Prussian blue analogues-derived zero valent iron to efficiently activate peroxymonosulfate for phenol degradation triggered via reactive oxygen species and high-valent iron-oxo complexes.

It is of great significance to develop the effective technique to treat phenol-containing wastewater. Herein, Fe-based prussian blue analogues-derived zero valent iron (ZVI) was successfully synthesized by one-step calcination method. Owing to high specific surface area and rich active sites, ZVI-2 possessed excellent performance in charge transfer. Notably, in comparison with conventional ZVI and Fe2+, ZVI-2 can effectively activate peroxymonosulfate (PMS) for achieving rapid degradation of phenol, and the highest removal efficiency of phenol reached 94.9% within 24 min. More importantly, developed ZVI-2/PMS oxidation system with good stability displayed strong anti-interference capability. Interestingly, Fe0 loaded on the surface of ZVI-2 can efficiently break the O-O bond of PMS to generate reactive oxygen species (i.e., SO4•-, OH•, O2•- and 1O2). As main adsorption sites of PMS, the existence of oxygen vacancy promote the formation of high-valent transition metal complexes (namely ZVI-2≡Fe4+=O). Under the combined action of reactive oxygen species and ZVI-2≡Fe4+=O, phenol can be eventually degraded into CO2 and H2O. The possible degradation pathways of phenol were also investigated. Furthermore, proposed ZVI-2/PMS oxidation system displayed great potential for application in the field of wastewater treatment. All in all, current work provided a valuable reference for design and application of Fe-based catalysts in PS-AOPs.

[Location design of ecological barriers for river-type reservoir based on flux analysis metho]. / 基于通量分析方法的河川型水库生态屏障区位设计.

Location selection is an important scientific issue in the research and construction of water ecological barrier. Considering the characteristics of river-type reservoir with various inflow modes and large topographic fluctuation, we presented a location selection method for ecological barrier of river type reservoir based on flux analysis with the removal function of non-point source pollution of water ecological barrier. Using this method, we examined the ecological barrier location in the Three Gorges Reservoir area of China. The results showed that the role of ecological barrier for water in the study area could not be brought into full play according to the design plan of 100 m width along the coast of the Three Gorges Reservoir area. The zone of optimal function accounted for 11% of the design area, and ineffective zone accounted for 10% of the design area. 79% of the total nitrogen and 93% of the total phosphorus were concentrated in the area accounting for 21% of the total ecological barrier area and entered the reservoir. According to the flux of pollutants and their process of flow and flux, we extracted the confluence area of pollutants with high flux and area with high pollutant concentration. Based on the protection target, the ecological engineering measures to reduce the total pollutants and ensure the standard reaching of pollutant concentration were carried out respectively. This method, with full consideration of the influence of terrain on pollutant flux and classification of the key protected areas in water ecological barrier, could effectively solve the problem of location design of water ecological barrier in river-type water.