Pure Water Research Articles

The comparison of the efficacy of 185/254 nm and 172 nm photolysis for the removal of sulfonamides and trimethoprim from aqueous solutions

The VUV (λ < 200 nm) photolysis can be used to eliminate organic substances without the addition of oxidant due to the efficient generation of OH from water. Two VUV light sources are commercially available: the low-pressure mercury vapor (LPM) and the Xe-excimer lamp, which emit 185/254 nm and 172 nm photons, respectively. This study compares the efficiency of the UV/VUV185nm and VUV172nm photolysis in removing four sulfonamides (SAs) and trimethoprim (TRIM) antibiotics. For the LPM lamp, 254 nm UV radiation ((4.21 ± 0.08) × 10−6 molphoton s−1) can contribute to the transformation of target substances besides the OH generated by the 185 nm VUV light. The VUV photon flux (1.02 × 10−5 molphoton s−1) of the Xe-excimer lamp significantly exceeded that of the LPM lamp (3.97 × 10−7 molphoton s−1); as H2O2 formation in pure water reflected, however, the efficiency of the transformation rate of the target substances was just slightly faster. For the LPM lamp, in addition to the direct UV photolysis of SAs, the 254 nm light enhances the OH formation via H2O2 photolysis, thereby partially compensating for the low VUV185nm photon flux. The high VUV172nm photon flux was primarily manifested in mineralization efficiency and not in the transformation rate of target compounds. The short penetration depth of 172 nm light favors the recombination of primary radicals and decreases the efficiency. The effect of the matrix and matrix components is complex; they act as a radical scavenger or (V)UV filter. The change of radical set and the role of the formed secondary radicals (Cl, Cl2−, and CO3−) in transformation must be considered.

A novel poly (lactic-acid) and poly (butylene adipate-co-terephthalate) blend membrane modified with hesperidin for oily water emulsions separation

The oily wastewater produced by a variety of industrial operations presents a serious threat to both humans and the environment. Separation efficiency, good mechanical stability, high flux, and recyclability are critical parameters for a suitable oil-water separation membrane. In this study, a novel blend membrane of (poly (lactic acid)/poly (butylene adipate-co-terephthalate)) with hesperidin-NPs was synthesized by using the phase inversion technique to effectively separate oily-water emulsions. Herein, hesperidin (HSP) was harnessed for the first time as a green agent to optimize its content in the polymeric matrix. (FTIR) Fourier transform infrared spectroscopy, (FESEM) Field emission scanning electron microscopy, (CA) contact angle, mechanical tester, pore size and porosity were utilized to comprehensively characterize the manufactured (PLA/PBAT/HSP) membranes. The current work presents the proposed interaction mechanism between the contents of PLA/PBAT/HSP and the interaction mechanism of PLA/PBAT/HSP membrane with H2O molecules. The synthesized (PLA/PBAT/HSP) membrane manifested high wettability and has a 49° water contact angle and oleophobicity under a water contact angle of 146±2° for diesel oil. The PLA/PBAT membrane exhibited a homogeneous and symmetric spongy-like structure from top to bottom across its entire cross-section with very tiny active layer observed at the top surface of the membrane in FESEM images. Meanwhile, incorporating of 0.0125wt.% HSP into the casting solution has resulted in a significant change in the structural morphology. Furthermore, upon adding the HSP to the polymeric matrix, distinct changes in the structure were formed, which resulted in enhancing the mechanical features (tensile strength) of the membranes. Modified membrane with 0.025wt.% HSP displayed an optimal flux for pure water (220.5L/m2.h1) and the modified membranes maintained a high rejection (more than 99%) against oil-water emulsions. Outcomes demonstrated that the improved permeation and separation characteristics of the (PLA/PBAT/HSP) membranes could present a potential option to treat applications that use oily wastewater.

PVDF-Halloysite-Ceria Multifunctional Membrane for One-step Treatment to Industrial Effluent

Industrial wastewater, containing diverse pollutants like dyes and oils, poses detrimental environmental challenges. Membrane technology addresses this complexity well but requires tailored nanofiller modifications that enhance hydrophilicity, oleophobicity, and antifouling potential for efficient separation. In this context, our work focuses on the development of mixed matrix membranes (PV-H-C) – PVDF, halloysite nanotubes (HNTs), and ceria nanoparticles – for effective dye and oil-water emulsion separation, enabling high flux recovery. The tubular structure of HNTs, with a lumen, enables the encapsulation and controlled distribution of ceria nanoparticles, preventing their agglomeration and leading to more uniform dispersion within the membrane matrix. HNTs porous structure, high surface area, and numerous adsorption sites within its nanotubes excel in rapid dye adsorption and ceria’s inherent hydrophobic properties along with low surface energy, forms a barrier against oil adhesion and spreading. Optimal results were achieved by loading 2% HNT and 1% ceria in the PVDF matrix, ensuring improved membrane performance. HNTs enhanced hydrophilicity and achieved pure water permeate flux of 1698L/m2.h.bar. Developed membranes are super-oleophobic with an underwater contact angle of 132° + 3°and show a 100% increase in dyes and oils separation efficiency as compared to the pristine PVDF membranes. This unique integration of ceria with halloysite nanotubes in PV-H-C membranes is pivotal, bestowing exceptional anti-fouling characteristics and reusability, while providing a one-step, comprehensive solution for the effective treatment of complex industrial wastewater that encompasses both oil and complex dyes.

Carbon nanotube incorporated quaternized lignin-based loose nanofiltration membrane toward dye/salt separation

Lignin is a promising raw material for membrane fabrication due to its abundant oxygen-containing functional groups, branched molecular structure, and high abundance in the botanic field. In this report, polydopamine (PDA) coated carbon nanotubes (PCNTs) are synthesized. Then, a PCNT-incorporated lignin-based loose nanofiltration membrane is fabricated using quaternized lignin (QL) as a raw material, triphosgene (TP) as a crosslinker, and PCNTs as nanoadditive by interfacial polymerization. The results show that the PCNTs uniformly distribute in the QL-based separation layer providing quick diffusion paths for water molecules and salt ions. The coated PDA layer improves the chemical compatibility between the PCNTs and the separation layer. The incorporated PCNTs optimize the membrane microstructure and elevate the pure water permeance to 45.5 LMH bar-1. The membrane exhibits high rejections to various dyes (> 90%) and high salt permeation (> 90%), demonstrating an excellent dye/salt separation performance. Moreover, it has satisfactory capabilities for resisting dye adsorption and fouling, and its separation capability also has good tolerances to the acid, alkali, and active chlorine treatments. The quaternary ammonium ions and hydrophilic surface endow the membrane with favorable bactericidal property (99.3%) and bacteria-adhesion resistance. Besides, TP is a better crosslinker than trimesoyl chloride for optimizing the membrane microstructure and crosslinking degree in terms of dye/salt separation.

Effect of Blood Contamination on Vickers Microhardness and Surface Morphology of Mineral Trioxide Aggregate

This study aimed to investigate the effects of blood contamination on the Vickers hardness and the surface morphology of premixed MTA and compare them with the effects on conventional MTA. The Vickers microhardness of Endocem MTA Premixed Regular (EP) and ProRoot MTA (PM) was assessed after immersion in fetal bovine serum (FBS) and saline. Stem cells from human exfoliated deciduous teeth (SHED) were seeded on MTA after immersion in FBS, saline, and deionized water (DW). Cell adhesion patterns and surface morphology were visualized via scanning electron microscopy (SEM). The surface microhardness of EP and PM in FBS was lower than in saline. However, short-term exposure of PM to FBS did not reduce the microhardness compared to saline. Angular crystals formed in water, while rounded crystals with more air voids appeared in FBS. Favorable SHED attachment occurred in all groups. Overall, the surface hardness of EP and PM decreased after FBS exposure, although PM was less influenced. We suggest minimizing the amount of bleeding when using MTA clinically; nevertheless, PM remains an option with more expected blood contamination than EP. In summary, exposure to FBS decreased mechanical performance but allowed cell adhesion for both MTAs, with PM being more resistant to these changes.

IoT Based Water Pollution Monitoring RC Boat

Abstract: As we all know that, water is life. And getting clean and pure water in our day-to-day life is becoming harder by the each passing day. Due the tremendous increase in pollution in water this is leading to poor health and unfulfilled need day to day needs of the mankind. Such increment inpollution of water is mainly seen in the rural areas. So, this particular project is aiming to find the solution for the increasing water pollution in different water bodies like lakes, ponds, etc. This project mainly contains the RC boat which willour inbuilt pollution detecting system. The main components ofthe system contain sensors like pH senor, and Turbidity senor, these sensors collect the value from the water bodies and send itto the thingspeak website. After that processing is being done onthe collected data and it will monitor the pollution level in the water. By creating this system, it becomes easier for us to detect and monitor the amount of trash or pollution being present in any water body. And further my knowing this it will help in theprevention of polluted water as well as treating the polluted water.

A high-efficiency photocatalytic hydrogen evolution system based on nickel-quinoxaline dithiolate complexes and water-soluble CdSe quantum dots

Photocatalytic water splitting of water for hydrogen evolution is one of the effective methods to obtain clean hydrogen energy. In the present work, the following materials were synthesized: two nickel quinoxaline thiolate complexes [NBu4]2 [Ni(qdt)2] (1, Bu = n-butyl, qdt = quinoxaline-dithiol), [NBu4]2 [Ni(qdt)2(NO2)2] (2) and water-soluble MPA-CdSe quantum dots (MPA-CdSe QDs, MPA = 3-mercaptopropionic acid). Subsequently, an efficient three-component photocatalytic hybrid system for hydrogen evolution was developed and tested under visible light irradiation, in which one of the target complex 1 or 2 was used as the catalyst, triethylamine (TEA) was used as the sacrificial electron donor, and MPA-CdSe QDs were used as the light harvesting reagent. The turnover numbers (TON) for H2 evolution of 8974 (vs. complex 1) and 6532 (vs. complex 2) were obtained under the optimal conditions with TEA concentration of 5 %, pH = 12, and concentration of complex 1 or 2 of 1 × 10−5 mol L−1 after 13 h of irradiation (λ > 420 nm) in pure water. The mechanism investigation indicated that critical steps of hydrogen production was formation of hydride intermediates Ni(II)-H and Ni(I)-H spices, followed by the reaction of two Ni(II)-H or Ni(I)-H species with protons generating H2 molecules and regenerating the catalyst Ni(II).

Investigation of Kinetic, Equilibrium, and Thermodynamic Modeling of Perfluorooctanoic Acid (PFOA) Adsorption in the Presence of Natural Organic Matter (NOM) by Dielectric Barrier Discharge Plasma-Modified Granular Activated Carbon (GAC)

Perfluorooctanoic acid (PFOA) contamination in water sources poses significant environmental and health concerns. The kinetic, equilibrium, and thermodynamic features of PFOA adsorption in the existence of natural organic matter (NOM) were thoroughly investigated in this work using granular activated carbon (GAC) modified by dielectric barrier discharge (DBD) plasma. The impacts of DBD plasma parameters on the adsorption process were systematically examined. The results demonstrated that GAC modified by DBD plasma exhibited enhanced adsorption performance for PFOA, even in the presence of NOM. The optimal condition for plasma-treated GAC was achieved with 20 min of plasma treatment time and 100 W of plasma power, resulting in 92% PFOA removal efficiency in deionized water (DIW) and 97% removal efficiency in Chao Phraya River water (CPRW). A kinetic investigation using the pseudo-first-order model (PFOM), the pseudo-second-order model (PSOM), and the Elovich model (EM) indicated that plasma treatment time and NOM presence influenced the adsorption capacity and rate constants of PFOA with the PSOM having emerged as the most fitting kinetic model. The Langmuir isotherm model indicates monolayer adsorption of PFOA on plasma-treated GAC, with higher maximum adsorption capacity while NOM is present. The Redlich–Peterson and Sips isotherm models indicated varying adsorption capacity and heterogeneity in the adsorption system. The Sips model was determined as the most fitting isotherm model. Furthermore, the favorable and spontaneous character of PFOA adsorption onto plasma-treated GAC was validated by thermodynamic analysis, with endothermic heat absorption during the process. Overall, this comprehensive investigation provides valuable insights into the adsorption characteristics of PFOA in the existence of NOM using GAC modified by DBD plasma.

Experimental study on the methane explosion suppression by ultra-fine water mist containing bacteria under degradation for five times.

In a semi-closed visualization pipeline, this experiment studied the inhibitory effect of ultra-fine pure water mist, ultra-fine water mist containing inorganic salt and ultra-fine water mist containing bacteria-inorganic salt on 9.8% methane explosion under five different quality of spray volume. Combined with the methane explosion suppression experiment, the ability of methane-oxidizing bacteria to degrade 9.8% of methane was studied in a simulated pipeline. Experiments showed that the addition of inorganic salt and the degradation of methane-oxidizing bacteria could improve the suppression explosion effect of ultra-fine water mist, and the suppression explosion effect was related to the volume of water mist. Under the same ultra-fine water mist condition, with the increase of the volume of water mist, the explosion suppression effect was improved. Compared with pure methane, pure water ultra-fine water mist, and inorganic salt ultra-fine water mist, the maximum explosion overpressure and flame propagation speed under the condition of bacteria-inorganic salt ultra-fine water mist were significantly reduced. Compared with the explosion of pure methane, due to the degradation of methane by methane-oxidizing bacteria, when the degradation time was 10 h, and the volume of ultra-fine water mist containing bacteria-inorganic salt was 12.5 mL, the maximum explosion overpressure dropped significantly from 0.663 to 0.343 MPa, a decrease of 48.27%. The appearance time of the maximum explosion overpressure was delayed from 208.8 to 222.6 ms. The peak flame velocity was 4 m s-1, which was 83.3% lower than that of 9.8% pure methane explosion. This study will contribute to the development of efficient ultrafine water mist synergistic inhibitors for the prevention of methane explosion disasters.

Effects of Nanoconfinement on Dynamics in Concentrated Aqueous Magnesium Chloride Solutions.

Water behavior in various natural and manufactured settings is influenced by confinement in organic or inorganic frameworks and the presence of solutes. Here, the effects on dynamics from both confinement and the addition of solutes are examined. Specifically, water and ion dynamics in concentrated (2.5-4.2 m) aqueous magnesium chloride solutions confined in mesoporous silica (2.8 nm pore diameter) were investigated using polarization selective pump-probe and 2D infrared spectroscopies. Fitting the rotational and spectral diffusion dynamics measured by the vibrational probe, selenocyanate, with a previously developed two-state model revealed distinct behaviors at the interior of the silica pores (core state) and near the wall of the confining framework (shell state). The shell dynamics are noticeably slower than the bulk, or core, dynamics. The concentration-dependent slowing of the dynamics aligns with behavior in the bulk solutions, but the spectrally separated water-associated and Mg2+-associated forms of the selenocyanate probe exhibit different responses to confinement. The disparity in the complete reorientation times is larger upon confinement, but the spectral diffusion dynamics become more similar near the silica surface. The length scales that characterize the transition from surface-influenced to bulk-like behavior for the salt solutions in the pores are discussed and compared to those of pure water and an organic solvent confined in the same pores. These comparisons offer insights into how confinement modulates the properties of different liquids.

Rudimentary Overview: Dehydration (Loss of Body Water) Recognition and Management

Dehydration occurs when the body loses more water than it gains, mostly from the intracellular volume (ICV). Low-intake dehydration is the consequence of consuming insufficient amounts of pure water, which increases the osmolality of both compartments and resulting in the loss of intracellular and extracellular fluid. Clinically, volume depletion affects the interstitial compartment and is brought on by excessive losses of fluid and salt, especially sodium and occasionally other elements. The main cause of the fluid loss is a decrease in extracellular volume (ECV); the serum osmolality will either be low or normal. From a physiological standpoint, it makes sense that many clinicians refer to any loss of total body water as dehydration in their routine clinical practice. Most people who have mild to moderate dehydration as a result of vomiting, diarrhoea, or fever can recover by drinking more liquids, such water. Full-strength fruit juice and soft drinks might make diarrhoea worse. If you work outside or exercise in hot or muggy weather, your best bet is cool water. The best way to treat dehydration is to replenish the body with enough of fluids, such as water, diluted squash, or diluted fruit juice. A salty snack can help you replace lost salt, while a sweet drink can help you replace lost sugar. We go over the causes, prevalence, accessible therapies, and present state of dehydration in this review study.

Monte Carlo simulation study of the structure of calcium and potassium chlorides ternary solutions

ABSTRACT Monte Carlo simulations were conducted on pure water and aqueous calciumand potassium chloride ternary solutions at different salts concentrations. To assess the local order within the solutions, the Monte Carlo simulations utilised the Madrid-2019 force field, usingtheTIP4P/2005 water model and scaled charges. The results demonstrate that as the salt concentrations increase, there is a notable decrease in the contribution of the structured tetrahedral arrangement of water molecules, favouring an unstructured configuration instead. The use of the nearest neighbour approach, provided unambiguous information regarding the radial and orientation characteristics of the unstructured configuration of water. Structures of the solvation shells around ions are also studied. The Monte Carlo simulations indicate that as the salt concentration increases, the hydration number around the cation decreases. This effect is likely due to the occasional substitution of some water molecules in the first hydration shell by chlorine ions.

A systematic study of solvation structure of asymmetric lithium salts in water.

Aqueous electrolytes are promising in large-scale energy storage applications due to intrinsic low toxicity, non-flammability, high ion conductivity, and low cost. However, pure water's narrow electrochemical stability window (ESW) limits the energy density of aqueous rechargeable batteries. Water-in-salt electrolytes (WiSE) proposal has expanded the ESW to over 3 V by changing electrolyte solvation structure. The limited solubility and WIS electrolyte crystallization have been persistent concerns for imide-based lithium salts. Asymmetric lithium salts compensate for the above flaws. However, studying the solvation structure of asymmetric salt aqueous electrolytes is rare. Here, we applied small-angle X-ray scattering (SAXS) and Raman spectroscope to reveal the solvation structure of imide-based asymmetric lithium salts. The SAXS spectra show the blue shifts of the lower q peak with decreased intensity as the increasing of concentration, indicating a decrease in the average distance between solvated anions. Significantly, an exponential decrease in the d-spacing as a function of concentration was observed. In addition, we also applied the Raman spectroscopy technique to study the evolutions of solvent-separated ion pairs (SSIPs), contacted ion pairs (CIPs), and aggregate ions (AGGs) in the solvation structure of asymmetric salt solutions.&#xD.

Solvent Regulation Induced Cathode Aggregation-Induced Electrochemiluminescence of Tetraphenylethylene Nanoaggregates for Ultrasensitive Zearalenone Analysis.

Zearalenone (ZEN) is an extremely hazardous chemical widely existing in cereals, and its high-sensitivity detection possesses significant significance to human health. Here, the cathodic aggregation-induced electrochemiluminescence (AIECL) performance of tetraphenylethylene nanoaggregates (TPE NAs) was modulated by solvent regulation, based on which an electrochemiluminescence (ECL) aptasensor was constructed for sensitive detection of ZEN. The aggregation state and AIECL of TPE NAs were directly and simply controlled by adjusting the type of organic solvent and the fraction of water, which solved the current shortcomings of low strength and weak stability of the cathode ECL signal for TPE. Impressively, in a tetrahydrofuran-water mixed solution (volume ratio, 6:4), the relative ECL efficiency of TPE NAs reached 16.03%, which was 9.2 times that in pure water conditions, and the maximum ECL spectral wavelength was obviously red-shifted to 617 nm. In addition, "H"-shape DNA structure-mediated dual-catalyzed hairpin self-assembly (H-D-CHA) with higher efficiency by the synergistic effect between the two CHA reactions was utilized to construct a sensitive ECL aptasensor for ZEN analysis with a low detection limit of 0.362 fg/mL. In conclusion, solvent regulation was a simple and efficient method for improving the performance of AIECL materials, and the proposed ECL aptasensor had great potential for ZEN monitoring in food safety.

Application of cutting fluids in micro-milling — A review

AbstractThis article provides an overview of micro-milling operation with a focus on cutting fluids and reviews and discusses dry machining, flood, cryogenic cooling, usage of minimum quantity lubrication (MQL) approach, nanoparticle suspensions, and vegetable oils. In conclusion, the article highlights the future trends and research gaps in field of micro-milling with cutting fluids. Based on works, it can be concluded that researchers explore substitutes for traditional cutting fluids in micro-milling, including vegetable oils, nanofluids, cryogenics, solid lubricants, and de-ionized water. Most cutting fluid studies have focused on micro-milling of aluminum, steel, and titanium, with surface roughness being the most measured output in micro-milling work involving cutting fluids. Overall, the article highlights the need for further research in various aspects of micro-milling operations with cutting fluids, including the development of new cutting strategies, the optimization of cutting fluid delivery methods, and the evaluation of various machinability parameters.

Particle size effect on surface/interfacial tension and Tolman length of nanomaterials: A simple experimental method combining with theoretical.

Surface tension and interfacial tension are crucial to the study of nanomaterials. Herein, we report a solubility method using magnesium oxide nanoparticles of different radii (1.8-105.0nm, MgO NPs) dissolved in pure water as a targeted model; the surface tension and interfacial tension (and their temperature coefficients) were determined by measuring electrical conductivity and combined with the principle of the electrochemical equilibrium method, and the problem of particle size dependence is discussed. Encouragingly, this method can also be used to determine the ionic (atomic or molecular) radius and Tolman length of nanomaterials. This research results disclose that surface/interfacial tension and their temperature coefficients have a significant relationship with particle size. Surface/interfacial tension decreases rapidly with a radius <10nm (while the temperature coefficients are opposite), while for a radius >10nm, the effect is minimal. Especially, it is proven that the value of Tolman length is positive, the effect of particle size on Tolman length is consistent with the surface/interfacial tension, and the Tolman length of the bulk does not change much in the temperature range. This work initiates a new era for reliable determination of surface/interfacial tension, their temperature coefficients, ionic radius, and Tolman length of nanomaterials and provides an important theoretical basis for the development and application of various nanomaterials.

Ultra-Efficient Removal of Mercury from Contaminated Water using Selected Phenylimidazole Derivatives

Heterocycles, including imidazole derivatives, are important chemicals due to their structural similarity to active natural molecules. This study explored the utilization of phenylimidazole derivatives for mercury removal from aqueous solutions. Three derivatives were tested, including one harboring a sulfhydryl functional group, thus offering distinct mercury-binding capabilities. Mercury binding experiments revealed modest mercury binding by two derivatives. However, extraordinary efficiency of mercury binding by the sulfhydryl-bearing compound was demonstrated through a reduction in mercury concentrations in pure water by 43-fold in just 15 min and decreasing below the analytical detection limit with prolonged exposure (30 min). Moreover, the ultra-efficiency of mercury binding was demonstrated by a capability to reduce mercury concentrations even in highly contaminated environmental water sample by a factor exceeding 1200-fold in 20 h, using minimal amounts of the compound. This phenylimidazole derivative exhibited comparable efficiency in binding mercury from authentic environmental water samples, hinting at practical applications for real-world remediation efforts. Kinetic investigations showed a pseudo-first order reaction with a rate constant of 0.26 min−1 and half-life of 2.69 min that governs mercury binding to this phenylimidazole derivative. These findings underscore the potential of the sulfhydryl-containing phenylimidazole derivative, as swift and effective binding material for aqueous mercury removal. Its rapid action, coupled with binding efficiency, suggests a promising material for addressing mercury contamination in highly contaminated environmental water samples.

PVDF membranes for membrane distillation prepared by VIPS – A combined study of artificial water channel effectiveness and membrane performance prediction

Background A combined VIPS-NIPS technique was used to investigate the potential of self-supporting flat-sheet polyvinylidene fluoride (PVDF) membranes containing amphiphilic I-quartet Artificial Water Channels (AWC) for Direct Contact Membrane Distillation (DCMD). The AWC are formed in situ by self-assembly of HC6 molecules upon contact with water during membrane formation. Methods A Design of Experiment (DoE) was used to investigate the influence of various experimental parameters and their interactions on membrane performance, namely polymer and AWC concentrations in the dope solution, relative humidity and duration of the VIPS treatment. Pure water permeability (PWP), Liquid Entry Pressure (LEP) and DCMD flux were used to characterize membrane performance. A Response Surface Methodology (RSM) was used to evaluate the DoE results and a second order model was fitted. Based on the model predictions several multiple response-optimized (MRO) membranes were prepared. Results The performance improvement of the MRO membranes was 7.0 times for PWP (M-T4) and 3.3 times for MD flux (M-T3) over the average performance of the DoE membranes, while maintaining LEP of 1.9 bar and Salt rejection of 99.9%. In addition, hybrid PVDF/HC6 MRO membranes improved PWP by 3.2 times and MD flux by 1.6 times over pure PVDF MRO membranes. Conclusions DoE in conjunction with RSM enabled the prediction of membrane PWP, LEP and MD flux performance by varying the levels of the experimental parameters within predefined limits. The HC6 additive improves PWP and MD flux without loss of LEP or selectivity. HC6 promotes the formation of porous skin and asymmetric cross-sections with finger-like structures. Probably by affecting diffusion during phase separation due to its amphiphilic properties.

Preparation and properties of asymmetric inverse opal-like microfiltration membranes

Most types of commercially available MF membranes suffer limited separation performances due to huge deviations in pore size and low porosity. In view of this, a new and facile assembly strategy was proposed to prepare an asymmetric inverse opal (IO) like microfiltration (MF) membrane with ordered pore structure, high porosity and large water flux, which is a composite of a disordered layer with three-dimensional pore structures made by dissolved N, N-dimethylformamide (DMF) and an ordered layer with uniform pore size by using a sacrificial template method. The effects of SiO2 microsphere size and DMF treatment on the structure and properties have been investigated. Different DMF treatment times can significantly change the asymmetric structure distribution of MF membrane and further affect the permeability. The water flux of the asymmetric membrane increases with the DMF infiltration time. Based on the SiO2 microsphere template size of 494 nm and the DMF treatment time of 90 s, the porosity and pure water flux can reach 78 % and 1810 L/m2h, respectively. The membrane retains the IO-like structure layer with uniform pore size, and features excellent retention (almost 100 %) for SiO2 microspheres, indicating the great potential of asymmetric IO-like MF membranes for membrane separation applications.

Study on the compounding optimization of surfactants and synergistic effects on the wettability of bituminous coal

To improve the wettability of surfactants on bituminous coal and to explore its wettability and wettability mechanism on bituminous coal, taking the Sandaogou bituminous coal as an example, a single factor experiment was carried out first. Through contact angle and surface tension experiments, three surfactants with good wettability were selected from among the nine surfactants and mixed in equal proportions two by two to determine the optimal compounding method and compounding concentration. The experimental results show that the compounding of nonionic and anionic, nonionic and zwitterionic, anionic and zwitterionic surfactants can have synergistic effects and significantly improve the wettability of bituminous coal. Among them, the 0.5 wt% SDS + 0.5 wt% CAB-50 (R2) compound surfactant had the best wettability on bituminous coal, and the contact angle and surface tension were only 15.24° and 23.62 mN/m, respectively. The surface electrostatic potential values of each material molecule were calculated by Materials Studio software based on the quantum chemistry method, and correlation analysis was carried out with wettability. The results show that the surface electrostatic potentials of CDEA, SDS and CAB-50 were greater than those of water and bituminous coal, and the region of maximum negative electrostatic potential corresponded to oxygen atoms, which are easier to adsorb on bituminous coal and water molecules. Then, through molecular dynamics simulation, the interaction energy and the distribution of contributions along the Z-axis of the water/compound surfactant/bituminous coal system at equilibrium were investigated, and finally, a spray dust reduction test was carried out in the Sandaogou Coal Mine. The results showed that the 0.5 wt% SDS + 0.5 wt% CAB-50 compound solution can be used as a water molecule adsorption carrier, prompting more water molecules to be embedded into coal molecules, increasing the relative concentration of water molecules on the surface of bituminous coal, restricting the diffusion of water molecules, and greatly improving the wettability. After the addition of 0.5 wt% SDS + 0.5 wt% CAB-50 as a spray agent, the concentration of total dust at the driver's position decreased from 65.14 to 9.11 mg/m3, the concentration of exhaled dust decreased from 30.07 to 3.35 mg/m3, and the efficiency of total and exhaled dust reduction compared with that of pure water was 86.01% and 89.35%, respectively.