Sucralose as an oxidative-attenuation tracer for characterizing the application of in situ chemical oxidation for the treatment of 1,4-dioxane

Abstract

In situ chemical oxidation (ISCO) has become a widely used soil and groundwater remediation method. Oxidative-attenuation tracers can be used to provide real-time, explicit delineation of contaminant mass-transfer and transformation behavior during an ISCO remediation project. The objective of this study was to evaluate the potential of employing sucralose, a widely used artificial sweetener, as an oxidative-attenuation tracer to characterize the remediation efficiency of 1,4-dioxane (dioxane) by persulfate-based ISCO. Batch and miscible-displacement experiments were conducted to examine the degradation rate and transport behavior of sucralose compared to that of dioxane. Comparable magnitudes and rates of degradation were observed for sucralose and dioxane in batch-reactor experiments with soil and persulfate. The breakthrough curves of sucralose and dioxane transport in a soil-packed column were coincident. The retardation factors were 1.1 for both compounds, indicating limited sorption for both sucralose and dioxane by the soil. Limited degradation was observed in the miscible-displacement experiments, consistent with the short residence time compared to the half-lives of sucralose and dioxane. Persulfate transport and decomposition behavior in the soil-packed columns was similar in the presence of sucralose or dioxane. A simulated tracer test was conducted to illustrate the application of sucralose as an oxidative-attenuation tracer at the pilot scale. These results demonstrate the potential of sucralose as an oxidative-attenuation tracer to support the robust design of ISCO applications for dioxane. The oxidative-attenuation tracer test method is anticipated to be an effective approach for characterizing mass-removal behavior of other emerging contaminants with appropriate selection of tracer.