Advanced reduction by the extremely strong reducing species, hydrated electron (e_aq⁻), is a promising and viable approach to eliminate a wide variety of persistent and toxic contaminants. In this study, we proposed a sulfite/iodide/UV process, which offered efficient production of e_aq⁻ for contaminant reduction. Using monochloroacetic acid (MCAA) as a simple e_aq⁻ probe, the availability of e_aq⁻ was assessed, and the mechanism involving the roles of S(IV) and iodide in the process was elucidated. A pronounced synergistic effect of S(IV) and iodide was observed in MCAA reductive dechlorination. The efficiency was much more dependent on the iodide concentration due to its higher absorptivity and quantum yield of e_aq⁻. S(IV) played a dual role by producing e_aq⁻ via photoionization of SO₃²⁻ and by reducing the reactive iodine species formed to avoid their scavenging of e_aq⁻. When S(IV) was available, cycling of iodide occurred, favoring the constant e_aq⁻ production. The formation and transformation kinetics of sulfite radical were studied to verify the roles of S(IV) and iodide in the process. A kinetic model of MCAA dechlorination was also developed to quantify the e_aq⁻-initiated reduction efficiency, highlighting the effects of S(IV), iodide, and pH. High pH favored the reduction, and the process was still effective in field surface water. This study underscores the importance of producing e_aq⁻ efficiently and of minimizing the e_aq⁻ scavenging of intermediates inherently formed and accumulated, and highlights the potential of the sulfite/iodide/UV process to efficiently eliminate recalcitrant contaminants.

先进减少由极强还原物质，水合电子（E_水溶液^- ），是消除各种持久性和毒性污染物的有希望的和可行的方法。在这项研究中，我们提出了亚硫酸盐/碘/ UV工艺，其提供了高效率的生产电子_含水^-为减少污染物。用一氯乙酸（MCAA），其为简单的电子_水溶液^-探针，电子可用性_水溶液^-进行了评估，阐明了在此过程中涉及S（IV）和碘化物作用的机理。在MCAA还原脱氯中观察到了S（IV）和碘化物的明显协同作用。效率是更依赖于碘化物浓度由于电子其较高的吸收率和量子产率_水溶液^- 。S（IV）通过产生Ë起到了双重作用_水溶液^-通过的SO光电离₃ ^2-，并通过减少形成以避免其电子清除反应性碘物质_水溶液^- 。当S（IV）是可利用的，碘化物的循环发生，有利于常数e_水溶液^-生产。研究了亚硫酸根的形成和转化动力学，以验证S（IV）和碘化物在该过程中的作用。MCAA脱氯的动力学模型也被开发来量化电子_水溶液^- -引发的还原效率，突出S（IV），碘化和pH的影响。高pH值有利于还原，该方法在田间地表水中仍然有效。本研究强调产生e的重要性_水溶液^-高效和最小化的电子_水溶液^-中间体的固有清除形成和积累，以及亮点的亚硫酸盐/碘/ UV处理的电位有效地消除顽固的污染物。