Liquid Solution Research Articles

Emission of Protonated Riboflavin Induced by Inhibition of Out-of-plane Vibration in a Rigid Polymer Network.

Chromophores incorporated into rigid polymer matrices may exhibit novel photophysical properties distinct from those in liquid solutions. In this work, we explored the decay path of the second ππ* state (2ππ*) of riboflavin in poly(vinyl alcohol) (PVA) solutions and films with various acidities. Highly efficient internal conversion from 2ππ* to the lowest ππ* state (1ππ*) induced by slight in-plane motion is demonstrated in all PVA solutions and films, irrespective of environmental acidity and rigidification. Ground-state protonation of riboflavin occurs in the highly acidic PVA film, and this cationic species emits fluorescence around 460 nm, in contrast to the ultrafast nonradiative relaxation in aqueous solution. The emission is demonstrated to originate from the 2ππ* state rather than the 1ππ* state. The 2ππ*-1ππ* internal conversion of protonated riboflavin is demonstrated to be induced by out-of-plane motion and impeded in a rigid PVA network, resulting in the anti-Kasha fluorescence.

Gas and Liquid Isotherms: The Need for a Common Foundation.

Sorption isotherms for gases and liquids have long been formulated separately. There is a fundamental problem with this approach: the popular isotherm models (such as Langmuir, BET, and GAB) for gases cannot be applied straightforwardly to sorption from solution. This contrasts with the theory of liquid solutions, where solute-solute interaction, mediated by the solvent, is captured as the potential of mean force, providing powerful interpretive tools (e.g., virial expansion) founded on the gas-liquid analogy. This analogy will be extended to sorption by adopting sorbate numbers and their fluctuations as the common foundation. This enables the gas and liquid isotherm equations to have an analogous mathematical form with a universal language for interfaces and liquid solutions.

Development of a CFD simulation for the analysis of CO2 separation percentage using novel [emim][C2N3] ionic liquid solution inside the gas–liquid contactor

Growing emission of environmentally-hazardous greenhouse pollutants (especially CO2) has motivated the researchers to apply gas–liquid membrane contactors as an easy-to-operate and cost-effective technique for increasing their separation efficiency from different sources. In the current decades, ionic liquids (ILs) have shown their potential in the gas separation industry owing to their noteworthy advantages such as great capacity, excellent adjustability and suitable thermal/chemical stability compared to commonly-employed amine absorbents. This investigation aims to analytically/numerically determine the separation yield of CO2 from CO₂/N2 gaseous flow using novel -Ethyl-3-methylimidazolium dicyanamide ([emim][C2N3]) IL inside the gas–liquid contactor. To fulfill the ultimate purpose, a CFD simulation has been proposed using COMSOL Multiphysics software to predict the results. Comparison of model outcome with experimental data has shown brilliant concurrence with the average relative deviation of almost 5%. Evaluation of the results has shown the excellent performance of [emim][C2N3] IL for the removal of CO2 (Separation efficiency of around 100%). Finally, the effects of some module/membrane parameters on increasing or decreasing the separation efficiency has been studies in detail.

IMPROVING ENTREPRENEURSHIP KNOWLEDGE OF STUDENTS IN MEULABOH STATE VOCATIONAL HIGH SCHOOL 3 WITH LIQUID DISH WASHER SOAP MAKING TRAINING

Liquid dishwashing soap is a liquid solution that contains surfactants that function to remove dirt, grease, and food residue from the surface of eating utensils such as plates, glasses, etc. The need for liquid dishwashing soap is increasing because it is easier to use, cleaner, and more hygienic. Currently, many basic ingredients for making liquid dishwashing soap are sold on the market, so people can make their own so that it is more economical and easier to obtain. This activity aims to improve the entrepreneurial spirit of vocational school students so that they can produce dishwashing soap products and market them through schools so that they can produce independent students after completing their schooling at vocational school by selling the liquid dishwashing soap products to the market or surrounding housewives. The training method for making dish soap products is the Production Based Training (PBT) method, a learning model that emphasizes direct practice and production. In this training, students will use materials and work tools in a simulated environment. This method is also carried out using theory classes, practical demonstrations, and guided exercises. In this training, liquid dishwashing soap was directly made using the necessary ingredients such as Texapon, Email Needle, Natrium Chloride (NaCl), Anti-Bacterial, Perfume Seeds, liquid/powder dye, and Mineral Water. This training process produces approximately 20 liters of liquid dishwashing soap. Apart from that, this dishwashing soap also has quite a large economic value so it can be a solution to improve the community's economy at a lower price compared to the price of factory production which is already sold on the market. This training can provide enthusiasm and stimulate entrepreneurship to vocational high school students.

Thermodynamic and Transport Properties of Lithium Bromide in Aqueous Solutions of Protic Ionic Liquids Based on 2-Hydroxyethylammonium Propionate at Different Temperatures

Thermodynamic and Transport Properties of Lithium Bromide in Aqueous Solutions of Protic Ionic Liquids Based on 2-Hydroxyethylammonium Propionate at Different Temperatures

Investigating the Restricted Dynamical Environment in and Around Aβ Peptide Oligomers in Aqueous Ionic Liquid Solutions.

It is widely believed that the aggregation of amyloid β (Aβ) peptides into soluble oligomers is the root cause behind Alzheimer's disease. In this study, we have performed room-temperature molecular dynamics (MD) simulations of aggregated Aβ oligomers of different sizes (pentamer (O(5)), decamer (O(10)), and hexadecamer (O(16))) in binary aqueous solutions containing 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid (IL). Investigations have been carried out to obtain a microscopic understanding of the effects of the IL on the dynamic environment around the exterior surfaces and within the confined nanocores of the oligomers. The calculations revealed that in contrast to nearly uniform dynamics near the exterior surface, heterogeneous structural distortions of oligomers of varying sizes and nonuniform distributions of water and IL components within their core volumes modify the core dynamics in a differential manner. It is demonstrated that increasingly restricted mobility of water and IL components is the origin behind the longer time scale of dynamic heterogeneity in and around the oligomers. Importantly, due to the equivalent nondirectional nature of the B-F bonds, BF4- anions are found to reorient on a time scale faster than that of water molecules. Further, the structural relaxation of protein-anion (PA) hydrogen bonds around the oligomers has been found to be correlated with sluggish translational motions of the anions but anticorrelated with their reorientational time scale. In addition, it is quantified that compared to the pure aqueous medium, strengthening of protein-water (PW) hydrogen bonds in the presence of the IL leads to their longer lifetimes.

Comparing Above and Underwater Visibility of Fluorescent Quinine-Based Liquid and Solid Tracers to Estimate Suspended Sediment Concentrations Under Low Luminosity Conditions

While exploring the use and visibility of fluorescent tracers for estimating flow velocities under varying water turbidity, this study introduces a technique for estimating suspended sediment concentration (SSC) in water. Laboratory and field experiments were conducted using a dual above/underwater optical camera monitoring system to measure and compare the visibility (brightness intensity) of fluorescent tracers applied into water under varying SSC loads. Based on the fluorescent properties of quinine under low luminosity conditions, a quinine solution, in both liquid and solid (ice cube) states, was applied to the water surface. Its visibility was recorded using the monitoring system, and brightness intensity was quantified using image processing techniques such as grayscale conversion, object segmentation, and pixel intensity extraction. Results indicate that the tracer brightness intensity decreases as SSC loads increase, with the underwater camera recording lower visibility than the above-water camera, particularly at higher SSC loads. Empirical regression equations were developed to describe the relationship between the tracer brightness intensity recorded by the underwater camera and the SSC loads. These findings suggest the ability of the presented monitoring system, using quinine solution in both liquid and solid states, along with an underwater camera, to estimate a relevant range of SSC loads under low luminosity conditions.

Visible Light Spectroscopy of Liquid Solutes from Femto- to Attoliter Volumes Inside a Single Nanofluidic Channel.

UV-vis spectroscopy is a workhorse in analytical chemistry that finds application in life science, organic synthesis, and energy technologies like photocatalysis. In its traditional implementation with cuvettes, it requires sample volumes in the milliliter range. Here, we show how nanofluidic scattering spectroscopy (NSS), which measures visible light scattered from a single nanochannel in a spectrally resolved way, can reduce this sample volume to the attoliter range for solute concentrations in the mM regime, which corresponds to as few as 105 probed molecules. The connection of the nanochannel to a microfluidic in-and-outlet system enables such measurements in continuous flow conditions, and the integrated online optical reference system ensures their long-term stability. On the examples of the nonabsorbing solutes NaCl and H2O2 and the dyes Brilliant Blue, Allura Red, and Fluorescein, we demonstrate that spectral fingerprints can be obtained with good accuracy and that solute concentrations inside the nanochannel can be determined based on NSS-spectra. Furthermore, by applying a reverse Kramers-Kronig transformation to NSS-spectra, we show that the molar extinction coefficient of the dye solutes can be extracted in good agreement with the literature values. These results thus advertise NSS as a versatile tool for the spectroscopic analysis of solutes in situations where nanoscopic sample volumes, as well as continuous flow measurements are critical, e.g., in single particle catalysis or nanoscale flow cytometry.

Influence of water on liquid ammonia-based sustainable dyeing of ramie fiber

Liquid ammonia dyeing emerges as an environmentally benign and sustainable option for the textile industry, characterized by a minimal ecological impact. However, its adoption is hampered by certain limitations, such as suboptimal dye exhaustion and issues with color uniformity, which present significant hurdles to its widespread industrial application. Building on the premise that the addition of water to an ethanol solvent can enhance reactive dye exhaustion in cotton fiber dyeing, this study delves into the dyeing behavior of ramie fiber using a water-liquid ammonia mixture with Reactive Red 195. The incorporation of water into the liquid ammonia solution was observed to marginally decrease the color strength (K/S value) of the dyed ramie fiber, compared to the dyeing with anhydrous liquid ammonia. This reduction is likely due to the diminished expansion of the amorphous regions within the fiber. However, the color levelness of the dyed ramie fiber was enhanced by the addition of water to the liquid ammonia. To decipher the influences on the dyeing process, the Taguchi method, utilizing an orthogonal array (L16), was applied. The analysis revealed that the dye mass factor was the predominant influencer (79.08 %), followed by the liquor ratio factor (18.53 %), with both factors demonstrating statistically significant effects (p < 0.05). A multifaceted analysis of the samples was conducted using advanced techniques such as XRD (X-ray diffraction), FTIR (Fourier transform infrared), TGA (thermogravimetric analysis), and SEM (scanning electron microscopy). These analyses confirmed that the water-liquid ammonia treatment induced changes in the samples’ properties. The treated samples exhibited lower barium activity numbers and breaking force values, indicating structural alterations. Furthermore, the molecular structure of Reactive Red 195 remained intact throughout the dyeing process in the water-liquid ammonia mixture, thereby affirming its viability for practical applications in the textile industry.

Effect of one-part geopolymer filler on the performance of cold bitumen emulsion mixtures

ABSTRACT This study aims to assess the performance of cold bitumen emulsion mixtures modified with a one-part geopolymer based on blast furnace slag and an alkaline activator. This material is generally prepared in a liquid solution, from an aluminosilicate source and an alkaline compound, and is dedicated to the precast sector. In this study, it was obtained by mechanosynthesis, a solvent-free process consisting of high-energy ball milling. The powder was incorporated as a filler in the formulation of 0/10 asphalt mixes. Other cold mixtures with limestone and blast furnace slag filler were manufactured to evaluate the influence of the additive nature on the cohesive strength at different curing times, compressive strength, water sensitivity, rutting resistance and resilient modulus. The potential chemical reactivity between each filler and each emulsion was monitored by in situ Fourier transform infrared spectroscopy. The results pointed out that the cohesive strength of the mixes containing one-part geopolymer is two to three times higher than that of the other formulations after 24 h curing. High compressive strength of the one-part geopolymer-based mixes is noticed; however, their compressive strength ratio is slightly lower, in comparison with the other mixes. The rutting percentage of the one-part geopolymer-based mixes reaches 4% at 30,000 cycles and their resilient modulus above 6,000 MPa at 15 °C. These results are attributed to the geopolymerisation reaction occurring between the filler and the emulsion, traduced by a shift in infrared spectroscopy. Therefore, the addition of one-part geopolymer filler, produced according to a non-solvent process, is a promising solution to enhance the implementation and durability of cold mixtures.

Polyethylene Glycol (PEG) Application Triggers Plant Dehydration but Does Not Accurately Simulate Drought.

Polyethylene glycol (PEG), especially at high molecular weights, is highly soluble in water, and these solutions have reduced water potential. It is convenient to use PEG in hydroponics (liquid nutrient solution) for experiments with plants. However, some authors have been found to describe the application of PEG to plants incorrectly, such as drought, dehydration, osmotic, or water stresses, which can mislead readers. The presented opinion paper shows our arguments for a terminology in such experiments that is strictly limited to 'PEG-induced' or 'simulated' or 'mimicked' dehydration, and osmotic or water stresses, with the best option being 'PEG-induced dehydration'. The most popular term, 'drought', is inappropriate to be used for hydroponics at all, with or without PEG. Traditionally, drought stress study was related to only plants in soil or other substrates mixed with soil. Based on 139 published papers, the examples presented in our opinion paper can demonstrate differences in gene expression between plants grown in containers with soil and under PEG-induced stress in hydroponics. Researchers can carry out any type of experiments suitable for the purposes of their study. However, clear and correct description of experiments and careful interpretation of the results are strongly required, especially with PEG, to avoid incorrect information. In all cases, at the final stage, results of experiments in controlled conditions have to be verified in field trials with naturally occurring drought.

Numerical exploration of performance enhancement in falling film liquid desiccant cooling system using additive materials

ABSTRACT Liquid desiccant dehumidification has garnered significant attention due to its numerous benefits. This study focuses on enhancing the efficiency of liquid desiccant dehumidification through the use of modified solutions, particularly by incorporating polyvinyl pyrrolidone (PVP) as an additive. PVP is a nonvolatile, odorless, and nontoxic surfactant that was selected to enhance the dehumidification performance of the liquid desiccant system. Computational fluid dynamics was employed to investigate the dehumidification performance of falling film liquid desiccant systems. The study aims to assess the impact of PVP, solution parameters, and moist air conditions (humidity concentration, temperature, and flow rate) on dehumidification effectiveness. The specific objectives of the numerical simulation include analyzing performance metrics such as dehumidification rate and effectiveness to evaluate the enhancement in the falling film liquid desiccant cooling system. The selection of lithium chloride (LiCl) as the base solution and PVP as an additive at 0.4 wt% is highlighted as a key aspect of the study. The findings indicate that PVP significantly improves dehumidification effectiveness by reducing the contact angle of liquid solution on the surface plate and increasing the surface wetting ratio, thereby enhancing moisture transfer capacity. Optimal dehumidification performance is achieved with the combination of LiCl and PVP at the specified concentration. The study reveals that increasing solution or air inlet temperature reduces the dehumidification rate, while raising solution or air inlet concentration, velocity, or air humidity strengthens the dehumidification process. Additionally, the efficacy of dehumidification increases with solution velocity but decreases with solution intake concentration or air velocity. Overall, the results demonstrate an average relative increase of 21.6% in dehumidification rate and 17.4% in dehumidification effectiveness, underscoring the effectiveness of PVP in enhancing vapor absorption capability and overall system efficiency in Liquid Desiccant Cooling systems (LDCs). This enhancement is attributed to the reduction in surface tension of the liquid desiccant, as evidenced by the decrease in contact angle from 58.6° to 28.9°.

Optimization of preventive maintenance in the design of photovoltaic plants

Two of the biggest problems worldwide are electrical energy and water, in this context the use of photovoltaic systems for the generation of electrical energy is increasingly profitable due to the constant reduction of prices in terms of the dollar watt and that supports the solution to the problem of energy supply at increasingly affordable prices. In this same scenario we have a reduction in CO2 emissions, contributing to the reduction of greenhouse gases, supporting the Kyoto protocol and the Paris agreement. On the other hand, the incorporation of ionized air for cleaning the photovoltaic modules allows the use of natural and demineralized water to be reduced to levels of around 98%, which allows us to be on par in saving solutions for this vital liquid.

Turfgrass quality, growth rates, and annual bluegrass contamination as affected by seasonal fertilizer distribution on red fescue putting greens

AbstractRed fescue (Festuca rubra L.) is the preferred turfgrass species for low‐input golf course putting greens in Northern Europe. While it is well recognized that fescue requires less fertilizer than bentgrasses (Agrostis spp.) or annual bluegrass (Poa annua L.), the optimal fertilizer distribution throughout the growing season has not been investigated. Our objective was to determine the effects of three seasonal fertilizer distributions on turfgrass quality, seasonal growth rates, root development, and competition from annual bluegrass on a sand‐based red fescue putting green at the NIBIO (Norwegian Institute of Bioeconomy Research) Turfgrass Research Center, Landvik, Norway (58° N). All fertilizer treatments comprised weekly inputs of a complete, liquid fertilizer solution for a total of 11 g N m−2 year−1, but the inputs were distributed with (1) the highest weekly rates from early May to mid‐summer (SPRING+), (2) equal weekly rate from early May through late September (FLAT), or (3) the highest weekly rates from mid‐August to late September (FALL+). SPRING+ fertilization resulted in higher turfgrass quality, deeper roots, and, in the second experimental year, less annual bluegrass than FALL+ fertilization. The advantage of FALL+ fertilization was faster green‐up and enhanced growth in September, October, and April, but this came at the expense of more annual bluegrass. Results are discussed in light of previously published data on temperature and fertilizer requirements for the growth of red fescue versus annual bluegrass.

Viscoelastic Soft Solid Electrolytes Enable Fast Zinc Ion Conductance and Highly Stable Zinc Metal Anode

AbstractAchieving both high ionic conductance and stable Zn metal anode simultaneously remains a challenge with current liquid and solid electrolytes. Here, a viscoelastic soft solid electrolyte (VSSE) strategy is presented that effectively balances Zn ion conduction and Zn anode stability. The VSSE is created by nano‐SiO2 inducing a liquid‐to‐solid transition in a liquid solution containing Zn(BF4)2 salt dissolved in an oligomer (glycerol polyoxyethylene‐b‐oxypropylene ether, GPE) and water. The plentiful oxygen functional group in VSSE provides enough hydrogen bonding sites for water molecules to be completely hydrogen‐bonded to form a state without free water. The bound water serves as a Zn‐O coordination modulator that can weaken the strong Zn‐O coordination, lowering the dissociation energy for Zn ions, realizing fast Zn ion decoupling motion mode. Consequently, the VSSE gives impressive Zn ion conductance of (2.28 ± 0.07) ×10−3 S cm−1 at room temperature 10–1000 times higher than reported solid polymer electrolytes. Simultaneously, the restricted molecular activity of bound water allows for excellent storage/cycle life of the Zn metal anode, which is confirmed by remarkably improved storage life (720 h), shelving‐recovery lifespan (850–1200 h), and cycling life (1400–2050 h). This study offers fresh perspectives on multifunctional electrolyte design strategies based on soft‐matter science.

The Electronic Spin State of Diradicals Obtained from the Nuclear Perspective: The Strange Case of Chichibabin Radicals.

With a view towards the development of molecular spintronics, non-linear optics, and qubits, a great amount of research effort aims to establish the factors which govern the spin classification of diradicals. Electron spin resonance (ESR) is an indispensable tool for such research. However, in some cases, the mere presence of an ESR spectrum is insufficient to ascertain that the presumed diradical is indeed a triplet state. In a comparative case study of a Chichibabin diradical and a monoradical analogue, we show how the signals from different spin states present in liquid solutions of these species may be disentangled. Ultimately, the correct spin classification depends on ESR techniques which probe the spin quantum number directly. In this work, electron nuclear double resonance experiments reveal that the nuclei provide a clear experimental probe of the electronic spin configuration.

Solution rheology of poly(ionic liquid)s: current understanding and open questions

AbstractPoly(ionic liquid)s are ion-containing polymers possessing ionic liquid structures on their repeating units. Owing to the unique physicochemical properties of ionic liquids, many existing studies have found that the properties of poly(ionic liquid)s are distinct from those of conventional ion-containing polymers, such as poly(sodium styrene sulfonate). A lot of scientific efforts have been made to understand the relationship between the chemical structure and the material properties of poly(ionic liquid)s, and several good review papers are available in the literature. The aim of this short review is to summarize key results on the viscoelastic properties of poly(ionic liquid)s in solution. We discuss in detail the counterion condensation and the charge screening in poly(ionic liquid) solutions. Graphical Abstract

Treatment of liquid fertilizer solutions by electrohydraulic effect and assessment of increasing the efficiency of plant nutrition

Abstract The article discusses the issue of increasing the efficiency of plant nutrition by treating liquid organic and mineral fertilizers with an electro-hydraulic effect. The amount of nitrates in water is reduced to 1.1 mg/l due to electro-hydraulic treatment. This creates the possibility of feeding plants and at the same time eliminating E. coli bacteria in liquid fertilizers from 2.23 mg/l. up to 102.7%, i.e. 82.55% compared to the control in exchange for its neutralization, which can prevent it from passing through the plant into the human and animal body, resulting in human health being maintained. As a result of the research, a process for electrohydraulic processing of liquid fertilizers was established, where the following processing modes and parameters were established to ensure the degree of grinding of solid particles in the liquid, processing voltage: U = 24 kV, capacitor capacity: C = 0.8 μF., number of pulses: n=175 pulses, which turned out to be sufficient. Due to electro-hydraulic processing the rate of fertilizer uptake by plants has been improved over existing technology by optimizing the breakdown of coarse fertilizers into liquid solution through electro-hydraulic treatment of liquid fertilizer solutions. As a result, it was possible to increase the yield to 33 g for tomatoes and 37 g for cucumbers per 1 hectare owned by the farm using the method of electro-hydraulic treatment of liquid fertilizers.

Removal of Cr6+ in water by superoxide anion-mediated redox reaction assisted by lignin-rich kiwifruit twig biochar: Application of DFT calculation.

This research aims to investigate the role of reactive oxygen species (ROS) in the adsorption and reduction of Cr6+ on lignin-rich biochar under dark conditions and under various oxygen treatment conditions. The research found that under aerobic conditions, the reduction content of Cr6+ (0.38 mg) and the production content of ·O2- (20.36 × 10-6 mg·L-1) are the highest, followed by untreated conditions (0.32 mg, 15.03 × 10-6 mg·L-1), and the lowest under anaerobic conditions (0.21 mg, 5.14 × 10-6 mg·L-1). Compared with anaerobic conditions, the reduction content of Cr6+ increased by 1.52 times under untreated conditions. Meanwhile, under anaerobic conditions, ·O2- disappeared, indicating that ·O2- had played an important role in the reduction of Cr6+. Kinetic results showed that the role of ·O2- in the reduction of Cr6+ mainly occurred in liquid solution. DFT calculations confirmed that C-OH was the main electron supplier in the reduction process of Cr6+, and there was a positive correlation between the production content of ·O2- and the content of C-OH in liquid solution. The present research is expected to provide a scientific basis for the transformation of Cr6+ on lignin-rich biochar in liquid solution.

Synergistic resource recovery of hydrogen sulfide and carbon dioxide in ionic liquid deep eutectic solution: Construction and development

Synergistic resource recovery of hydrogen sulfide and carbon dioxide in ionic liquid deep eutectic solution: Construction and development