Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions

In this work, nanosized calcium deficient hydroxyapatite (nCDHA) was synthesized by the precipitation method, and then utilized as an adsorbent for removal of Fe (II), Cu (II), Ni (II) and Cr (VI) ions from aqueous solutions after characterizing it by various techniques as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and BET method. A possible structure of synthesized nCDHA was proposed. The adsorption study indicated that the adsorption equilibrium is well fitted with Langmuir isotherm model with the maximum adsorption capacities followed the order of Fe (II) > Cu (II) > Ni (II) > Cr (VI) with the values of 137.23, 128.02, 83.19 and 2.92 mg/g, respectively. The ion-exchange mechanism was dominant for the adsorption of metal ions onto nCDHA at initial metal concentrations lower than 0.01 mol/L. Along with the ion-exchange mechanism, there was an additional precipitation occurred on the surface of nCDHA in the case of Fe (II) and Cu (II) at initial concentrations higher than 0.01 mol/L.

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Pyromorphite formation from montmorillonite adsorbed lead

Mineralogia ◽

10.2478/v10002-011-0008-5 ◽

2011 ◽

Vol 42 (2-3) ◽

pp. 75-91 ◽

Cited By ~ 2

Author(s):

Tomasz Bajda ◽

Tomasz Marchlewski ◽

Maciej Manecki

Keyword(s):

Ion Exchange ◽

Aqueous Solutions ◽

Phosphate Concentration ◽

High Concentration ◽

Exchange Effect ◽

System A ◽

New Phase

Pyromorphite formation from montmorillonite adsorbed lead The reaction of Pb-adsorbed montmorillonite with aqueous solutions of PO4 and Cl ions results in the decrease in phosphate concentration associated with the formation of a new phase - pyromorphite Pb5(PO4)3Cl. Pyromorphite crystals range in size from hundreds of nm to several tens of μm, depending on the PO4, K, and Ca concentrations in the reacting system. A strong ion-exchange effect of K+ and Ca2+ cations on desorption of Pb2+ from Pb-adsorbed montmorillonite was observed. Also, a high concentration of cations leads to a rapid desorption of Pb and the formation of fine pyromorphite crystals. In contrast, low PO4, K and Ca concentrations result in the formation of relatively large euhedral crystals. Final Pb concentrations are much lower in experimental sets than in control experiments with no phosphate present.

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Mössbauer Spectroscopic Studies of K2SnCl6and SnCl4·5H2O in Frozen Aqueous Solutions and in Ion Exchange Resins

Journal of the Chinese Chemical Society ◽

10.1002/jccs.198400031 ◽

1984 ◽

Vol 31 (3) ◽

pp. 221-227

Author(s):

H. S. Cheng ◽

C. M. Hsu ◽

T. M. Uen ◽

P. K. Tseng

Keyword(s):

Ion Exchange ◽

Aqueous Solutions ◽

Spectroscopic Studies ◽

Ion Exchange Resins ◽

Exchange Resins

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Natural zeolites for heavy metals removal from aqueous solutions: Modeling of the fixed bed Ba2+/Na+ ion-exchange process using a mixed phillipsite/chabazite-rich tuff

Chemical Engineering Journal ◽

10.1016/j.cej.2012.12.075 ◽

2013 ◽

Vol 219 ◽

pp. 37-42 ◽

Cited By ~ 28

Author(s):

Francesco Pepe ◽

Bruno de Gennaro ◽

Paolo Aprea ◽

Domenico Caputo

Keyword(s):

Heavy Metals ◽

Ion Exchange ◽

Aqueous Solutions ◽

Exchange Process ◽

Fixed Bed ◽

Natural Zeolites ◽

Heavy Metals Removal ◽

Ion Exchange Process ◽

Metals Removal

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Amberlite IRC-718 ion chelating resin extraction of hazardous metal Cr (VI) from aqueous solutions: equilibrium and theoretical modeling

Water Science & Technology ◽

10.2166/wst.2021.309 ◽

2021 ◽

Author(s):

Abdelhamid Addala ◽

Moussa Boudiaf ◽

Maria Elektorowicz ◽

Embarek Bentouhami ◽

Yacine Bengeurba

Keyword(s):

Ion Exchange ◽

Aqueous Solutions ◽

Exchange Process ◽

Ion Exchange Resin ◽

Exchange Capacity ◽

Chelating Resin ◽

Exchange Potential ◽

Chromium Vi ◽

Ion Exchange Process ◽

Hazardous Metal

Abstract Under varied conditions, the IRC 718 ion-exchange resin is used to extract chromium (VI) ions from aqueous solutions. On chromium (VI) removal effectiveness, the effects of adsorption dosage, contact time, beginning metal concentration, and pH were examined. The batch ion exchange process reached equilibrium after around 90 minutes of interaction. With an initial chromium (VI) concentration of 0.5 mg/dm3, the pH-dependent ion-exchange mechanism revealed maximal removal in the pH 2.0–10 range . The adsorption mechanism occurs between Cr(VI) determined as the electron acceptor, and IRC 718 determined as the electron donor. The equilibrium ion-exchange potential and ion transfer quantities for Amberlite IRC 718 were calculated using the Langmuir adsorption isotherm model. The overall ion exchange capacity of the resin was determined to be 187.72 mg of chromium (VI)/g of resin at an ideal pH of 6.0.

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