Removal of 8-quinolinecarboxylic acid pesticide from aqueous solution by adsorption on activated montmorillonites.
Sodium montmorillonite (Na-M), acidic montmorillonite (H-M), and organo-acidic montmorillonite (Org-H-M) were applied to remove the herbicide 8-quinolinecarboxylic acid (8-QCA). The montmorillonites containing adsorbed 8-QCA were investigated by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction analysis, X-ray fluorescence thermogravimetric analysis, and physical adsorption of gases. Experiments showed that the amount of adsorbed 8-QCA increased at lower pH, reaching a maximum at pH 2. The adsorption kinetics was found to follow the pseudo-second-order kinetic model. The Langmuir model provided the best correlation of experimental data for adsorption equilibria. The adsorption of 8-QCA decreased in the order Org-H-M > H-M > Na-M. Isotherms were also used to obtain the thermodynamic parameters. The negative values of ΔG indicated the spontaneous nature of the adsorption process.
Laboratoire de Chimie Organique, Macromoléculaire et des Matériaux, Université de Mascara, Bp 763, Mascara, 29000, Algeria.
M
M
Mekhloufi
A
A
Zehhaf
A
A
Benyoucef
C
C
Quijada
E
E
Morallon
D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D011804:Quinolines / Q000032:analysis / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
D010575:Pesticides; D011804:Quinolines; D014874:Water Pollutants, Chemical; D001546:Bentonite