Enhanced oil recovery by using modified ZnO nanocomposites in sandstone oil reservoirs.

Recently, nanocomposites were employed to improve the extraction of oil in different reservoirs. Due to the unique characteristics of nanoparticles such as small size, efficient altering main mechanisms such as IFT, CA, and viscosity reduction, have received wide attention among researchers. This study investigated the application of a newly designed ZnO-cerium N-composite for EOR at reservoir conditions, and the performance was compared to the standalone ZnO nanoparticles. After performing the morphology of the N-composite, the effect of the N-composites on the wettability alteration, interfacial tension, viscosity, Zeta potential, pH, and density was studied at different N-composites concentrations at reservoir conditions. Based on the results of rock/fluid interactions at the static phase, an optimum concentration was chosen for performing dynamic core flooding experiments. At 100 ppm, the highest stability and the highest reduction in capillary force were observed. The presence of Ce in the structure of the N-composite changes the pore volume of ZnO-Ce compared to ZnO nanoparticles, which affects the surface charge. IFT (mN/m), CA (°), and zeta potential (mV) were (22.51, 40.83, and - 44.36), and (30.50, 50.21, and - 31.05) for ZnO-Ce and ZnO, respectively at 100 ppm. By application of the optimized nanofluid in an oil displacement study, RF in the presence of ZnO-Ce, and ZnO were 37.11% and 71.40%, respectively.

Enhanced photocatalytic performance of milkvetch-derived biochar via ZnO-Ce nanoparticle decoration for reactive blue 19 dye removal.

In this research, the photocatalytic removal of reactive blue 19 (RB19) dye is investigated employing zinc oxide/cerium (ZnO@Ce) nanoparticles decorated with biochar under LED irradiation. Synthesis of ZnO@Ce nanoparticles decorated with biochar was performed utilizing the co-precipitation procedure and, then, the texture and morphology of the fabricated nanocomposite were analyzed using energy dispersive X-ray (EDX), field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and Fourier transform infrared (FTIR) spectroscopy techniques. Moreover, FE-SEM images demonstrate that ZnO-Ce nanoparticles were successfully decorated on the surface of biochar. The specific surface areas of biochar and biochar/ZnO-Ce were 519.75 and 636.52 m2/g, respectively. To achieve the maximum yield in the removal of RB19 dye, the effects of operating variables including dye concentration, LED lamp power, biochar@ZnO-Ce catalyst dose, pH and H2O2 dose were explored. Besides, the maximum percentage of RB19 dye removal was 96.47% under optimal conditions, i.e. catalyst dosage of 100 mg, H2O2 dosage of 1 mL, pH of 9, initial dye concentration of 5 ppm, LED power of 50 W, and reaction time of 140 min. Furthermore, the kinetic analysis reveals that the removal of RB19 dye follows the pseudo-first order kinetic model, with calculated values of a reaction rate constant of 0.045 min-1 and a correlation coefficient of R2 = 0.99, respectively. Moreover, the reusability and recyclability of biochar@ZnO/Ce nanocatalyst was promising over five runs, with only a 6.08% decrease in RB19 dye removal efficiency. Therefore, it can be concluded that the biochar @ZnO/Ce photocatalyst can be promisingly applied for the removal of azo dyes in aqueous solutions.

Improving Simultaneous Water Alternative Associate Gas Tests in the Presence of Newly Synthesized γ-Al2O3/ZnO/Urea Nano-Composites: An Experimental Core Flooding Tests.

Nano-composites positively impact subsurface porous media's properties during enhanced oil recovery. In this paper, γ-Al2O3/ZnO/urea nano-composites were selected to improve simultaneous water alternative associate gas (SWAG) tests based on better results in comparison to pure γ-Al2O3 in the static phase. According to the interfacial tension (lowest), contact angle (lowest), zeta potential (highest absolute value), and viscosity (lowest) tests in the presence of nano-composites, 80 ppm was chosen as the optimum concentration (OP) to perform SWAG experiments. The interfacial tension (mN m-1) and contact angle (°) values of nano-fluids at concentrations of 20, 40, 60, 80, 100, and 120 ppm were higher than that of alumina and were (27.50, 130.12), (24.38, 80.32), (21.63, 70.98), (15.63, 40.69), (10.75, 8.50), and (6.80, 46.01) mN m-1, respectively. It was evident that considering effective, efficient parameters before performing the main SWAG test was important, and due to using OP, the recovery factor increased from 55.9 to 83.1% at a constant SWAG ratio (1:1) and temperature (40 °C). Furthermore, higher instant oil and lower produced water were seen as OP during the nano-composite-assisted SWAG test at 80 ppm.

Experimental Core Flooding Investigation of New ZnO-γAl2O3 Nanocomposites for Enhanced Oil Recovery in Carbonate Reservoirs.

Generally, crude oil production in mature oil reservoirs is difficult. In this regard, some nanoparticles have been used to upgrade injected water into oil reservoirs. These nanoparticles can be used in a variety of injectable waters, including smart water (SMW) with special salinity. This study aims to evaluate the performance of the injection of SMW with ZnO-γAl2O3 nanoparticles in enhanced oil recovery (EOR). The performance of SMW with ZnO-γAl2O3 nanoparticles in regard to contact angle (CA), interfacial tension (IFT) reduction, and oil production with core flooding tests was investigated. The newly prepared ZnO-γAl2O3 structure was characterized by energy dispersive X-ray (EDX), Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses in this research. The effects of different concentrations of nanofluids on zeta potential (ZP) and conductivity were investigated. The ZP test confirmed the results of the stability tests of the developed nanofluids in water-based solutions. After the introduction of ZnO-γAl2O3 nanoparticles into the formation of brine and SMW solutions, oil-water (O/W) IFT was reduced. Based on the results, the IFT decreased more when nanoparticles and ions were present in the system. The results of the present study showed that at the concentration of SW+300 ppm ZnO-γAl2O3, the IFT value reached 11 mN/m from 27.24 mN/m. The results of the CA tests showed that improving the capabilities of salt water in the presence of nanoparticles has resulted in a very effective reduction. Also, in this regard, very hydrophilic wettability was achieved using SMW with stable nanoparticles. Moreover, the results of the present study showed that at the concentration of SMW+300 ppm ZnO-γAl2O3 nanoparticles, the CA value reached 31 from 161°. In the end, the solution of SW+300 ppm ZnO-γAl2O3 improved the OR by 15 and 24%. This research indicated that it is possible to develop and implement different nanoparticles by combining SMW to manage reservoir rock wettability and maximize OR from carbonate reservoirs. Thus, this combination as an effective agent could significantly increase reservoir sweep efficiency. Thus, as a result, using the established hybrid technique has distinct advantages over using SMW flooding alone.

Virus load and incidence of olfactory, gustatory, respiratory, gastrointestinal disorders in COVID-19 patients: A retrospective cohort study.

OBJECTIVES: This study investigated the relationship between viral load and the incidence of olfactory and gustatory dysfunction (OD and GD), the incidence of respiratory and gastrointestinal symptoms and the recovery of OD and GD in COVID-19 patients. DESIGN: A retrospective cohort study. SETTING AND PARTICIPANTS: This study was conducted on 599 outpatients' cases in Golestan province between February and June 2020. MAIN OUTCOME MEASURES: The incidence, severity (complete or partial) and recovery time of OD and GD and their associations with cycle threshold (CT) values of SARS-CoV-2 polymerase chain reaction were assessed. RESULTS: The mean age of patients was 38.27 ± 13.62 years. The incidence of general symptoms included myalgia 70.1%, headache 51.8%, fever 47.7% and dyspnoea 21.4%. 41.9% of patients had gastrointestinal symptoms, including abdominal pain 26.5%, diarrhoea 25.2%, nausea 20.5% and vomiting 12.9%. 12.2% of patients had comorbidity. The trimester recovery rates of OD and GD were 93.94% and 94.74% respectively. The mean recovery time of OD and GD was 14.56 ± 13.37 and 13.8 ± 3.77 days respectively. The mean CT value in all patients was 27.45 ± 4.55. There were significant associations between the mean of CT value with headache (p = 0.04), GD (p = 0.002) and OD (p = 0.001). CONCLUSIONS: The finding of this study indicates a possible association between viral load with incidence of OD and GD in COVID-19 patient's cases and assures the recovery of OD/GD in these patients.

Carboxymethyl cellulose improved adsorption capacity of polypyrrole/CMC composite nanoparticles for removal of reactive dyes: Experimental optimization and DFT calculation.

In this study, polypyrrole/carboxymethyl cellulose nanocomposite particles (PPy/CMC NPs) were synthesized and applied for removal of reactive red 56 (RR56)and reactive blue 160 (RB160) as highly toxic dyes. The amount of CMC was found significantly effective on the surface adsorption efficiency. Different optimization methods including the genetic programming, response surface methodology, and artificial neural network (ANN) were used to optimize the effect of different parameters including pH, adsorption time, initial dye concentration and adsorbent dose. The maximum adsorption of RR56 and RB160 were found under the following optimum conditions: pH of 4 and 5, adsorption time of 55 min and 52 min for RR56 and RB160, respectively, initial dye concentration of 100 mg/L and adsorbent dose of 0.09 g for both dyes. were obtained for RR56 and RB160, respectively. Also, the results indicated that ANN method could predict the experimental adsorption data with higher accuracy than other methods. The analysis of ANN results indicated that the adsorbent dose is the main factor in RR56 removal, followed by time, pH and initial concentration, respectively. However, initial concentration mostly determines the RB160 removal process. The isotherm data for both dyes followed the Langmuir isotherm model with a maximum adsorption capacity of 104.9 mg/g and 120.7 mg/g for RR56 and RB160, respectively. In addition, thermodynamic studies indicated the endothermic adsorption process for both studied dyes. Moreover, DFT calculations were carried out to obtain more insight into the interactions between the dyes and adsorbent. The results showed that the hydrogen bondings and Van der Waals interactions are dominant forces between the two studied dyes and PPy/CMC composite. Furthermore, the interaction energies calculated by DFT confirmed the experimental adsorption data, where PPy/CMC resulted in higher removal of both dyes compared to PPy. The developed nanocomposite showed considerable reusability up to 3 cylces of the batch adsorption process.

Evaluation of Cytogenetic Alterations in Peripheral Blood Lymphocytes of Esophageal Cancer Patients Treated with Radiotherapy or Chemoradiotherapy using Cytokinesis-Blocked Micronucleus Assay.

The effects of combined radiotherapy (RT) and chemotherapy in the severity of cytogenetic alterations expressed as micronucleus (MN) in peripheral blood lymphocytes of patients treated for esophageal cancer was evaluated. To do this, blood was obtained from 23 and 15 esophageal cancer patients scheduled for chemo-radiotherapy and RT alone, respectively, before, during, and after treatment. Blood samples were cultured in RPMI-1640 complete medium containing 1% phytohemagglutinin and incubated in a CO2 incubator. Cytochalasin-B was added to the cultures at a final concentration of 5 µg/ml. Finally, harvesting, slide making, and analysis were performed according to standard procedures. Results indicate that there was no significant difference between the frequencies of MN in lymphocytes of individuals before being treated with RT alone or chemo-radiotherapy. In the middle of treatment, (after 12 fractions of RT) the frequency of MN increased significantly compared with their concurrent pre-treatment samples in both groups (four-fold). However, the frequency of MN observed for RT patients was not significantly different with those received chemo- and radiotherapy. At the end of treatment, (after 24 fractions of radiotherapy) an increase in the MN frequency was observed for chemo-radiation group significantly higher than RT group (P=0.022). Mild increase in MN frequency in lymphocytes of patients receiving chemoradiation only after the completion of treatment course might be indicative of resistance induced by chemotherapeutics to the clastogenic effects of radiation. Therefore, using these agents repeatedly for cancer treatment in combination with radiation might not cause severe adverse biological effects in normal tissues.