No abstract

In the perennial river, environmental base flow, associated with environmental flow, is the base flow that should be maintained within the river channel throughout the year, especially in the dry season, to sustain basic ecosystem functions and prevent the shrinkage or discontinuity of a river. The functions of environmental base flow include eco-environmental functions, natural functions, and social functions. In this study, we provided a method based on these functions; this method estimated the function values per unit area, introduced the scarcity coefficient, multiplied by the corresponding water area, and summed over to quantify the value of environmental base flow from 1973 to 2015 in the Wei River Basin, the largest tributary of the Yellow River in Northwest China. We observed that there was a positive correlation between the total value of environmental base flow and its water yield, whereas this outcome was completely different in the benefit per unit discharge of environmental base flow, which was closely associated with the shortage of environmental base flow. This method can thus present the considerable value of environmental base flow in monetary terms in a simple and effective way and lay the foundation for further reasonable protection levels of environmental base flow.

No abstract

No abstract

Organic–inorganic hybrid materials [Rmim]4Mo8O26 (1-alkyl-3-methylimidazolium polyoxomolybdate, alkyl = n-C4H9, n-C6H13, and n-C8H17) were prepared, and various characterization techniques have proven the hybrids’ successful synthesis. Meanwhile, the oxidative desulfurization (ODS) performance of both model and real diesel has been evaluated with H2O2 as the oxidant and acetonitrile (MeCN) as the extractant. Notably, these catalysts, initially insoluble in MeCN solution, fulfill a H2O2-responsive phase transfer into the MeCN phase to improve the ODS performance, facilitating the S compound extraction to the MeCN phase. After the ODS reaction, the hybrids precipitated from the MeCN phase, completed the heterogeneous separation, and regenerated simply by drying. Hybrid materials [Omim]4Mo8O26 (1-octyl-3-methylimidazolium polyoxomolybdate) with the longest alkyl chain displayed the highest desulfurization efficiency, achieving 99.8% dibenzothiophene (DBT) removal at the optimum reaction conditions of 50 °C, O/S = 5, Mo/S = 1:1, and V­(MeCN/diesel) = 1:5. Even for real diesel, the hybrid exhibited more than 97% sulfur removal in diesel with sulfur contents of 3000 μg/g through the two-stage extraction-coupled oxidation desulfurization (ECODS) process. High catalytic recycling capability has been manifested by no obvious decrease in ODS activity after five cycles. This extraction-promoted H2O2-responsive phase transfer catalysis guarantees a promising industrial ODS system, not only substantially improves the catalytic desulfurization activity but also shows superior recycling performance with a simple catalyst regeneration method.

No abstract

The rational allocation of ecological and economic water is a topic of high interest for water resource sciences. Taking into consideration the difficulties to maintain the basic ecologic functions of rivers, we propose a calculation model for compensation for agricultural economic losses by restoration of the healthy eco-hydrological sequences of rivers. Firstly, healthy eco-hydrological sequence of rivers was constructed by assessing the response relationship between hydrological processes and ecological functions of ecological base flow of rivers. Following, the ecological water shortage was analyzed qualitatively and quantitatively. Finally, the compensation for agricultural economic losses caused by restoration of healthy eco-hydrological sequence of rivers was calculated. Taking the Baoji section of the Weihe River as a case study, compensation for agricultural economic losses caused by the recovery of the healthy eco-hydrological sequence of rivers were calculated and further analyzed. The results show that the current water diversion in the area of study is excessive and the ecological water shortage is relatively obvious. The compensation for agricultural economic losses caused by the recovery of healthy eco-hydrological sequence of rivers mainly focus on the non-flood season, which is up to 218 million yuan for 2009 year.

There are two independent mol­ecules in the asymmetric unit of the title compound, C16H16N2O3, in which the dihedral angles between the two aromatic rings are 13.0 (3) and 6.4 (3)°. Intra­molecular O—H⋯N and N—H⋯O hydrogen bonds are observed in both mol­ecules, forming S(6) rings in all cases.