Treatment of sulfolane in groundwater: A critical review

This review critically examined the existing technologies for the treatment of sulfolane, which is an emerging groundwater contaminant. In general, sulfolane plumes are difficult to contain and mitigate because sulfolane is highly mobile and does not biodegrade to an appreciable extent under anoxic conditions typical of many subsurface environments. Several studies have shown that sulfolane biodegradation can be enhanced in the presence of oxygen, suggesting that in situ biosparging or ex-situ (i.e., pump and treat) aerobic biodegradation can potentially be effective means of remediating sulfolane-contaminated sites. While highly reactive species such as SO₄^•- and ^•OH radicals have been shown to oxidize sulfolane, whether sulfolane can be effectively treated by ex situ advanced oxidation processes (AOPs) or by in situ chemical oxidation (ISCO) needs to be further examined. Besides chemical and biological treatments, pump and treat by adsorption on granular activated carbon (GAC) has been applied to remove sulfolane at several sites. To optimize the treatment as well as to identify more effective adsorbents, additional research is needed to investigate the mechanism and factors affecting sulfolane adsorption. In addition to assessing the treatment of sulfolane, this review also discussed the analytical methods for the quantification of sulfolane in the context that guidelines for sulfolane will likely become more stringent and, therefore, analytical methods with lower detection limit will be needed for future research.