A visible light-induced carbene reactivity of acceptor diazoalkanes has been developed toward synthesis of difunctionalized ethers from cyclic ethers and various N/O/S nucleophiles. The carbene transfer reactions involve oxonium ylide...

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Vanadium isotope compositions (δ­(51V)) in marine carbonates are a potential proxy to trace global redox states of ancient oceans. Although high-precision δ­(51V) analyses are available for many geological materials, carbonate-hosted δ­(51V) data have not been reported yet due to extremely high matrix elements and low V contents (generally below 10 μg g–1). In this study, we developed an Fe coprecipitation method combined with an Fe column to preconcentrate V from the major matrix elements and subsequent four-step chromatographic procedures to further purify V in carbonates. The δ­(51V) values were measured using a sample–standard bracketing method by MC-ICP-MS. The robustness of this method was assessed by analyzing element-doped and matrix-spiked synthetic carbonate solutions containing an in-house δ­(51V) standard, USTC-V. The mean δ­(51V) value of the synthetic carbonate solutions (0.06 ± 0.08‰; 2SD, n = 33) is in good agreement with the recommended value of the USTC-V relative to the Oxford AA solution (0.07 ± 0.08‰; 2SD, n = 347). In addition, the consistency in the δ­(51V) value of the igneous carbonatite standard, COQ-1, which was processed in parallel with the whole purification (−0.48 ± 0.04‰; 2SD, n = 3) and a four-step chromatographic procedure (−0.43 ± 0.08‰; 2SD, n = 3), further validates the robustness of our method. For the first time, we obtained δ­(51V) values of four carbonate reference materials: JDo-1, −0.56 ± 0.09‰ (2SD, n = 27); JLs-1, −0.61 ± 0.14‰ (2SD, n = 33); GBW07217a, −0.79 ± 0.09‰ (2SD, n = 6); GBW07214a, −0.51 ± 0.13‰ (2SD, n = 48). The long-term external precision of carbonate-hosted δ­(51V) analyses is better than ±0.14‰ (2SD). Our method can be applied to measure carbonate-hosted δ­(51V) to trace the evolution in global marine redox states throughout the Earth’s history.

The removal of antimony (Sb) from textile and dyeing wastewater is a challenging task. To meet the discharge limit and the demand for water reuse, the currently available treatment process was complicated: first, coagulation with polyaluminum chloride (PAC) and polyacrylamide (PAM) prior to membrane filtration to remove turbidity and then coagulation with polyferric sulfate (PFS) after membrane filtration to remove Sb from the concentrate. Such a process is troublesome in operation and generates a large amount of hazardous sludge. Here, we report that using a titanium xerogel coagulant (TXC) prior to membrane filtration could simultaneously remove the turbidity and the residual Sb in one-step. With TXC as the coagulants, no after-membrane coagulation was needed. Moreover, the TXC coagulation significantly alleviated the membrane fouling. A 24-day running of a pilot-scale test demonstrates that addition of 60 mg/L of TXC reduced the residual Sb concentration in the effluent from 226–894 μg/L to below the discharge limit (<50 μg/L). Meanwhile, the operating time of the ultrafiltration (UF)–reverse osmosis (RO) membrane system was prolonged, because of alleviated membrane fouling. This work indicates that TXC coagulation is a promising strategy for the treatment of Sb-containing wastewater. The simplified treatment procedure and the alleviated membrane fouling are helpful in reducing the processing costs for water reuse.

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