Aqueous Research Articles

Construction and demolition waste as a low-cost adsorbent for water treatment: kinetics, isotherm, thermodynamics, and Fenton regeneration.

The present study proposes to investigate the feasibility of using construction and demolition waste (CDW) as an aqueous remediation agent through adsorption. The CDW, with and without chemical and thermal pre-activation, was evaluated to remove the methylene blue (MB) dye from the water solution. Variables interfering with adsorption processes, such as adsorbent dosage, solution pH, and particle size, were evaluated. The material was characterized by pHZPC, FTIR, XRD, SEM, EDS, and TG. The kinetic and equilibrium data better fitted the Elovich and Sips models, respectively. A maximum adsorption capacity of 18.62mgg-1 at 60°C was observed. Thermodynamic data indicated that adsorption occurred through a spontaneous and favorable process governed mainly by physical processes. The regeneration studies were carried out using processes based on the Fenton reaction, where the catalytic action of the iron naturally present in the CDW was evaluated. The results showed that the desorption balance was the main limiting factor for the effective regeneration of the saturated material. Adding Fe2+ to the system made this process suitable for the regeneration of the CDW and degradation of the pollutant in the aqueous phase. A regeneration efficiency of 65%, maintained practically constant during five adsorption-regeneration cycles, was observed. These results highlight the high potential of using CDWs as an adsorbent material.

Contribution of Protonation to the Dielectric Relaxation Arising from Bacteriopheophytin Reductions in the Photosynthetic Reaction Centers of Rhodobacter sphaeroides

The pH dependence of the free energy level of the flash-induced primary charge pair P+IA− was determined by a combination of the results from the indirect charge recombination of P+QA− and from the delayed fluorescence of the excited dimer (P*) in the reaction center of the photosynthetic bacterium Rhodobacter sphaeroides, where the native ubiquinone at the primary quinone binding site QA was replaced by low-potential anthraquinone (AQ) derivatives. The following observations were made: (1) The free energy state of P+IA− was pH independent below pH 10 (–370 ± 10 meV relative to that of the excited dimer P*) and showed a remarkable decrease (about 20 meV/pH unit) above pH 10. A part of the dielectric relaxation of the P+IA− charge pair that is not insignificant (about 120 meV) should come from protonation-related changes. (2) The single exponential decay character of the kinetics proves that the protonated/unprotonated P+IA− and P+QA− states are in equilibria and the rate constants of protonation konH +koffH are much larger than those of the charge back reaction kback ~103 s−1. (3) Highly similar pH profiles were measured to determine the free energy states of P+QA− and P+IA−, indicating that the same acidic cluster at around QB should respond to both anionic species. This was supported by model calculations based on anticooperative proton distribution in the cluster with key residues of GluL212, AspL213, AspM17, and GluH173, and the effect of the polarization of the aqueous phase on electrostatic interactions. The larger distance of IA− from the cluster (25.2 Å) compared to that of QA− (14.5 Å) is compensated by a smaller effective dielectric constant (6.5 ± 0.5 and 10.0 ± 0.5, respectively). (4) The P* → P+QA− and IA−QA → IAQA− electron transfers are enthalpy-driven reactions with the exemption of very large (>60%) or negligible entropic contributions in cases of substitution by 2,3-dimethyl-AQ or 1-chloro-AQ, respectively. The possible structural consequences are discussed.

Lipid-Based Nanoformulations for Drug Delivery: An Ongoing Perspective

Oils and lipids help make water-insoluble drugs soluble by dispersing them in an aqueous medium with the help of a surfactant and enabling their absorption across the gut barrier. The emergence of microemulsions (thermodynamically stable), nanoemulsions (kinetically stable), and self-emulsifying drug delivery systems added unique characteristics that make them suitable for prolonged storage and controlled release. In the 1990s, solid-phase lipids were introduced to reduce drug leakage from nanoparticles and prolong drug release. Manipulating the structure of emulsions and solid lipid nanoparticles has enabled multifunctional nanoparticles and the loading of therapeutic macromolecules such as proteins, nucleic acid, vaccines, etc. Phospholipids and surfactants with a well-defined polar head and carbon chain have been used to prepare bilayer vesicles known as liposomes and niosomes, respectively. The increasing knowledge of targeting ligands and external factors to gain control over pharmacokinetics and the ever-increasing number of synthetic lipids are expected to make lipid nanoparticles and vesicular systems a preferred choice for the encapsulation and targeted delivery of therapeutic agents. This review discusses different lipids and oil-based nanoparticulate systems for the delivery of water-insoluble drugs. The salient features of each system are highlighted, and special emphasis is given to studies that compare them.

Multi-Responsive Polymer Nanoparticles: A Versatile Platform for Double-Security Anticounterfeiting and Smart Food Packaging.

Potential applications of colloidal polymer nanoparticles in the preparation of smart inks are investigated by physical incorporation of the oxazolidine molecules. Precise adjusting the polymer chain flexibility and polarity is achieved by controlling the ratio of methyl methacrylate and butyl acrylate monomers in the polymerization reaction. In addition, nanofibrous indicators of acid-base vapors are prepared from the latex nanoparticles. This can be beneficial for creating materials that sense and respond to environmental changes, such as humidity or moisture and acidity. Thermochromic inks are prepared by microencapsulating crystal violet lactone dye (CVL) in polymer matrices to prevent their release into the aqueous media. Combining two distinct systems with varying triggers, such as light and temperature, provides an effective strategy for double-encryption anticounterfeiting and crack and scratch detection and indication applications. Preparing labels impregnated with double-responsive inks, a novel approach is developed for food spoilage detection and preservation indication. Labels are manufactured using polymer nanoparticles, which contain photoluminescent oxazolidine molecules, as well as a trinary mixture of CVL within core-shell latex particles as the thermochromic dye. The combination of these two responsive elements transforms traditional packaging into a dynamic and interactive sentinel for the food it holds.

Crowding for Confinement: Reversible Isomerization of First-Generation Donor-Acceptor Stenhouse Adduct Derivatives in Water Modulated by Thermoresponsive Dendritic Macromolecules

Mimicking nature, the reversible isomerization of hydrophobic dyes in aqueous solutions is appealing for bio-applications. Here, we report on the reversible isomerization of first-generation solvatochromic donor-acceptor Stenhouse adducts (DASAs) in water within dendritic matrices, realized either through the dendronization of DASAs or the incorporation of DASA pendants into dendronized copolymers. These dendritic macromolecules contain three-fold dendritic oligoethylene glycols (OEGs), which afford the macromolecules water-solubility and unprecedented thermoresponsive behavior. The thermoresponsive behavior of both dendronized DASAs and dendronized copolymers is dominated by the peripherals of dendritic OEGs. However, the hydrophilicity of the acceptor from DASA moieties also play a role in mediating their thermal phase transitions, and more importantly, tailor the hydrophobic interactions between dendritic OEGs and DASA moieties. Intriguingly, dendritic topologies contribute confinement to encapsulate the DASA moieties through crowding effects, and cooperative interactions from the crowded dendritic OEGs modulate the DASA moieties with different isomerization in aqueous media. The thermally induced collapse of dendritic OEGs, accompanied by the aggregation of dendritic macromolecules, leads to the formation of hydrophobic domains, which exert enhanced crowding effects to efficiently encapsulate the DASA moieties. Compared to the low molar mass of dendronized DASAs, thermally collapsed dendronized copolymers can efficiently retard the hydration of DASA pendants through cooperation between neighboring dendritic OEGs and afford the DASA pendants with better confined microenvironments to mediate their isomerization recovery by up to 90% from a cyclic charged (hydrophilic) state into a noncharged (hydrophobic) linear state in water. This dendritic confinement exhibits excellent fatigue resistance after several cycles of alternating photo-irradiation and thermal annealing at elevated temperatures.

Nucleotide-mediated modulation of chemoselective protein functionalization in a liquid-like condensed phase

Liquid-like protein condensates are ubiquitous in cellular system and are increasingly recognized for their roles in physiological processes. Condensed phase harbors distinctive chemical microenvironment, markedly different than dilute aqueous phase. Herein, we demonstrate chemoselective modification pattern of nucleophilic canonical amino acid sidechains (namely – cysteine, tyrosine and lysine) of the protein towards 4-chloro-7-nitrobenzofurazan in the dilute and condensed phase. We also delineate how the effect of nucleotides and their in situ enzymatic dissociation temporally modulate the protein condensate’s pH and the protein’s corresponding chemoselective modification. We have shown that the pH of the condensate decreases in the presence of nucleoside triphosphate, whereas it increases in the presence of nucleoside monophosphates or phosphate ion. For instance, we find lysine-specific modification gets inhibited in the presence of adenosine triphosphate (ATP), but significantly enhanced in the presence of monophosphates. This feature enables us to gain temporal control over dynamic change in protein functionalization via enzymatic ATP hydrolysis. Overall, this work substantiates the alteration in pH-responsiveness of Brønsted basicity of a protein’s ε-amine in the condensed phase. Furthermore, this environment sensitivity in chemoselective protein functionalization in condensed phase will be important in adaptable protein engineering to the chemical biology of protein phase separation.

Curcumin Administration Routes in Breast Cancer Treatment

Breast cancer is a public health concern worldwide, characterized by increasing incidence and mortality rates, requiring novel and effective therapeutic strategies. Curcumin is a bioactive compound extracted from turmeric with several pharmacological activities. Curcumin is a multifaceted anticancer agent through mechanisms including the modulation of signaling pathways, inhibition of cell proliferation, induction of apoptosis, and production of reactive oxygen species. However, the poor water solubility and bioavailability of curcumin create important barriers in its clinical application. This review elaborates on the therapeutic potential of curcumin in breast cancer treatment, focusing on the efficacy of different administration routes and synergistic effects with other therapeutic agents. The intravenous administration of curcumin-loaded nanoparticles significantly improves bioavailability and therapeutic outcomes compared to oral routes. Innovative formulations, such as nano-emulsifying drug delivery systems, have shown promise in enhancing oral bioavailability. While intravenous delivery ensures higher bioavailability and direct action on tumor cells, it is more invasive and expensive than oral administration. Advancing research on curcumin in breast cancer treatment is essential for improving therapeutic outcomes and enhancing the quality of life of patients.

Impact of a Dual Treatment on Resistant Starch Level and Techno‐Functional Properties of Pea and Faba Bean Flours

AbstractStarch‐rich pulses’ flours, which are rich in fiber and resistant starch (RS), can be an interesting gluten‐free ingredient for the development of novel healthy foods. The study aims to increase the RS content of protein‐reduced fraction of legume flours (pea [P] and faba bean [FB]) by the application of thermal (autoclaving‐cooling) and dual (thermal plus high‐hydrostatic pressure) treatments. Both treatments enhance the RS contents, reaching 6.8% in P flour after dual treatment. The techno‐functional properties are dependent both on the type of flour and the treatment applied. A loss of water solubility (WS) and an increase in water binding capacity are observed. The WS index and emulsion activity remained unchanged or slightly changed, but emulsion stability decreased significantly. The viscosity of the samples is modified according mainly to the flour type. P flour is more affected by the dual treatment than FB flour, which is evidenced by the greater changes shown in RS, WS, and pasting properties.

Adsorptive Removal of Bisphenol A by Polyethylene Meshes Grafted with an Amino Group-Containing Monomer, 2-(Dimethylamino)ethyl Methacrylate

The adsorptive removal of Bisphenol A (BPA) with the PE meshes photografted with 2-(dimethylamino)ethyl methacrylate (DMAEMA) was performed by varying the grafted amount, pH value, BPA concentration, and temperature, and the adsorption performance was correlated by the equilibrium, kinetic, and isotherm models. In addition, the regeneration of DMAEMA-grafted PE (PE-g-PDMAEMA) meshes was discussed from the repetitive adsorption/desorption process. The adsorption capacity had the maximum value at the grafted amount of 2.6 mmol/g and at the initial pH value of 8.0. The increase in the protonation of dimethylamino groups on grafted PDMAEMA chains and the dissociation of phenol groups of BPA present in the outer solution during the adsorption process results in the increase in BPA adsorption. The adsorption process followed the pseudo second-order equation. The BPA adsorption was enhanced by increasing the BPA concentration and the equilibrium data fit to Langmuir equation. The adsorption capacity stayed almost constant with the increase in the temperature, whereas the k2 value increased against the temperature. These results comprehensively emphasized that BPA adsorption occurred through the chemical interaction or ionic bonding of a BPA anion to a terminal protonated dimethylamino group. Desorption of BPA increased by increasing the NaOH concentration and BPA was entirely desorbed at more than 20 mM. The cycle of adsorption at pH 8.0 and desorption in a NaOH solution at 100 mM was repeated five times without loss or structural damage. These results indicate PE-g-PDMAEMA meshes can be used as a regenerative adsorbent for BPA removal from aqueous medium.

Application of Date Palm Tree Branch-Based Activated Carbon for Aqueous Toxicity Reduction

The Kingdom of Saudi Arabia (KSA) has millions of date palm trees for commercial scale date-fruit production. The respective industry also generates agricultural waste including date palm tree branches. This rich bio-resource can be used for several beneficial applications. The present study therefore investigated the application of granular activated carbon (GAC) produced using date palm tree branches to successfully remove phenol, p-cresol, and copper from synthetic wastewater. The respective adsorption equilibrium results fitted well to the Langmuir-type adsorption isotherm. Furthermore, the pH-dependent adsorption results both for phenol and p-cresol appeared to follow an anionic-type adsorption behavior (i.e., decreasing adsorption with an increase in aqueous phase equilibrium pH). However, the pH-dependent adsorption finding for copper showed a cationic-type adsorption behavior. These adsorption trends were explained employing the pH-dependent speciation of the respective pollutants. In general, findings from the present work indicate that a high-specific-surface-area (SSABET) GAC material from the date palm tree branches can be successfully employed for aqueous phase pollution control.

Inorganic–Organic Hybrid Nonwoven Fabrics with Colorimetric Detection Capability for Borate Ions in Aqueous Solutions

Abstract A nonwoven fabric sheet with an immobilized colorimetric reagent was prepared to detect borate anions in aqueous media. The fabric comprised immobilized chromotropate and 1-butanesulfonate anions and chromotropate, as the colorimetric reagent, per anion-exchange capacity of the layered double hydroxide. The resulting sheet quantitatively detected borate anions through photoluminescence measurements. Thus, it can be used for onsite quantitative analysis of dissolved boron in water, with promising potential for water quality monitoring and consequently, sustainable and safe water resources globally.

Trace Ru Incorporation Boosted Co2P Nanorods for Superior Water Electrolysis and Substrate-Paired Electrolysis Toward Value-Added Chemicals in Alkaline Medium.

Electro-valorization of biomass-derived chemicals has ensured sustainable production of value-added products, an effective approach for reducing carbon footprint, through renewable energy. Electrochemical oxidation and reduction reactions in aqueous media using H2O as a potential source for active hydrogenated and oxygenated species fulfill the purpose. In this study, Ru─Co2P nanorods are explored as a bifunctional electrocatalyst toward valorization of Organics at basic media. The in-situ electrogenerated Co3+ and Co4+ species act as active oxidants toward product selectivity. An overpotential of 68mV is found for hydrogen evolution reaction (1m NaOH) with Ru─Co2P. Further, used as cathode, Ru─Co2P effectively reduces furfuraldehyde to furfuryl alcohol and p-nitrophenol to p-aminophenol. Ru doping enables ease of formation of active species both for reduction and oxidation, faster charge transfer between catalyst to absorbates. Density Functional Theory calculation establishes Ru incorporation in Co2P surface results in enhanced adsorption of substrates. Ru doping modulates the electronic structure of Co2P which changes the density of states resulting in faster water dissociation and water splitting. To reach 10mAcm-2 current density only 1.6V is required for water electrolysis, whereas 1.4V is enough for substrate-paired electrolysis with simultaneous oxidation of benzyl alcohol and reduction of p-nitro phenol.

Eu3+-Doped Mixed-Ligand UiO-66-Type Metal-Organic Framework for Ratiometric Fluorescence Sensing Fluoride Ions with Ultralow Detection Limit.

Metal-organic frameworks (MOFs) have emerged as a highly promising platform for various sensing applications due to their tunable structures and functionalities. In the present work, a Eu3+-doped mixed-ligand MOF, namely, the Eu3+@UiO-66-IPA, exhibited excellent luminescent properties and high fluorescence stability in aqueous media, displaying dual-emission peaks under 395 and 615 nm excitation that were readily visible to the naked eye. Importantly, the presence of fluoride ions (F-) promoted the "antenna effect" between the ligand and the Eu3+ centers, which significantly enhanced the emission intensity of the Eu3+ characteristic peak. In addition, the addition of F- also inhibited the quenching effect of high-energy O-H bonds existing in the aqueous environment. Notably, Eu3+@UiO-66-IPA demonstrated exceptional selectivity for F- over a range of competing anions, with a remarkable limit of detection as low as 0.22 μM. The developed Eu3+-doped mixed-ligand MOF system offers a highly promising strategy for the simple and accurate sensing of F- in practical applications.

Ring-Opening Metathesis Polymerization of Thianorbornenes.

A series of exo-7-thiabicyclo[2.2.1]hept-5-ene-2,3-dicarboximides were synthesized and polymerized using Schrock's catalyst, 2,6-diisopropylphenylimidoneophylidene molybdenum(VI) bis(hexafluoro-tert-butoxide). The ring-opening metathesis polymerization (ROMP) reactions were found to proceed in a controlled manner, enabling chain extensions and tuning of polymer molecular weight. The polymers were characterized using size exclusion chromatography (SEC) as well as spectroscopic (NMR, FT-IR), thermal (TGA, DSC), and optical techniques. The physical, chemical, and optical properties of the polymers were found to be affected by the embedded sulfur atoms and the pendant substituents. Copolymers with norbornene were also synthesized and characterized. Treatment of a poly(thianorbornene) with potassium hydroxide led to ring-opening hydrolysis and afforded a derivative that was soluble in aqueous media.

Enzymatic Glycosylation of 4′-Hydroxychalcones: Expanding the Scope of Nature’s Catalytic Potential

Chalcones, including 4′-hydroxychalcones, have garnered significant attention in the area of drug discovery due to their diverse pharmacological properties, such as anti-inflammatory, antioxidative, and anticancer effects. However, their low water solubility and bioavailability limit their efficacy in vivo. Glycosylation presents a promising approach to enhance the water solubility, stability, and metabolic properties of chalcones. This study investigates the enzymatic glycosylation of eight chemically synthesized 4′-hydroxychalcones using a diverse set of sugar glucosyltransferases from bacterial, plant, and fungal sources, alongside Glycine max sucrose synthase (GmSuSy) in a cascade reaction. Among the tested enzymes, five exhibited a remarkable versatility for glycoside production, and for large-scale biotransformation, flavonoid 7-O-glucosyltransferase Sbaic7OGT from Scutellaria baicalensis was selected as the most effective. As a result of the experiments conducted, eight trans-chalcone glycosides were obtained. During the purification of the reaction products, we also observed the isomerization of the products by simple sunlight exposure, which resulted in eight additional cis-chalcone glycosides. This study highlights the novel use of a cascade reaction involving Glycine max sucrose synthase (GmSuSy) for the efficient glycosylation of trans-4′-hydroxychalcones, alongside the unexpected discovery of cis-chalcone glycosides during the purification process.

An efficient and environmental friendly synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione in aqueous hydrotropic medium

An efficient and environmental friendly synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione in aqueous hydrotropic medium

Green extraction of colorants from achiote seeds for dyeing mordanted nylon fabric

The extraction of sustainable colorants requires energy efficient technology for their eco-application in different fields. For current study on nylon fabric, the natural dye from achiote (Bixa orellana) has been extracted in aqueous and acidic media and valorized through microwave (MW) radiation. MW treatment has been applied to both extracted biomolecule and nylon fabric up to 10 min and the dyeing variables were optimized using statistical model. For getting permanent shades eco-salts of Al (III) and Fe (II) as well as biomolecules from waste plant materials (pomegranate and myrobalan) were utilized. ISO methods for assessment of colorfast shades have been employed. It was found that for nylon, by MW treatment of the dye material and polymeric stuff for 4 min, good color yield in terms of color strength (K/S=29.52) is obtained. It has been observed that when MW treated extract (pH=6) is employed at 40 °C for 55 min, good quality shade of high strength is obtained by using selected amounts of eco-chemical and organic molecules. It is concluded that MW treatment should be given to dyeing process for getting effective yield and tannin based green molecules as organic mordant can used to make dyeing process more ecofriendly and sustainable.

Water-Soluble Chitosan-Europium Hybrid Sensor for Singlet Oxygen Detection.

The ability to effectively monitor singlet oxygen (1O2) with fluorescence probes in biological systems is severely restricted mainly by the background autofluorescence of these systems. Though the application of lanthanide complexes as 1O2 monitors successfully resolves this problem with time-gated luminescence measurements, the insolubility of these complexes in an aqueous medium heavily limits their application in biological systems. Here, we present a water-soluble 1O2 sensor based on a chitosan-europium hybrid material. A procedure for the modification of chitosan to expand its solubility to neutral and basic pH, while maintaining its free active amine groups, is described. These are then coupled covalently to a europium-based probe for the detection of 1O2. The resulting hybrid sensor is readily soluble in water across the pH scale and efficiently signals the presence of 1O2 at physiological pH, with the characteristic Eu3+ emission at 611 nm yielding up to a 15-fold increase in emission intensity and a decay time of 332 μs. Being of particular interest for time-gated measurements, this long decay time, coupled with the biocompatibility of chitosan, describes a material with potential biological applications, where 1O2 plays a vital role.

Multi-Stimuli Responsive Viologen-Imprinted Polyvinyl Alcohol and Tricarboxy Cellulose Nanocomposite Hydrogels

Photochromic inks have shown disadvantages, such as poor durability and high cost. Self-healable hydrogels have shown photostability and durability. Herein, a viologen-based covalent polymer was printed onto a paper surface toward the development of a multi-stimuli responsive chromogenic sheet with thermochromic, photochromic, and vapochromic properties. Viologen polymer was created by polymerizing a dialdehyde-based viologen with a hydroxyl-bearing dihydrazide in an acidic aqueous medium. The viologen polymer was well immobilized as a colorimetric agent into a polyvinyl alcohol (PVA)/tricarboxy cellulose (TCC)-based self-healable hydrogel. The viologen/hydrogel nanocomposite films were applied onto a paper surface. The coloration measurements showed that when exposed to ultraviolet light, the orange layer printed on the paper surface switched to green. The photochromic film was used to develop anti-counterfeiting prints using the organic hydrogel composed of a PVA/TCC composite and a viologen polymer. Reversible photochromism with strong photostability was observed when the printed papers were exposed to UV irradiation. A detection limit was monitored in the range of 0.5–300 ppm for NH3(aq). The exposure to heat (70 °C) was found to reversibly initiate a colorimetric change.

Medicinal cannabis delivery systems: A perspective

In recent years, cannabis derivatives have been proposed for the treatment of various medical conditions, including pain, inflammation, epilepsy, sleep disorders, multiple sclerosis, anorexia, schizophrenia, neurodegenerative diseases, nausea, and cancer. While the benefits of cannabis derivatives, primarily cannabinoids, have been demonstrated and continue to be studied, their use presents various challenges associated with their low water solubility, rapid metabolism, erratic and poor bioavailability, and erratic pharmacokinetics, which directly affect their efficacy. In this context, a great deal of research is being carried out to overcome these drawbacks by designing delivery systems capable of improving solubility/bioavailability, potency, and efficacy, while addressing the purity and quality issues required by the pharmaceutical industry. This article aims to critically review the major trends and challenges in designing controlled-release cannabinoid delivery systems and their potential application in the pharmaceutical industry.