Water-rich Solution Research Articles

Development of a HPLC system using a phase-separation multiphase flow as an eluent: an influence of column pressure on phase separation and chromatogram at room temperature.

We have developed a HPLC system where phase-separation multiphase flow works in the separation column as an eluent. We call the novel separation mechanism a phase-separation mode. The ternary mixed solution of water/acetonitrile/ethyl acetate, which is one of the two-phase-separation mixed solutions, caused the phase-separation multiphase flow via phase change from homogeneous to heterogeneous with the temperature effect (from 20 to 0°C). In this study, we tried to perform phase-separation multiphase flow with the pressure effect instead of the temperature one. The fused-silica capillary tube (50cm length and 50µm inner diameter) was allied to the downstream of the column to apply the pressure of 5.5MPa to the system. Model analytes of 2,6-naphthalenedisulfonic acid (2,6-NDS) and 1-naphthol (1-NA) were examined. For example, solutions (the volume% of water/acetonitrile/ethyl acetate; 20:55:25, organic-rich) and (60:30:10, water-rich) were used as eluent. The model analytes were not separated with both solutions at the pressure of 1.5MPa and 20°C. But with the organic-rich solution, 1-NA and 2,6-NDS were separated in this order and with the water-rich solution, they were separated in the reverse order at the pressure of 5.5MPa and 20°C. The phase-separation mode could be performed at the high pressure even at the room temperature.

Review Paper Based On Organic Vertical Farming With Aquaponic Model In Urban Areas

The modern agriculture is an evolving approach to new farming practices and agricultural innovations. Vertical and organic farming have gained significant attention due to their potential address the challenges of limited space, water scarcity and the need for sustainable food production whereas hydroponics, aeroponics and aquaponics are innovative cultivation methods that offer efficient and environmentally friendly solutions. Hydroponics involves growing plants in a nutrient water rich water solution, eliminating the need for soil. Aeroponics takes the concept further by suspending plant roots in a moist environment, where nutrient rich solutions are directly sprayed onto the roots. Aquaponics combines hydroponics with aquaculture, creating a symbiotic system where fish or aquatic animals provide nutrients for the plants, while plants filter and purify the water for fish. The combination of this new innovative agricultural practices offers numerous benefits includes higher crop yield, reduce water consumption etc. Further research and development in these areas are essential to optimize system designs, increases productivity and make these methods more accessible.

Simultaneous visual and spectroscopic multi-analyte detection of Al3+ and AsO2− using simple salicylidene based D-π-A chromophore

The salicylidene-isoniazide Schiff base D-π-A chromophore ( L1 ) exhibits chromogenic and fluorogenic dual responsive behaviour with multiple ICT-PET-ESIPT interplaying sensing mechanism and provides diverse optical signals promising to selectively and simultaneously track multiple analytes in water rich media. • Salicylidene-isoniazide Schiff base ( L1) exhibited naked-eye detectable distinctive colour changes for Al 3+ and AsO 2 - • It displayed turn-on type distinct fluorogenic response for both Al 3+ and AsO 2 - • Multiple ICT-PET-ESIPT interplaying mechanism provided diverse optical signals to simultaneously track multiple analytes. • Applied for fluorescence imaging of Al 3+ and AsO 2 - in living cells. The present communication reports the efficacy of a salicylidene-isoniazide Schiff base based donor-π-acceptor (D-π-A) chemosensor ( L1 ) for chromogenic and fluorogenic dual mode sensing of Al 3+ and AsO 2 - in water rich semi-aqueous solution. L1 offers multiple benefits of simplicity, ease of synthesis, inexpensive, suitable binding sites for cations and anions, high sensitivity, noteworthy colourimetric response, naked-eye detection, selectivity, and good detection limits of 1.89 μM for Al 3+ and 2.2 μM for AsO 2 - . It shows selective turn-on fluorescence response for both Al 3+ and AsO 2 - , attributed to CHEF due to the combined effect of arrest of PET, inhibition of -CH=N- geometrical isomerization, prevention of ESIPT process and increase in conformational rigidity. Owing to specific interaction between Mo(VI) and arsenite, L1 -Mo(VI) ensemble system is successfully utilized for colourimetric detection of arsenite through displacement approach. The binding modes of the receptor L1 to these analytes are established through Job’s plot and 1 H-NMR spectroscopic analysis. The reversible off-on-off fluorescence switching behaviour of L1 upon binding to Al 3+ and AsO 2 - are applied to construct combinational OR, AND, and NOT molecular logic gates. Fluorescence turn-on sensing, cell permeability and low toxicity of the chemosensor allows monitoring of these analytes in living cells.

Effect of the Temperature and Tetrahydrofuran (THF) Concentration on THF Hydrate Formation in Aqueous Solution

The knowledge of the mechanism of clathrate hydrate formation is crucial for studying the formation of a natural gas hydrate and developing hydrate-based technologies. In this study, low-field nuclear magnetic resonance (NMR) is applied to observe the processes of tetrahydrofuran (THF) hydrate formation from the solutions with different THF concentrations, and from the analysis of the NMR transverse relaxation time (T2) of hydrates and solutions, the formation mechanism of THF hydrate is discussed. A quantitative relationship between the NMR T2 spectral area and the mass of THF hydrate is established, and it is applied to estimate the hydrate amount in the formation process of THF hydrate. The results obtained show that T2 of THF solution is controlled by the temperature and THF concentration: longer at a higher temperature and shorter at a higher THF concentration. Moreover, the initial THF concentration does not affect the final concentration of the remaining solution after hydrate crystallization, and the formation of THF hydrate from solution follows the thermodynamics of solution reaction, with the THF concentration of the solution ending at the phase line after hydrate crystallization. The kinetics of THF hydrate formation is affected by the temperature and THF concentration: a higher formation rate in the solution with stoichiometric composition (19.06 wt % THF) of THF hydrate than either THF-rich or water-rich solution and a lower formation rate at a higher temperature.

New State-Diagram of Aqueous Solutions Unveiling Ionic Hydration, Antiplasticization, and Structural Heterogeneities in LiTFSI-H2O.

Here, we report a new state-diagram for aqueous solutions based on concentration-dependent glass-transition temperatures of concentrated and ice freeze-concentrated solutions. Different from the equilibrium phase diagram, this new state-diagram can provide comprehensive information about the hydration numbers of solutes, nonequilibrium vitrification/cold-crystallization, and vitrification/devitrification processes of aqueous solutions in three distinct concentration zones separated by two critical water-content points of only functions of the hydration number. Based on this new state-diagram, we observe the comparable hydration ability of LiTFSI to LiCl and an atypical concentration-dependent cold-crystallization behavior of the LiTFSI-H2O system. These results unveil the negligible hydration ability of TFSI- in a water-rich solution, characterize the antiplasticizing effect of water induced by the strengthened Li+-TFSI--H2O interaction when only hydration water and confined water are present, and confirm the increasing fraction of water-rich domains with the decrease in water content when the cation and anion become incompletely hydrated on average. These results highlight the novel water-content-mediated interactions among the anion, cation, and H2O for LiTFSI-H2O.

Review on Hydroponic Feed Value to Livestock Production

In agriculture hydroponics is an advanced technology. Hydroponic production is used to guarantee a constant production of high quantity of green forage throughout the year for livestock feed with suitable prices. Therefore, this review aims to review hydroponic feed value on livestock production. Hydroponics is a technique of growing of plants without soil but in water or nutrient rich solution in a greenhouse. This fodder increases up to 20-30cm height consisting of roots, seeds and plants. About 1.50-3.0 liters of water is required to produce one kg of fresh hydroponics fodder in seven days since water can be reused. However, DM content of 11-14% is common for hydroponics maize and yields of 5-6 folds on fresh basis. Since the hydroponics, fodder is more palatable, digestible and nutritious while imparting other health benefits to the animals and improve production performance of livestock. The cost of seed contributes about 90% of the total cost of production of hydroponics maize fodder as compared to conventional which is much lower. Supplementing is 5-10 kg fresh hydroponics maize fodder per cow per day. Digestibility of the nutrients of the ration could increase in milk production (8- 13%) by feeding hydroponics fodder. Hydroponics fodder can be produced by farmers to feed their dairy animals using low cost diet in situations, where conventional green fodder cannot be grown successfully. Therefore, there is a need for more research and development endeavor for better utilization in the future.

A liquid-liquid transition in supercooled aqueous solution related to the HDA-LDA transition.

Simulations and theory suggest that the thermodynamic anomalies of water may be related to a phase transition between two supercooled liquid states, but so far this phase transition has not been observed experimentally because of preemptive ice crystallization. We used calorimetry, infrared spectroscopy, and molecular dynamics simulations to investigate a water-rich hydrazinium trifluoroacetate solution in which the local hydrogen bond structure surrounding a water molecule resembles that in neat water at elevated pressure, but which does not crystallize upon cooling. Instead, this solution underwent a sharp, reversible phase transition between two homogeneous liquid states. The hydrogen-bond structures of these two states are similar to those established for high- and low-density amorphous (HDA and LDA) water. Such structural similarity supports theories that predict a similar sharp transition in pure water under pressure if ice crystallization could be suppressed.

Structural properties of hydrogen-bond network in liquid formamide-water mixtures

Molecular dynamics simulations have been performed to investigate the structural properties of the extended hydrogen-bond (H-bond) network of liquid formamide(FA)-water(W) mixtures over the whole concentration range. Instruments of complex network analysis have been utilized to identify and quantify the structural aspects of the H-bond networks involving FA-FA, W-W, and FA-W H-bonding interactions. These include the degree distributions, the distributions of network neighborhood numbers up to the second order, and the geodesic distributions. Collectively, they provide information regarding not only the local H-bonding environment of the species but also the H-bonding environment beyond their immediate neighbors. These analyses revealed that although the connectivity patterns within the H-bond network of the mixtures are altered significantly with the composition, the degree of connectivity of the networks are well maintained. Neighborhood analysis revealed that in the water rich solution nearly all FA molecules form the H-bonded clusters of the form FA⋯W⋯W and that the H-bonded cluster [W⋯W⋯FA⋯FA⋯W⋯W ] is the dominant structural motif involving FA dimers. According to the geodesic analysis, population of the chain-like H-bond pathways composed of one type of molecular species increases with the increasing mole fraction of the other type of species, until the mixture reaches the equimolar composition.

Fouling prevention in the membrane distillation of phenolic-rich solution using superhydrophobic PVDF membrane incorporated with TiO2 nanoparticles

Membrane distillation (MD) was applied to concentrate phenolic rich solution because of the requirement of low pressure and temperature. However, fouling occurred and caused a great drop in permeate flux using the neat PVDF membrane. The PVDF/TiO2 membranes with and without silane modification were fabricated and their separation performance, fouling and self-cleaning property were evaluated. The TiO2 nanoparticles were either pre-modified before blending into PVDF casting solution or post-modified after phase inversion. The water contact angle of the pre-modified membrane was 151° while the post-modified membrane achieved near superhydrophobicity (140°). The separation performance of these membranes in MD was tested using pure water or phenolic rich solution (100 g/L gallic acid) for 8 h. All the membranes exhibited superior phenolic rejection of 99%. The pre-modified and post-modified PVDF/TiO2 membranes showed less flux decline (17% and 12%, respectively) compared to the neat PVDF membrane and the unmodified PVDF/TiO2 membrane. However, the post-treated PVDF/TiO2 membrane achieved the highest permeates flux due to the formation of great porosity in phase inversion without the disturbance of silane modification. As shown in the scanning electron microscope images, the neat PVDF membrane with large pore size experience serious pore plugging. Meanwhile, the internal pore blocking could occur in the unmodified PVDF/TiO2 membrane because of membrane wetting. All the membranes with TiO2 could be easily cleaned under UV light and they achieved flux recovery ratio more than 0.9.

Time-Resolved Spectroscopic and Density Functional Theory Study of the Photochemistry of Irgacure-2959 in an Aqueous Solution

The photocleavage reaction mechanism of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure-2959) was investigated using femtosecond (fs) and nanosecond (ns) transient absorption (-TA) spectroscopy and also picosecond (ps) and nanosecond (ns) time-resolved resonance Raman (-TR(3)) spectroscopy experiments in a water-rich (volume ratio of acetonitrile/water = 3:7) solution. TA spectroscopy was used to study the dynamics of the benzoyl radical growth and decay as well as to investigate the radical quenching process by the radical scavenger methyl acrylate. ps- and ns-TR(3) spectroscopies were employed to monitor the formation of the benzoyl radical and also to characterize its electronic and structural properties. The fs-TA experiments results indicate that the Irgacure-2959 lowest lying excited singlet state S1 underwent efficient intersystem crossing (ISC) to convert into its triplet state with a time constant of 4 ps. Subsequently, this triplet species dissociated into the benzoyl and alkyl radicals with a corresponding maximum absorption band at 415 nm. The TR(3) results in conjunction with results from DFT calculations confirmed that Irgacure-2959 cleaved into the benzoyl and alkyl radicals at a fast rate on the tens of picosecond time scale.

Evaporation triggered self-assembly in aqueous fragrance–ethanol mixtures and its impact on fragrance performance

The present study demonstrates how the evaporation of a ternary ethanol–water–fragrance solution leads to a transition from an unstructured ternary ethanol-rich solution, to a structured water-rich solution by crossing the so-called pre-ouzo region of its phase diagram. The exothermal nature of this self-assembly revealed by calorimetry suggests that it is coupled to molecular transfer between coexisting micro-domains.Surprisingly, fragrance evaporation is first accelerated in the pre-ouzo region as evidenced unambiguously by simultaneous on-line gravimetric, calorimetric and gas chromatographic monitoring during drying. Upon further drying, a transition from the pre-ouzo to the two-phase turbid region of the phase diagram is observed as the loss of water becomes more important that of ethanol. At this stage, the size of the fragrance-rich domain increases by three orders of magnitude as fragrance droplets surrounded by ethanol molecules are entrapped in water-rich external media and the fragrance evaporation is depressed.This initial acceleration and subsequent retardation of the evaporation kinetics of fragrance molecules are general for all perfumery ingredients. The path of the compositional change in the phase diagram during evaporation is investigated under strong inert gas flux for the first time to our knowledge by two combining on-line methods.

Effect of Water Content in Mobile Phase on Chromatographic Behaviors of Low Molecular Compounds in RP-HPLC using Methacrylate-based Monolithic Column

The effect of water content in a mobile phase on chromatographic behavoirs was studied with a monolithc stationary phase of poly(butyl methacrylate-co-ethylene dimethacrylate). A drastic decrease in the separation efficiency was observed when the water content was up to 90%, i.e., 10% acetonitrile (ACN) aqueous solution. Interestingly, the magnitude of the efficiency decrease significantly depended on the retention factor of the analytes, in particular, the separation efficiencies of the slightly retained compounds (0.1 < k < 1, in 10% ACN) were inferior. Furthermore, with a mobile phase of 10% ACN, the acceleration of the flow rate decreased the retention factor of these less retained compounds. The higher flow rate suppressed the interaction in RP-HPLC only when the water rich solution was used. The reduction in the retention factor produced non-theoretical relations in an H-u plot. The change in the monolith structure was also indicated by the variation in the permeability in 10% ACN.

Direct molecular diffusion and micro-mixing for rapid dewatering of LiBr solution

A slow molecular diffusion rate often limits the desorption process of an absorbate molecule from a liquid absorbent. To enhance the desorption rate, the absorbent is often boiled to increase the liquid–vapor interfacial area. However, the growth of bubbles generated during the nucleate boiling process still remains mass-diffusion limited. Here, it is shown that a desorption rate higher than that of boiling can be achieved, if the vapor–absorbent interface is continuously replenished with the absorbate-rich solution to limit the concentration boundary layer growth. The study is conducted in a LiBr–water solution, in which the water molecules' diffusion rate is quite slow. The manipulation of the vapor–solution interface concentration distribution is enabled by the mechanical confinement of the solution flow within microchannels, using a hydrophobic vapor-venting membrane and the implementation of microstructures on the flow channel's bottom wall. The microstructures stretch and fold the laminar streamlines within the solution film and produce vortices. The vortices continuously replace the concentrated solution at the vapor–solution interface with the water-rich solution brought from the bottom and middle of the flow channel. The physics of the process is described using a combination of experimental and numerical studies.

Preparation of chabazite membranes by secondary growth using zeolite-T-directed chabazite seeds

Chabazite crystals were directly prepared from template-free aluminosilicate gel with the addition of nano-sized zeolite T (∼100nm). This new route requires only one thirtieth seeds amount for a certain product, and one twentieth synthesis time compared with the classic one by the conversion of zeolite Y crystals. A pure and dense chabazite membrane was prepared on macroporous supports by secondary growth. The membrane synthesis parameters such as seeds, supports and synthesis time on membrane formation and pervaporation performance were also studied. Eight chabazite membranes prepared on macroporous stainless-steel supports showed a high average flux of 3.4kgm−2h−1 and high average selectivity of 2100 with low deviations on the flux and selectivity for a water/ethanol (10/90wt%) mixture at 75°C, indicating membrane synthesis using stainless-steel supports had a good reproducibility. The as-synthesized chabazite membranes also showed good hydrothermal stability under pervaporation test in a water-rich ethanol aqueous solution.

Spontaneous emulsification between incompatible aqueous solutions in the water/ethanol/benzene system

Two aqueous solutions on the de-mixing line in the water/benzene/ethanol system formed an O/W emulsion, when mixed. Contacting the solutions without mixing gave a slow spontaneous emulsification over several hours. The emulsion in question was found exclusively in the solution of greater water fraction and the dimension of the emulsion layer expanded as the square root of time. The reduction in the volume fraction the solution with less water was divided by the volume fraction of the emulsion, giving an – albeit exaggerated - measure of the volume fraction of the dispersed phase in the emulsion. It reached 0.6 after 1h, after which it remained constant for 3h. The composition change from the initial stage to the final equilibrium was calculated using a combination of the phase diagram features and earlier diffusion flux calculations in a similar system to estimate the fraction of the compounds transferred between the layers. These transfers were unexpectedly clear-cut, 95wt% of the water in the less water solution was transferred into the water rich solution as was 80% of the ethanol. In the same manner 95% of the benzene in the water rich solution was relocated into the water poor solution.

Elution Behavior of Lambda-DNA with Ternary Mixed Carrier Solvents in an Open-Tubular Capillary under Laminar Flow Conditions

An open-tubular capillary chromatography was developed based on the tube radial distribution of the ternary mixed carrier solvents that generated the inner and outer phases under laminar flow conditions. This is called "tube radial distribution chromatography" (TRDC). In this report, the elution behavior of lambda-DNA (48502 bp) as a biopolymer was examined by the TRDC system. The ternary mixture of water-acetonitrile-ethyl acetate, 15:3:2 or 3:8:4 volume ratio, as a carrier solution was fed into the capillary tube made of polytetrafluoroethylene (PTFE) or fused-silica. The mixture of hydrophobic 1-naphthol and hydrophilic lambda-DNA was subjected to the TRDC system using the water-rich carrier solution. Lambda-DNA and 1-naphthol were distributed between the inner and outer phases due to their hydrophilic and hydrophobic nature, and then eluted in this order, undergoing chromatographic separation. The mixture of hydrophilic 2,6-naphthalenedisulfonic acid and hydrophobic lambda-DNA that was treated with surfactants was also examined with the organic solvent-rich carrier solution. The modified hydrophobic DNA and 2,6-naphthalenedisulfonic acid were distributed and eluted in this order due to their nature.

Biomolecule Analyses in an Open-Tubular Capillary Chromatography Using Ternary Mixed Carrier Solvents with Chemiluminescence Detection

We examined the elution behavior of isoluminol isothiocyanate (ILITC)-labeled biomolecules (α-amino acids, peptides, and proteins) in an open-tubular capillary chromatography system using an untreated fused-silica capillary tube and a water-acetonitrile-ethyl acetate mixture carrier solution. Such an open-tubular capillary chromatography is called "tube radial distribution chromatography (TRDC)" for convenience. A mixture of ILITC and ILITC-labeled biomolecules was analyzed using TRDC with chemiluminescence detection that provided simple instrument without a light source and complex optical devises. The ILITC and the labeled twenty α-amino acids were separated, in this order or the reverse order, or not separated with an organic solvent-rich and water-rich carrier solution. Their elution behavior was considered to be of hydrophilic or hydrophobic nature of ILITC and the labeled α-amino acids. The ILITC and the labeled protein, alcohol dehydrogenase and bovine serum albumin, were separated in this order with an organic solvent-rich carrier solution, while they were eluted in the reverse order with a water-rich carrier solution, based on the TRDC separation performance. The TRDC system worked with the untreated open-tubular capillary tube not using any specific capillary tubes, such as coated, packed, or monolithic.

Effects of Tube Materials on Capillary Chromatography Based on Tube Radial Distribution of Ternary Mixture Carrier Solvents under Laminar Flow Conditions

A capillary chromatography system was developed using an open capillary tube and a ternary solvents carrier solution of water-hydrophilic/hydrophobic organic solvent mixture. The chromatography is called a tube radial distribution chromatography (TRDC) system. The TRDC system works without applying high voltages or using specific columns, such as monolithic and packed columns. In this study, the effects of tube materials on separation performance were examined in the TRDC system, by using poly(tetrafluoroethylene) (PTFE; 100–400 μm inner diameter), polyethylene (PE; 200 μm inner diameter), and copolymer of (tetrafluoroethylene–perfluoroalcoxyethylene) (PTFE–PFAE; 100 μm inner diameter) capillary tubes. An analyte solution of 2,6-naphthalenedisulfonic acid and 1-naphthol as a model was subjected to the system with a water–acetonitrile–ethyl acetate carrier solution; 15:3:2 volume ratio (water-rich carrier) and 3:8:4 volume ratio (organic solvent-rich carrier). The flow rates were adjusted to be 0.5 μL min−1 for PTFE and PTFE–PFAE tubes as well as 2.0 μL min−1 for PE tube under laminar flow conditions. These analytes in the solution were separated in this order with the water-rich carrier solution with baseline separation in the three capillary tubes, while they were eluted in the reverse order or not separated with the organic solvent-rich carrier solution. The effects of tube temperature on separation were also examined with the water-rich carrier solution; the best resolutions were observed at 0 °C of the tube temperature. The obtained results were compared with those of fused-silica capillary tube and discussed.

Separation of dansyl-dl-amino acids by open tubular capillary chromatography based on tube radial distribution phenomenon of the ternary mixed carrier solvents

Separation of enantiomers, dansyl-DL-amino acids, was carried out by open-tubular capillary chromatography based on the tube radial distribution of the carrier solvents. An untreated poly(tetrafluoroethylene) capillary tube (100 μm inner diameter and 90 cm effective length) as a separation column and a water–acetonitrile–ethyl acetate mixture containing cyclodextrin as a carrier solution were used in the chromatography. An analyte solution of dansyl-DL-amino acids, such as dansyl-DL-methionine, was injected into the capillary tube by a gravity method. The analyte solution was subsequently delivered through the capillary tube with the carrier solution by a microsyringe pump. The ternary mixed carrier solution (water-rich carrier solution) was radially distributed in the capillary tube based on the tube radial distribution phenomenon, causing the formation of inner (water-rich) and outer (organic solvent-rich) phases. The outer or capillary wall phase acted as a pseudo-stationary phase in the chromatography. The analytes were separated through the capillary tube with on-capillary detection by an absorption or a fluorescence detector. The D-enantiomer and the L-enantiomer were eluted in this order with a baseline separation. The separation mechanism of the enantiomers in the open-tubular capillary using cyclodextrin was discussed.

Fluidic Behavior of Polymer Compounds in an Open-Tubular Capillary with Ternary Mixed Carrier Solvents under Laminar Flow Conditions

An open-tubular capillary chromatography is developed based on tube radial distribution of the ternary mixed carrier solvents of water-hydrophilic/hydrophobic organic under laminar flow conditions. This is called “tube radial distribution chromatography” (TRDC). Fluidic behavior of the polymer compounds, FluoSpheres (1.0 m diameter), was examined by the TRDC system. The ternary mixture of water-acetonitrile-ethyl acetate, 15:3:2 (water-rich) or 3:8:4 (organic solvent-rich) volume ratio, as a carrier solution was fed into the fused-silica capillary tube under laminar flow conditions. The peak of the FluoSpheres appeared with the apex at the maximum linear velocity and the slope of the non-Gaussian peak did not last longer than the elution time at the average linear velocity with the water-rich carrier solution. With the organic solvent-rich carrier solution FluoSpheres was eluted at near the average linear velocity.