Surfactant-induced Changes in Physicochemical Characters of Bentonite Clay

Aims: In the present study a cationic surfactant i.e. cetyl tri methyl ammonium bromide (CTAB) was used in order to explore adsorption potential of natural bentonite for organic pollutant and anionic molecules.

Place and Duration of Study: The study was conducted during 2016-17 in the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University.

Methodology: Pure bentonite and CTAB modified bentonite were characterized by means of Fourier transformation infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy(TEM), Atomic force microscopy (AFM), Brunauer–Emmett–Teller (BET) surface area and cation exchange capacity.

Results: An effective intercalation of quaternary ammonium ion between the clay layers was confirmed by FTIR study. Basal Spacing of bentonite was increased from 12.70 Ao to 19.24 Ao after CTAB modification. The roughness of bentonite clay has been decreased from 16.05 nm to 10.07 nm while surface area decreased from 33.03 m2 g-1 to 10.41 m2 g-1 after CTAB modification and was confirmed by SEM and AFM. Congo red (CR) an organic dye extensively used and disposed in soil and waste water was potentially adsorbed to a taller end from 12.2 mg g-1 to 49.53 mg g-1 by surfactant modified bentonite clay.

Conclusion: Cationic surfactant can put forward certain changes in physicochemical properties of bentonite clay. The CTAB modified bentonite clay can be used as a potential adsorbent for the anionic/organic pollutant.