Technological innovation is one of the potential engines to mitigate environmental pollution. However, the implementation of new technologies sometimes fails owing to socioeconomic constraints from different stakeholders. Thus, it is essential to analyze constraints of environmental technologies in order to build a pathway for their implementation. In this study, taking three technologies on rural sewage treatment in Hangzhou, China as a case study, i.e., wastewater treatment plant (WTP), constructed wetland (CW), and biogas system, we analyzed how socioeconomic constraints affect the technological choices. Results showed that socioeconomic constraints play a key role through changing the relative opportunity cost of inputs from government as compared to that of residents to deliver the public good—sewage treatment—under different economic levels. Economic level determines the technological choice, and the preferred sewage treatment technologies change from biogas system to CW and further to WTP along with the increase of economic level. Mismatch of technological choice and economic level results in failures of rural sewage treatment, e.g., the CW only work well in moderately developed regions in Hangzhou. This finding expands the environmental Kuznets law by introducing the coproduction theory into analysis (i.e., inputs from both government and residents are essential for the delivery of public goods and services such as good environmental quality). A match between technology and socioeconomic conditions is essential to the environmental governance.
La-EDTA-Fe3O4 was prepared by a chemical co-precipitation method. The magnetic composite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, the adsorption properties of La-EDTA-Fe3O4 toward phosphate in water were investigated. The uptake rate of phosphate in water by La-EDTA-Fe3O4 was 3-1000 times than that of EDTA-Fe3O4 , and reached 97.8% at 7 hr. The adsorption process agreed well with the Freundlich model and kinetics studies showed that the adsorption of phosphate proceeds according to pseudo second-order adsorption kinetics. The maximum removal rate was achieved at pH 6.0-7.0. The La-EDTA-Fe3O4 had good adsorption properties and could be separated well from aqueous solution by a permanent magnet. Therefore, this nanomaterial has potential application for the removal of phosphate from large water bodies. 相似文献
Nine compounds were isolated from the spikes of Prunella vulgaris by various kinds of chromatography. Their structures were established on the basis of spectral analysis as polygalacerebroside (1), ursolic acid (2), β-amyrin (3), quercetin (4), quercetin-3-O-β-D-galactoside (5), α-spinasterol (6), stigmasterol (7), β-sitosterol (8), daucosterol (9). Compound 1 was isolated from this genus for the first time. Phytochemical investigation on the spikes of P. vulgaris provided chemical constituents diversity, which were performed to facilitate further development and utilization of P. vulgaris pharmaceutical resource. 相似文献
Microcystis panniformis is a bloom forming species with flat panniform-like colonies. This species was recently found in Lake Taihu, China. To specifically characterize M. panniformis based on isolated strains, morphological examination on colonial transition and genetic examination are needed. Three M. panniformis strains isolated from a water bloom sample in Lake Taihu were characterized by molecular analysis and toxin quantification. Phylogenetic analysis based on both 16S rRNA gene and internal transcribed spacer(ITS) between 16S and 23S rRNA genes were performed and compared to facilitate easy identification of the species.Relatively high similarities(98%–99%) were shown in 16S rDNA sequences between the strains of M. panniformis and those of other Microcystis species, whereas the similarities for ITS sequences were 88%–95%. In the phylogenetic tree based on the 16S rDNA sequences, the M. panniformis and M. aeruginosa strains were intermixed together with no clear division,whereas all of the M. panniformis strains were clustered together in a single clade based on the ITS sequences based phylogenyetic tree. The mcyE gene was detected in all three strains, and microcystin was determined by high-performance liquid chromatography. The molecular detection and toxin production of M. panniformis strains are of great significance for the environmental risk assessment of Microcystis blooms. 相似文献