Sorption of herbicides on inorganic and organic modified natural montmorillonite from Bogovina

Abstract

Efficiency of inorganic and organic modified montmorillonites from Bogovina for sorption of the S-metolachlor and clomazone was determined using batch adsorption method. Montmorillonite samples were pretreated with NaCl solution and then with different concentrations of organic complexes. Adsorption isotherms were measured by treatment of the samples with different concentrations of herbicide. Detailed mineralogical characterization of samples was performed using the X-ray diffraction method. Results of interaction between organic complexes and herbicides were obtained using X-ray diffraction, optical, thermal and spectroscopic analysis. Based on the results obtained using X-ray diffraction, it was concluded that all examined organic complexes and herbicides intercalated into interlayer space of montmorillonite. Montmorillonites modified with HDTMA complex exhibited monolayer, bilayer and pseudotrilayer arrangement of HDTMA+ cations in interlayer space, depending on degree of saturation. It has been found that the HDTMA+ cations are forming the partition phase for the herbicide on the surface of the montmorillonite. On the other hand, montmorillonite modified with PTMA complex exhibited monolayer arrangement of cations on the surface of montmorillonite in such a way that the cations act as pillars in interlayer space. The molecules of herbicides in this case were adsorbed on the surface of the montmorillonite. Which functional groups were involved in bonding processes between montmorillonite, organic complex and herbicide best describes infrared spectroscopy. High sorption of examined herbicides on some organic modified montmorillonites creates an opportunity for application of these substrates as potentially useful material for removal of S-metolachlor and clomazone from the environment.

fikasnost prilikom sorpcije S-metolahlora i klomazona od strane neorganskih i organski modifikovanih montmorionita sa lokaliteta Bogovina odreĎena je metodom bach adsorpcije. Uzorci montmorionita su tretirani prvo rastvorom NaCl a zatim i različitim koncentracijama organskih kompleksa. Adsorpcione izoterme su dobijene tretiranjem uzoraka različitim koncentracijama herbicida. Detaljna mineraloška karakterizacija uzoraka uraĎena je metodom rendgenske difrakcije. Rezultati interakcije montmorionita sa organskim kompleksima i herbicidima dobijeni su primenom rendgenskih, optičkih, termičkih i spektroskopskih metoda. Na osnovu rezultata rendgenskih ispitivanja uzoraka, utvrĎeno je prisustvo organskih kompleksa i herbicida u meĎuslojnom prostoru montmorionita. Montmorioniti modifikovani sa HDTMA kompleksom pokazivali su jednoslojnu, dvoslojnu i pseudotroslojnu orijentaciju HDTMA+ katjona u meĎuslojnom prostoru. UtvrĎeno je da HDTMA+ katjoni formiraju particionu fazu na površini montmorionita, na kojoj dolazi do sorpcije molekula herbicida. Sa druge strane, montmorioniti modifikovani sa PTMA kompleksom pokazivali su jednoslojnu orijentaciju katjona na površini montmorionita i to na takav način da se katjoni ponašaju kao stubovi koji u zavisnosti od dimenzija dovode do širenja meĎuslojnog prostora. Molekuli herbicida se u tom slučaju vezuju za površinu montmorionita. Primenom metode infracrvene spektroskopije utvrĎeno je koje funkcionalne grupe učestvuju u interakciji izmeĎu montmorionita, organskih kompleksa i herbicida. Visoka sposobnost sorpcije odreĎenih uzoraka organski modifikovanih montmorionita otvara mogućnost njihove primene kao potencijalne sirovine za uklanjanje S-metolahlora i klomazona iz ţivotne sredine...