Degradation of Heptachlor by High-Carbon Iron Filings (HCIF)

The contamination of groundwater due the extensive use of organochlorine pesticide (OCP) has posed a serious threat to human life. The in situ remediation of contaminated groundwater by the use of zerovalent iron (ZVI) has acquired the deserved attention from researchers around the world. High-carbon iron filling (HCIF) was used to treat the aqueous solution of Heptachlor in batch reactors, which revealed the decline in the aqueous concentration of Heptachlor due to reductive dehalogenation and adsorption process. The expression \(\frac{{{\mathbf{d}}\varvec{C}_{\varvec{T}} }}{{{\mathbf{d}}\varvec{t}}} = \varvec{ } - \varvec{k}_{1} \varvec{ } \cdot \varvec{M} \cdot \varvec{ C}_{\varvec{a}}^{\varvec{N}}\) described the decline in the total concentration of Heptachlor solution (C _T ) as a function of its aqueous concentration (C _a ), where M is the mass concentration of HCIF. The kinetic coefficients N and k ₁ were derived to be 2.24 and 1.69 × 10⁻³ h⁻¹ g⁻¹ iron L respectively. Freundlich isotherm, expressed as \(\varvec{C}_{\varvec{S}} = \varvec{K } \cdot \varvec{C}_{\varvec{a}}^{\varvec{m}},\) could be employed to describe the equilibrium partitioning of Heptachlor to the HCIF surface, where K = 4.76 × 10⁻³ g⁻¹ L and m = 0.9717 was observed. The experiments revealed that HCIF can be potentially used as reactive material for in situ treatment of groundwater contaminated with Heptachlor.