Increase In Water Permeability Research Articles

Fruit Structure in Amphicarpic Annual Gymnarrhena micrantha (Asteraceae, Gymnarrheneae) in Relation to the Species Biology

In the amphicarpic annual Gymnarrhena micrantha Desf. (Asteraceae), aerial and subterranean fruits differ in morphology, dispersal ability and germination behavior. The aim of our work was to study their structural features in relation to the eco-physiological properties, using light and scanning electron microscopes. Five fruit morphs were found, three of aerial achenes: ebracteate, bracteate and double bracteate ones, and two subterranean fruits with achenes, enveloped in involucral bracts, developed from (I) sessile or (II) not sessile different heads. This species shows divergent fruit differentiation, an increase in their diversity along several lines of morphological differentiation, which corresponds to a multiple seed dispersal and germination strategy. In addition to the already known distinctive features of subterranean achenes (larger size, undeveloped pappus, poor pubescence), they also differ in the simplified structure of the apical and basal achene regions, the absence of the corolla expanded base (cupula) and nectary, other cells parameters in the exotesta and endosperm, another form of the disproportionately developed embryo. The peculiarities of probably subterranean fruit II (seemingly originated through apomixis) extend to various color, pappus structure, sparse pubescence, and the ability of the fruit wall to delaminate. The lack of dense pubescence in the subterranean achenes is a key trait that could lead to increased water permeability of the fruit wall and affect germination rate. Possible adaptive significance of aerial achene structural features is discussed, including specialized corolla cupula, which may be an adaptation to dissemination by rainwater and ants.

Biomimetic MXene membranes with negatively thermo-responsive switchable 2D nanochannels for graded molecular sieving

Negatively thermo-responsive 2D membranes, which mimic the stomatal opening/closing of plants, have drawn substantial interest for tunable molecular separation processes. However, these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation. Here, we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly (N-isopropylacrylamide) (PNIPAm) onto MXene nanosheets. The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes. As expected, the constructed membrane exhibits ultrahigh water permeance of 95.6 L m−2 h−1 bar−1 at 25 °C, which is eight-fold higher than the state-of-the-art negatively thermo-responsive 2D membranes. Moreover, the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye- and antibiotic-based ternary mixtures. This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes, showing promising applications in micro/nanofluidics and molecular separation.

Justification of parameters of working body of deep loosener

The article presents the analysis results on the study of physical-mechanical properties of soils in Uzbekistan and experimental studies on the influence of parameters and rational geometric shape of working tools on the quality of soil tillage while reducing energy costs. It has been established that soil moisture and hardness in the periods of basic and pre-sowing tillage differ significantly according to weather conditions, agrophonous background, and sowing and harvesting technology of agricultural crops. The peculiarities of different soils and the main directions of preserving and increasing their fertility are considered. The problems of optimization of physical properties and issues of the fertility state of irrigated soils are highlighted. Special attention is paid to the problems of improving soil's basic physical and mechanical properties. The use of effective technologies for improving and ameliorating irrigated lands, increasing fertility, and reducing and preventing soil salinization is proposed. For prevention of decrease and preservation of soil fertility, purposeful measures on improvement of physical properties of soils are recommended, the mechanism of which solution is the application of innovative technology of processing providing purposeful growth and development of root system, moderate moisture of soil, increased water permeability, moisture stocks, and reduction of salinization. To prevent intensive moisture evaporation after deep tillage, it is recommended to carry out agrophobic treatment by maximum leveling and creating a shallow crumbly surface layer. To substantiate the parameters of the deep loosener were based on the fact that the degree and magnitude of soil deformation depend on both the shape and parameters of interacting working bodies and on the physical and mechanical properties of the cultivated medium.

Effect of Cellulose Nanofibrils on the Physical Properties and Frost Resistance of Pervious Concrete.

Pervious concrete has good water permeability and, if used in construction, it can alleviate the heat island effect. However, its low strength and poor durability are major obstacles to its use. This study shows that nano-reinforced pervious concrete created by incorporating cellulose nanofibrils (CNFs) can improve the physical properties and increase the durability of pervious concrete. CNFs were added to the concrete mix in proportions ranging from 0.05% to 0.2% by weight of binder. The additions were found to alter matrix rheology. The hydration kinetics of matrix with differing CNF contents were compared and analyzed. The experimental results show the addition of CNFs delayed peak heat flow and maximum cumulative heat. The 28 d compressive strength of pervious concrete increased by up to 26.5% and 28 d flexural strength by up to 25.8% with the addition of 0.05-0.2% CNFs. Addition of 0.1% and 0.2% CNFs increased water permeability. Addition of 0.05-0.15% CNFs decreased mass loss by 73.2-83.7% after 150 freeze-thaw cycles, which corresponded to an increase in frost resistance. Denser matrices and stronger interfacial transition zones were observed using scanning electron microscopy when 0.05-0.2% CNFs were added.

Post-synthetic modification of MOFs to enhance interfacial compatibility and selectivity of thin-film nanocomposite (TFN) membranes for water purification

Efficient discrimination of ions and small neutral contaminants remains a challenge for polyamide thin-film nanocomposite (TFN) water separation membranes due to the presence of interfacial defects and particle-agglomeration-induced nonselective voids in the polyamide layer. In this work, highly selective TFN membranes were successfully fabricated by leveraging post-synthetic modifications of (3-glycidyloxypropyl)triethoxysilane (GPTES) and trimesoyl chloride (TMC) on MIL-101(Cr)–NH2 MOF filler nanoparticles. GPTES modification suppresses particle agglomeration during interfacial polymerization for membrane formation by forming a stable particle suspension in the organic monomer solution, while TMC-induced in situ chemical crosslinking between filler particles and polyamide addresses the phase compatibility and interfacial issues at the filler–polyamide interface. The resulting TFN membranes show high NaCl, MgCl2, Na2SO4, and MgSO4 rejections of 99.0–99.6% at 150 psi with a water permeance of 0.9 L m−2 h−1 bar−1. Compared to the thin-film composite (TFC) control membrane, the incorporation of the MOF particles yields a 53.0% and 24.5% increase in water permeance and NaCl rejection. Importantly, the TFN membranes also exhibit excellent rejections to small neutral contaminants such as PEG200 (99.2% rejection) and boric acid (89.0% rejection at a pH value of 7.5) at a relatively low pressure of 150 psi, which is higher than the respective value obtained by the commercial Dow SW30XLE TFC control membrane at the same conditions. The outstanding long-term performance stability revealed the robust structure of the MOF TFN membranes. Our results demonstrate a facile strategy to effectively control particle agglomeration and interfacial defects in polyamide TFN membranes by manipulating the surface chemistry of the filler nanoparticles, which can be applied to the fabrication of effective TFN membranes with molecular level size-exclusion selectivity.

Artificial water channels engineered thin-film nanocomposite membranes for high-efficient application in water treatment

Inspired by biological aquaporins, artificial water channels (AWCs) can achieve high-performance for thin-film composite (TFC) reverse osmosis (RO) membranes. In our work, two types of liposomes (C18lyso and D5A liposomes) with superior permeability serving as AWCs were designed by regulating the molecular structures of lipids, in which D5A liposomes have a better ability to water transport water molecules. Herein, liposome-based RO membranes (TFN-C18lyso and TFN-D5A) were fabricated via in situ interfacial polymerizations (IP). The resulting TFN-C18lyso shows an increase in water permeability of ∼ 51.4 % (up to 3.83 L m−2 h−1 bar−1) while TFN-D5A displays an increase in water permeability of ∼ 67.2 % (up to 4.23 L m−2 h−1 bar−1), and both membranes keep high rejection of ∼ 98.6 %. Moreover, both TFN-C18lyso and TFN-D5A present good separation stability, chemical resistance, and good desalination. Our work provides a valid and versatile foundation for developing advanced biomimetic membranes in water treatment.

Surface decoration of bis-aminosilane cross-linked multiwall carbon nanotube ultrafiltration membrane for fast and efficient heavy metal removal

Heavy metals (HMs) are highly toxic water pollutants abundant in industrial wastewater. Herein, a bis[3-(trimethoxysilyl)propyl]amine (BTMSPA) cross-linked multiwalled carbon nanotube (MWCNT) nanomaterial (CQACNT) was synthesized by silanization of MWCNT-OH followed by grafting of positively charged quaternary ammonium groups (glycidyl trimethyl ammonium chloride (GTMAC)) by an epoxide ring-opening reaction. The composite membranes were prepared by the incorporation of CQACNT into the poly(ether sulfone) (PES) polymer matrix. The CQACNT-6 composite membrane exhibited a 3.5-fold increase in pure water permeability (PWP; 312.8 L m−2 h−1 bar−1) as compared to the pristine PES (CQACNT-0) membrane (89.6 L m−2 h−1 bar−1). Moreover, the CQACNT-6 composite membrane showed high HM removal rates (Pb: 89.53%; Ni: 90.42%; Cu: 91.43%; Zn: 91.86%) as compared to the CQACNT-0 membrane (Pb: 39.73%; Ni: 40.32%; Cu: 42.52%; and Zn: 43.91%). After 9 treatment cycles, the CQACNT-6 membrane retained up to 87%, and 94% of its initial PWP and initial Cu2+ rejection, respectively, compared to only 58%, and 54%, respectively for pristine CQACNT-0. The positively charged quaternary ammonium groups enhanced the surface features of PES and MWCNTS, resulting in competitive HM removal rates due to the electrostatic repulsion between the HM and the porous membranes, as well as high PWP.

Optimization of Polyacrylic Acid Coating on Graphene Oxide-Functionalized Reverse-Osmosis Membrane Using UV Radiation through Response Surface Methodology.

Reverse osmosis (RO) is affected by multiple types of fouling such as biofouling, scaling, and organic fouling. Therefore, a multi-functional membrane capable of reducing more than one type of fouling is a need of the hour. The polyacrylic acid and graphene oxide (PAA-GO) nanocomposite functionalization of the RO membrane has shown its effectiveness against both mineral scaling and biofouling. In this research, the polyacrylic acid concentration and irradiation times were optimized for the PAA-GO-coated RO membrane using the response surface methodology (RSM) approach. The effect of these parameters on pure water permeability and salt rejection was investigated. The models were developed through the design of the experiment (DoE), which were further validated through the analysis of variance (ANOVA). The optimum conditions were found to be: 11.41 mg·L−1 (acrylic acid concentration) and 28.08 min (UV activation times) with the predicted results of 2.12 LMH·bar−1 and 98.5% NaCl rejection. The optimized membrane was prepared as per the model conditions, which showed an increase in both pure water permeability and salt rejection as compared to the control. The improvement in membrane surface smoothness and hydrophilicity for the optimized membrane also helped to inhibit mineral scaling by 98%.

EFFECT OF NORMAL BENTONITE CLAY, MINERAL FERTILIZERS, AND IRRIGATION REGIME ON WINTER WHEAT

In addition to the norm N150P105K75 kg/ha of mineral fertilizers for winter wheat under conditions of typical gray soils of the Tashkent region, 3000 kg/ha of bentonite clay was applied for plowing, with soil moisture before irrigation during the growing season in the irrigation mode 60-70-60 and 70-80- 70% of the LFMC at the end of the growing season, the bulk density of the soil relative to the control variant decreased to 0,03-0,05 g/cm3 in the 0-30 cm. layer and to 0,07-0,11 g/cm3 in the 30-50 layer see, an increase in soil water permeability from 30 m3 to 100 m3/ha was noted. When irrigating under irrigation regimes of 60–70–60 and 70–80–70% of the LFMC and additional application of bentonite clay at a rate of 3000 kg/ha against the background of mineral fertilizers at a rate of N150P105K75 kg/ha, the increase in grain yield was 11,9–13,4 c/ha, and the level of profitability increased by 18,9–21,1% compared to the control.

Fabrication of PVDF/EVOH blend hollow fiber membranes with hydrophilic property via thermally induced phase process

In this study, thermally induced phase separation (TIPS) technology was used to fabricate the PVDF/EVOH blend hollow fiber membranes using water-soluble mixed diluents. An interconnected bulk structure was formed by L-L phase separation for both the pristine membrane and blend membrane. The surface enrichment for EVOH during the cooling process enhanced the hydrophilicity of prepared hollow fiber membranes. It was found that the tensile strength of the blend membrane significantly increased from 2.6 MPa to 8.8 MPa. The variation of the membrane structure made the water permeability increase from 60 L m−2 h−1 bar−1 to 287 L m−2 h−1 bar−1 for the optimized blend membrane. Compared with the pristine membrane, EVOH blend membrane exhibited higher antifouling properties for BSA, HA, and oil-in-water emulsion filtrations.

Renal Transplantation in Pure Autonomic Failure.

Renal Transplantation in Pure Autonomic Failure.

Imidazole assisted molecular-scale regulation of polyamide for preparing reverse osmosis membrane with enhanced water permeance

The development of reverse osmosis (RO) technology is still hindered by many obstacles, especially the low water permeance of RO membrane. Herein, an interfacial polymerization regulated by N-acyl imidazole chemistry was proposed to fabricate high permeance RO membranes. The improvement of membrane performance was achieved by simply adding 2-Methylimidazole (Hmim) into aqueous phase. More angstrom-scale free volume elements, which acted as water molecule transport channels, were formed in the polyamide separation layer due to the reaction and hydrolysis of Hmim. As a result, a substantial increase in water permeance was achieved while maintaining high NaCl rejection. In addition, more carboxylic acid groups were formed on the membrane surface due to the hydrolysis of N-acyl imidazole, thereby imparting higher hydrophilicity and anti-fouling properties to the membrane. With the addition of 1.5 w/w% Hmim, the water permeance of the prepared RO membrane was improved to 4.4 L m−2 h−1 bar−1, nearly 4.5 times compared to the control group, while maintaining a high NaCl rejection of above 98 %, thus successfully overcoming the permeability-selectivity trade-off limit. This work paves a new idea for the development of additives in the preparation of RO membranes.

High‐Precision and High‐Flux Separation by Rationally Designing the Nanochannels and Surface Nanostructure of Polyamide Nanofiltration Membranes

High‐precision separation with increased water permeability is critical for efficient membrane‐based water treatment processes. To achieve high selectivity toward different targeted species while allowing rapid water transportation, the structure of the membrane polyamide selective layer requires delicate regulation. Herein, an effective approach to systematically expand the pore size of polyamide layers by incorporating ammonium ion‐modified carbon dots (CDs) into the polyamide network is developed. The ammonium ions with different alkyl chain lengths attached to the CDs create nanochannels of different sizes in the network to lower the energy barrier for water transportation while maintaining high selectivity to targeted species. When the alkyl chain length of the ammonium ions reaches eight carbon atoms (i.e., C8 ions), the amphiphilic C8‐CDs induce the formation of the ridged nanostructure on the membrane surface and hence the increased membrane filtration area. The resultant thin‐film nanocomposite (TFN) membrane, denoted as the TFN‐C8‐CDs membrane, demonstrates a higher Na2SO4 rejection of 98.9% and NaCl/Na2SO4 selectivity of 83.1 than the pristine polyamide membrane, together with a tripled pure water permeability of 29.0 L m−2 h−1 bar−1. Herein, a viable approach for ingeniously designing the nanochannels and surface nanostructure of polyamide membranes for more efficient filtration processes is provided.

Tailoring the substrate of thin film reverse osmosis membrane through a novel β-FeOOH nanorods templating strategy: An insight into the effects on interfacial polymerization of polyamide

The tailoring of the physico-chemical properties of thin film composite (TFC) membranes is essential to augment their separation performances. Maintaining a good balance between water productivity and rejection is one of the important criteria for efficient water treatment. This work reports a nanomaterial-enabled templating strategy used for the construction of a TFC substrate layer. Beta ferric oxy-hydroxides (β-FeOOH) nanorods were used as a pore forming template for polysulfone (PSf) substrate. The templating strategy using β-FeOOH nanorods increased the porosity and pore space connectivity of the PSf substrate, hence facilitating the formation of homogenous and defect-free polyamide selective layers through interfacial polymerization (IP) on top of the PSf substrate. The best membrane, a-TFC β2 which was fabricated using etched PSf substrate preloaded with 1 wt% β-FeOOH exhibited an increase in water permeance by 3-fold compared to the neat TFC membrane while maintaining NaCl rejection of 97.5%. Furthermore, the templating strategy endowed the membrane with better 72 h operational stability, where the water permeance and selectivity were not much deteriorated compared to that of neat membrane. This study demonstrates the feasibility of using substrate templating technique to finetune the porosity and surface pore properties for an optimized IP reaction and hence, enhancing the desalination performance.

Seed-coat thickness explains contrasting germination responses to smoke and heat in Leucadendron

AbstractFire stimulates the germination of most seeds in fire-prone vegetation. Fruits of Leucadendron (Proteaceae) are winged achenes or nutlets that correlate with their requirements for smoke and/or heat in promoting germination. We describe five possible smoke–heat dormancy-release/germination syndromes among plants, of which Leucadendron displays three (no response, smoke only, smoke and heat). As seed-coat thickness varies with seed-storage location (plant or soil) and morphology (winged or wingless), we tested its possible role in water uptake and germination. Species with winged seeds achieved 100% germination in the absence of smoke/heat, seed coats were an order of magnitude thinner, and their permeability greatly exceeded that of nutlets. As seed-coat thickness increased (1) imbibitional water uptake declined at a decreasing rate, and (2) the response to smoke, and to a lesser extent heat, increased linearly to reach levels of germination approaching those of winged seeds. For species responsive to smoke and heat, there was no additive effect when applied together, suggesting that they may have promoted the same physiological process. We conclude that seed-coat thickness holds the key to germination requirements in this genus, independent of seed-storage location or morphology. By what mechanisms (1) the smoke response is greater the thicker the seed coat and (2) smoke chemicals might increase water permeability to explain the non-additive effect of smoke and heat, warrant further investigation.

Modulating interfacial polymerization with phytate as aqueous-phase additive for highly-permselective nanofiltration membranes

Modulating interfacial polymerization (IP) process has been recognized as an effective way to optimize the physicochemical structure of polyamide membranes and thus elevating nanofiltration performance. Herein, phytic acid dodecasodium salt (PADS), a small molecule salt with high solubility, is used as an aqueous-phase additive to modulate the piperazine (PIP) monomers diffusion behavior via electrostatic interaction during the IP process. The PADS with a high charge density can form long-range electrostatic interaction with the PIP molecules to retard their diffusion. The diffusion coefficient of PIP can be effectively modulated within an order of magnitude (∼10−5-10−6 cm2 s−1) by varying the amount of PADS. Accordingly, the growth of polyamide layer is inhibited and the membrane thickness is reduced from 95 nm to 50 nm. The optimized membrane presents a two-fold increase in water permeance while maintaining excellent salt rejection performance (Na2SO4 rejection >97%), outperforming the benchmark commercial nanofiltration membranes.

Atomistic Simulations of the Permeability and Dynamic Transportation Characteristics of Diamond Nanochannels.

Through atomistic simulations, this work investigated the permeability of hexagonal diamond nanochannels for NaCl solution. Compared with the multilayer graphene nanochannel (with a nominal channel height of 6.8 Å), the diamond nanochannel exhibited better permeability. The whole transportation process can be divided into three stages: the diffusion stage, the transition stage and the flow stage. Increasing the channel height reduced the transition nominal pressure that distinguishes the diffusion and flow stages, and improved water permeability (with increased water flux but reduced ion retention rate). In comparison, channel length and solution concentration exerted ignorable influence on water permeability of the channel. Further simulations revealed that temperature between 300 and 350 K remarkably increased water permeability, accompanied by continuously decreasing transition nominal pressure. Additional investigations showed that the permeability of the nanochannel could be effectively tailored by surface functionalization. This work provides a comprehensive atomic insight into the transportation process of NaCl solution in a diamond nanochannel, and the established understanding could be beneficial for the design of advanced nanofluidic devices.

Fabrication and Characterization of Bio-Nanocomposites Based on Halloysite-Encapsulating Grapefruit Seed Oil in a Pectin Matrix as a Novel Bio-Coating for Strawberry Protection.

In the framework of designing a novel bio-coating for the preservation of fresh fruits, this paper reports the design, preparation, and characterization of novel bio-nanocomposites based on pectin loaded with grapefruit seed oil (GO), a natural compound with antimicrobial properties, encapsulated into halloysite nanotubes (HNTs). The vacuum-based methodology was used for the encapsulation of the oil into the hollow area of the nanotubes, obtaining nano-hybrids (HNT-GO) with oil concentrations equal to 20, 30, and 50 wt%. Physical properties (thermal, mechanical, barrier, optical) were analyzed. Thermal properties were not significantly (p < 0.05) affected by the filler, while an improvement in mechanical performance (increase in elastic modulus, stress at breaking, and deformation at breaking up to 200%, 48%, and 39%, respectively, compared to pure pectin film) and barrier properties (increase in water permeability up to 480% with respect to pure pectin film) was observed. A slight increase in opacity was detected without significantly compromising the transparency of the films. The release of linoleic acid, the main component of GO, was followed for 21 days and was correlated with the amount of the hybrid filler, demonstrating the possibility of tailoring the release kinetic of active molecules. In order to evaluate the effectiveness of the prepared bio-composites as an active coating, fresh strawberries were coated and compared to uncoated fruit. Qualitative results showed that the fabricated novel bio-coating efficiently extended the preservation of fresh fruit.

Proteoliposome-Incorporated Seawater Reverse Osmosis Polyamide Membrane: Is the Aquaporin Water Channel Effect in Improving Membrane Performance Overestimated?

The water channel feature of the aquaporin (AQP) is considered to be the key in improving the permselectivity of AQP-based thin-film composite (TFC) polyamide (PA) membranes, yet much less attention has been paid to the physicochemical property changes of the PA layer induced by AQP-reconstituted proteoliposomes. This study systematically investigated the roles of proteoliposome constituents (liposome/detergent/AQP) in affecting the physicochemical properties and performance of the membranes. For the first time, we demonstrated that the constituents in the proteoliposome could facilitate the formation of a PA layer with enlarged protuberances and thinner crumples, resulting in a 79% increase in effective surface area and lowering of hydraulic resistance for filtration. These PA structural changes of the AQP-based membrane were found to contribute over 70% to the water permeability increase via comparing the separation performance of the membranes prepared with liposome, detergent, and proteoliposome, respectively, and one proteoliposome-ruptured membrane. The contribution from the AQP water channel feature was about 27% of water permeability increase in the current study, attributed to only ∼20% vesicle coverage in the PA matrix, and this contribution may be easily lost as a result of vesicle rupture during the real seawater reverse osmosis process. This study reveals that the changed morphology dominates the performance improvement of the AQP-based PA membrane and well explains why the actual AQP-based PA membranes cannot acquire the theoretical water/salt selectivity of a biomimetic AQP membrane, deepening our understanding of the AQP-based membranes.

Differential Interaction of Cannabidiol with Biomembranes Dependent on Cholesterol Concentration.

Cannabidiol (CBD), the major nonpsychoactive component of plant-derived cannabinoids, has been reported to have a broad range of potential beneficial pharmacological effects on the central nervous system (CNS). In this study, the droplet interface bilayer, a model cell membrane, is used to examine the effects of CBD on passive water permeability, a fundamental membrane biophysical property. The presence of CBD decreases the water permeability of model lipid membranes composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and at low concentrations of cholesterol (Chol) (20 mol %) in DOPC, whereas when higher concentrations of Chol are present (33 mol %), CBD has an opposing effect, increasing water permeability. The diametric effect in water permeability change upon addition of CBD to Chol-low and Chol-high bilayers signifies a variant interaction of CBD, depending on the initial state of bilayer packing and fluidity. Additionally, differential scanning calorimetry studies provide evidence that there are selective changes in thermotropic behavior for CBD with DOPC and with DOPC/Chol membranes, respectively, supportive of these varying membrane interactions of CBD dependent upon cholesterol. The intriguing ability of CBD to sensitively respond to membrane Chol concentrations in modifying physical properties highlights the significant impact that CBD can have on heterogeneous biomembranes including those of the CNS, the neurons of which are enriched in Chol to a point where up to a quarter of the body's total Chol is in the brain, and defective brain Chol homeostasis is implicated in neurodegenerative diseases.