Prediction of Aqueous Solution Surface Tension of Some Surfactant Mixtures and Composition of Their Monolayers at the Solution–Air Interface

Measurements of the surface tension of the aqueous solution of SDDS mixture with fluorocarbon surfactants (FC) were carried out and considered in light of the surface tension of aqueous solutions of individual surfactants. Similar analyses were made for many other aqueous solutions of binary and ternary mixtures, taking into account the literature data of the surface tension of aqueous solutions of TX100, TX114, TX165, SDDS, SDS, CTAB, CPyB and FC. The possibility of predicting the surface tension of the aqueous solution of many surfactant mixtures from that of the mixture components using both the Szyszkowski, Fainerman and Miller and Joos concepts was analyzed. The surface tension of the aqueous solutions of surfactant mixtures was also considered based on the particular mixture component contribution to the water surface tension reduction. As a result, the composition of the mixed surface layer at the solution–air interface was discussed and compared to that which was determined using the Hua and Rosen concept. As follows from considerations, the surface tension of the aqueous solution of binary and ternary surfactant mixtures can be described and/or predicted.

Low-cost production and application of lipopeptide for bioremediation and plant growth by Bacillus subtilis SNW3

At present time, every nation is absolutely concern about increasing agricultural production and bioremediation of petroleum-contaminated soil. Hence, with this intention in the current study potent natural surfactants characterized as lipopeptides were evaluated for low-cost production by Bacillus subtilis SNW3, previously isolated from the Fimkessar oil field, Chakwal Pakistan. The significant results were obtained by using substrates in combination (white beans powder (6% w/v) + waste frying oil (1.5% w/v) and (0.1% w/v) urea) with lipopeptides yield of about 1.17 g/L contributing 99% reduction in cost required for medium preparation. To the best of our knowledge, no single report is presently describing lipopeptide production by Bacillus subtilis using white beans powder as a culture medium. Additionally, produced lipopeptides display great physicochemical properties of surface tension reduction value (SFT = 28.8 mN/m), significant oil displacement activity (ODA = 4.9 cm), excessive emulsification ability (E24 = 69.8%), and attains critical micelle concentration (CMC) value at 0.58 mg/mL. Furthermore, biosurfactants produced exhibit excellent stability over an extensive range of pH (1–11), salinity (1–8%), temperature (20–121°C), and even after autoclaving. Subsequently, produced lipopeptides are proved suitable for bioremediation of crude oil (86%) and as potent plant growth-promoting agent that significantly (P < 0.05) increase seed germination and plant growth promotion of chili pepper, lettuce, tomato, and pea maximum at a concentration of (0.7 g/100 mL), showed as a potential agent for agriculture and bioremediation processes by lowering economic and environmental stress. Graphical Abstract

Paenibacillus polymyxa A26 and Its Surfactant-Deficient Mutant Degradation of Polycyclic Aromatic Hydrocarbons

We compared the ability of two bacterial strains, Paenibacillus polymyxa A26 and P. polymyxa A26Sfp, for biodegradation of naphthalene (NAP). The studies were performed under simulated laboratory conditions, in liquid medium and soil with different carbon sources, pH and salt contents. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in degradation mixtures during 7 days of incubation. While both strains expressed the best growth and NAP degradation ability in the minimal salt medium containing sucrose and 5% NaCl at pH 7 and 8, the mutant strain remained effective even under extreme conditions. A26Sfp was found to be an efficient and potentially industrially important polycyclic aromatic hydrocarbon degradation strain. Its extracellular polysaccharide production is 30%, and glucan production is twice that of the wild type A 26. The surface tension reduction ability was ascertained as 25–30% increased emulsification ability.

A predictive thermodynamic framework of cloud droplet activation for chemically unresolved aerosol mixtures, including surface tension, non-ideality, and bulk–surface partitioning

This work presents a thermodynamically consistent framework that enables self-contained, predictive Köhler calculations of droplet growth and activation with considerations of surface adsorption, surface tension reduction, and non-ideal water activity for chemically complex and unresolved surface-active aerosol mixtures. The common presence of surface-active species in atmospheric aerosols is now well-established. However, the impacts of different effects driven by surface activity, in particular bulk–surface partitioning and resulting bulk depletion and/or surface tension reduction, on aerosol hygroscopic growth and cloud droplet activation remain to be generally established. Because specific characterization of key properties, including water activity and surface tension, remains exceedingly challenging for finite-sized activating droplets, a self-contained and thermodynamically consistent model framework is needed to resolve the individual effects of surface activity during droplet growth and activation. Previous frameworks have achieved this for simple aerosol mixtures, comprising at most a few well-defined chemical species. However, atmospheric aerosol mixtures and more realistic laboratory systems are typically chemically more complex and not well-defined (unresolved). Therefore, frameworks which require specific knowledge of the concentrations of all chemical species in the mixture and their composition-dependent interactions cannot be applied. For mixtures which are unresolved or where specific interactions between components are unknown, analytical models based on retrofitting can be applied, or the mixture can be represented by a proxy compound or mixture with well-known properties. However, the surface activity effects evaluated by such models cannot be independently verified. The presented model couples Köhler theory with the Gibbs adsorption and Szyszkowski-type surface tension equations. Contrary to previous thermodynamic frameworks, it is formulated on a mass basis to obtain a quantitative description of composition-dependent properties for chemically unresolved mixtures. Application of the model is illustrated by calculating cloud condensation nuclei (CCN) activity of aerosol particles comprising Nordic aquatic fulvic acid (NAFA), a chemically unresolved and strongly surface-active model atmospheric humic-like substance (HULIS), and NaCl, with dry diameters of 30–230 nm and compositions spanning the full range of relative NAFA and NaCl mixing ratios. For comparison with the model presented, several other predictive Köhler frameworks, with simplified treatments of surface-active NAFA, are also applied. Effects of NAFA surface activity are gauged via a suite of properties evaluated for growing and activating droplets. The presented framework predicts a similar influence of surface activity of the chemically complex NAFA on CCN activation as was previously shown for single, strong surfactants. Comparison to experimental CCN data shows that NAFA bulk–surface partitioning is well-represented by Gibbs adsorption thermodynamics. Contrary to several recent studies, no evidence of significantly reduced droplet surface tension at the point of activation was found. Calculations with the presented thermodynamic model show that throughout droplet growth and activation, the finite amounts of NAFA in microscopic and submicron droplets are strongly depleted from the bulk, due to bulk–surface partitioning, because surface areas for a given bulk volume are very large. As a result, both the effective hygroscopicity and ability of NAFA to reduce droplet surface tension are significantly lower in finite-sized activating droplets than in macroscopic aqueous solutions of the same overall composition. The presented framework enables the influence of surface activity on CCN activation for other chemically complex and unresolved aerosol mixtures, including actual atmospheric samples, to be systematically explored. Thermodynamic input parameters can be independently constrained from measurements, instead of being either approximated by a proxy or determined by retrofitting, potentially confounding several mechanisms influenced by surface activity.

Surfactant-based therapy against COVID-19: A review

The coronavirus disease 2019 (COVID-19) has led to serious health and economic damage to all over the world, and it still remains unstoppable. The SARS-CoV-2, by using its S-glycoprotein, binds with an angiotensin-converting enzyme 2 receptor, mostly present in alveolar epithelial type II cells. Eventually pulmonary surfactant depletion occurs. The pulmonary surfactant is necessary for maintaining the natural immunity as well as the surface tension reduction within the lung alveoli during the expiration. Its insufficiency results in the reduction of blood oxygenation, poor pulmonary regeneration, lung fibrosis, and finally the respiratory system collapses. Exogenous surfactants have previously shown great promise in the treatment of infant respiratory distress syndrome, and they may also aid in the healing of damaged alveolar cells and the prevention of respiratory failure. Surfactant based therapy has been advised for the prevention of COVID-19, and the trials have begun around the world. Furthermore, greater research on the timing, dose, and the distribution of surfactant to the COVID-19 patients is required before this technique can be implemented in clinical practice.

Biodegradation of naphthalene mediated by the plant growth promoting rhizobacteria

We compared the ability of two bacterial strains, Paenibacillus polymyxa A26 and P. polymyxa A26Sfp, for biodegradation of naphthalene (NAP). The studies were performed under simulated laboratory conditions, in liquid medium and soil with different carbon sources, pH and salt contents. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in degradation mixtures during 7 days of incubation. While both strains expressed the best growth and NAP degradation ability in the minimal salt medium containing sucrose and 5% NaCl at pH 8, the mutant strain remained effective even under extreme conditions. A26Sfp was found to be an efficient and potentially industrially important polycyclic aromatic hydrocarbon degradation strain. Its extracellular polysaccharide production is 30% and glucan production twice that of the wild type A 26. The surface tension reduction ability was ascertained as 25 to 30% increased emulsification ability.

Sustainable Low-Cost Surfactin Production And Optimization By Bacillus Subtilis SNW3, Product Characterization, And Its Suitability For Plant Growth Promotion And Bioremediation of Crude Oil

At present time, every nation is absolutely concern about increase agricultural production and bioremediation of petroleum contaminated soil. Hence, with this intention in current study potent natural surfactant (surfactin) was evaluated for low-cost production by Bacillus subtilis SNW3, previously isolated from Fimkessar oil field, Chakwal Pakistan. The best results were obtained using substrates in combination (white beans powder (6% w/v) plus waste frying oil (1.5% w/v) and (0.1% w/v) urea) with surfactin production of about 1.17 g/L contributing 99% reduction in cost required for medium preparation. To the best of our knowledge, no single report is present describing surfactin production by Bacillus subtilis using white beans powder as a culture medium. Surfactin was confirmed as the principal product characterized by thin-layer chromatography (TLC) and Fourier-transform infrared spectroscopy (FTIR). Additionally, produced surfactin display great physicochemical properties of surface tension reduction value (SFT=28.8 mN/m), significant oil displacement activity (ODA=4.9 cm), excessive emulsification ability (E24=69.8 %), and attains critical micelle concentration (CMC) value at 0.58 mg/mL. Furthermore, surfactin exhibits excellent stability over an extensive range of pH (1-11), salinity (1-8%), temperature (20-121°C) and even after autoclaving. Subsequently, surfactin produced proved suitable for bioremediation of crude oil (86%) and as potent plant growth-promoting agent that significantly (P<0.05) increase seed germination and plant growth promotion of chili pepper, lettuce, tomato and pea maximum at concentration of (0.7 g/100 mL), proved as potential agent for agriculture and bioremediation processes by lowering economic and environmental stress.

A novel biosurfactant producing Kocuria rosea ABR6 as potential strain in oil sludge recovery and lubrication

At various stages of crude oil refining, solid and semi-solid wastes, known as petroleum sludge, are produced. Accumulation of oil waste in the refinery leads to reduced efficiency of oil refining and its release causes environmental pollution Biosurfactant-producing isolates were isolated from the oil reservoirs of the Isfahan refinery, Iran, and screened by oil expansion test, droplet collapse, and surface tension reduction measurement. Oil recovery from oil sludge was measured under constant conditions. The effect of factoring biosource lubrication on crude oil in pipelines was investigated in vitro. Also, the optimization of biosurfactant production in different conditions was measured as a single factor and Response surface Methodology. The best biosurfactant-producing bacterium was identified as Kocuria rosea ABR6, and its sequence was registered in the gene bank with access number of MK100469 registered. Chemical analysis proved that the biosurfactant produced was a lipopeptide. 7% of crude oil was recovered from petroleum sludge by biosurfactant obtained from Kocuria rosea ABR6.Also, the speed of crude oil transfer in pipelines was reduced from 64 seconds to 35 seconds. The highest biosurfactant production was measured at pH 9, aeration rate of 120 rpm and 96 hours after incubation. The use of biosurfactants produced by Kocuria rosea ABR6 is recommended to remove oil sludge and lubricate oil in pipelines recommended in the oil industry

Interactions of organosulfates with water vapor under sub- and supersaturated conditions

Organosulfates (OSs) are important constituents of secondary organic aerosols, but their hygroscopic properties and cloud condensation nucleation (CCN) activities have not been well understood. In this work we employed three complementary techniques to characterize interactions of several OSs with water vapor under sub- and supersaturated conditions. A vapor sorption analyzer was used to measure mass changes in OS samples with relative humidity (RH, 0 %–90 %); among the 11 organosulfates examined, only sodium methyl sulfate (methyl-OS), sodium ethyl sulfate (ethyl-OS), sodium octyl sulfate (octyl-OS) and potassium hydroxyacetone sulfate were found to deliquesce as RH increased, and their mass growth factors at 90 % RH were determined to be 3.65 ± 0.06, 3.58 ± 0.02, 1.59 ± 0.01 and 2.20 ± 0.03. Hygroscopic growth of methyl-, ethyl- and octyl-OS aerosols was also studied using a humidity tandem differential mobility analyzer (H-TDMA); continuous hygroscopic growth was observed, and their growth factors at 90 % RH were determined to be 1.83 ± 0.03, 1.79 ± 0.02 and 1.21 ± 0.02. We further investigated CCN activities of methyl-, ethyl- and octyl-OS aerosols, and their single hygroscopicity parameters (κccn) were determined to be 0.459 ± 0.021, 0.397 ± 0.010 and 0.206 ± 0.008. For methyl- and ethyl-OS aerosols, κccn values agree reasonably well with those derived from H-TDMA measurements (κgf) with relative differences being < 25 %, whereas κccn was found to be ∼ 2.4 times larger than κgf for octyl-OS, likely due to both the solubility limit and surface tension reduction.

Detergent properties of aqueous extract of Aatreelal (Ammi majus L.) and Babchi (Psoralea corylifolia L.)

Aim of the study: To evaluate the detergent activity of aqueous extract of Ammi majus L. and Psoralea corylifolia L. Materials and methods: The detergent activity of aqueous extract of test drugs was evaluated by using a standard physicochemical test with Sodium lauryl sulfate (SLS) as a standard drug. Surface tension was measured by Du Nouytensiometer; Dirt dispersion by using Indian ink; Cleaning ability by greasy wool yarn test; Foaming properties by cylinder shake method and Wetting ability by canvas disc method. pH values and total saponin was also determined. Both the test and standard drugs were analyzed in 1% and 5% concentrations. Results: The aqueous extract of both the test drugs produced a significant detergent effect at both the concentration but less than SLS as it exhibited a pronounced effect in all the parameters except detergency. The test drugs were found to be acidly balanced; exhibited a prominent surface tension reduction, high foaming, wetting, and cleaning ability with a good quantity of saponin. Conclusions: Based on the above results it can be concluded that the aqueous extract of test drugs has significant surface-active properties thus these drugs can be used as a natural surfactant.