The Exchange Adsorption of Ions from Aqueous Solutions by Organic Zeolites. I. Ion-exchange Equilibria1

1947 ◽  
Vol 69 (11) ◽  
pp. 2818-2829 ◽  
Author(s):  
G. E. Boyd ◽  
J. Schubert ◽  
A. W. Adamson
1969 ◽  
Vol 24 (6) ◽  
pp. 659-662 ◽  
Author(s):  
Mukhtar Singh ◽  
O. P. Bansal

The changes in pH and electrical conductivity of ferric tellurate, chromium tellurate and aluminium tellurate sols during their slow coagulation in the presence of KCl, K2SO4 and K3Fe(CN)6 have been studied in comparison with that of the aqueous solutions of ferric chloride, chromium chloride and aluminium chloride acting as the dispersion medium (the socalled intermicellar liquid), being of the same conductance as that of the respective sol. On adding the electrolyte, the maximum changes in conductance and pH have been observed to occur immediately indicating that the phenomena like ion-exchange, adsorption or surface neutralisation during the slow coagulation are instantaneous processes.


Author(s):  
Abdul Sattar Jatoi ◽  
Humair Ahmed Baloch ◽  
Shaukat Ali Mazari ◽  
N. M. Mubarak ◽  
Nizamuddin Sabzoi ◽  
...  

2019 ◽  
Vol 56 ◽  
pp. 17-27
Author(s):  
Van Dat Doan ◽  
Van Thuan Le ◽  
Hoang Sinh Le ◽  
Dinh Hien Ta ◽  
Hoai Thuong Nguyen

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.


2011 ◽  
Vol 85 (9) ◽  
pp. 1652-1659 ◽  
Author(s):  
L. A. Shelkovnikova ◽  
O. T. Gavlina ◽  
V. A. Ivanov

Mineralogia ◽  
2011 ◽  
Vol 42 (2-3) ◽  
pp. 75-91 ◽  
Author(s):  
Tomasz Bajda ◽  
Tomasz Marchlewski ◽  
Maciej Manecki

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.


2012 ◽  
Vol 9 (4) ◽  
pp. 1823-1834 ◽  
Author(s):  
P. N. Palanisamy ◽  
A. Agalya ◽  
P. Sivakumar

Poly Pyrrle saw dust composite was prepared by reinforcement of natural wood saw dust (obtained fromEuphorbia Tirucalli Lwood) and Poly Pyrrole matrix phase. The present study investigates the adsorption behaviour of Poly Pyrrole Saw dust Composite towards reactive dye. The batch adsorption studies were carried out by varying solution pH, initial dye concentration, contact time and temperature. The kinetic study showed that adsorption of Reactive Red by PPC was best represented by pseudo-second order kinetics with ion exchange adsorption. The equilibrium data were analyzed by Freundlich and Langmuir isotherm model. The equilibrium isotherm data were fitted well with Langmuir isotherm model. The maximum monolayer adsorption capacities calculated by Langmuir model were 204.08 mg/g for Reactive Red at 303 K. The thermodynamic parameters suggest the spontaneous, endothermic nature of ion exchange adsorption with weak Vader walls force of attraction. Activation energy for the adsorption of Reactive by Poly Pyrrole Composite was 11.6387 kJ/mole, Isosteric Heat of adsorption was 48.5454 kJ/mole also supported the ion exchange adsorption process in which forces of attraction between dye molecules and PPC is weak.


Sign in / Sign up

Export Citation Format

Share Document