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
Data files
May 05, 2025 version files 20.18 KB
-
EST_Tae_CCR_Rawdata_Figure1.csv
3.82 KB
-
EST_Tae_CCR_Rawdata_Figure2.csv
3.83 KB
-
EST_Tae_CCR_Rawdata_Figure3.csv
5.63 KB
-
EST_Tae_CCR_Rawdata_Figure4.csv
2.79 KB
-
README.md
4.11 KB
Abstract
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.
Dataset DOI: 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.