title: Adsorption of arsenic(V) into modified lamellar Kenyaite.
abstract: 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+/-1K. 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 (Delta(int)H=-4.08 to -5.94 kJ mol(-1)) accompanied by increase in entropy (Delta(int)S=41.29-62.09 J K(-1)mol(-1)) and Gibbs energy (Delta(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.
authors: Instituto de Química, Universidade Estadual de Campinas, Cp 6154, 13084-971 Campinas, SP, Brazil. dlguerra@iqm.unicamp.br
authors: Denis Lima
authors: DL
authors: Guerra
authors: Claudio
authors: C
authors: Airoldi
authors: Rúbia Ribeiro
authors: RR
authors: Viana
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000302:isolation & purification*; D002151:Calorimetry; D008670:Metals; D013816:Thermodynamics
chemical_list: D008670:Metals; D001151:Arsenic