Adsorption of arsenic(V) into modified lamellar Kenyaite

• Published in: Journal of hazardous materials Vol. 163; no. 2; pp. 1391 - 1396
• Main Authors: Guerra, Denis Lima, Airoldi, Claudio, Viana, Rúbia Ribeiro
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30-04-2009; Elsevier
• Subjects: Adsorption; Applied sciences; Arsenic; Arsenic - isolation & purification; Calorimetry; Chemical engineering; Exact sciences and technology; Intercalation reaction; Kenyaite; Metals; Pollution; Thermodynamic properties; Thermodynamics; Intercalation reaction; Arsenic; Thermodynamic properties; Kenyaite; Equilibrium constant; Liquid solid interface; Adsorption; Arsenates; Adsorption isotherm; pH; Entropy
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.06.095

The synthetic Kenyaite sample was used for organofunctionalization process with
N-propyldiethylenetrimethoxysilane and bis[3-(triethoxysilyl)propyl]tetrasulfide. The resulted materials were submitted to process of adsorption with arsenic solution at pH 2.0 and 298
±
1
K. The adsorption isotherms were adjusted using a modified Langmuir equation with regression non-linear; the net thermal effects obtained from calorimetric titration measurements were adjusted to a modified Langmuir equation. The adsorption process was exothermic (Δ
int
H
=
−4.08 to −5.94
kJ
mol
−1) accompanied by increase in entropy (Δ
int
S
=
41.29–62.09
J
K
−1
mol
−1) and Gibbs energy (Δ
int
G
=
−22.33 to −24.45
kJ
mol
−1). The energetic effect caused by metal cation adsorption was determined through calorimetric titration at the solid–liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.