Calix[4]pyrrole macrocycle: Extraction of fluoride anions from aqueous media

Abbas, Ismail; Hammud, Hassan H.; Shamsaldeen, Hasan

doi:10.5155/eurjchem.3.2.156-162.542

Cited by 14 publications

(5 citation statements)

References 49 publications

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“…The extraction efficiency is much better than most other reported examples of fluoride extraction using an uncharged hydrogen bonding receptor. Typically, 60%–80% of receptor saturation has been obtained when the starting water layer contained molar or submolar concentrations of fluoride. ,,,− The high extraction efficiency is due in large part to the core–shell architecture of the extracted dimeric complexes that contain one or two F – ions surrounded by two copies of self-associated 2 . All of the polar functional groups are buried within the dimer core, whereas nonpolar functionality dominates the exterior surface.…”

Section: Discussionmentioning

confidence: 99%

Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor

2019

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A neutral tetralactam macrocycle was prepared in a few minutes in one pot and at high concentration using commercially available starting materials. NMR titration studies in DMSO revealed an anion affinity order of F– > AcO– > Cl– > Br–. The receptor affinity for F– is very high due in part to formation of a self-complementary dimer comprised of two “saddle shaped” complexes. An X-ray crystal structure showed that the two F– ions within the dimer are separated by 3.39 Å. The electrostatic penalty for this close proximity is compensated by attractive interactions provided by the surrounding tetralactam molecules. Reactivity experiments showed that stabilization of F– as a supramolecular complex abrogated its capacity to induce elimination and substitution chemistry. This finding raises the idea of using tetralactam macrocycles to stabilize fluoride-containing liquid electrolytes within redox devices such as room-temperature fluoride-ion batteries. A lipophilic version of the tetralactam macrocycle was prepared and used to extract F– from water into a chloroform layer with high efficiency. The favorable extraction is due to the architecture of the extracted dimeric complex, with all the polarity located within the core of the self-associated dimer and all the nonpolar functionality on the exterior surface.

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Section: Discussionmentioning

confidence: 99%

Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor

2019

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“…However, these techniques have some disadvantages such as high cost, low efficiency, low selectivity, high-energy requirements, and sludge generation [11]. Compared to other methods, uptake is simple and effective [12][13][14]. Several kinds of materials were used as adsorbent for removal of chromate and phosphate pollutants [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…Among these are fly ash [17], blast furnace slag [18], iron oxide tailing [19], red mud [20], Ca-based adsorbents, and iron-based compounds [21]. Since the last decade, polymers [22][23][24] and macrocyclic derivatives of pyrrole [14] have attracted more attention as adsorbents of anionic and cationic pollutants from water because of their nontoxicity, good environmental stability, low cost and ease of preparation [25][26][27]. In this context, polypyrrole-coated sawdust [28] and Fe 3 O 4 coated polypyrrole magnetic nanocomposite [22] were used to remove phosphate and chromium (VI) ions from water respectively.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and thermodynamics of chromate and phosphate uptake by polypyrrole: batch and column studies

Hammud

Abbas

Al-khalili

2015

J Incl Phenom Macrocycl Chem

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Polypyrrole sorption performance for removal of phosphate and chromate anions from water was evaluated by batch and column studies. The uptake isotherms, kinetics, chromate recycling, and experimental conditions such as temperature, pH, and dosage were optimized. The uptake data fitted Freundlich isotherm model very well, and the removal process was found to be endothermic and spontaneous in nature. The results indicate that the removal of both anions is a physisorption process. The kinetic data were described better by the pseudo second-order kinetic model. The maximum uptake capacities for phosphate and chromate anions were 120 and 26 mg/g respectively. The uptake equilibrium for phosphate and chromate was attained in 120 and 60 min respectively. The solution pH showed insignificant effect on anions removal over a pH range from 2.0 to 10.0. Three well known column uptake models, Thomas, Yoon and Nelson and Yan et al., were used to analyze the experimental data of chromate removal from water by polypyrrole. Thomas model showed better fitting than other models. Polypyrrole was regenerated and reused by using 0.1 M HCl solution. This polymer is a promising sorbent than other materials for phosphate and chromate removal from wastewater.

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“…Disadvantages such as high cost, low selectivity and little efficiency are restricting the wide use of some of these treatment methods [17]. Adsorption is considered as a simple and effective method in removing inorganic pollutants from wastewater [18,19]. Many adsorbents such as clays, zeolites, resins and silicates have been investigated for the removal of phenol derivatives [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Application of calixpyrrole modified silica for the removal of 4-chlorophenol from aqueous media

2019

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In this research, calixpyrrole modified silica (III) was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and scanning electron microscope (SEM) techniques. The synthesized material was used as an extractant for the removal of 4-chlorophenol from aqueous solution. Its efficiency was examined through both batch and column extraction methods. The effects of temperature, pH, initial chlorophenol concentration and mass of the adsorbent were examined using removal efficiencies. Initial concentration and quantity of adsorbent show a noticeable influence on the uptake capacity of the adsorbent. The kinetics and thermodynamics of chlorophenol removal from aqueous media were also investigated. Kinetic studies indicated that the extraction data can be best represented by pseudo second order model. Column extraction data were analyzed through Thomas, Yoon-Nelson and Yan et al. models to calculate kinetic coefficients and maximum sorption capacity of the modified silica (III). The adsorbent silica was regenerated by acid treatment without changing its properties.

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Calix[4]pyrrole macrocycle: Extraction of fluoride anions from aqueous media

Cited by 14 publications

References 49 publications

Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor

Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor

Kinetics and thermodynamics of chromate and phosphate uptake by polypyrrole: batch and column studies

Application of calixpyrrole modified silica for the removal of 4-chlorophenol from aqueous media

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