Effects Of Divalent Cations Research Articles

Phosphatidylinositol phase behavior in symmetric and asymmetric model membranes.

Phosphatidylinositol (PI) is a precursor to phosphoinositides (PIPs) which are important cellular signaling molecules. While the phase behavior of PI in simple model membranes has been investigated, little is known about its phase behavior in the presence of PIPs. Furthermore, the effect of divalent cations on PI/PIP interaction has not been detailed. Determining PI/PIP phase behavior is of physiological relevance because it potentially affects the lateral distribution of PIPs in cellular membranes and hence the spatiotemporal control of protein function. For diplamitoylphosphatidylinositol (DPPI) we find in pH 7.2 buffer a phase transition temperature of 43.6°C, while in the presence of Ca2+ and Mg2+ the phase transition temperature shifts to 55.8°C and 51.6°C, respectively. In addition, we investigate divalent cation dependent PI/PI(4,5)P2 phase behavior. To study PI phase behavior in asymmetric lipid bilayers, we fabricate asymmetric giant unilamellar vesicles (aGUVs) using the hemifusion method. We describe the conditions to obtain aGUVS with PI in the outer leaflet and characterize their domain morphology.

The Effect of Moringa Seeds Oil and Shea Butter Oil Waxing On the Post-Harvest Life of Tomato Fruit (Solanum lycopersicum)

Tomato belongs to the family, Solanaceae and the genus Lycopersicon, is considered as one of the best healthy foods in the world due to its rich source of vitamin B and phyto-nutrients and abundant in carotenoids and lycopene. There has not been alternative means of preservation asides refrigeration as fast ripening disorder sets in and reduce its shelf life as the level of its calcium and potassium reduces during these processes. Post-harvest waxing has proved to be the alternative means of extending its shelf life. Standard analytical methods were used to test for colour, hardness, ash content, moisture content, total solid, brix, pH and total titrable acidity for two single and eight composite waxing (shea butter and moringa) of tomato fruits from day one to seven respectively. Waxing helps to delay the effect of divalent cations, which played an essential role in pectin metabolism and result to tissue softening in the pericarp of tomato fruit during ripening. The result obtained indicated that single oil waxing at 100%MOT (100% moringa oil) yielded good result up to five days while composite oil waxing at 10:90MST (10%moringa and 90%shea butter) could retard the effect of divalent cations for ripening for four days than the rest of waxing in single and composite oil waxing respectively.

Unraveling Distinct FO Performance of NF-Like Membranes Fabricated by Deposition of Bilayers Containing Polyamines with Minor Structural Differences

Nanofiltration (NF)-like membranes have shown potential for implementing forward osmosis (FO) for resource recovery. Despite the popular use of poly(allylamine hydrochloride) (PAH) as a polycation in the layer-by-layer (LbL) coating of NF-like membranes, it remained ambiguous whether substantial changes could result from the minor structural difference in polyamine when employing polyvinylamine (PVAm) as the polycation. This study systematically assessed the filtration capability of the NF-like membranes with varying combinations of the PAH- and PVAm-containing bilayers in an FO process. The FO experiments revealed that the dominance of PVAm-containing bilayers in the upper part of the active layer could result in decreases in both the water permeability and the rejection of divalent salts. Subsequent fouling tests demonstrated that the membrane coated solely with PVAm-containing bilayers (i.e., the VVV membrane) exhibited the fastest flux decline in the fouling tests with sodium alginate (SA), whereas the fouling layer could be more easily removed by the crossflow. Optical coherence tomography (OCT) characterization indicated that the bridging effect of divalent cations could promote the aggregation of SA to form a particulate layer more susceptible to the shear effect. All the results shed light on the improvement of NF-like FO by regulating the formation of the active layer via the LbL assembly.

Inhibition and Activation of Humoral Phenoloxidase and Their Effect on Divalent Cations in the Hemolymph of Freshwater Prawn Macrobrachium rosenbergii (De Man, 1879)

The aim of the present study is to examine phenoloxidase (PO), a copper-containing enzyme that plays a crucial role in the immune responses of arthropods, especially crustaceans and insects. However, PO activity is present in the plasma of the hemolymph without pathogenic infections. Here we report the PO activity in the plasma of M. rosenbergii was spectrophotometrically studied. The phenylthiourea (PTU) inhibition of PO activity was found to be the highest at a 10 mM concentration. The determination of PO activity was also highest activated by trypsin (2 mg.ml-1), detergents like sodium dodecyl sulphate (SDS; 8 mg.ml-1) and laminarin (4 mg.ml-1) enzyme expression. The effect of divalent cations on PO activity like sodium chloride (100 mM), calcium chloride, magnesium chloride, manganese chloride, and potassium chloride (10 mM) affected the activation of PO activity in trypsin, SDS, and laminarin. However, these divalent cations only slightly affected PTU inhibition of PO activity. In addition to calcium chloride, the PO activity with trypsin and laminarin is more or less the same as with control, but a great enhancement was found in SDS, which indicates that the combination of SDS with calcium chloride is required for increasing the PO activity in M. rosenbergii. The concentration of ethylenediaminetetraacetic acid (EDTA) of 1–10 mM has the maximum inhibition in PTU and activation of trypsin, SDS, and laminarin, which indicates that EDTA is a divalent cation chelator that affects the PO activity in M. rosenbergii. Hence, an attempt has been made to optimize the conditions for inhibitor, activators, divalent cations, EDTA sensitivity, and phenoloxidase activity in the plasma of the freshwater prawn M. rosenbergii.

A Mechanistic Study of Wettability Alterations in Sandstone by Low Salinity Water Injection (LSWI) and CO2 Low Salinity Water-Alternating-Gas (WAG) Injection

Low salinity water injection (LSWI), an emerging Enhanced Oil Recovery (EOR) method, has proven to be effective in increasing oil recovery by wettability alteration. As low salinity water is injected into the reservoir, the pre-established equilibrium is disturbed. The chemical reactions among the oil/brine/rock system alters the existing wettability, resulting in enhanced oil recovery. Water-alternating-gas (WAG) injection is also a leading EOR flooding process in light to medium oil sandstone and carbonate reservoirs. A recently proposed hybrid EOR method, CO2 low salinity (LS) WAG injection, shows promise based on experimental and simulation studies, compared to LSWI or CO2 injection alone. Wettability alteration is considered as the dominant mechanism for CO2 LSWAG injection. In this study, a new displacement contact angle measurement which better mimics the actual displacement process taking place in a reservoir is used, aiming to investigate the effect of monovalent and divalent cations, CO2, and injection schemes. It is found that the injection of NaCl low salinity water alters the wettability towards slightly water-wet, and the injection of CaCl2 low salinity water alters the wettability towards slightly oil-wet. The injection of CO2 promotes water-wetness and geochemical reactions between oil and brine. Injection scheme of CO2 and NaCl low salinity water is more efficient than WAG cycle of CO2/NaCl in wettability alteration towards more water-wet. However, the opposite trend is observed with CaCl2 low salinity water, of which WAG cycle of CO2/CaCl2 is more efficient in altering wettability towards water-wet. The oil drop deformation process during LSWI resembles the process of oil removal using surfactant. As CO2 is introduced, due to the acidic effect of CO2 and ion exchange, it acts to wet the rock surface, leading to a more water-wet state. With introduction of CO2, the oil drop deformation resembles the “roll-up” oil removal process.

Theoretical analysis of divalent cation effects on aptamer recognition of neurotransmitter targets.

Aptamer-based sensing of small molecules such as dopamine and serotonin in the brain, requires characterization of the specific aptamer sequences in solutions mimicking the in vivo environment with physiological ionic concentrations. In particular, divalent cations (Mg2+ and Ca2+) present in brain fluid, have been shown to affect the conformational dynamics of aptamers upon target recognition. Thus, for biosensors that transduce aptamer structure switching as the signal response, it is critical to interrogate the influence of divalent cations on each unique aptamer sequence. Herein, we demonstrate the potential of molecular dynamics (MD) simulations to predict the behaviour of dopamine and serotonin aptamers on sensor surfaces. The simulations enable molecular-level visualization of aptamer conformational changes that, in some cases, are significantly influenced by divalent cations. The correlations of theoretical simulations with experimental findings validate the potential for MD simulations to predict aptamer-specific behaviors on biosensors.

Release of drugs used in the treatment of osteoporosis from zeolites with divalent ions-Influence of the type of ion and drug on the release profile.

Bisphosphonates are drugs that are used to treat osteoporosis that causes the low mineral density of the bones. These drugs can be delivered in several ways, but each method has disadvantages. Materials with high potential as carriers of these drugs are zeolites with divalent ions. The aim of this study was to investigate the effect of divalent cations (calcium, magnesium, zinc) and drug type (risedronate, zoledronate) on sorption and release of the drug for osteoporosis. It was proved that drug sorption occurs on all zeolites presented in this work. Risedronate sorption was highest in zinc zeolite and lowest in calcium zeolite. In the case of zoledronate, sorption was most effective in magnesium zeolite and the least effective in zinc zeolite. Very large differences in drug release profiles were also observed. Risedronate was released several times longer than zoledronate. The diversity of the results indicates that the examined materials can be used in different types of drug delivery systems. They can be used, for example, intravenously or in the form of implants due to the different release profiles. Furthermore, the proposed carriers also release magnesium and calcium ions which are used in the prevention of osteoporosis, and zinc ions which have antibacterial properties.

Formation of Organic Fouling during Membrane Desalination: The Effect of Divalent Cations and the Use of an Online Visual Monitoring Method.

Reverse osmosis (RO) is the most popular technology for brackish, seawater and wastewater desalination. An important drawback of RO is membrane fouling, which reduces filtration effectiveness and increase the cost of produced water. This study addresses two important topics of membrane fouling: (i) the impact of different divalent ions on the formation of organic fouling and (ii) online monitoring and prediction of fouling formation. In the absence of divalent ions, dissolved organic matter had little effect on fouling formation, even at 3.5 mgC/L, in the upper range of groundwater concentration. Calcium, strontium and iron enhanced (organic) fouling formation, whereas barium had negligible effect. However, while iron affected fouling throughout the entire tested range (0-0.5 mg/L), calcium and strontium enhanced organic fouling only at high concentrations: more than 140 mg/L and 10 mg/L for calcium and strontium, respectively. An online system was developed for monitoring the formation of organic fouling, consisting of (i) an ex-situ RO cell with a transparent cover, (ii) a video camera continually monitoring the surface of the membrane and (iii) an algorithm which automatically identified changes in the color of the membrane caused by fouling, using a specially designed membrane spacer with colored reference dots. Changes in the color of the membrane surface were normalized to the reference colors, to eliminate all non-fouling related interference. The system was used to record and analyze changes in membrane color during numerous filtration tests. The data was successfully correlated to changes in specific flux (and subsequently to fouling formation rate) and can be applied to monitor and predict the formation of membrane fouling during desalination.

Physical modification on gelation of fish gelatin by incorporating Nicandra physalodes (Linn.) Gaertn. pectin: Effect of monovalent and divalent cation ions

Fish gelatin (FG) is more appreciated by religious people than mammalian gelatin. However, the relatively poor gelling capacity of FG limits its applicability in the food industry. In this study, Nicandra physalodes (Linn.) Gaertn. pectin (NPGP) was incorporated into FG to modify its gelling capacity, and the effect of monovalent (Na+) and divalent cations (Ca2+) on the gelation process of FG/NPGP mixtures was investigated. At a fixed concentration of FG (5.0 %, w/v) and NPGP (0.2 %, w/v), mixing the two polymers at natural pH condition (pH ≈ 6.0) led to significant intermolecular electrostatic association, which increased the gel hardness by producing an FG-dominant network augmented by NPGP molecules. When Na+ and Ca2+ were introduced, the electrostatic association was greatly decreased, which further weakened the gels. At low Ca2+ concentration (5 mM), however, FG, NPGP and Ca2+ formed tertiary complexes, which provided additional crosslinks and thus increased the gel strength.

Evaluation of factors affecting tetracycline and diclofenac adsorption by agricultural soils using response surface methodology

AbstractThe adsorption process of the pharmaceutical pollutant in the soil is affected by its physicochemical properties and soil properties. In this study, the factors affecting the adsorption of tetracycline and diclofenac onto two different soils (S and M) were investigated using response surface methodology (RSM). The RSM design was used to optimize the five variable factors (pH (2–10), contact time (5–180 min), soil amount (1–10 g/L), temperature (25–45°C)) on the adsorption of tetracycline and diclofenac. The predicted optimal conditions obtained by RSM showed that pH was the most important variable affecting the adsorption of tetracycline and diclofenac. The optimum pH for the adsorption of tetracycline and diclofenac onto the soil samples S and M were found to be 4 and 2, respectively. The adsorbed amounts of tetracycline and diclofenac onto the soils S and M were calculated to be 14.82 mg/g, 12.43 mg/g, 189.40 mg/g, and 144.81 mg/g, respectively. In addition, the effects of soil organic matter, salt, and divalent cations on the adsorption of tetracycline and diclofenac onto soils were studied. The removal of soil organic matter slightly increased tetracycline adsorption, while inhibiting diclofenac adsorption. The presence of salt and divalent cations prominently suppressed the adsorption of tetracycline and diclofenac onto soils. A possible complex mechanism was proposed for TC and DCF adsorption, including ion exchange, electrostatic interaction, and some chemical bonds.

Microfiltration pretreatment of polymer-flooding produced wastewater before desalination: Role of Ca2+ and Mg2+ in membrane fouling

To better control membrane fouling during microfiltration pretreatment of polymer-flooding produced wastewater (PFPW) before desalination, an accurate elaboration of the fouling mechanisms of anionic polyacrylamide (APAM) in high-salinity environments is vital. Herein, the effects of divalent cations (Ca2+ and Mg2+) on APAM-induced membrane fouling were comprehensively investigated. Both Ca2+ and Mg2+ aggravated membrane fouling. The pseudo-stable flux decreased from 0.38/0.38 to 0.35/0.32, 0.28/0.25, 0.23/0.20, and 0.19/0.15 as the ionic strength of Ca2+/Mg2+ increased from 0 to 1000, 2000, 5000, and 10,000 mg/L. Results of fouling resistances, morphology images of fouled membranes, and extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory supported this. In comparison with hydrated Mg2+, the charge density of hydrated Ca2+ is larger, which provides more efficient electrostatic screening. Moreover, Ca2+ can coordinate with APAM carboxylate to form APAM-Ca2+ complexes with a regular porous structure. Consequently, under identical ionic concentration, APAM-Ca2+ could provide weaker osmotic pressure. Accordingly, lower fouling resistances, rejection rates, and higher flux recovery rates were achieved in the case of Ca2+. This study distinguishes the roles of Ca2+ and Mg2+ in microfiltration membrane fouling by polymeric organics, which will be targeted to guide the efficient microfiltration process of PFPW before advanced desalination.

Effects of polyamide microplastic on the transport of graphene oxide in porous media

With the rapid development of the nano-material and chemical industry, more and more microplastic (MP) and nano-material were discharged into the environment. In this study, a two-dimensional (2D) surface of Extended Darjaguin-Landau-Verwe-Overbeek (XDLVO) is proposed to quantitatively investigate the effect of polyamide (PA) on the transport of graphene oxide (GO) in porous media. The influences of mass fraction of PA, flow rate, GO concentration, ionic type and strength on the migration of GO in saturated porous media are investigated by column experiments and numerical models. The two-dimensional (2D) surfaces of XDLVO interaction energy between GO and GO, GO and QS, GO and PA, are firstly calculated to analyze the transport of GO in saturated porous media. Experimental results suggest the mobility of GO is enhanced when flow velocity and initial concentration of GO are increased. However, the mobility of GO is inhibited when the mass fraction of PA and ionic strength are increased. More important, the inhibitory effect of divalent cations on GO migration is stronger than that of monovalent cations. Simultaneously, XDLVO results suggest that ionic types and strengths are important factors affecting the mobility of GO in porous media, and the critical ionic strength is observed from the continuous variation of the secondary minimum trap of XDLVO interaction energy. Model results show that there is a linear relationship between the logarithm of the secondary minimum trap of XDLVO interaction energy and the parameters related to GO mobility, which suggests XDLVO energy surface has an important application significance in the accurate quantification of GO mobility in porous media. These findings contribute to GO transport affected by microplastic in porous media, thus laying a significant foundation for the environmental risk and contamination remediation.

Effects of Axonal Demyelination, Inflammatory Cytokines and Divalent Cation Chelators on Thalamic HCN Channels and Oscillatory Bursting.

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is characterized by the progressive loss of oligodendrocytes and myelin and is associated with thalamic dysfunction. Cuprizone (CPZ)-induced general demyelination in rodents is a valuable model for studying different aspects of MS pathology. CPZ feeding is associated with the altered distribution and expression of different ion channels along neuronal somata and axons. However, it is largely unknown whether the copper chelator CPZ directly influences ion channels. Therefore, we assessed the effects of different divalent cations (copper; zinc) and trace metal chelators (EDTA; Tricine; the water-soluble derivative of CPZ, BiMPi) on hyperpolarization-activated cyclic nucleotide-gated (HCN) channels that are major mediators of thalamic function and pathology. In addition, alterations of HCN channels induced by CPZ treatment and MS-related proinflammatory cytokines (IL-1β; IL-6; INF-α; INF-β) were characterized in C57Bl/6J mice. Thus, the hyperpolarization-activated inward current (Ih) was recorded in thalamocortical (TC) neurons and heterologous expression systems (mHCN2 expressing HEK cells; hHCN4 expressing oocytes). A number of electrophysiological characteristics of Ih (potential of half-maximal activation (V0.5); current density; activation kinetics) were unchanged following the extracellular application of trace metals and divalent cation chelators to native neurons, cell cultures or oocytes. Mice were fed a diet containing 0.2% CPZ for 35 days, resulting in general demyelination in the brain. Withdrawal of CPZ from the diet resulted in rapid remyelination, the effects of which were assessed at three time points after stopping CPZ feeding (Day1, Day7, Day25). In TC neurons, Ih was decreased on Day1 and Day25 and revealed a transient increased availability on Day7. In addition, we challenged naive TC neurons with INF-α and IL-1β. It was found that Ih parameters were differentially altered by the application of the two cytokines to thalamic cells, while IL-1β increased the availability of HCN channels (depolarized V0.5; increased current density) and the excitability of TC neurons (depolarized resting membrane potential (RMP); increased the number of action potentials (APs); produced a larger voltage sag; promoted higher input resistance; increased the number of burst spikes; hyperpolarized the AP threshold), INF-α mediated contrary effects. The effect of cytokine modulation on thalamic bursting was further assessed in horizontal slices and a computational model of slow thalamic oscillations. Here, IL-1β and INF-α increased and reduced oscillatory bursting, respectively. We conclude that HCN channels are not directly modulated by trace metals and divalent cation chelators but are subject to modulation by different MS-related cytokines.

Fluorescence microscopic imaging of single desmin intermediate filaments elongated by the presence of divalent cations in vitro

The formation of intermediate filaments (IFs), a paradigmatic assembly system in biological macromolecules, depends on cations. Herein, to explore the combined effect of ionic strength and divalent cations, we used fluorescence microscopy and examined the in vitro effects of MgCl2, CaCl2, and SrCl2 on the KCl concentration-dependent growth of desmin IFs. Fluorescently-labeled desmin IF assembly initiated by KCl and 5 mM divalent cations led to the formation of single desmin IFs in the KCl concentration range of 25–50 mM. Addition of divalent cations resulted in increased fluorescence intensity in the filament images. KCl concentrations lower or higher than the aforementioned range resulted in the induction of networks of entangled IFs, which were visualized at high resolution via direct stochastic optical reconstruction microscopy. These findings provide insights into the versatility of the IF assembly mechanism and the optimization of fluorescence microscopy of single desmin IFs.

Hemagglutinins from the green algae, Chlorophyta

The extracts from 30 species of the green algae were examined for hemagglutination activity with a variety of different animal and human erythrocytes which were untreated and treated with enzymes. Almost all extracts showed the activity at least toward one type of erythrocytes tested. Strong activity was detected in the extracts from 5 Chlorophyta species (Anadyomene plicata, Avrainvillea erecta, Boodlea struveoides, Halimeda velasquezii and Halimeda discoidea) with enzyme-treated rabbit and sheep erythrocytes. The hemagglutinins of some active species were examined for carbohydrate binding specificity, pH and temperature stability, and effect of divalent cation on their hemagglutination activities. All of the hemagglutinins had no affinity for monosaccharides, except hemagglutinin of Codium arabicum whose activities were inhibited by N-acetyl-D-galactosamine and N-acetyl-D-glucosamine. On the other hand, hemagglutination activities of the hemagglutinins were inhibited by some glycoproteins. The inhibition profiles with glycoproteins were different, depending on hemagglutininproducing species, and suggest the presence of lectins specific for high mannose N-glycans, complex N-glycans, or O-glycans. The hemagglutination activities of the green algal hemagglutinins were stable in a wide range of pH and temperature, and independent on divalent cations. Therefore, Vietnamese green algae may promise as a valuable source of new lectins for application.

Tuning transport in graphene oxide membrane with single-site copper (II) cations

SummaryControlling the ion transport through graphene oxide (GO) membrane is challenging, particularly in the aqueous environment due to its strong swelling tendency. Fine-tuning the interlayer spacing and chemistry is critical to create highly selective membranes. We investigate the effect of single-site divalent cations in tuning GO membrane properties. Competitive ionic permeation test indicates that Cu2+ cations dominate the transport through the 2D channels of GO membrane over other cations (Mg2+/Ca2+/Co2+). Without/With the single-site M2+ modifications, pristine GO, Mg-GO, Ca-GO, and Cu-GO membranes show interlayer spacings of ∼13.6, 15.6, 14.5, and 12.3 Å in wet state, respectively. The Cu-GO membrane shows a two-fold decrease of NaCl (1 M) permeation rate comparing to pristine GO, Mg-GO, and Ca-GO membranes. In reverse osmosis tests using 1000 ppm NaCl and Na2SO4 as feeds, Cu-GO membrane shows rejection of ∼78% and ∼94%, respectively, which are 5%–10% higher than its counterpart membranes.

Probing the Effects of Divalent Cations on the Lubricating Properties of Daily-Wear Contact Lenses

Purpose: Previous research has demonstrated an increase in the magnitude and variability of Coefficient of Friction (CoF) for delefilcon A (L1) after simulated in vitro wear and is believed to be a result of interaction and disruption of its ionic surface layers with divalent cations in tear-like fluid (TLF). To demonstrate these divalent interactions and their effects on tribological performance, the CoF values of L1 were measured under three conditions (i.e. out-of-blister (OOB), standard TLF cycling (TLF18hr), and cycling in TLF without Ca2+/Mg2+ (TLF18hr-CM)), and compared to other daily-wear contact lenses (CLs), including senofilcon A (L2), etafilcon A (L3), and verofilcon A (L4).

Divalent metal cations stimulate skeleton interoception for new bone formation in mouse injury models

Bone formation induced by divalent metal cations has been widely reported; however, the underlying mechanism is unclear. Here we report that these cations stimulate skeleton interoception by promoting prostaglandin E2 secretion from macrophages. This immune response is accompanied by the sprouting and arborization of calcitonin gene-related polypeptide-α+ nerve fibers, which sense the inflammatory cue with PGE2 receptor 4 and convey the interoceptive signals to the central nervous system. Activating skeleton interoception downregulates sympathetic tone for new bone formation. Moreover, either macrophage depletion or knockout of cyclooxygenase-2 in the macrophage abolishes divalent cation-induced skeleton interoception. Furthermore, sensory denervation or knockout of EP4 in the sensory nerves eliminates the osteogenic effects of divalent cations. Thus, our study reveals that divalent cations promote bone formation through the skeleton interoceptive circuit, a finding which could prompt the development of novel biomaterials to elicit the therapeutic power of these divalent cations.

Effect of bacteria on oil/water interfacial tension in asphaltenic oil reservoirs

Microbial enhanced oil recovery (MEOR), due to the formation of biofilm and the presence of biosurfactants generated by microorganisms in the reservoir, can play a role in reducing interfacial tension (IFT) and wettability alteration. In this work, the fluid-fluid interaction by measuring the IFT has been evaluated for combining two EOR methods, including low salinity water and MEOR, due to the high importance of fluid-fluid interaction in EOR. GeoBacillus stearothermophilus has been used as a bacterium to study changes in IFT. The effect of different salts, including monovalent and divalent cations and anions at different salinities, on biosurfactant performance, is investigated using IFT measurements. Also, the type of oil is evaluated in terms of its acidic and basic properties on the performance of biosurfactants. According to the results of this study, injection of GeoBacillus stearothermophilus bacteria reduces interfacial tension in acidic oil by 10.26% and in basic oil by 5.26%. According to the results, increasing salinity in the presence of oil-containing asphaltene with basic properties increases the IFT of the solution containing GeoBacillus stearothermophilus bacteria, but in the presence of acidic oil, a decrease in IFT is observed. The most significant effect of reducing the IFT of acidic oil and solution containing GeoBacillus stearothermophilus is obtained in the presence of the following salts, respectively: CaCl2 > MgCl2 > NaCl. The results show that with increasing CaCl2 concentration, the IFT between basic oil and GeoBacillus stearothermophilus solution gradually increases. This ascending trend is in the presence of NaCl salt with a lower slope. However, in the presence of MgCl2 salt, dual behavior is observed before and after the concentration of 1000 ppm, so that before this concentration, the IFT increases and then decreases. The findings of this study can help for a better understanding of the interaction of bacteria with asphaltenic oils in the presence of effective salts for low salinity water injection. The results of this study showed that by combining low salinity water with bacteria, less IFT could be obtained than low salinity water or bacteria alone.

Formation of Organic Fouling During Membrane Desalination: The Effect of Divalent Cations and the Use of Online Visual Monitoring Method

Formation of Organic Fouling During Membrane Desalination: The Effect of Divalent Cations and the Use of Online Visual Monitoring Method