Salt-containing Water Research Articles

Synchronously coupled magnetic field weakening the dynamic deformation response of salt-containing droplet to an electric field

Combining a magnetic field with an electric field offers a promising approach for enhancing oil–water separation, yet its underlying mechanisms are not fully understood. We systematically investigated the dynamic deformation of salt-containing water droplet suspended in oil under an electric–magnetic coupling field. Integrating high-speed camera experiments with molecular dynamics simulations, we found that the dynamic response amplitude of droplet is reduced compared to a single electric field. Our analysis suggests that ions deflect under electric–magnetic coupling, affecting ion enrichment and water molecule polarization, thereby weakening droplet tip charge and induced electric forces, which suppresses droplet deformation. Increasing the electric capillary number and ion concentration enhances suppression, whereas improving the electric field frequency to 500 Hz almost eliminates this suppression effect. Notably, the degree of droplet deformation inhibition remains consistent across different viscosity ratios. These research findings offer insights for designing dehydrators to intensify oil–water separation.

Multi-carboxyl based zwitterionic nanofiltration membrane with ion selectivity and anti-scaling performance

Membrane scaling is one of the drawbacks of nanofiltration (NF) impeding its wide application in treatment of salt-containing water. Especially, the high concentration of Ca2+ and SO42− easily lead to a CaSO4 scale layer on the membrane surface, limiting the separation process. Herein, a zwitterionic NF membrane with anti-scaling performance was fabricated through multi-carboxyl carboxylate (sodium citrate) incorporated by interfacial polymerization. Due to the synergistic effect of sodium citrate, the resulting NF membrane had a more negatively charged surface and a larger pore size than the pristine membrane. In desalination, this zwitterionic NF membrane exhibited a high selectivity (15.9) between SO42− (73.1 ± 2.4% rejection) and Ca2+ (4.6 ± 1.4% rejection) with a flux of 39.6 LMH, much higher than that of the commercial NF membrane (NF-270, a selectivity of 1.5). Based on the high SO42− and Ca2+ selectivity, it is difficult to form a CaSO4 scale layer on the membrane surface, which yields an excellent anti-scaling performance of the resulting membrane. Furthermore, the zwitterionic monomer endowed the membrane with an anti-fouling effect due to zwitterions materials have strong hydration to resist nonspecific protein adsorption. This design strategy of ion selectivity zwitterionic membranes through the incorporation of carboxylate provides guidance for the design of highly ion selective anti-scaling NF membranes, which has potential applications in water treatment for salt-containing solutions.

Beetle-inspired oil-loaded shape memory micro-arrays with switchable adhesion to both solid and liquid

Surfaces with switchable adhesion have been vigorously investigated over the past decades by mimicking the unique adhesive mechanisms of living systems. However, designing a universal intelligent adhesive surface for both solid and liquid remains a challenge. Herein, drawing inspiration from the controllable capillary forces generated by muscle movements and oil-secretion on the foot pads of the beetle (Hemisphaerota cyanea), we report a novel oil-loaded shape memory polymer (SMP) micropillars with such smart controllability. Based on the shape memory effect (SME) of the SMP, the pillars can be reversibly switched between the tilted state and the upright state, which simultaneously changes the distribution of the trapped oil, and thus generates different capillary forces. This variation results in reversible adhesion behaviors of the surface to diverse solids including flat glass, CD disk, polytetrafluoroethylene (PTFE), rough glass, sandpaper, nylon net, and liquid droplets like acid, basic, salt-containing water droplets, and some organic liquids such as glycol, glycerol, and formamide. Given its smart adhesion, the surface was further applied in in-situ gripping/release of solid objects and directed liquid shedding. This work provides a new design strategy for smart adhesive materials, which may contribute to the development of smart grippers, microfluidics, etc.

Titanium oxide improves boron nitride photocatalytic degradation of perfluorooctanoic acid

Boron nitride (BN) has the newly-found property of degrading recalcitrant polyfluoroalkyl substances (PFAS) under ultraviolet C (UV-C, 254 nm) irradiation. It is ineffective at longer wavelengths, though. In this study, we report the simple calcination of BN and UV-A active titanium oxide (TiO2) creates a BN/TiO2 composite that is more photocatalytically active than BN or TiO2 under UV-A for perfluorooctanoic acid (PFOA). Under UV-A, BN/TiO2 degraded PFOA ∼ 15 × faster than TiO2, while BN was inactive. Band diagram analysis and photocurrent response measurements indicated that BN/TiO2 is a type-II heterojunction semiconductor, facilitating charge carrier separation. Additional experiments confirmed the importance of photogenerated holes for degrading PFOA. Outdoor experimentation under natural sunlight found BN/TiO2 to degrade PFOA in deionized water and salt-containing water with a half-life of 1.7 h and 4.5 h, respectively. These identified photocatalytic properties of BN/TiO2 highlight the potential for the light-driven destruction of other PFAS.

A Novel Constructed Wetland Combined with Microbial Desalination Cells and its Application.

Wastewater recycling can alleviate the shortage of water resources. Saline water is seldom treated with biological processes, and its recycling rate is low. Constructed wetland (CW) is a safe, economical, and ecological water treatment method. However, the saline water treatment performance of CW is not good. Microbial desalination cells (MDC) utilizing a bioelectrochemical approach achieve functions of desalination and power generation. In this study, MDC was used to strengthen CW to form a composite system, MDC-CW. Through optimization of design parameters, MDC-CW was applied in the treatment of salt-containing water. The average total nitrogen removal rate in MDC-CW-P1 reached 87.33% and the average COD removal rate was 92.79%. The average desalination rate of MDC-CW-P1 was 55.78% and the average voltage of MDC-CW-P1 reached 0.40mV. Planting Canna indica in the MDC-CW was conducive to the functions of desalination and power generation. The above results were also verified by the microbial analysis results of gravels in the substrate, plant rhizosphere, and electrodes. In addition, the decontamination of the device mainly depended on the function of the bacteria commonly used in water treatment, such as Proteobacteria and Bacteroidetes, whereas the generation of power depended on the function of Geobacter. Salt ions moved spontaneously to the cathode and anode under the influence of current generation so that the desalination function was realized under the selective isolation function of exchange membranes. The device design and laboratory applications of MDC-CW experimentally achieved the electrochemical function and broadened the treatment scale of CW.

Effectiveness of sodium sulfite as an electron acceptor for bioenhanced treatment of salt-containing water produced from ASP flooding

The wastewater produced from alkaline-surfactant-polymer (ASP) flooding is a complex multiphase mixture that contains oil, polymers, surfactants and other pollutants and is thus a salt-containing industrial waste recalcitrant to treatments. Through laboratory tests, this study assessed the effectiveness of using sodium sulfite as an electron acceptor for a modified anaerobic baffled reactor (ABR) for removing oil, suspended solids, polymers and surfactants from salt-containing wastewater produced from ASP flooding. During the 90-day operation, the method established in this study successively removed 52.8%, 98.6%, 77.0%, 21.2% and 21.5% of the chemical oxygen demand (COD), oil, suspended solids, polymers and surfactants, respectively, from the wastewater. The changes in organic compounds in the reactor during the treatment were monitored through gas chromatography-mass spectrometry (GC-MS), and the results showed that the established method was very effective in removing alkanes, alkenes, cycloalkanes, aromatic hydrocarbons and esters, and the organic macromolecules in the wastewater were degraded to small molecules. The main bacterial species and microbial communities in the reactor were characterized using molecular biological techniques, and the results indicated that under the stress of high pH and salts, Halomonas sp. gradually dominated and played a major role in degrading hydrocarbons. The findings of this study can aid the development of a cost-effective biological system to treat the water produced from ASP flooding.

Polydopamine functionalized cellulose-MXene composite aerogel with superior adsorption of methylene blue

Incorporation of nanoparticles into a three-dimensional porous framework to enhance adsorption capacity and recyclability of nanomaterial is of great significance for water contamination removal. Herein, a functionalized cellulose/MXene composite aerogel is prepared by the oxidative self-polymerization of dopamine hydrochloride and freeze-drying, which exhibits an excellent adsorption performance for methylene blue (MB). Characterization results show the successful combination of PDA and Ti3C2Tx into the cellulose aerogel with merits of light weight, high structural stability and high porosity. The adsorption process is understood more deeply through the adsorption kinetics. The Langmuir isotherm model was used to better fit the adsorption process, and the maximum adsorption capacity for MB reaches 168.93 mg g−1. Such a superior adsorption ability for MB is maintained in salt-containing water, or even a little higher when the concentration of NaCl is above 3%, recommending the functionalized cellulose/MXene composite aerogel for efficient removal of dyes in high-salt water environment.

Application of novel metal organic framework, MIL-53(Fe) and its magnetic hybrid: For removal of pharmaceutical pollutant, doxycycline from aqueous solutions

As a pharmaceutical pollutant, doxycycline causes contamination when enters into the environment. In this research MIL-53(Fe), and its magnetic hybrid MIL-53(Fe)/Fe3O4 were synthesized and employed for removal of doxycycline from aqueous solutions. The adsorbents were characterized by XRD, SEM, BET, FTIR, EDAX, VSM and TG-DTG technique. The effect of different variables such as DOC concentration, pH, contacting time, and adsorbent dose on the removal efficiency was studied and under optimized conditions the adsorption capacity of 322mgg−1 was obtained. The adsorption process was kinetically fast and the equilibration was attained within 30min. The used adsorbent was easily separated from the solution by applying external magnetic field. The regenerated adsorbent retained most of its initial capacity after six regeneration steps. The effect of ionic strength was studied and it was indicated that removal of doxycycline from salt-containing water with moderate ionic strengths was quite feasible. Langmuir, Freundlich, Tempkin and Dubinin–Redushkevich isotherms were employed to describe the nature of adsorption process. The sorption data was well interpreted by the Longmuir model.

Sodium Chloride Does Not Ensure Microbiological Safety of Foods: Cases and Solutions.

Addition of salt or salt-containing water to food is one of the oldest and most effective preservation methods in history; indeed, salt-cured foods are generally recognized as microbiologically safe due to their high salinity. However, a number of microbiological risks remain. The microbiological hazards and risks associated with salt-cured foods must be addressed more in-depth as they are likely to be underestimated by previous studies. This review examined a number of scientific reports and articles about the microbiological safety of salt-cured foods, which included salted, brined, pickled, and/or marinated vegetables, meat, and seafood. The following subjects are covered in order: (1) clinical cases and outbreaks attributed to salt-cured foods; (2) the prevalence of foodborne pathogens in such foods; (3) the molecular, physiological, and virulent responses of the pathogens to the presence of NaCl in both laboratory media and food matrices; (4) the survival and fate of microorganisms in salt-cured foods (in the presence/absence of additional processes); and (5) the interaction between NaCl and other stressors in food processes (e.g., acidification, antimicrobials, drying, and heating). The review provides a comprehensive overview of potentially hazardous pathogens associated with salt-cured foods and suggests further research into effective intervention techniques that will reduce their levels in the food chain.

Effect of oil exploration and production on the salinity of a marginally permeable aquifer system in the Thar Jath-, Mala- and Unity Oilfields, Southern Sudan

The study area, located in the Subtropics west of the East African Rift, is characterized - on the basis of its hydrology - by an alluvial aquifer system that is made up of predominantly fi ne-grained early Tertiary and Quaternary sediments. These sediments were deposited by the River Nile in large lakes. Nowadays, there is little natural new water recharge from seeping precipitation, due to marginal permeability and the formation of extensive wetlands. In order to search for possible links between an increasingly high salinity in drinking water and the exploration and production of oil in Unity State, South Sudan, a total of 90 water samples from 76 different sampling sites were take n, 74 have been analysed in detail. The samples were taken from the surface water of swamps, from boreholes in various settlements in the area, from produced water storage basins, from production facilities of the oil industry and from mud pits at abandoned as well as from still active exploration drilling sites. Results of these analyses facilitated the identifi cation of six water types that were hydro- chemically distinguishable, and that were characterized by signifi cantly variable ionic relationships and salt contents. Waters unaffected by human activity are characterized by prograde quality development, controlled by water-rock reactions, and they range from a hydrogen carbonate type to a sulphate type. The total dissolved content increases only gradually with the geogenic, prograde evolution of groundwater close to the surface, and ranges in terms of electrical conductivity from 6,000 μS/cm) with simultaneous dominance of chloride and sulphate contents. This anion dominance occurs also partially in produced water storage basins of oil production facilities, especially in mud pits of exploration operations. Due to the direction of groundwater fl ow, the spatial distribution of salt contamination and the hydro-geological boundary conditions found in low water permeable alluvial deposits, the cause of high conductivities in drinking water wells can only be attributed to selective seepage of salt-containing water from the basins and mud pits of those three oilfi elds operating in the study area. Other sources of salt contamination, e.g. deepwater rises or groundwater affected by evaporation, were not identifi ed. In order to guarantee the supply of drinking water for the population in the region, initially two deep wells were sunk (down to 280 m and 300 m depth respectively), and drinking water was pumped from the deepest aquifer, which had not yet been explored and developed. The latter has sulphate-dominated water of low to medium conductivity, which circulates in thin lenses of sand as well as in predominantly silty, fi ne sand layers. A clay layer, approximately 50 m thick, separates the fi rst partly salinized aquifer from the underlying newly explored groundwater horizon. This horizon is supplied only by very slow processes of new accumulation (re-charge) processes, extending over decades. With Open Access Article

Salt excretion through the cuticle without disintegration of fine structures in the salt glands of Rhodes grass (Chloris gayana Kunth)

Some salt-tolerant plants belonging to the Poaceae possess bicellular salt glands that excrete salt-containing water. To clarify the excretion process from the outer cell of the bicellular salt gland (cap cell), unwashed and washed fresh leaves of Rhodes grass (Chloris gayana Kunth), Poaceae, were cryo-fixed rapidly, and the surface fine structures of the leaves were observed by cryo-scanning electron microscopy with high resolution. The cuticle on the cap cell did not have any pores or signs of rupturing. The cuticle of the cap cells lacks the epicuticular waxes that cover most surfaces of leaf epidermis. After excreted droplets on the salt glands were completely removed by washing with water, re-excreted droplets were observed 3h later. These findings indicate that the bicellular salt glands of Rhodes grass excrete salt-containing water continuously through the wax-free cuticle of the cap cell without disintegration of the cuticular structure.

Experiment Research on Industrial Saline Wastewater Treatment Base on Evaporative Concentration Method

For rational utilization of industrial wastewater containing salt, this paper puts forward a method to evaporate and concentrate salty water by applicating no padding evaporative cooling tower. This paper has established a testing bench of evaporation and concentration of salt-containing wastewater and fresh water recovery system. The actual operating characteristic of the testing bench is also tested. Tests showed that evaporated quantity of water of the system ranged from 1.8 to 2.2t/h under the conditions of salt water inlet temperature between 30°C and 40°C.It proves that the proposed salt-containing wastewater treatment is feasible.

Effect of gamma-ray irradiation on the deoxygenation of salt-containing water using hydrazine

In spent fuel pools at the Fukushima Daiichi nuclear power plant, hydrazine was added to salt-containing water in order to reduce dissolved oxygen. Hydrazine is known to reduce dissolved oxygen in high-temperature pure water, but its deoxygenation behavior in salt-containing water at ambient temperature in the presence of radiation is unknown. Deoxygenation using hydrazine in salt-containing water was thus investigated using a 60Co gamma-ray source and artificial seawater at room temperature. Water samples containing a small amount of hydrazine were irradiated at dose rates of 100–10,000 Gy/h. The concentration of dissolved oxygen in the water samples was measured before and after irradiation. Notably, a decrease in the dissolved oxygen was only observed after irradiation, and the dissolved oxygen concentration decreased with increasing dose rate and irradiation time. The rate of decrease in the amount of dissolved oxygen using hydrazine was slow in the presence of salts. Kinetic considerations suggested that the deoxygenation of the salt-containing water exposed to gamma-ray irradiation using hydrazine was suppressed by chloride ions.

Solvation at nanoscale: Alkali-halides in water clusters

The solvation of alkali-halides in water clusters at nanoscale is studied by photoelectron spectroscopy using synchrotron radiation. The Na 2p, K 3p, Cl 2p, Br 3d, and I 4d core level binding energies have been measured for salt-containing water clusters. The results have been compared to those of alkali halide clusters and the dilute aqueous salt solutions. It is found that the alkali halides dissolve in small water clusters as ions.

Modernization of a Gas-Drying Absorber 1800 mm in Diameter

A natural reduction in production pressure during the exploitation of a gas field results in a corresponding change in the operating parameters of all production equipment in the plant used for complex gas preparation (PCGP) and, among other things, the gas-drying absorbers. In maintaining the design output of gas, the actual velocity of the gas flow in the absorber is appreciably increased, and the moisture content of the initial gas also increases. Moreover, the operating velocities of the gas are increased even in the well; this has contributed to flooding, and salt and mechanical-impurity contamination of the raw gas that proceeds into the PCGP in preparing it for transport. In addition, the glycol that circulates continuously within the system of the drying and regeneration plant is contaminated during operation by compressor oil, hydrocarbons, decomposition products, and salts. The increase in contamination of the glycol by salts with decreasing production pressure is also caused by high gas velocities in the well and by the entrainment of salt-containing water by the gas flow with subsequent accumulation of the salts in the glycol [1]. The interplate carry-over of liquid into the mass-exchange section of a plate gas-drying absorber increases with decreasing production pressure due to higher gas velocities in the plate absorber; this diminishes its operating efficiency, and occasionally leads to malfunction of overflow hoppers and the section on the whole. The liquid load on the filtering section of the absorber, which is arranged (along the path of motion of the gas) after the mass-exchange section, increases at the same time. Contamination of the glycol by the indicated impurities results in clogging of the filtering elements, a reduction in thei r effective surface, and an increase in resistance with a simultaneous increase in gas velocity in the subassembly in question. The increase in gas velocity causes the glycol film discharging through the surface of the filtering element to disperse; here, drops of glycol are picked-up by the gas flow with its increased velocity and are carried away with the dried gas. All of the above-enumerated factors involved with the pressure drop lead to a reduction in operating efficiency of the plate absorbers, a decrease in the time to overhaul, and an increase in glycol lost with the dried gas. In recent years, structured packings have come into increasingly widespread use to improve the operating efficien

A Simplified Analytical Procedure for the Determination of Organically Bound Halogens in Salt‐containing Water Samples

AbstractA method was developed for the determination of organic halogens in water samples with the aim of minimizing matrix effects and simplifying the sample preparation technique commonly used. The method is based on the adsorption of organic halogens in modified hydrophilic divinylbenzene polymer columns and their elution with methanol. The adsorbent used enables rapid adsorption and desorption due to comparatively high operating flow rates and minimized solvent amounts. Furthermore, no additional reconcentration steps are needed. The methanol extract obtained is combusted with a standard EOX (extractable organic halogen) analyzer and the concentration of organically bound halogens is determined by microcoulometric analysis. The matrix effects are considerably reduced compared to the standard procedure (EN 1485) commonly used. A detection limit of 13 μg/L was established.

Variation of Susceptibility as Observed by Magnetic Levitation of Liquid Droplets

Abstract The magnetic force is applied for the precisely controlled levitation of salt-containing water droplets in oil phase. This levitation phenomena analyses were achieved by the analytical calculation of the inhomogeneous space distribution of the field and force in the bore of a vertical superconducting magnet. The tiny effects on the droplet position are explained as variation of the diamagnetic susceptibility in the course of levitation.

Decreasing Out-of-Round in Poly(α-Methylstyrene) Mandrels by Increasing Interfacial Tension

Currently, poly(α-methylstyrene) mandrel precursors are suspended in a salt-containing water bath during curing. Matching the density of the precursors to their bath almost, but not quite, eliminates shell sagging caused by gravity. This sagging is opposed by the interfacial tension between the plastic containing oil solution and the water bath, but the tension is barely adequate to give satisfactory sphericity. We found that adding a small amount (<0.1 wt%) of high-molecular-weight poly(acrylic acid) to the water bath substantially increased the interfacial tension. Combining that change with a gentler shell curing process enabled consistent production of more spherical mandrels.

The Effects of Controlling Osmotic Pressure on a Pαms Microencapsulated Mandrel During Curing

Poly(α-methylstyrene) (PαMS) mandrel precursors (a PαMS containing fluorobenzene solution surrounding a water core) are suspended in a salt-containing water solution during curing. The salt is necessary to suppress the growth of water drops in the curing oil phase (resulting in vacuoles in the dried mandrel). However the use of salts in this manner results in a chemical potential difference between the inner pure water droplets and the outer bath. This results in a loss of water from the inner water phase, shrinking the mandrel as it cures and potentially wrinkling its surface.We have quantified the degree of mandrel shrinkage and expansion as a function of the difference in salt concentration. Expansion is not proportional to concentration difference. It does not appear that osmotically driven expansion removes wrinkles; the large wrinkle amplitudes were seen with all salt concentrations.

Interfacial behavior of proteins in three-phase partitioning using salt-containing water/ tert-butanol systems

Three-phase partitioning (TPP) was used to investigate the partitioning of four model proteins (bovine serum albumin, ovalbumin, lysozyme and gelatine) in a system containing water, tert-butanol and an inorganic electrolyte ((NH 4) 2SO 4). Phase diagrams of the ternary (protein-free) system and interfacial tensions between the equilibrium upper and lower liquid phases have been determined. The amount of protein precipitated in the middle layer was delineated as a function of the composition of the partitioning system as well as the initial protein concentration. No dependence of the relative amount of protein accumulated in the midlayer on the total amount of protein was observed. The constant partitioning ratio found in TPP emphasizes the partitioning character of the process. The interfacial adsorption of a single protein (indicated by the decreasing interfacial tension between the immiscible liquid phases) shows a good correlation with the accumulation of the same protein in TPP as a middle layer for the various proteins investigated.