Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

Abstract

This study was undertaken to determine the impact of the organic complex concentration on the adsorption of herbicide (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina (Boljevac municipality, Serbia) was used for organic modification. Cation-exchange capacity of this montmorillonite was determined using a methylene blue method (86mmol/100g of clay). Montmorillonite has been modified first with NaCl and then with hexadecyltrimethylammonium bromide (HDTMA-bromide) organic complex. Saturation of cation exchange capacity (CEC) was 50%, 100%, and 150%. Changes in the properties of the inorganic and organic montmorillonite have been examined using the X-ray diffraction, Fourier transform infrared spectroscopy, and batch equilibrium method. Montmorillonite modified with HDTMA-bromide demonstrated higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, it can be seen that the adsorption of acetochlor decreased in the series: 0.5 CEC HM > 1 CEC HM > 1.5 CEC HM > NaM.