and CH2/CH3 ratio of the treated coal, while the detachment of volatile compounds from the coal matrix caused an evident variation in the mesopore structure of the coal. The aromaticity and CH2/CH3 ratio of coal organics are found to correlate with the volumes of super-micropores and mesopores, respectively. The super-micropores are identified as comprising the inter-layer distance between stacks of aromatic rings, and mesopores are the spaces between macromolecular aromatic rings which are inter-connected via aliphatic chains.

Calcium-enhanced ferric hydroxide co-precipitation of arsenic in the presence of silicate.

This study focuses on the effectiveness of calcium (Ca2+) improving ferric (hydro)oxides precipitation and its subsequent effects on arsenic co-precipitation with ferric (hydro)oxides. The effects of Ca2+ on surface charge characteristics and precipitating behavior, which are respectively represented as zeta (zeta) potential and R(PDA), are investigated for ferric (hydro)oxides precipitates. The presence of Ca2+ increases the potential of ferric (hydro)oxides, and a more significant effect is observed at higher pH conditions. Calcium apparently facilitates ferric (hydro)oxide floc aggregation, increasing the maximum R(PDA) from 3.19 to 5.27% (in the presence of 3.5 mg/L silicate as silicon). These positive effects contribute to reduce the adverse effects resulting from the presence of silicate and enhance arsenic removal via ferric (hydro)oxides co-precipitation under different conditions. Furthermore, the effect of Ca2+ facilitating ferric precipitation (and therefore providing more precipitated solids for arsenic) is predominant in favoring arsenic removal compared with that of increasing surface charge. Calcium plays an important role in arsenic co-precipitation with ferric (hydro)oxides in the presence of silicate.

CuFe2O4/activated carbon composite: a novel magnetic adsorbent for the removal of acid orange II and catalytic regeneration.

CuFe2O4/activated carbon magnetic adsorbents, which combined the adsorption features of activated carbon with the magnetic and the excellent catalytic properties of powdered CuFe2O4, were developed using a simple chemical coprecipitation procedure. The prepared magnetic composites can be used to adsorb acid orange II (AO7) in water and subsequently, easily be separated from the medium by a magnetic technique. CuFe2O4/activated carbon magnetic adsorbents with mass ratio of 1:1, 1:1.5 and 1:2 were prepared. Magnetization measurements, BET surface area measurements, powder XRD and SEM were used to characterize the prepared adsorbents. The results indicate that the magnetic phase present is spinel copper ferrite and the presence of CuFe2O4 did not significantly affect the surface area and pore structure of the activated carbon. The adsorption kinetics and adsorption isotherm of acid orange II (AO7) onto the composites at pH 5.2 also showed that the presence of CuFe2O4 did not affect the adsorption capacity of the activated carbon. The thermal decomposition of AO7 adsorbed on the activated carbon and the composite was investigated by in situ FTIR, respectively. The results suggest that the composite has much higher catalytic activity than that of activated carbon, attributed to the presence of CuFe2O4. The variation of the adsorption capacity of the composites after several adsorption-regeneration cycles has also been studied.

Preparation and evaluation of a novel Fe-Mn binary oxide adsorbent for effective arsenite removal.

Arsenite (As(III)) is more toxic and more difficult to remove from water than arsenate (As(V)). As there is no simple treatment for the efficient removal of As(III), an oxidation step is always necessary to achieve higher removal. However, this leads to a complicated operation and is not cost-effective. To overcome these disadvantage, a novel Fe-Mn binary oxide material which combined the oxidation property of manganese dioxide and the high adsorption features to As(V) of iron oxides, were developed from low cost materials using a simultaneous oxidation and coprecipitation method. The adsorbent was characterized by BET surface areas measurement, powder XRD, SEM, and XPS. The results showed that prepared Fe-Mn binary oxide with a high surface area (265 m2 g(-1)) was amorphous. Iron and manganese existed mainly in the oxidation state +III and IV, respectively. Laboratory experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of solution pH values on arsenic removal. Batch experimental results showed that the adsorbent could completely oxidize As(III) to As(V) and was effective for both As(V) and As(III) removal, particularly the As(III). The maximal adsorption capacities of As(V) and As(III) were 0.93 mmol g(-1) and 1.77 mmol g(-1), respectively. The results compare favorably with those obtained using other adsorbent. The effects of anions such as SO4(2-), PO4(3-), SiO3(2-), CO3(2-) and humic acid (HA), which possibly exist in natural water, on As(III) removal were also investigated. The results indicated that phosphate was the greatest competitor with arsenic for adsorptive sites on the adsorbent. The presence of sulfate and HA had no significant effect on arsenic removal. The high uptake capability of the Fe-Mn binary oxide makes it potentially attractive adsorbent for the removal of As(III) from aqueous solution.

The electrocatalytic reduction of nitrate in water on Pd/Sn-modified activated carbon fiber electrode.

The Pd/Sn-modified activated carbon fiber (ACF) electrodes were successfully prepared by the impregnation of Pd2+ and Sn2+ ions onto ACF, and their electrocatalytic reduction capacity for nitrate ions in water was evaluated in a batch experiment. The electrode was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and temperature programmed reduction (TPR). The capacity for nitrate reduction depending on Sn content on the electrode and the pH of electrolyte was discussed at length. The results showed that at an applied current density of 1.11 mA cm(-2), nitrate ions in water (solution volume: 400 mL) were reduced from 110 to 3.4 mg L(-1) after 240 min with consecutive change of intermediate nitrite. Ammonium ions and nitrogen were formed as the main final products. The amount of other possible gaseous products (including NO and N2O) was trace. With the increase of Sn content on the Pd/Sn-modified ACF electrode, the activity for nitrate reduction went up to reach a maximum (at Pd/Sn = 4) and then decreased, while the selectivity to N2 was depressed. Higher pH value of electrolyte exhibited more suppression effect on the reduction of nitrite than that of nitrate. However, no significant influence on the final ammonia formation was observed. Additionally, Cu ion in water was found to cover the active sites of the electrode to make the electrode deactivated.

[Preparation of triolein-embedded CA membrane and its characteristics].

Triolein is successfully embedded into cellulose acetate (CA) by phase inversion. This prepared flat membrane can effectively remove trace lipophilic organic pollutants from water. Structure of hybrid membrane is mainly observed by scanning electron microscope (SEM). Triolein dispersion by mechanical rabbling and ultrasound are investigated. Ultrasound can more effectively strengthen triolein dispersion than mechanical rabbling. Effect of casting membrane temperature (room temperature, 0 degrees C) shows low temperature can help to forming smaller triolein droplets. In addition, interaction between triolein and CA belongs to physical mixing by the observation of FT-IR, accordingly triolein structure is not changed and adsorptive capacity for persistent organic pollutants is not affected. Triolein in hexane is analyzed by fluorometric measure. The results show that triolein is completely embedded into membrane, so it is impossible that triolein leaks into water in the process of the adsorption.

[In situ FTIR spectroscopic studies of the catalytic combustion of acid red B on CuFe2O4 in the presence and absence of O2].

The reaction process of catalytic combustion of ARB on CuFe2O4 in the presence and absence of O2 was studied by in situ DRIFT spectroscopy. The results showed that the decomposition of the sulfonic group of ARB molecule was not affected by the reaction atmosphere, but the decompositions of azo group and aromatic ring were markedly affected by the presence or absence of O2. The catalytic combustion of ARB was faster in air atmosphere than that in N2 atmosphere, and ARB could be completely oxidized to CO2 and nitrate at 300 degrees C. But in N2 atmosphere, it was very difficult for the decomposition of ARB to complete at 300 degrees C, even though air was introduced following this process. The temperature required for the rapid and complete decomposition would be as high as 500 degrees C.

[Effectiveness and mechanism of permanganate enhancing arsenite co-precipitation with ferric chloride].

The effectiveness and mechanism of permanganate enhancing arsenite (As(III)) co-precipitation with ferric chloride is investigated. Effects of parameters such as pH, natural organic matter (NOM) on As removal are studied. Permanganate significantly enhances As(III) removal for ferric co-precipitation (FCP) process. With Fe(III) dosage increasing from 2mg/L to 8mg/L, As removal increased from 41.3% to 75.4% for FCP process; for permanganate oxidation-ferric co-precipitation (POFCP) process, however, corresponsive As removal increased from 61.2% to 99.3% . As removal increased with higher pH for both processes; comparing to FCP process, pH had less effects on As removal for POFCP process; the presence of NOM reduced As removal for FCP process whereas no obvious reduction was observed for POFCP process. Permanganate oxidizing As(III) to As(V) is the main course for enhancing As(III ) removal; furthermore, products of permanganate reduction, hydrous MnO2 (s), also contribute to removing As. POFCP process exhibits good potential of removing As(III ) to assure chemical safety of drinking water.

Magnetic powder MnO-Fe2O3 composite--a novel material for the removal of azo-dye from water.

Fine powder adsorbents or catalysts often show better adsorptive or catalytic properties, but they encounter the difficulties of separation and recovery in application. In this study, four inexpensive magnetic powder MnO-Fe2O3 composites used as adsorbent-catalyst materials were prepared and characterized. These materials could be recovered efficiently by a magnetic separation method. Their adsorptive properties for the removal of an azo-dye, acid red B (ARB), from water and the regeneration of adsorbents containing ARB by catalytic combustion was studied. These powder adsorbents showed excellent adsorption towards ARB under acidic conditions. A very fast adsorption rate was observed and could be well described by a pseudo-second-order kinetics model. The adsorption capacity increased with increasing Fe content and surface area of the adsorbent, and the highest adsorption capacity of 105.3 mg/g was obtained at pH 3.5. The adsorption was not affected by the presence of Cl-, but was significantly affected by SO4(2-). The adsorbent containing ARB can be regenerated by catalytic combustion of adsorbed ARB at 400 degrees C in air. Laboratory experiments demonstrated that this material is reusable.

[Arsenic adsorption by magnetic adsorbent CuFe2O4].

By the fact that Cu(II) and Fe(III) have strong affinity toward inorganic arsenic, the present paper reported the preparation of the magnetic adsorbent CuFe2O4 for the removal of arsenic. This adsorbent was composed with Cu(II) and Fe(III) oxides and can be recovered by magnetic separation technique. The characterization and the arsenic adsorption properties of the magnetic adsorbent were also studied. The sorption capacity was related to the pH of arsenic containing solution and the adsorption was more efficient for removing arsenic from acid and neutral solutions. As(V) was found to be more strongly adsorbed than As(III) on the adsorbent, and its adsorption capacity was 10 mg/g at equilibrium concentration of 10 micrograms/L (pH 3.5-6.5). Arsenic adsorption was not influenced by the presence of chloride and phosphate, but slightly influenced by sulfate at 10-20 times concentration of arsenic. As(V) desorption was performed more efficiently than As(III) desorption using 0.1 mol/L NaOH, which was the result of the different adsorption mechanism for the two arsenic species on adsorbent.