Asphaltene precipitation causes several problems during crude oil production, transportation, and refinery processes. Therefore, finding an inhibitor to prevent or delay asphaltene precipitation is of paramount importance. In this work, effects of TiO2, ZrO2, and SiO2 fine nanoparticles in organic-based nanofluids have been investigated to study their potential for stabilizing asphaltene particles in oil. To this end, polarized light microscopy has been applied to determine the onset of asphaltene precipitation by titration of dead oil samples from Iranian crude oil reservoirs with n-heptane in the presence of nanofluids. Results show that rutile (TiO2) fine nanoparticles can effectively enhance the asphaltene stability in acidic conditions and act inversely in basic conditions. It was found that the required amount of n-heptane for destabilizing the colloidal asphaltene is considerably higher in presence of TiO2 nanofluids at pH below 4. The FTIR spectroscopy indicates changes in n-heptane insoluble asphaltene when acidic TiO2 nanofluid is used as inhibitor. According to the results obtained by FTIR spectroscopy, TiO2 nanoparticles can enhance the stability of asphaltene nanoaggregates through formation of hydrogen bond at acidic conditions. This is while other materials used in this experiment, as well as the TiO2 nanoparticles in basic conditions, are unable to form any hydrogen bond – hence their incapability to prevent asphaltene precipitation. Dynamic light scattering (DLS) measurements also have been performed to explain the mechanism of asphaltene precipitation in the presence of nanoparticles.

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Antibiotic contaminants in water and wastewater can cause serious damage to the environment and human health. Hence, their effective removal from water matrices is crucial. Effective removal of antibiotics using the adsorption process is a promising technique thanks to its easy regeneration, low cost, and high efficiency. In this work, the adsorption of amoxicillin (AMX) was investigated on a synthesized flexible metal−organic framework MIL-53(Al). The MIL-53(Al) adsorbent with a high surface area was synthesized using the hydrothermal method. It was then characterized by N 2 adsorption− desorption, FE-SEM, TEM, XRD, FT-IR, EDS, and TG analyses. The batch adsorption experiments were performed to examine the effects of solution pH, ionic strength, contact time, adsorbent dosage, and initial AMX concentration. Furthermore, the adsorption mechanism and adsorption kinetics as well as isotherms were studied experimentally. The adsorption kinetics indicated that the adsorption process was more compatible with the pseudo-secondorder kinetic model. The equilibrium adsorption data were well fitted using the Langmuir model. The MIL-53(Al) exhibited an excellent saturated adsorption capacity of 758.5 mg g −1 at 303 K and pH = 7.5 ± 0.1, surpassing all previous reported MOF-based adsorbents. The adsorption process was spontaneous and exothermic, although the entropy value decreased during the adsorption process. Furthermore, the MIL-53(Al) adsorbent had a good regeneration and reusability such that the adsorption capacity diminished slightly after reuse for four cycles. These results revealed that MIL-53(Al) would be a promising adsorbent for the adsorption of AMX from water matrices for environmental protection.

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Fluconazole (FLZ) application as a highly successful commercial antifungal azole agent to treat the fungal infections is limited due to emergence of FLZ-resistant candida. In this study, the potential of green synthesised silver nanoparticles (NPs) as an antifungal agent against Candida albicans fungal pathogen is investigated. The extract of ginger (Zingiber officinale) and thyme (Thymus vulgaris) plays as reducing agent, capping agent and antifungal agent. The UV-visible spectroscopy shows the peak of surface plasmon resonance of synthesised Ag NPs after a period of time. The synthesised Ag NPs are spherical, with average sizes of 12 and 18 nm based on ginger and thyme extract, respectively. Fourier transform infrared spectroscopy confirms the adsorption of the plant extract on the surface of the as-prepared Ag NPs. Based on the minimum inhibitory concentration (MIC) method against Candida albicans, the antifungal activity of as-prepared green synthesised Ag NPs shows higher inhibitory in comparison to FLZ. Finally, the Ag NPs synthesised via thyme extract shows no cytotoxicity with concentration below 3.5 ppm, which can be considered as an appropriate candidate instead of FLZ to treat the superficial fungal infections.

In this study, the effect of initial water saturation on the oil recovery for carbonate rocks is investigated using spontaneous imbibition experiments. The experiments are performed using 20 times diluted sea water as imbibing fluid and the sea water as initial water. In addition, the impact of pH and Ca 2+ , Mg 2+ , Na +, and K + cations concentration change of imbibing fluid are investigated during tests. These results help to identify the active cations in the wettability alteration process of carbonate rocks during the low-salinity water injection. A mechanism is proposed to describe the effect of initial water saturation on the oil recovery by low-salinity water injection. The impact of initial water saturation on the wettability alteration might be positive or negative depending on its value and the rock permeability. The comparison of divalent cations concentrations shows that the minimum adsorption of Ca 2+ and maximum desorption of Mg 2+ lead to maximum oil recovery of spontaneous imbibition. The results confirm that three cations of Ca 2+ , Mg 2+ , and Na + are active for wettability alteration of carbonate rocks in the presence of sea water as initial water and diluted sea as imbibing fluid, whilst the amounts of potassium remain constant.