Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics
Kaplanec, Iva
Recnik, Aleksander
Mali, Gregor
Rajić, Nevenka
Clinoptilolite-rich tuff (Z) enriched with Fe(III) was studied in the removal of phosphate ions present in aqueous medium at pH = 6.5. Fe(III) modification was performed by a simple wet impregnation giving the product (FeZ) with about 18 wt% Fe. Transmission electron microscopy showed the presence of a flaky Fe(III) amorphous precipitate on the clinoptilolite sheets and a preserved clinoptilolite crystallinity. The modification increased the specific surface area from 28.6 to 140.3 m(2) g(-1). FeZ effectively adsorbed phosphate, the removal rate at 298 K varying from 86% to 42.5% (for C-0 = 50 mg dm(-3) and C-0 = 400 mg dm(-3)). The sorption isotherms were in accord with the Langmuir model, giving for the Langmuir constant (R-L) values in the range 0-1 that are characteristic of a favourable adsorption. The data for adsorption kinetics were best described by the pseudo-second-order model suggesting chemisorption as the phosphate sorption mechanism. Intra-particle diffusion was present ...in the adsorption, but it was not the rate-limiting step. A P-31 static spin-echo mapping nuclear magnetic resonance (NMR) measurement was performed for studying the phosphate-FeZ interaction. The results showed that the phosphate adsorption on FeZ proceeds through electrostatic interactions and covalent bonding, the latter being more pronounced.
Clinoptilolite / Phosphate adsorption / Adsorption mechanism / P-31 NMR / Kinetics / TEM
Desalination and Water Treatment, 2017, 78, 231-240
Desalination Publ, Hopkinton
Oxide-based environmentally-friendly porous materials for genotoxic substances removal (RS-172018)
DOI: 10.5004/dwt.2017.20875
AU  - Kaplanec, Iva
AU  - Recnik, Aleksander
AU  - Mali, Gregor
AU  - Rajić, Nevenka
AB  - Clinoptilolite-rich tuff (Z) enriched with Fe(III) was studied in the removal of phosphate ions present in aqueous medium at pH = 6.5. Fe(III) modification was performed by a simple wet impregnation giving the product (FeZ) with about 18 wt% Fe. Transmission electron microscopy showed the presence of a flaky Fe(III) amorphous precipitate on the clinoptilolite sheets and a preserved clinoptilolite crystallinity. The modification increased the specific surface area from 28.6 to 140.3 m(2) g(-1). FeZ effectively adsorbed phosphate, the removal rate at 298 K varying from 86% to 42.5% (for C-0 = 50 mg dm(-3) and C-0 = 400 mg dm(-3)). The sorption isotherms were in accord with the Langmuir model, giving for the Langmuir constant (R-L) values in the range 0-1 that are characteristic of a favourable adsorption. The data for adsorption kinetics were best described by the pseudo-second-order model suggesting chemisorption as the phosphate sorption mechanism. Intra-particle diffusion was present in the adsorption, but it was not the rate-limiting step. A P-31 static spin-echo mapping nuclear magnetic resonance (NMR) measurement was performed for studying the phosphate-FeZ interaction. The results showed that the phosphate adsorption on FeZ proceeds through electrostatic interactions and covalent bonding, the latter being more pronounced.
PB  - Desalination Publ, Hopkinton
T2  - Desalination and Water Treatment
T1  - Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics
DO  - 10.5004/dwt.2017.20875
author = "Kaplanec, Iva and Recnik, Aleksander and Mali, Gregor and Rajić, Nevenka",
abstract = "Clinoptilolite-rich tuff (Z) enriched with Fe(III) was studied in the removal of phosphate ions present in aqueous medium at pH = 6.5. Fe(III) modification was performed by a simple wet impregnation giving the product (FeZ) with about 18 wt% Fe. Transmission electron microscopy showed the presence of a flaky Fe(III) amorphous precipitate on the clinoptilolite sheets and a preserved clinoptilolite crystallinity. The modification increased the specific surface area from 28.6 to 140.3 m(2) g(-1). FeZ effectively adsorbed phosphate, the removal rate at 298 K varying from 86% to 42.5% (for C-0 = 50 mg dm(-3) and C-0 = 400 mg dm(-3)). The sorption isotherms were in accord with the Langmuir model, giving for the Langmuir constant (R-L) values in the range 0-1 that are characteristic of a favourable adsorption. The data for adsorption kinetics were best described by the pseudo-second-order model suggesting chemisorption as the phosphate sorption mechanism. Intra-particle diffusion was present in the adsorption, but it was not the rate-limiting step. A P-31 static spin-echo mapping nuclear magnetic resonance (NMR) measurement was performed for studying the phosphate-FeZ interaction. The results showed that the phosphate adsorption on FeZ proceeds through electrostatic interactions and covalent bonding, the latter being more pronounced.",
publisher = "Desalination Publ, Hopkinton",
journal = "Desalination and Water Treatment",
title = "Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics",
pages = "240-231",
doi = "10.5004/dwt.2017.20875"
Kaplanec, I., Recnik, A., Mali, G.,& Rajić, N.. (2017). Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics. in Desalination and Water Treatment
Desalination Publ, Hopkinton., 78, 231-240.
https://doi.org/10.5004/dwt.2017.20875
Kaplanec I, Recnik A, Mali G, Rajić N. Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics. in Desalination and Water Treatment. 2017;78:231-240.
doi:10.5004/dwt.2017.20875 .
Kaplanec, Iva, Recnik, Aleksander, Mali, Gregor, Rajić, Nevenka, "Study of the iron(III)-modified clinoptilolite in the adsorption of phosphate from aqueous medium: mechanism and kinetics" in Desalination and Water Treatment, 78 (2017):231-240,
https://doi.org/10.5004/dwt.2017.20875 . .