Presence Of Mineral Salts Research Articles

Application of Bi2WO6/N-TiO2 catalyst immobilized on FTO in a tray photoreactor for textile color degradation from aqueous solutions: Effects of mineral salts

The Bi2WO6/N-TiO2composite was synthesized hydrothermally, andcharacterized by using XRD, XRF, FE-SEM, EDX, FT-IR, BET, PL, and UV–VIS DRS analyses.The improvement in the catalytic activity of the prepared composite is related to lower recombination, and narrow bandgap.ThedegradationofAcid Black172 was examined undercontinuous conditions by using a tray photoreactor in which the catalyst was supported on the FTO through spin coating. The effect of independent factors such asinitial pH (5–9),contaminantto photocatalyst mass ratio (10–30 mg/g), andflow rate (1.5–4.5 ml/min) on the degradation efficiency was investigated. The results indicated that at the optimum conditions ofpH = 5,contaminantto photocatalyst = 10 mg/g,flow rate = 1.5 min/mL, textile color removal efficiency was81%,andTOC removal efficiency was 75%under visible light intensity = 20 w/m2. In addition, a decrease and an increase in degradation in the presence of mineral salts and more light intensity under optimum conditions, respectively. The degradation efficiency decreased slightly after several uses which confirmed the good performance and reusability of the catalysts.

In vitro co-metabolism of epigallocatechin-3-gallate (EGCG) by the mucin-degrading bacterium Akkermansia muciniphila.

Akkermansia muciniphila is a Gram-negative bacterium that resides within the gut mucus layer, and plays an important role in promoting gut barrier integrity, modulating the immune response and inhibiting gut inflammation. Growth stimulation of A. muciniphila by polyphenols including epigallocatechin-3-gallate (EGCG) from difference sources is well-documented. However, no published in vitro culture data on utilization of polyphenols by A. muciniphila are available, and the mechanism of growth-stimulating prebiotic effect of polyphenols on it remains unclear. Here in vitro culture studies have been carried out on the metabolism of EGCG by A. muciniphila in the presence of either mucin or glucose. We found that A. muciniphila did not metabolize EGCG alone but could co-metabolize it together with both these substrates in the presence of mineral salts and amino acids for mucin and protein sources for glucose. Our metabolomic data show that A. muciniphila converts EGCG to gallic acid, epigallocatechin, and (-)-epicatechin through ester hydrolysis. The (-)-epicatechin formed is then further converted to hydroxyhydroquinone. Co-metabolism of A. muciniphila of EGCG together with either mucin or glucose promoted substantially its growth, which serves as a further demonstration of the growth-promoting effect of polyphenols on A. muciniphila and provides an important addition to the currently available proposed mechanisms of polyphenolic prebiotic effects on A. muciniphila.

Effect of Flue Gases' Corrosive Components on the Degradation Process of Evaporator Tubes.

Corrosion of boiler tubes remains an operational and economic limitation in municipal waste power plants. The understanding of the nature, mechanism, and related factors can help reduce the degradation process caused by corrosion. The chlorine content in the fuel has a significant effect on the production of gaseous components (e.g., HCl) and condensed phases on the chloride base. This study aimed to analyze the effects of flue gases on the outer surface and saturated steam on the inner surface of the evaporator tube. The influence of gaseous chlorides and sulfates or their deposits on the course and intensity of corrosion was observed. The salt melts reacted with the steel surface facing the flue gas flow and increased the thickness of the oxide layer up to a maximum of 30 mm. On the surface not facing the flue gas flow, they disrupted the corrosive layer, reduced its adhesion, and exposed the metal surface. Beneath the massive deposits, a local overheating of the inner surface of the evaporator tubes occurred, which resulted in the release of the protective magnetite layer from the surface. Ash deposits reduce the boiler’s thermal efficiency because they act as a thermal resistor for heat transfer between the flue gases and the working medium in the pipes. The effect of insufficient feedwater treatment was evinced in the presence of mineral salts in the corrosion layer on the inner surface of the tube.

Impact of produced water mineralization on the secondary treatment of hydrate development inhibitors

In the process of completion gas-condensate fields is observed an intensive increase of lifted out produced water and its mineralization influencing the process of regeneration of hydrate development inhibitors. The presence of mineral salts in the system of “hydrate development inhibitor – produced water” results in the decrease of saturated vapor pressure upon the solvent. The decrease of saturated vapors significantly influences the phase balance of the system. Moreover, the presence of salts changes the boiling temperature of water solutions of hydrate development inhibitors. This factor was not considered in the calculation and designing of existing regeneration set. The paper presents the data on the pressure of saturated vapor under the produced water with various mineralization based on which the correction coefficients were calculated and boiling temperature depending on the salt content specified as well.

Evaluation of biotechnological potential of thermotolerant microorganisms for oil degradation

The problem of pollution of natural ecosystems with oil and oil products is extremely acute in manycountries of the world, including Kazakhstan. A significant part of oil-contaminated sites is located inregions with a hot climate, and in such countries studies are underway to isolate thermotolerant oildegrading microorganisms with a view to their further use for remediation of oil-contaminated territories.The circle of such microorganisms is quite wide and diverse.The effectiveness of the method of bioremediation of oil-polluted ecosystems largely depends onbiotic and abiotic factors, for example, salinity, temperature, ability to produce surfactants, pH, etc.Earlier from the soils of Western Kazakhstan, we isolated and identified thermotolerant oil-oxidizing microorganisms capable of oxidizing oil hydrocarbons in a wide temperature range. The aim of this workwas to study the ability of active thermotolerant oil-oxidizing microorganisms to degrade oil at different concentrations of mineral salts (Cl-, SO42-) and to determine the emulsifying activity to assess theirbiotechnological potential.It was established that all selected strains are halotolerant. Moreover, the temperature factor influenced the degree of oil degradation in the presence of mineral salts. The highest percentage of oildegradation was at 35°C. At this temperature, strains K-3, 4/5, P1-35-14 showed high activity at allstudied NaCl concentrations (3, 5 and 10%) – 73.6-85.9%, 62.7-91.1 % and 73.6-75.7%, respectively.At 40°C, the strain IP-40-4 showed the highest activity – 41.4-51.2%. At 50°C, the destruction abilityof the studied cultures was approximately at the same level at all NaCl concentrations. The cultivationof selected strains with a high content of MgSO4 in the medium showed that the K-3 strain was the moststable, which remained highly active at all temperatures.It was shown that active strains of thermotolerant oil-oxidizing microorganisms had emulsifying activity. High values of emulsifying activity are observed at a temperature of 35°C, and with a subsequentincrease in temperature, the formation of surfactants decreased. At 35°C, strain P2-35-9 had the greatestemulsifying activity, and at 40°C and 50°C – strain K-3.Key words: bioremediation, thermotolerant hydrocarbon-oxidizing bacteria, salinity, halotolerance,emulsifying activity.

Incidence of Calcic, Sulfates and Phosphates Salts on the Coagulation-Flocculation of Organic Compounds by Aluminium Sulfate

The objective of this work is to evalute the coagulation-flocculation efficiency of the aluminum sulfate for the elimination of aromatic organic molecules (phenylalanine and catechol) in the presence of mineral salts of Ca2+, SO42-and PO43-.Trials were conducted on the one hand on synthetic solutions of aromatic compounds in distilled water enriched by ions of calcium, sulphates and phosphate ions introduced in various forms (CaCl2; CaSO4; MgSO4; Na2SO4; NaH2PO4; KH2PO4), and on the other hand on Algerian drilling waters of different physicochemical characteristics. Results show that the addition of minerals salts seems to improve the yields of elimination of aromatic compounds tested and affects the optimal pH range of coagulation. The application of this process on mineralized waters (water drilling) leads to improve yields compared with those obtained in distilled water. It was also found that the process efficiency depends on the nature and the number of functional groups on the molecules and on their position relative to each other. The main mechanisms would be either a physical adsorption ,an exchange of ligand or a complexation on the floc surface of aluminum hydroxides.

Biotransformation of soybean oil to a self-healing biopolymer

Soybean oil in the presence of mineral salts, peptone, carbohydrates, lipase, and lipopeptide transformed to a soft tissue-like material after 10-day incubation at 37°C with shaking at 200 rpm. When damaged, the resultant soft tissue self-healed in an aqueous medium. Analysis revealed that during the self-assembly process, components present in the aqueous medium were entangled in the soft tissue; upon damage, release of these components accelerated healing. Superficial damage resulted in smooth healing, whereas deep damage gave uneven healing similar to deep skin wounds.

Significance of Mineral Salts in Prebiotic RNA Synthesis Catalyzed by Montmorillonite

The montmorillonite-catalyzed reactions of the5'-phosphorimidazolide of adenosine used as a model generated RNA type oligomers. These reactions were found to be dependent on the presence of mineral salts. Whereas montmorillonite (pH 7) produced only dimers and traces of trimer in water, addition of sodium chloride (0.1-2.0M) enhanced the chain length of oligomers to 10-mers as detected by HPLC. Maximum catalytic activity was observed with sodium chloride at a concentration between 0.8 and 1.2M. This concentration of sodium chloride resembled its abundance in the ancient oceans (0.9-1.2M). Magnesium chloride produced a similar effect but its joint action with sodium chloride did not produce any difference in the oligomer chain length. Therefore, Mg(2+) was not deemed necessary for generating longer oligomers. The effect of monovalent cations upon RNA chain length was: Li(+)>Na(+)>K(+). A similar effect was observed with the anions with enhanced oligomer length in the following order: Cl(-)>Br(-)>I(-). Thus, the smaller ions facilitated the formation of the longest oligomers. Inorganic salts that tend to salt out organic compounds from water and salts which show salt-in effects had no influence on the oligomerization process indicating that the montmorillonite-catalyzed RNA synthesis is not affected by either of these hydrophobic or hydrophilic interactions. A 2.3-fold decrease in the yield of cyclic dimer was observed upon increasing the sodium chloride concentration from 0.2 to 2.0M. Inhibition of cyclic dimer formation is vital for increasing the yield of linear dimers and longer oligomers. In summary, sodium chloride is likely to have played an essential role in any clay mineral-catalyzed prebiotic RNA synthesis.

FED-BATCH FERMENTATION OF BACILLUS CLAUSII FOR EFFICIENT PRODUCTION OF ALKALINE PROTEASE USING DIFFERENT FEEDING STRATEGIES

The effect of different feeding strategies, involving constant rate and linear feeding with negative and positive slopes, on protease production of an indigenous Bacillus clausii was investigated. The results indicated that alkaline protease was produced at high levels soon after glucose was completely consumed. Alkaline protease activity was at a maximum during the constant feeding rate and in the absence of glucose and presence of mineral salts and yeast extract in the feed medium. Maximum protease production in the fed-batch culture using an optimized level of feeding composition was 2430 ± 67 U/mL, which increased by up to 35% when compared to the 1800 ± 14 U/mL produced during batch culture. During batch fermentation, the protease yield and productivity obtained were 90000 U/g and 64285 U/L · h; however, under fed-batch conditions, these were 121500 U/g and 71470 /L · h, respectively. Hence, the suggested strategy has the potential to be applied to industrial production of protease used in detergent products.

Ethanol modulates the VR-1 variant amiloride-insensitive salt taste receptor. I. Effect on TRC volume and Na+ flux.

The effect of ethanol on the amiloride- and benzamil (Bz)-insensitive salt taste receptor was investigated by the measurement of intracellular Na+ activity ([Na+]i) in polarized rat fungiform taste receptor cells (TRCs) using fluorescence imaging and by chorda tympani (CT) taste nerve recordings. CT responses were monitored during lingual stimulation with ethanol solutions containing NaCl or KCl. CT responses were recorded in the presence of Bz (a specific blocker of the epithelial Na+ channel [ENaC]) or the vanilloid receptor-1 (VR-1) antagonists capsazepine or SB-366791, which also block the Bz-insensitive salt taste receptor, a VR-1 variant. CT responses were recorded at 23°C or 42°C (a temperature at which the VR-1 variant salt taste receptor activity is maximally enhanced). In the absence of permeable cations, ethanol induced a transient decrease in TRC volume, and stimulating the tongue with ethanol solutions without added salt elicited only transient phasic CT responses that were insensitive to elevated temperature or SB-366791. Preshrinking TRCs in vivo with hypertonic mannitol (0.5 M) attenuated the magnitude of the phasic CT response, indicating that in the absence of mineral salts, transient phasic CT responses are related to the ethanol-induced osmotic shrinkage of TRCs. In the presence of mineral salts, ethanol increased the Bz-insensitive apical cation flux in TRCs without a change in cell volume, increased transepithelial electrical resistance across the tongue, and elicited CT responses that were similar to salt responses, consisting of both a transient phasic component and a sustained tonic component. Ethanol increased the Bz-insensitive NaCl CT response. This effect was further enhanced by elevating the temperature from 23°C to 42°C, and was blocked by SB-366791. We conclude that in the presence of mineral salts, ethanol modulates the Bz-insensitive VR-1 variant salt taste receptor.

Ethanol Modulates the VR-1 Variant Amiloride-insensitive Salt Taste Receptor. II. Effect on Chorda Tympani Salt Responses

The effect of ethanol on the amiloride- and benzamil (Bz)-insensitive salt taste receptor was investigated by direct measurement of intracellular Na+ activity ([Na+]i) using fluorescence imaging in polarized fungiform taste receptor cells (TRCs) and by chorda tympani (CT) taste nerve recordings. CT responses to KCl and NaCl were recorded in Sprague-Dawley rats, and in wild-type (WT) and vanilloid receptor-1 (VR-1) knockout mice (KO). CT responses were monitored in the presence of Bz, a specific blocker of the epithelial Na+ channel (ENaC). CT responses were also recorded in the presence of agonists (resiniferatoxin and elevated temperature) and antagonists (capsazepine and SB-366791) of VR-1 that similarly modulate the Bz-insensitive VR-1 variant salt taste receptor. In the absence of mineral salts, ethanol induced a transient decrease in TRC volume and elicited only transient phasic CT responses. In the presence of mineral salts, ethanol increased the apical cation flux in TRCs without a change in volume, increased transepithelial electrical resistance across the tongue, and elicited CT responses that were similar to salt responses, consisting of both a phasic component and a sustained tonic component. At concentrations <50%, ethanol enhanced responses to KCl and NaCl, while at ethanol concentrations >50%, those CT responses were inhibited. Resiniferatoxin and elevated temperature increased the sensitivity of the CT response to ethanol in salt-containing media, and SB-366791 inhibited the effect of ethanol, resiniferatoxin, and elevated temperature on the CT responses to mineral salts. VR-1 KO mice demonstrated no Bz-insensitive CT response to NaCl and no sensitivity to ethanol. We conclude that ethanol increases salt taste sensitivity by its direct action on the Bz-insensitive VR-1 variant salt taste receptor.

Analysis of membrane fouling in the treatment of water solutions containing humic acids and mineral salts

The separation of humic substances from aqueous solution by ultrafiltration was investigated with flat Intersep Nadir membranes. Special consideration was given to the decrease of membrane permeability in the course of the ultrafiltration process. The decrease of membrane permeability was related to the increase of pH and calcium ion concentration in the solution. Transport properties were found to be strongly dependent on the hydrophilicity of the membranes. The membrane made of regenerated cellulose, the most hydrophilic of the membranes tested, displayed the highest permeability with respect to both water and humic substance containing solutions, and the lowest proneness to fouling by organic colloids. Analysis of the relationship between the properties of the solution and the course of the separation process revealed that the rise of pH from 4.6 to 7.0 reduced membrane fouling. The presence of mineral salts in the solution deteriorated the separation and transport properties of the membranes and intensified the fouling process.

The production of interfacial emulsions by bacterial isolates from diesel fuels

Four bacterial isolates from contaminated diesel fuels were tested for their ability to produce surface-active substances. One organism, identified as a Pseudomonas species, gave the highest activity, followed by a Bacillus sp. The Pseudomonas produced surfactant in the presence of mineral salts and glucose only, but the emulsifying activity increased dramatically on the addition of sterile diesel oil, producing levels similar to those quoted by other workers.

Mises au point sur les différents facteurs physico-chimiques influant sur la mesure de concentration de traceurs fluorescents et leurs conséquences pratiques en hydrologie

The use of xanthenic dyes in hydrology can, in certain circumstances, lead to alteration in the quantitative interpretation of the experimental results due to failure to recognize the physico-chemical phenomena which affect the measurement of fluorescence, namely, the nature of the solvent, pH, temperature and the presence of mineral salts. In this paper we recall the essentials of these mechanisms and illustrate the consequences. In succession, some particular circumstances of the use of fluorescent xanthenic tracers (in environments with strong ionic activity, in the presence of sodium iodide, and in the presence of deactivating saline ions) are examined as well as the precautions which users must observe to maintain the quality of the measurements and to prevent photodegradation or absorption processes. Attention is drawn to the difficulties of interpreting the measurements of concentration of the fluorescent-tracer elutant collected on activated carbon (“fluotransducers”) and a method of measurement, by selective extinction, is proposed for two fluorescent tracers present simultaneously in the same environment.

Optically active diamide as a model for studying interactions between mineral salts and nylon type polyamides in methanol solutions

AbstractN,N′‐Dicaproyl (–)1,2‐diaminopropane (I) was used as a convenient model for the study of the optical activity of a nylon type polyamide: polysebacamide (–)1,2‐diaminopropane (II). ORD of I was measured in different solvents. A peculiar behavior is observed in methanol in the presence of mineral salts. The influence of 0.1M potassium salts (Cl−, Br−, SCN−, NO3−, SO4−2) and 0.1M alkaline chlorides and alkaline earth chloride hexahydrates on the optical activity of I in methanol are described. Alkaline salts and MgCl2 give approximately the same effect: there is a decrease of the rotations without change of sign. SrCl2 and CaCl2 shift ORD curves towards the negative rotations, the last one giving complete inversion. This inversion is directly related to the CaCl2 concentration and is attributed to adduct formation between amide groups and salt. Assuming that the different species are at equilibrium, an apparent equilibrium constant is obtained from the optical rotations for a complex of one mole of CaCl2 with one mole of I. Results are used to discuss the complex ORD of poly(−) 1,2‐diaminopropane sebacamide in methanol saturated with CaCl2.