Publications (3)12.11 Total impact
-
Article: EDTA modified LDHs as Cu(II) scavengers: Removal kinetics and sorbent stability
[show abstract] [hide abstract]
ABSTRACT: EDTA modified layered double hydroxides (LDHs) were investigated as potential sorbents to remediate heavy metals pollution. The polidentate ligand was introduced by an exchange method in a Zn–Al-LDH, which takes place with partial erosion of the layers, causing the intercalation of [Zn(EDTA)] 2− complex instead of the ligand. [Cu(H 2 O) 6 ] 2+ cation was selected as a model cation to study the uptake mechanism, exploring the elimination kinetics from the first minutes up to the steady state. A flow injection analysis system coupled to an amperometric detector (FIA-AM) was applied to perform fast and reliable [Cu(H 2 O) 6 ] 2+ determinations in monodisperse solid–aqueous solution systems. Furthermore, the sorbent stability was determined as a function of the pH and the nitrate concentration. The [Cu(H 2 O) 6 ] 2+ elimination is produced by an exchange reaction with [Zn(EDTA)] 2− anions placed either in the solid interlayer or in the aqueous solution, this last being released from the sorbent. Additional [Cu(H 2 O) 6 ] 2+ removal is produced by Cu(OH) 2 precipitation at high copper concentrations due to the LDHs high pH buffering capacity. The sorbent removes [Cu(H 2 O) 6 ] 2+ with high affinity in a wide concentration range. The elimination process reaches equilibrium in less than 30 min and leaves metal cation concentrations lower than 0.05 ppm in the supernatants.Journal of Colloid and Interface Science 01/2009; 331:425-431. · 3.07 Impact Factor -
Article: EDTA modified LDHs as Cu2+ scavengers: removal kinetics and sorbent stability.
[show abstract] [hide abstract]
ABSTRACT: EDTA modified layered double hydroxides (LDHs) were investigated as potential sorbents to remediate heavy metals pollution. The polidentate ligand was introduced by an exchange method in a Zn-Al-LDH, which takes place with partial erosion of the layers, causing the intercalation of [Zn(EDTA)](2-) complex instead of the ligand. [Cu(H(2)O)(6)](2+) cation was selected as a model cation to study the uptake mechanism, exploring the elimination kinetics from the first minutes up to the steady state. A flow injection analysis system coupled to an amperometric detector (FIA-AM) was applied to perform fast and reliable [Cu(H(2)O)(6)](2+) determinations in monodisperse solid-aqueous solution systems. Furthermore, the sorbent stability was determined as a function of the pH and the nitrate concentration. The [Cu(H(2)O)(6)](2+) elimination is produced by an exchange reaction with [Zn(EDTA)](2-) anions placed either in the solid interlayer or in the aqueous solution, this last being released from the sorbent. Additional [Cu(H(2)O)(6)](2+) removal is produced by Cu(OH)(2) precipitation at high copper concentrations due to the LDHs high pH buffering capacity. The sorbent removes [Cu(H(2)O)(6)](2+) with high affinity in a wide concentration range. The elimination process reaches equilibrium in less than 30 min and leaves metal cation concentrations lower than 0.05 ppm in the supernatants.Journal of Colloid and Interface Science 12/2008; 331(2):425-31. · 3.07 Impact Factor -
Article: Layered Ni(II)-Zn(II) hydroxyacetates. Anion exchange and thermal decomposition of the hydroxysalts obtained
[show abstract] [hide abstract]
ABSTRACT: First published as an Advance Article on the web 21st February 2002 Layered Ni,Zn hydroxyacetates have been prepared by hydrothermal methods and have been used for anion exchange of the original acetate anions by chloride, bromide, carbonate, nitrate, sulfate, and phosphate. Exchange was complete in all cases. The solids have been characterised by elemental chemical analysis, powder X-ray diffraction, thermal analysis (thermogravimetric and differential), FT-IR spectroscopy and electron microscopy; XAS spectra were also recorded in some cases. Thermal decomposition in air leads to removal of interlayer water at 150–200 uC. Mixed NiO–ZnO oxides are formed at higher temperatures. Chloride, sulfate, and phosphate salts are also formed at intermediate calcination temperature, and phosphate remains even after calcination at 1000 uC.Journal of Materials Chemistry 02/2002; 12:1071-1078. · 5.97 Impact Factor
