Nitrate is the most intensively applied nutrient to agricultural land. Being a very mobile anion, even more in tropical acidic soils, its leaching contaminates surface and groundwater and causes large financial loss for farmers. The main scope of this proposal is to study an environmentally sustainable concept to intelligently control the movement (leaching) of charged ions, e.g. nitrate, through providing oppositely charged substrate. To inhibit nitrate mobility, layered double hydroxide (LDH) could be an excellent substrate because of their positively charged surfaces and intercalated structures. Easy and low cost large-scale production of LDH by available minerals like iron and manganese are other interesting advantages. In this study, complementary kinetic and equilibrium batch experiments will be performed together with miscible displacement (breakthrough) experiments in soil columns, to quantify the retention and transport of nitrate loaded LDH in soils with different properties. Simultaneously, the dissolution of cations released from LDH and nitrate intercalation and competition with other anions will be observed by XRD patterns and FTIR spectra. The study envisages predictions about the viability of applications on a larger agricultural scale will be inferred from reactive transport modeling, based on obtained reaction data from batch experiments, mechanisms and transport parameters from the soil column studies.
News published in Agência FAPESP Newsletter about the scholarship: