Unexpected difference in phenol sorption on PTMA- and BTMA-bentonite.
The comparison of phenol sorption on phenyltrimethylammonium (PTMA)- and benzyltrimethylammonium (BTMA)-bentonite shows a clear difference as far as phenol sorption isotherms are concerned. For PTMA-bentonite the sorption isotherm is of a straight-line character which results from simple partitioning of phenol between the aqueous and organic phases sorbed on the bentonite surface. For BTMA-bentonite the isotherm has a convex shape, characteristic of physicochemical sorption. For the first time a three-parametric model, including the dissociation constant of phenol pK(a), distribution constant of phenol Kd(phen) and phenolate anion Kd(phen)(-) between the aqueous phase and the bentonite phases is used for the evaluation of phenol sorption on organoclays with pH change. The model shows that the values of Kd(phen) are higher than those of Kd(phen)(-) for all investigated initial phenol concentrations. The inspection of the FTIR spectrum of BTMA-bentonite loaded with phenol in the regions 1300-1600 and 1620-1680 cm(-1) shows the features of pi-pi electron interaction between the benzene rings of phenol and the BTMA cation together with the phenol-water hydrogen bond strengthened by this interaction.
Majdan
Marek
M
Faculty of Chemistry, Maria Curie Skłodowska University, Pl MC Skłodowskiej 2, 20-031 Lublin, Poland. majdan.marek@gmail.com
Bujacka
Monika
M
Sabah
Eyup
E
Gładysz-Płaska
Agnieszka
A
Pikus
Stanisław
S
Sternik
Dariusz
D
Komosa
Zofia
Z
Padewski
Aleksander
A
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010636:Phenols / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D010636:Phenols; D000644:Quaternary Ammonium Compounds; D001546:Bentonite; C000168:benzyltrimethylammonium; C009571:phenyltrimethylammonium