School of Resources and Environmental Science, Wuhan University, Wuhan, 430079, PR China.
State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China; Hubei Key Laboratory of Water System Science for Sponge City Construction, Wuhan University, Wuhan, 430072, China.
Chemosphere. 2021 Oct;281:130860. doi: 10.1016/j.chemosphere.2021.130860. Epub 2021 May 13.
Although sulfite-based advanced oxidation processes (AOPs) have received renewed attention due to the production of oxysulfur radicals, the feasibility of using ultrasound (US) to activate sulfite remains unknown. In this work, low frequency ultrasound has been applied for the first time to develop a novel sulfite activation process (US-S(IV)) for enhanced oxidation of arsenite (As(III)). Our results showed that the US-S(IV) process with 1 mM sulfite addition and 20 kHz 650 W ultrasound can achieve approximately 2.9-fold increase in As(III) oxidation rate compared to the US process at pH 7. The mechanisms underpinning the US-S(IV) process have been probed through radical-scavenging experiments and electron spin resonance (ESR) spectrometry. Direct ultrasonolysis of sulfite has been demonstrated to be the predominant pathway producing the primary sulfite radical (SO⁻) in the US-S(IV) process. Besides, the US-S(IV) process also works well in the treatment process of natural water, suggesting that this process could be promising in commercial scale application. This work not only provides a new application of ultrasound in sulfite-based AOP, but also provides further insights into how sulfite impacts the US process.
尽管基于亚硫酸盐的高级氧化工艺（AOPs）由于产生氧硫自由基而受到重新关注，但利用超声波（US）激活亚硫酸盐的可行性尚不清楚。在这项工作中，低频超声首次被应用于开发一种新型的亚硫酸盐激活工艺（US-S(IV)），以增强亚砷酸盐（As(III)）的氧化。我们的结果表明，在 pH 7 下，添加 1 mM 亚硫酸盐并使用 20 kHz、650 W 的超声波的 US-S(IV)工艺可使 As(III)的氧化速率比 US 工艺提高约 2.9 倍。通过自由基清除实验和电子自旋共振（ESR）光谱探测到了支持 US-S(IV)工艺的机理。直接超声降解亚硫酸盐被证明是 US-S(IV)工艺中产生主要亚硫酸盐自由基（SO⁻）的主要途径。此外，US-S(IV)工艺在天然水的处理过程中也能很好地发挥作用，表明该工艺在商业规模应用中具有广阔的前景。这项工作不仅为超声在基于亚硫酸盐的 AOP 中的应用提供了新的途径，还进一步深入了解了亚硫酸盐对 US 工艺的影响。
