ABSTRACT
Adsorption characteristics of 2,4-dichlorophenoxyacetic acid (2,4-D) (herbicide) and flumequine (bactericide) on synthetic goethite are presented here. The nature of interactions between adsorbate and adsorbent has been investigated by solution depletion, electrophoretic mobility, and infrared spectroscopic methods.
The adsorption has been found to be due to the interactions between the surface charge of goethite and the ionized acids as pH plays an important role. In the case of flumequine, which adsorbs more strongly than 2,4-D, the possibility of adsorption of neutral molecules also exists. While the results of all the methods complement each other in the case of flumequine, there seems to be some discrepancy in the case of 2,4-D. Solution depletion results indicate weak interactions whereas infrared and electrophoretic mobility measurements show the possibility of specific interactions for 2,4-D. The results are discussed to arrive at a possible mechanism of adsorption.
