Efficient abatement of an iodinated X-ray contrast media iohexol by an emerging sulfite autoxidation advanced oxidation process is demonstrated, which is based on transition metal ion–catalyzed autoxidation of sulfite to form active oxidizing species. The efficacy of the combination of sulfite and transition metal ions (Ag(I), Mn(II), Co(II), Fe(II), Cu(II), Fe(III), or Ce(III)) was tested for iohexol abatement. Co(II) and Cu(II) are proven to show more pronounced catalytic activity than other metals at pH 8.0. According to the quenching studies, sulfate radical (SO4??) is identified to be the primary species for oxidation of iohexol. Increasing dosages of metal ion or sulfite and higher pH values are favorable for iohexol abatement. Inhibition of iohexol abatement is observed in the absence of dissolved oxygen, which is vital for the production of SO5?? and subsequent formation of SO4??. Overall, activation of sulfite to produce reactive radicals with extremely low Co(II) or Cu(II) concentrations (in the range of μg L?1) in circumneutral conditions is confirmed, which offers a potential SO4??-based advanced oxidation process in treatment of aquatic organic contaminants.
China launched the One Belt & One Road (OBOR) initiative to minimize the energy resource shortage. The China’s nearby countries are rich in energy resources especially Middle East and North Africa (MENA) and Asian countries which make them ideal locations to cooperate with China in terms of energy resources, as 42.8% of world energy consumption belongs to OBOR countries. The present study elaborates the spatial distribution pattern of energy consumption disparities and its impact on environment. To do this, an entropy approach is utilized to compute the energy consumption inequalities in OBOR and its regions. The spatial and Pareto analysis show that MENA, East, and Southeast Asian economies have the highest degree of energy consumption inequalities, while European and Central Asian economies show the lowest energy consumption inequalities in OBOR region. The long-run estimates indicate that energy consumption inequalities enhance the CO2 emission in OBOR and its region except South and Southeast Asia. Financial development also has a significantly positive impact on CO2 emission in all models for OBOR and its regions except East Asia. Based on findings, the spatial distribution analysis is applicable to maintain balance in regional energy consumption inequality within OBOR and its regions.
Surface sediment samples were collected at 27 stations of Bohai Bay, North China. Sequential extractions were carried out in this study. REE were leached out from four labile fractions: Exchangeable (L1), bound to carbonates (L2), bound to Fe–Mn oxides (L3), bound to organic matter (L4), and the remainder was residual (R5). The total contents of REE fluctuate slightly in Bohai Bay, and are mainly concentrated in the middle region, showing relatively higher levels in the north than that in the south of Bohai Bay. Percentages of L1, L2, L3, L4, and R5 for REE suggest that the residual fraction accounts for the major component of REE, whereas Fe–Mn oxides also play important roles in combining labile REE. As the REE complex is not stabilized, the competition of complex could induce dissociation of the complex and redistribution of the REE in various environments. According to REE patterns and Y/Ho ratios of samples, REE are not anthropogenic or oceanic sources but riverine input, whereas suitable environment varieties can slightly affect the patterns and fractionations of REE. As powerful tracers for the variable of environment, higher anomaly of Eu and Ce in southern regions indicates a greater reduction in the condition of surface sediment in the south than that in the north of Bohai Bay. 相似文献