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The primary, most obvious parameter indicating water quality is the color of the water. Not only can it be aesthetically disturbing, but it can also be an indicator of contamination. Clean, high-quality water is a valuable, essential asset. Of the available technologies for removing dyes, adsorption is the most used method due to its ease of use, cost-effectiveness, and high efficiency. The adsorption process is influenced by several parameters, which are the basis of all laboratories researching the optimum conditions. The main objective of this review is to provide up-to-date information on the most studied influencing factors. The effects of initial dye concentration, pH, adsorbent dosage, particle size and temperature are illustrated through examples from the last five years (2017–2021) of research. Moreover, general trends are drawn based on these findings. The removal time ranged from 5 min to 36 h (E = 100% was achieved within 5–60 min). In addition, nearly 80% efficiency can be achieved with just 0.05 g of adsorbent. It is important to reduce adsorbent particle size (with Φ decrease E = 8–99%). Among the dyes analyzed in this paper, Methylene Blue, Congo Red, Malachite Green, Crystal Violet were the most frequently studied. Our conclusions are based on previously published literature.

In recent era, with increasing heavy metal pollution, several sorbents are used to remove heavy metals from environment. Application of chemical adsorbents and biosorbents for uptake of heavy metals from soil and waste water is studied thoroughly. Very less attention has been paid to the recovery of heavy metals from sorbents and their reuse. Few researches have been performed to evaluate the recovery of heavy metals from sorbents and regeneration of sorbents for further adsorption processes. This review explains desorption of heavy metals from metal loaded adsorbents and regeneration of adsorbents. Various desorbing eluents and their utilization in desorption of certain metals are compiled along with the techniques and setups followed to achieve better recovery and regeneration rates. The prospect of such eluents in recovery of heavy metals from electronic wastes (e-waste) is scrutinized. This comprehensive study would be advantageous to determine methods and the most suitable desorbents for particular heavy metals for conducting adsorption–desorption cycles.

The identification and quantification of phenolic compounds and flavonoids in various natural food products is typically conducted using HPLC analysis. Their analysis is particularly complex since most natural food products contain a large number of different phenolic compounds, many of which have similar chemical characteristics such as polarity, which makes complete separation of all eluents extremely difficult. In this work we present and validate a method for the quantitative determination of the concentration of two compounds with similar retention times, i.e. they show overlapping peaks in a mixed solution. Two pairs of phenolic compounds were investigated: caffeic and vanillic acids and ferulic and p-coumaric acids. This technique takes advantage of the different absorbances of the two phenolic compounds in the eluent at various wavelengths and can be used for the quantitative determination of the concentration of these compounds even if they are not separated in the HPLC column. The presented method could be used to interpret the results of HPLC analysis of food products which possess a vast spectrum of phenolic compounds and flavonoids.

Iodine eluent is a type of secondary waste that adsorbs radioactive iodine during the reprocessing of used nuclear fuel. To better deal with it, Na 2 SiO 3 and NaAlO 2 were used to immobilize iodine eluents by synthesizing iodosodalite via a hydrothermal method. Orthogonal experiments were designed to investigate the effects of four factors: mass ratio of iodine eluent, Al/Si ratio, temperature, and aging time. Powder X-ray diffraction with Rietveld refinements was performed to characterize the structures and phases of the samples, of which iodosodalite and hydrosodalite are the primary phases that immobilize iodine effluents. Fourier-transform infrared spectroscopy and scanning electron microscopy results demonstrated a cage-like sample structure. Energy-dispersive X-ray spectroscopy revealed a homogeneous distribution of Na, Al, Si, O, and I on the sample surfaces. X-ray photoelectron spectroscopy indicated the presence of both iodide and iodate in the synthesized products. The optimal synthesis process is a reaction temperature of 190 ℃, NaI + NaIO 3 :Na 2 SiO 3  + NaAlO 2 ratio of 1:5, Si/Al ratio of 1:1, and aging time of 7 d. The leaching rate of iodine (including I − and IO 3 − ) indicates considerable chemical durability of the optimized sample.

Effective treatment of per- and polyfluoroalkyl substances (PFAS) in an affordable manner is highly demanded to meet stringent water protection standards. Herein, we introduce a fluoroamine dual-site hydrogel (QFgel) designed to structurally match amphipathic PFAS molecules, facilitating selective interactions for the effective PFAS removal from water. Specifically, the synergistic effects of quaternized and fluorinated functional groups in QFgel can promote electrostatic-fluorophilic dual-site interactions with both the perfluoroalkyl and anionic headgroups at the ends of PFAS. As a result, these dual-site interactions achieve high selectivity (sorption coefficients ranging from 1.75 to 4.0) and ultrahigh sorption capacity (up to 2,835 mg g -1 ), resulting in over 95.6% removal of 17 PFAS types at environmentally relevant concentrations in real water matrices. Notably, pilot-scale applications with a kilogram-scale QFgel-adsorber effectively treats up to 12,400 and 9,215 bed volumes of PFAS-contaminated drinking water (i.e., tap water) before the breakthrough point of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) ([PFAS] 0  = ~ 0.35 µg L -1 , 2 m 3 per day). After 46 days of continuous operation, the adsorber is regenerated using a saline-methanol mixed eluent, achieving 96.5% desorption and up to 1,633-fold PFAS enrichment, while reducing eluent use by 70% compared to commercial sorbents. This work advances PFAS remediation by offering a scalable, cost-effective solution, and contributes to sustainable water resource protection. PFAS poses significant threats to human health and aquatic ecosystems. Here, a fluoroamine-functionalized QFgel is proposed and exhibits high selectivity and removal efficiency for 17 PFAS in water at environmentally relevant concentrations.

Magnetite nanoparticles hold quite immense applications in the fields of drug delivery, environmental remedies, and magnetic resonance imaging as they are biocompatible and can stabilize and reduce. An eco-friendly approach that is viable and sustainable for synthesizing magnetite nanoparticles with controlled properties has new avenues for their applications in various fields. Magnetite nanoparticles are often used in the removal of organic eluents as they can adsorb heavy metals which binds on the surface and cleans the polluted area. Magnetite nanoparticles synthesized from the roots of Mirabilis Jalapa have a variety of uses in the treatment of lesion infections. As antioxidants, they reduce the oxidative stress caused by free radicals. Morphology, size, and form of Magnetite nanoparticles are determined by UV-visible spectroscopy, SEM, EDX, TEM, TGA, XRD, and FTIR, respectively.

For selecting the best leaching agent and optimizing the leaching conditions, the present study investigated the effects of six leaching agents (hydrochloric acid, oxalic acid, water, citric acid, phosphoric acid, and EDTA) on chromium elution from contaminated soil under various elution conditions. To determine the total chromium concentration in soil, 0.10 g soil sample was digested with a mixture of HNO3-HClO4-HF (5 mL:2 mL:1 mL) for 12 h at 180 °C. The total chromium content in soil and the chromium concentration in the leaching agent were determined using a flame atomic absorption spectrophotometer. During the comparative study, the removal of total chromium by multiple leaching agents with the best eluent was studied. Also, the optimum elution conditions and the optimal number of leaches were determined. Conclusively, the removal efficiency of total chromium by composite eluent was investigated. The results showed that high concentrations (1 mol/L) of citric acid and oxalic acid had better chromium removal efficiencies, with removal rates of 58.6% and 54.8%, respectively. The combined eluent composed of equal volumes of 0.6 mol/L oxalic acid and 0.6 mol/L citric acid has a better elution efficiency, with a total chromium removal rate of 62.0%. Citric acid is an environmentally friendly eluent that can avoid secondary pollution. In conclusion, citric acid with a 0.6 mol/L concentration is the best eluent, which conveys higher efficiency (58.6%) at a solid–liquid ratio of 1:10 for 8 h of leaching. This study provides a theoretical basis for the efficient remediation of chromium-contaminated soil by ectopic leaching.

Environmentally friendly natural deep eutectic solvents (NADES) have been shown to efficiently extract a wide range of phenolic compounds from virgin olive oil (VOO). The objective of this work was to optimize the yield of olive oil phenols extracted by NADES based on xylitol/choline choride (Xyl/ChCl). Different extraction and recovery conditions were investigated, including the effect of different extraction operating parameters (temperature, time, VOO:NADES ratio) and subsequent recovery conditions (XAD resin height, wash-water and eluent volume and pH). The highest concentration of phenols (555.36 mg/kg VOO) was obtained from extraction at 40 °C for 1 h, with a 1:1 ratio, using an adsorption resin XAD-16 with bed height of 10 cm, 250 mL acidified wash-water and 300 mL EtOH 100% as eluent. No statistically significant loss of the sum of phenolic compounds was observed when compared with the concentration values obtained by direct analysis in HPLC without the elimination of NADES. Additionally, a sequential desorption with different concentration of ethanol was used to determine the effect of the solvent concentration on polyphenol yield. Polar compounds, such as hydroxytyrosol and tyrosol, were recovered at 81.7% and 83.6%, respectively with 50 and 80% ethanol; however, 100% ethanol was required for the complete elution of oleacein (3,4-DHPEA-EDA) and oleocanthal (p-HPEA-EDA). In this paper we present an effective process for the extraction of polyphenols from VOO by NADES for direct analysis in HPLC and for the recovery and concentration of polyphenols by removing the solvent (NADES) with no losses of yield and solvent recycling.

Use of thermoplastic material in orthodontics, either as aligner or as retainer appliances, is common practice and is likely to increase in the years to come. However, no systematic assessment on safety considerations of these adjuncts has been implemented up to date. The aim of this systematic review was to collectively appraise the existing evidence from both clinical and laboratory studies, on whether these appliances are associated with any estrogenic/cytotoxic effects or bisphenol-A (BPA) and monomer leaching. Eight electronic databases were searched with no limits in December 22, 2019, for published and unpublished research. Eligibility criteria comprised of studies of any design, describing use of any type of thermoplastic aligner. Study selection, data extraction and risk of bias (RoB) assessment was done independently, either in duplicate or confirmed by a second reviewer. Random effects meta-analyses of weighted mean differences (WMD) with associated 95% Confidence Intervals (CIs) were planned. Quality of the evidence was evaluated with Grading of Recommendations Assessment, Development and Evaluation (GRADE). A total of 58 articles were initially identified, while 5 were included in qualitative synthesis and 2 of those contributed to the quantitative syntheses. Four studies were in-vitro, while one was a randomized controlled trial; all assessed some type of orthodontic aligner or retainer, either as-received or retrieved. Risk of bias recordings ranged between unclear and high for all studies. Proliferation induction capacity of thermoplastic appliances’ eluents on MCF-7 cells failed to be confirmed compared to beta-estradiol (2 studies: 5% v/v, WMD: −182.08; 95% CI: −198.83, −165.33; p-value < 0.001; and 20% v/v, WMD: −184.53; 95% CI: −206.17, −162.88; p-value < 0.001). No cytotoxic activity was detected as well. In addition, although evidence from in-vitro studies was indicative of no traceable detection of BPA or other monomers, the findings from a single clinical trial were allied to increased levels of BPA in whole stimulated saliva, after up to 30 days of thermoplastic retainer usage, compared to standard Hawley retainer. The quality of the evidence overall was low to medium. Current data from in-vitro research are indicative of an absence of an estrogenic or cytotoxic effect of thermoplastic aligners or retainers. Regarding BPA or monomer release, evidence from clinical and laboratory studies appear inconsistent.

This paper describes an LC-MS/MS method to determine the concentration of spironolactone and its metabolites 7-alpha-methylthiospironolactone and canrenone in blood plasma samples. The resulting assay is simple (using protein precipitation for sample preparation) and sensitive (the lower limit of quantification is close to 0.5 ng/ml) while requiring only 50 mu l of plasma, making it especially suitable for analyzing samples obtained from pediatric and neonatal patients where sample sizes are limited. The sensitivity is achieved by using ammonium fluoride as an eluent additive, which in our case amplifies the signal from our analytes in the plasma solution on average about 70 times. The method is fully validated according to the European Medicines Agency's guideline and used for the measurement of pediatric patients' samples in clinical trials for evaluating oral spironolactone's and its metabolites' pharmacokinetics in children up to 2 years of age.