Enhanced coagulation coupled with cyclic IX adsorption-ARP regeneration for removal of PFOA in drinking water treatment

Laboratory investigations were conducted to demonstrate a potentially transformative, cost-efficient per- and polyfluoroalkyl substances (PFAS) treatment approach, consisting of enhanced coagulation and repeated ion exchange (IX)-advanced reduction process (ARP) for concurrent PFAS removal and IX resin regeneration. Enhanced alum coagulation at the optimal conditions (pH 6.0, 60 mg/L alum) could preferentially remove high molecular-weight, hydrophobic natural organic matter (NOM) from 5.0- to ~1.2-mg/L DOC in simulated natural water. This facilitated subsequent IX adsorption of perfluorooctanoic acid (PFOA, a model PFAS in this study) (20 μg/L) using IRA67 resin by minimizing the competition of NOM for functional sites on the resin. The PFOA/NOM-laden resin was then treated by ARP, generating hydrated electrons (eaq - ) that effectively degraded PFOA. The combined IX-ARP regeneration process was applied over six cycles to treat PFOA in pre-coagulated simulated natural water, nearly doubling the PFOA removal compared with the control group without ARP regeneration. This study underscores the potential of enhanced coagulation coupled with cyclic IX-ARP regeneration as a promising, cost-effective solution for addressing PFOA pollution in water. PRACTITIONER POINTS: Enhanced alum coagulation can substantially mitigate NOM to favor the following IX removal of PFOA in water. Cyclic IX adsorption-ARP regeneration offers an effective, potentially economical solution to the PFOA pollution in water. ARP can effectively degrade PFOA during the ARP regeneration of PFOA/NOM-laden resin.

Development of Child-Friendly Lisdexamfetamine Chewable Tablets Using Ion Exchange Resin as a Taste-Masking Carrier Based on the Concept of Quality by Design (QbD)

Taste masking is critical to improving the compliance of pediatric oral dosage forms. However, it is challenging for extremely bitter lisdexamfetamine dimesylate (LDX) with a long half-life and given in large dose. The present study aims to develop an immediate-release, taste-masked lisdexamfetamine chewable tablet. Lisdexamfetamine-resin complexes (LRCs) were prepared using the batch method. The molecular mechanism of taste masking was explored by PXRD, PLM, STA, and FT-IR. The results showed that taste masking was attributed to the ionic interaction between drug and the resin. The ion exchange process conformed to first-order kinetics. The rate-limiting step of drug release was the diffusion of ions inside the particles, and the concentration of H⁺ was the key factor for immediate release. The masking efficiency of the prepared LRCs in saliva exceeded 96%, and the drug could be completely released within 15 min in aqueous HCl (pH 1.2). Furthermore, the SeDeM expert system was used for the first time to comprehensively study the powder properties of LRCs and to quickly visualize their defects (compressibility, lubricity/stability, and lubricity/dosage). The selection of excipients was targeted rather than traditional screening, thus obtaining a robust chewable tablet formulation suitable for direct compression. Finally, the difference between chewable tablets containing LRCs and chewable tablets containing lisdexamfetamine dimesylate was compared by in vitro dissolution test, electronic tongue, and disintegration test. In conclusion, an immediate-released, child-friendly lisdexamfetamine chewable tablets without bitterness was successfully developed by the QbD approach, using the SeDeM system, which may help in further development of chewable tablets.

Polymer-Supported Phosphoric, Phosphonic and Phosphinic Acids-From Synthesis to Properties and Applications in Separation Processes

Efficient separation technologies are crucial to the environment and world economy. The challenge posed to scientists is how to engineer selectivity towards a targeted substrate, especially from multicomponent solutions. Polymer-supported reagents have gained a lot of attention in this context, as they eliminate a lot of inconveniences concerning widely used solvent extraction techniques. Nevertheless, the choice of an appropriate ligand for immobilization may be derived from the behavior of soluble compounds under solvent extraction conditions. Organophosphorus compounds play a significant role in separation science and technology. The features they possess, such as variable oxidation states, multivalence, asymmetry and metal-binding properties, highlight their status as a unique and versatile class of compounds, capable of selective separations proceeding through different mechanisms. This review provides a detailed survey of polymers containing phosphoric, phosphonic and phosphinic acid functionalities in the side chain and covers main advances in the preparation and application of these materials in separation science, including the most relevant synthesis routes (Arbuzov, Perkow, Mannich, Kabachnik-Fields reactions, etc.), as well as the main stages in the development of organophosphorus resins and the most important achievements in the field.

Evaluating Alternatives to Cold Stabilization in Wineries: The Use of Carboxymethyl Cellulose, Potassium Polyaspartate, Electrodialysis and Ion Exchange Resins

The tartaric stabilization of wines before bottling to avoid the precipitation of tartaric acid salts is an important and common step during wine production. The presence of precipitated salt crystals in bottled wines is detrimental to their quality and can even be a legal issue in some countries. Different methodologies are used in wineries to substitute the classical low-temperature stabilization process, which is an effective but costly process. This study comprises two years of experiments with red wines at an industrial scale. In the first year of the experiment, two subtractive methods (ionic exchange resins and electrodialysis) were tested, whereas two additive methods (potassium polyaspartate and carboxymethyl cellulose, both of them containing gum Arabic) were tested the second year. The tartaric stability of the wines, together with the oenological, chromatic and sensory characteristics, were followed during one year in the bottle. The results indicate that carboxymethyl cellulose and potassium polyaspartate (both combined with gum Arabic) were best at maintaining the sensory and chromatic characteristics during storage, with potassium polyaspartate providing a good tartaric stability to the treated wine and this wine being, in general, preferred in a sensory analysis test.

Formulation and evaluation of meloxicam oral disintegrating tablet with dissolution enhanced by combination of cyclodextrin and ion exchange resins

CONTEXT

The bitter taste of drug is masked by the exchange of ionized drugs with counter ions of ion exchange resin, forming "resinate". Cyclodextrin reduces the unpleasant taste and enhances the drug solubility by encapsulating drug molecules into its central cavity.

OBJECTIVE

Oral disintegrating tablets (ODTs) using the combination of ion exchange resin and cyclodextrin was developed, to mask the bitter taste and enhance drug dissolution.

METHODS

Meloxicam (MX) was selected as a model drug. Formulations containing various forms of MX (free drug, MX-loaded resin or resinate, complexes of MX and 2-hydroxypropyl-β-cyclodextrin (HPβCD) or MX/HPβCD complexes, and a mixture of resinate and MX/HPβCD complexes) were made by direct compression. The ODTs were evaluated for weight variation, thickness, diameter, hardness, friability, disintegration time, wetting time, MX content, MX release, degree of bitter taste and stability.

RESULTS AND DISCUSSION

The tablet hardness was ∼3 kg/in(2), and the friability was <1%. Tablets formulated with resinate and the mixture of resinate and MX/HPβCD complexes disintegrated rapidly within 60 s, which is the acceptable limit for ODTs. These results were corresponded to the in vivo disintegration and wetting times. However, only tablets containing the mixture of resinate and MX/HPβCD complexes provided complete MX dissolution and successfully masked the bitter taste. In addition, this tablet was stable at least 6 months.

CONCLUSIONS

The combination of ion exchange resin and cyclodextrin could be used in ODTs to mask the bitter taste and enhance the dissolution of drugs that are weakly soluble in water.

Hyperkalemia revisited

Hyperkalemia is a common clinical condition that can induce deadly cardiac arrhythmias. Electrocardiographic manifestations of hyperkalemia vary from the classic sine-wave rhythm, which occurs in severe hyperkalemia, to nonspecific repolarization abnormalities seen with mild elevations of serum potassium. We present a case of hyperkalemia, initially diagnosed as ventricular tachycardia, to demonstrate how difficult hyperkalemia can be to diagnose. An in-depth review of hyperkalemia is presented, examining the electrophysiologic and electrocardiographic changes that occur as serum potassium levels increase. The treatment for hyperkalemia is then discussed, with an emphasis on the mechanisms by which each intervention lowers serum potassium levels. An extensive literature review has been performed to present a comprehensive review of the causes and treatment of hyperkalemia.

Removal of transition metals from motor oil using ion exchange resins

A variety of polystyrene-divinylbenzene resins functionalized with such groups as SO₃H, N(CH₂COOH)₂, and SH were tested in the slurry batch mode for the removal of transition metals from used motor oil. Naturally occurring materials such as coal and clay were also tested. The N(CH₂COOH)₂ resin (Chelex 100) and the SH resin (Duolite GT-73) were found effective removing on the average 70 and 78% of metals such as Fe, Pb, Zn, Cu, Ni, and Mn, respectively. About 700 mLs of hot oil when pumped through a 37 × 0.9 cm column packed with the Duolite resin could be demetalized to the extent of about 80% if the column was first washed with hexane.