Interaction between Diclofenac and Soil Humic Acids

The interaction between the non-steroidal anti-inflammatory drug diclofenac and standard humic acids(HAs) in bulk solution was studied using two complementary analytical methods: UV-Visible spectroscopy and square wave voltammetry. The observed UV-Vis spectra and Ip/V curves suggested that, at our experimental conditions, albeit both substances being negatively charged at pH 6.5, interaction between the pharmaceutical and the soil humic acids may led to the formation of diclofenac-humic acids supramolecules. Our results could contribute to give information on the behaviour of diclofenac into the soil environment, thus suggesting its migration as HAs-micelles through the coarse soil profile.