DOI: 10.5061/dryad.wdbrv160s
title: Data from: Mineralization of a fully halogenated organic compound by persulfate under conditions relevant to in situ reduction and oxidation: Reduction of hexachloroethane by ethanol addition followed by oxidation

description: Fully halogenated compounds are difficult to remediate by in situ chemical
 oxidation (ISCO) because carbon–halogen bonds react very slowly with the
 species that typically initiate contaminant transformation: sulfate
 radical (SO4•–) and hydroxyl radical (•OH). To enable the remediation of
 this class of contaminants by persulfate (S2O82–)-based ISCO, we employed
 a two-phase process to dehalogenate and oxidize a representative
 halogenated compound (i.e., hexachloroethane). In the first phase, a
 relatively high concentration of ethanol (1.8 M) was added, along with
 concentrations of S2O82– that are typically used for ISCO (i.e.,
 450 mM). Hexachloroethane underwent rapid dehalogenation when
 carbon-centered radicals produced by the reaction of ethanol and radicals
 formed during S2O82– decomposition reacted with carbon–halogen
 bonds. Unlike conventional ISCO treatment, hexachloroethane transformation
 and S2O82– decomposition took place on the time scale of days
 without external heating or base addition. The presence of O2, Cl–, and
 NO3– delayed the onset of hexachloroethane transformation when
 low concentrations of S2O82– (10 mM) were used, but these solutes
 had negligible effects when S2O82– was present at concentrations
 typical of in situ remediation (450 mM). The second phase of the reaction
 was initiated after most of the ethanol had been depleted when thermolytic
 S2O82– decomposition resulted in production of
 SO4•– that oxidized the partially dehalogenated transformation
 products. With proper precautions, S2O82–-based ISCO with ethanol could be
 a useful remediation technology for sites contaminated with fully
 halogenated compounds.
description: # Mineralization of a fully halogenated organic compound by persulfate
 under conditions relevant to in situ reduction and oxidation: Reduction of
 hexachloroethane by ethanol addition followed by oxidation Dataset DOI:
 [10.5061/dryad.wdbrv160s](10.5061/dryad.wdbrv160s) ## Description of the
 data and file structure ### Files and variables #### File:
 EST\_Tae\_CCR\_Rawdata.xlsx #### **Variables – Figure 1–4 Dataset
 Description** This dataset contains raw and processed GC/MS and ancillary
 analytical data used to generate **Figures 1 through 4** in the manuscript
 titled *“Mineralization of a Fully Halogenated Organic Compound by
 Persulfate under Conditions Relevant to in Situ Reduction and Oxidation*.”
 **Figure 1: Temperature-Dependent Hexachloroethane Reduction** The “Figure
 1” sheet presents data on the transformation of hexachloroethane and
 concurrent persulfate decomposition under different temperatures (2, 30,
 and 50 °C) relevant to ISCO conditions. * **Columns A–I**: GC/MS raw peak
 area data showing HCA degradation at each temperature. * **Columns N-V**:
 Normalized concentration data and associated replicate sets across
 timepoints. * **Columns X–AF**: Averaged normalized values and standard
 deviations used for plotting Figure 1. Figure 1 demonstrates that higher
 temperatures significantly accelerate both hexachloroethane reduction and
 persulfate loss, confirming the temperature sensitivity of the
 radical-driven chain reaction mechanism. **Figure 2: Temperature-Dependent
 Product Distribution During HCA Degradation** The “Figure 2” sheet
 presents data on the formation of dehalogenation
 products—pentachloroethane and tetrachloroethene—from hexachloroethane
 during treatment with ethanol and persulfate at various temperatures. *
 **Columns A–I**: GC/MS peak area data for hexachloroethane (Hexa),
 pentachloroethane (Penta), and tetrachloroethene (Tetra) at 2 °C, 30 °C,
 and 50 °C. * **Columns N–V**: Normalized concentrations of each compound
 across timepoints. * **Columns X–AF**: Final average values and standard
 deviations used in plotting product formation trends. * Columns AH-AM:
 Calibration results (slope) of pentachloroethane (PCA), tetrachloroethene
 (PCE), and trichloroethene (TCE). Figure 2 illustrates that the extent and
 composition of dehalogenated byproducts vary with temperature, supporting
 radical chain reaction pathways for sequential dehalogenation. **Figure 3:
 Dissolved Oxygen Impact on Reductive Dehalogenation** The “Figure 3” sheet
 presents data on the role of dissolved oxygen ([O₂]) in influencing the
 rate of hexachloroethane transformation and persulfate decomposition. *
 **Columns A–L**: GC/MS data showing HCA transformation under various
 dissolved O₂ concentrations (66, 150, 225 µM). * **Columns N–Y**: Control
 data without ethanol. * **Columns Z–AK**: Normalized concentrations,
 reaction timepoints, and error metrics for plotting. Figure 3 highlights
 that oxygen initially inhibits reductive dehalogenation, but once
 depleted, reduction proceeds at rates similar to oxygen-free conditions.
 **Figure 4: Monitoring the Oxidative Phase via Benzoic Acid Degradation**
 The “Figure 4” sheet presents data tracking benzoic acid degradation and
 dissolved oxygen dynamics during the transition from reductive to
 oxidative ISCO phases. * **Columns A–K**: HPLC-DA data for benzoic acid
 concentrations and desired O₂ levels over time during ISCO with excess
 persulfate and limited ethanol. * **Columns N–V**: Normalized benzoic acid
 and O₂ values reflecting the progression from reductive to oxidative
 conditions. * **Columns Y–AG**: Averaged values, transformation rates, and
 standard deviations used in plotting Figure 4. Figure 4 demonstrates that
 after ethanol is depleted, benzoic acid degradation accelerates due to
 increased sulfate radical (SO₄•⁻) activity, marking the oxidative phase
 onset in the two-stage ISCO process. ## Access information Data was
 derived from the following sources: * Our data was generated through
 experimental procedures.