Iron hydroxide intercalates for degradation of chlorinated solvents in sediment and groundwater

A newly discovered class of layered iron hydroxides intercalated with fatty acids (carboxylate-LIH) will be used as reactive sorbents to degrade chlorinated solvents. Soil and groundwater polluted by halogenated hydrocarbons present one of the most serious treats to drinking water resources and human health – and efficient clean-up of these sites continues as one of the major challenges in environmental technology. The project comprise engineering of the LIH particles to optimise their efficiency for degradation of chloro-alkanes and -alkenes in sediments and aquifers. We will quantify sorption and subsequent reduction kinetics and pathways depending on the formulation of LIH. Sorbent size selectivity will be induced by pillaring, while an “on/off” reactivity mechanism will be attempted using silicate “switches”. The geochemical functioning of the optimised LIH particles will be tested first in sediment batch and column studies and next in situ by pressurized geoprobe injection of LIH or LIH-oil suspensions into contaminated sediments, either in the contaminant source area and/or into the pollutant plume with subsequent monitoring of degradation products. Conceptual models based on the intrinsic sorption and reactivity properties of the LIH particles modified by flow characterstics will be developed to describe the performance of LIH for clean-up of chlorinated solvents.