Organo-clays and nanosponges for acquifer bioremediation: Adsorption and degradation of triclopyr

To avoid the problem of groundwater contamination, mitigation techniques have been proposed that consist of creating barriers made of suitable materials that can facilitate the adsorption and degradation of the pollutants. This study aims at evaluating the capacity of two organo-clays (Dellite 67G and Dellite 43 B) and one nanosponge to adsorb the herbicide, triclopyr. Triclopyr was chosen because it is a good example of a moderately mobile, leacheable molecule. The rate of degradation of the molecule in the soil, both with and without the presence of the materials under examination, was also determined. Both the organo-clays adsorbed more than 90% of the herbicide. The nanosponge and the soil adsorbed less than 10% triclopyr. When the soil was added with the two organoclays, adsorption increased to 92%. When added to the soil, the materials accelerated the degradation of triclopyr. The half-life in soil was 30days, whereas in soil with Dellite 67 G and Dellite 43 B it was 10 and 6days respectively. The addition of the nanosponge to the soil decreased the half life by 50%. These results lead us to suggest that they be used in creating reactive barriers for the remediation of soils and aquifers.