Solubility, Hansen solubility parameter and thermodynamic properties of etodolac in twelve organic pure solvents at different temperatures

A new set of solute descriptors to calculate solubility of drugs in mono-solvents

A new set of solute parameters derived from a correlation model using Catalan parameters. The parameters represent the interaction of the solute with the mono-solvents at 298.15K. The computational procedure was adopted from Abraham's solvation model and the obtained results are promising. In this work, the calculated parameters were used to back-calculate the drugs solubility in various mono-solvents at different temperatures employing the van't Hoff's model as the skeleton on the derived model. The obtained mean percentage deviations (MPDs) were in the range of 3.1 to 88.5% with the overall MPD of 29.1%. (1) Derivation of a new set of solute parameters from a correlation model using Catalan parameters; (2) adoption of the calculation method of Abraham's solvation model with the skeleton of van't Hoff's equation; (3) using the achieved parameters for back-calculation of drugs solubility in various mono-solvents; (4) obtaining an overall acceptable mean percentage deviation of 29.1% from calculations.

A colorimetric detection of polystyrene nanoplastics with gold nanoparticles in the aqueous phase

Nanoplastics has become a growing environmental concern because these tiny particles can easily penetrate biological tissues and have possible toxic effects. FT-IR and Raman spectroscopy methods are currently used to analyze microplastics (5 mm or less), but they encounter difficulty when the particles are below 1 μm. On the other hand, thermoanalysis of nanoplastics does not provide the size information. Therefore, herein, we proposed the colorimetric detection method with gold nanoparticles (AuNPs) to measure the concentration of polystyrene nanoplastics (PSNPs, size = 350 and 880 nm) through a color change that is obvious to the naked eye. A mixed dispersion of PSNPs and AuNPs was added with acetone, a good solvent for polystyrene. In this colorimetric detection, acetone acted as a key component to enhance or hinder the aggregation of AuNPs around PSNPs. Namely, acetone itself promoted AuNPs aggregation, but it was dissolved partially PS chains from PSNSs to act as inhibitor of aggregation of AuNPs. These two contradictory feature of acetone to AuNPs and PSNPs affect the aggregation and color of AuNPs (dispersed = red, aggregated = blue). Finally, the heat-map between PSNSs and acetone was prepared to use for estimation of concentration of PSNPs in the aqueous solution with naked eye. To the best of our knowledge, this is the first attempt to measure nanoplastics by colorimetry.

Solid-Liquid Equilibrium Behavior and Solvent Effect of Gliclazide in Mono- and Binary Solvents

The solubility data of gliclazide in 10 mono-solvents (1,2-dichloroethane, 1,4-dioxane, 2-methoxyethanol, n-propyl acetate, isopropyl acetate, n-butyl acetate, pentyl acetate, dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMA), and 2-butanone) and one kind of binary solvent (DMA + water) were measured between 278.15 and 323.15 K under atmospheric pressure by the gravimetric method. The Hansen solubility parameters and the KAT-LSER equation were used to investigate the solubility order and the influence of solvent effects on solubility. The experimental data were correlated by six thermodynamic models (the λh model, the Yaws model, the Apelblat model, the Jouyban model, the modified Jouyban-Acree model, and the Sun model). The results show that all of these models can correlate the experimental data well. Among them, the Apelblat model is the most suitable for correlating the solubility data of gliclazide in mono-solvents and binary solvents.

Green Solvent Cleaning Removes Irrecoverable Foulants from End-of-Life Membranes in Membrane Bioreactors: Efficacy and Mechanisms

Removal of irrecoverable foulants, which cannot be removed by conventional chemical cleaning, from end-of-life (EOL) membranes remains a substantial challenge due to the strong interaction between the foulants and membrane matrix. Herein, we developed a green solvent cleaning strategy based on Hansen solubility parameters to achieve the removal of irrecoverable foulants from the EOL polyvinylidene fluoride (PVDF) membranes serving for 6 years in a large-scale membrane bioreactor (MBR). We selected methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (MDMO) as the green solvent due to its strong interaction with the PVDF material, which might enable the substitution of binding sites of irrecoverable foulants. After the MDMO cleaning, the water permeance of the EOL membrane recovered from 47.6 ± 4.7 to 390.9 ± 8.2 L m^-2 h^-1 bar^-1 (with a flux recovery ratio of ∼100%), with its rejection ability and stability maintained. The main components of irrecoverable fouling were humic acid-like substances revealed by spectroscopic characterization. Molecular dynamic simulation further elucidated the cleaning mechanisms: the strong interaction of MDMO-PVDF enabled substitution of binding sites of irrecoverable foulants by MDMO, followed by desorption of the irrecoverable foulants from PVDF and diffusion of the irrecoverable foulants into the bulk phase of MDMO. Evaluation in a lab-scale MBR treating real municipal wastewater verified the reusability of green solvent cleaned-EOL membranes. This study provides a novel, effective, and green cleaning strategy to remove irrecoverable foulants and prolong the service life of membranes in MBRs, facilitating sustainable wastewater treatment using membrane-based processes.