Electromagnetic induction of nanoscale zerovalent iron for enhanced thermal dissolution/desorption and dechlorination of chlorinated volatile organic compounds

Abstract

A major problem plaguing the success of in situ dechlorination using NZVI is the slow rate of dissolution of chlorinated volatile organic compounds (CVOCs) from dense nonaqueous phase liquid (DNAPL) or slow desorption of CVOCs from soil in the aqueous phase. This is because the dechlorination using NZVI is surface mediated; therefore, contaminants must be dissolved to transport to the NZVI surface. For this reason, any action to enhance the DNAPL dissolution or desorption of CVOCs from the soil and DNAPL can speed the reaction rate and improve the electron utilization efficiency of the remediation. This chapter summarizes the state of knowledge about using a low-frequency (LF) electromagnetic field (EMF) (150 kHz) with NZVI to enhance the CVOC degradation rate in a DNAPL system and in a soil and groundwater system via thermal-enhanced CVOC dissolution or desorption followed by enhanced dechlorination using NZVI. NZVI is a ferromagnetic particle capable of magnetic induction heating under an applied LF EMF. The heat generated can speed up the dechlorination reaction and can promote DNAPL dissolution or desorption of contaminants from soils. The most recent work on using this novel approach is summarized as a proof of concept. The CVOC degradation kinetics in groundwater and in soil with groundwater as well as in a DNAPL system by NZVI both with and without LF EMF were compared to quantify the benefits of using LF EMF for enhanced thermal dissolution and magnetically enhanced NZVI corrosion.