An ATR-FTIR study of different phosphonic acids adsorbed onto boehmite.
An ATR-FTIR study of the vibrational spectra of N,N-bis(2-hydroxyethyl) aminomethylphosphonic acid (BHAMP), 1-hydroxyethane-1,1'-diphosphonic acid (HEDP) and nitrilotris(methylenephosphonic acid) (NTMP) adsorbed onto boehmite is presented. The study was performed in the pH range from 5 to 9, and bands assignments are given in the 1200-900 cm(-1) wavenumber range, where the bands associated with various P-O(H) vibrations can be found. The three phosphonic acids adsorb onto boehmite by forming inner-sphere surface complexes. ATR-FTIR data indicates the presence of both protonated and deprotonated mononuclear surface species. In all cases, the surface-bound ions undergo protonation reactions as pH is decreased. The results are in good agreement with previously proposed surface complexation models.
Departamento de Química, Universidad Nacional del Sur, Bahía Blanca, Buenos Aires, Argentina. mzenobi@criba.edu.ar
María C
MC
Zenobi
Carina V
CV
Luengo
Marcelo J
MJ
Avena
Elsa H
EH
Rueda
D000327:Adsorption; D000536:Aluminum Hydroxide / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D063065:Organophosphonates / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared
D063065:Organophosphonates; D009943:Organophosphorus Compounds; D012996:Solutions; C041182:(nitrilotris(methylene))triphosphonic acid; D000536:Aluminum Hydroxide; C069471:aluminum oxide hydroxide; D000537:Aluminum Oxide