Publications by authors named "Shichao Cai"

The solid-solid reaction of microscale zero-valent iron (mZVI) with elemental sulfur (S) in water can form sulfidated mZVI (S-mZVI) with high reactivity and selectivity. However, the inherent passivation layer of mZVI hinders the sulfidation. In this study, we demonstrate that ionic solutions of Me-chloride (Me: Mg, Ca, K, Na and Fe) can accelerate the sulfidation of mZVI by S.

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Ball milling is an effective technique to not only activate and reduce the size of commercial microscale zero valent iron (mZVI) but also to mechanochemically sulfidate mZVI. Yet, little is known about the difference between how chlorinated ethenes (CEs) interact with ball milled mZVI (mZVI) and mechanochemically sulfidated mZVI (S-mZVI). We show that simple ball milling exposed the active Fe sites, while mechanochemical sulfidation diminished Fe sites and meanwhile increased S sites.

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Sulfidation can enhance both the reactivity and selectivity (i.e., electron efficiency, ε) of zero-valent iron (ZVI) in contaminant removal, which may make this technology cost-effective for a wider range of water treatment applications.

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Groundwater pH is one of the most important geochemical parameters in controlling the interfacial reactions of zero-valent iron (ZVI) with water and contaminants. Ball milled, microscale ZVI (mZVI) efficiently dechlorinated TCE at initial stage (<24 h) at pH 6-7 but got passivated at later stage due to pH rise caused by iron corrosion. At pH > 9, mZVI almost completely lost its reactivity.

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