The potential removal of imidacloprid from water by heat-treated kerolites.

The adsorption of imidacloprid [1-(6-chloro-3-pyridinylmethyl)-N-nitroimidazolidin-2-ylideneamine] on heat-treated kerolite samples at 110 degrees C (K-110), 200 degrees C (K-200), 400 degrees C (K-400) and 600 degrees C (K-600) from pure water solution at 25 degrees C has been studied. The evolution of the surface properties of the kerolite samples, such as specific surface area and porosity, after heat treatment were analysed. The clays were characterised by using FTIR spectroscopy, X-ray diffraction, thermogravimetric and differential thermogravimetric analysis, surface analysis and Hg porosimetry. The experimental adsorption data points were fitted to the Freundlich equation in order to calculate the adsorption capacities (Kf) of the samples; Kf values ranged from 242 mg kg(-1) for the K-110 sample to 1005 mg kg(-1) for the K-600 sample. The values obtained for the removal efficiency (R) ranged from 62.8% for K-110 to 87.2% for K-600. The adsorption experiments showed that the stronger the heat treatment, the more effective was the adsorption of imidacloprid from pure water. This work shows the potential use of heat-activated kerolite for the removal of imidacloprid from environmental waters and drinking water resources.