Ammonium ions have positive effects on the sulfidization flotation of malachite; however, the underlying mechanisms remain poorly understood. In the present work, micro-flotation tests, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and solution analysis for ammonium nitrogen were carried out. The flotation results showed positive effects of ammonium on the sulfidization flotation of malachite. Macroscopically, the sulfidized malachite produced with ammonium exhibited a darker color than that without ammonium, whereas the opposite appeared to be true for their corresponding residual liquids. FESEM images highlighted the larger particle size and higher converge density of the sulfidization product when the presence of ammonium. Furthermore, XPS results indicated a higher sulfur concentration on malachite surfaces when the presence of ammonium. XRD results showed that Cu31S16 (djurleite) and Cu7S4 (anilite) comprised the sulfidization products, regardless of the presence or absence of ammonium. However, neither EDS nor XPS analysis showed nitrogen on malachite surfaces; moreover, the residual-ratio results for ammonium nitrogen clearly demonstrated that most ammonium continued to be held in solution before and after malachite sulfidization. Based on these findings, we inferred that ammonium ions may mediate the nucleation and growth of sulfidization product during malachite sulfidization, rendering larger sulfidization product particles. The larger size of sulfidization products may result in a darker, stabler and denser sulfidization product coating layer, and then may reduce the generation of colloidal copper sulfide in the residual liquids. Ultimately, ammonium facilitates better performance of sulfidization flotation of malachite.
Atmospheric environment governance requires necessary cost input. Only by accurately calculating regional atmospheric environment governance cost and scientifically allocating it within a region can the operability and realization of the coordinated governance of the regional environment be ensured. Firstly, based on the consideration of avoiding the technological regression of decision-making units, this paper constructs a sequential SBM-DEA efficiency measurement model and solves the shadow prices of various atmospheric environmental factors, that is, their unit governance costs. Secondly, combined with the emission reduction potential, the total regional atmospheric environment governance cost can be calculated. Thirdly, the Shapley value method is modified to calculate the contribution rate of each province to the whole region, and the equitable allocation scheme of the atmospheric environment governance cost is obtained. Finally, with the goal that the allocation scheme based on the fixed cost allocation DEA (FCA-DEA) model converges with the fair allocation scheme based on the modified Shapley value, a modified FCA-DEA model is constructed to achieve the efficiency and fairness of the allocation of atmospheric environment governance cost. The calculation and allocation of the atmospheric environmental governance cost in the Yangtze River Economic Belt in 2025 verify the feasibility and advantages of the models proposed in this paper.
The methane adsorption at room temperature in the interlayer of the kaolinite–methanol complex (Kln–Me) with different methanol content is investigated with grand canonical Monte Carlo (GCMC) simulation. The mechanism and structure of methanol intercalated kaolinite (Kln) is proposed, and the effect of methanol on methane adsorption by Kln–Me is discussed. The results indicate that the methanol adsorption in the Kln interlayer is mostly physical with non-bonded energy. The interlayer spacing ( d) of Kln–Me optimized by the DREIDING force field is in good agreement with the experimental data measured with X-ray diffraction. The configuration, adsorption properties, and adsorption isotherms are obtained for eight Kln–Me systems with different number (2–20) of methanol molecules in interlayer space. By comparing methane adsorption in the Kln–Me interlayer with different number of methanol molecules, we discover the complex interplay of factors influencing methane adsorption in the Kln–Me interlayer, especially the number of methanol molecules and free volume. It is found that the adsorption capacity of Kln can be enhanced by inserting methanol molecules into its interlayer. This analysis also underscores the GCMC simulation as a viable tool to calculate kaolinite/organic intercalation composites for potential applications.
This study investigates how environmental regulations and social norms affect farmers’ chemical fertilizer reduction behaviors (CFRBs) and investigates the mediating role played by social norms and the moderating role played by social networks. As the analysis tool, a structural equation model is employed to analyze the data collected from a questionnaire survey with 402 valid samples of Chinese citrus growers. This study reveals that (1) environmental regulations and social norms have a significant effect on farmers’ CFRBs; (2) injunctive social norms are a partial mediator of the relationship between incentive-based environmental regulations and farmers’ CFRBs; (3) social networks play a positive moderating role in the relationship between injunctive social norms and farmers’ CFRBs; and (4) large-scale farmers’ CFRBs are more susceptible to the impact of environmental regulations and social norms than small-scale farmers. The result of this study provides a significant scientific foundation for the Chinese agricultural sector to develop policies to combat soil pollution in agriculture.
The new order of aves, Gansuiformes, is established on the basis of the fossil specimens,including a tibiotarsus and a tarsometatarsus with four complete digits derived from the LowerCretaceous of Yumen, Gansu Province. The new bird probably represents the oldest one incontinental deposits. As Archaeopteryx is now considered as the ancestor of all landbirds,Gansus, the new bird is supposed to be the ancestor of shorebirds and waterbirds. Gansui-formes is similar to Charadriformes and some waterbirds in certain characters.
Worldwide, urban rivers suffer various degrees of ecological degradation. Rehabilitating heavily modified urban rivers requires holistic approaches, including environmental flow management. We examine the case of Lower Yongding River, Beijing’s mother river, which had dried up since the 1980s and is undergoing a flow replenishment experiment, receiving 342 million m3 of water during 2019–2020 for ecosystem enhancement. Considering the massive cost of replenishment, we address the urgent need to evaluate its outcomes and inform future management through an interdisciplinary modeling approach under the circumstance of severe data shortage. We simulated the study reach’s landscape evolution under five flow scenarios and assessed their ecological effects using the CAESAR-Lisflood model and habitat suitability index method. Despite overall minor morphological differences across scenarios, individual reaches presented pronounced physical changes. Higher-flow scenarios shaped a distinct channel in certain reaches, but historic channel modifications by mining and farming caused minimal responses in others. Additionally, higher-flow scenarios generally created larger and more evenly distributed habitat areas but showed a low payback given the higher flow volumes needed. Targeted channel-floodplain geomorphological restoration is essential for flows to generate desired ecological outcomes. The demonstrated modeling framework offers great promise, informing future rehabilitation actions for heavily modified urban streams.
As the world’s largest carbon emitter, China is under great pressure to cut down carbon emissions. Understanding the evolution of carbon emissions across Chinese cities is important for policymakers when allocating carbon emission quota among these cities. This paper draws upon the Open-source Data Inventory for Anthropogenic CO 2 to calculate city-level per capita carbon emissions in China from 2001 to 2016. Overall, we find that per capita carbon emissions of Chinese cities have been generally on the rise during the 2001–2016 period. However, there has been on average a modest decline in per capita carbon emissions of cities in China’s Yangtze River Delta region and Pearl River Delta region from 2011 to 2016, after a remarkable increase during the 2001–2011 period. Besides, the average north-south gap has been enlarged, with northern cities having a relatively higher level of per capita carbon emissions.
Shale gas development throughout the world has resulted in a revolution in the field of global energy and has also become an important topic in China in recent years. While organic-rich shale is widely distributed in China and the initial commercialization of shale gas has been achieved, the research, exploration, and development of shale gas remain at an early stage. Problems exist with crucial technologies, innovation, institutional mechanisms, environmental protection, and other aspects of the industry. The shale gas exploration and development industry in China can learn from the experiences of other countries and strengthen its position in the market, with the support of new government policy. Given its unique geological conditions, China should speed up the introduction of technical innovation and establish its unique systems and methods for shale gas exploration and development.
Presently, China is in a critical period of economic transformation and upgrading. At the same time, it is also facing the pressure of serious atmospheric environmental pollution, which seriously threatens human health and hinders the sustainable economic development. Air pollutants are closely related to economic sectors, which together constitute a complex network. Air pollutants form an input–output ecological metabolic relationship among different sectors. Therefore, from the perspective of complex metabolic network, this study first constructs an environmental input–output model and then comprehensively uses the relevant methods of ecological network analysis and complex network analysis to analyze the characteristics of China’s air pollutant emission system. Secondly, the key joint sectors of NOx and PM emissions are determined from the supply side and the demand side, respectively. Finally, the corresponding emission reduction measures are proposed for the identified key sectors.
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