Effects of Al doping on the structure and properties of goethite and its adsorption behavior towards phosphate

Al substitution in goethite is common in soils, and has strong influence on the structure and physicochemical properties of goethite. In this research, a series of Al-doped goethites were synthesized, and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The adsorption behavior of these samples towards PO₄^3 − was also investigated. Characterization results demonstrated that increasing Al content in goethite led to a reduction in crystallinity, increase in specific surface area (SSA), and morphology change from needle-like to granular. Rietveld structure refinement revealed that the lattice parameter a remained almost constant and b slightly decreased, but c was significantly reduced, and the calculated crystal density increased. EXAFS analysis demonstrated that the Fe(Al)–O distance in the structure of the doped goethites was almost the same, but the Fe–Fe(Al) distance decreased with increasing Al content. Surface analysis showed that, with increasing Al content, the content of OH groups on the mineral surface increased. The adsorption of phosphate per unit mass of Al-doped goethite increased, while adsorption per unit area decreased owing to the decrease of the relative proportion of (110) facets in the total surface area of the minerals. The results of this research facilitate better understanding of the effect of Al substitution on the structure and properties of goethite and the cycling of phosphate in the environment.     

臭气强度在恶臭污染物环境空气影响中的应用研究

以兰州某石化公司化工污水处理厂恶臭治理项目为例,在确定恶臭气体的污染源源强的基础上,采用AERMOD模式预测污染物扩散情况。结果表明,添置除臭装置后,NH3的臭气浓度减少了90%,VOCs的臭气浓度减少了88%。同时,当恶臭污染物浓度达到环境质量浓度标准时,NH3的臭气强度为1．40级,VOCs的臭气强度为0．82级,人们仍能感觉到气味。因此石化企业在进行恶臭治理过程中需综合考虑污染物的环境空气质量浓度标准和臭气强度,以期改善环境空气质量。     

Comparative Analysis of Inundation Mapping Approaches for the 2016 Flood in the Brazos River,Texas

Accurate and timely flood inundation maps serve as crucial information for hydrologists, first‐responders, and decision makers of natural disaster management agencies. In this study, two modeling approaches are applied to estimate the inundation area for a large flooding event that occurred in May 2016 in the Brazos River: (1) Height Above the Nearest Drainage combined with National Hydrograph Dataset Plus (NHDPlus‐HAND) and (2) International River Interface Cooperative — Flow and Sediment Transport with Morphological Evolution of Channels (iRIC‐FaSTMECH). The inundation extents simulated from these two modeling approaches are then compared against the observed inundation extents derived from a Landsat 8 satellite image. The simulated results from NHDPlus‐HAND and iRIC‐FaSTMECH show 56% and 70% of overlaps with the observed flood extents, respectively. A modified version of the NHDPlus‐HAND model, considering networked catchment behaviors, is also tested with an improved fitness of 67%. This study suggests that NHDPlus‐HAND has the potential for real‐time continental inundation forecast due to its low computational cost and ease to couple with the National Water Model. Better performance of NHDPlus‐HAND can be achieved by considering the inter‐catchment flows during extreme riverine flood events. Overall, this study presents a comprehensive examination made of remote sensing compared with HAND‐based inundation mapping in a region of complex topography.     

Association between population density and infection rate suggests the importance of social distancing and travel restriction in reducing the COVID-19 pandemic

Environmental Science and Pollution Research - Currently, 2019-nCoV has spread to most countries of the world. Understanding the environmental factors that affect the spread of the disease COVID-19...     

Environmental efficiency and its determinants in the development of China’s western regions in 2000–2014

In this study, we measure the environmental efficiency of western China in 2000–2014 by the super-efficiency slacks-based measure model which considers the undesirable outputs. The results show that the environmental efficiency of western China is low and rank behind in the national level. The environmental efficiency is lower than the traditional efficiency which reflects that the economic growth in 2000–2014 has paid high environmental costs. The difference between the traditional efficiency and environmental efficiency experienced “inverted U”-type trend change. The environmental efficiency of the western provinces presented differentiated developing trend and the differences between the western provinces were enlarging. The environmental efficiency of the western regions was not only lower than that in the eastern regions with a big gap but also lower than that in the central regions. Through the convergence test, we found that the environmental efficiency gap between the western and the eastern regions was gradually expanding; meanwhile, the environmental efficiency gap between the central and the western regions was narrowing. This paper also analyzes the determinants of environmental efficiency by the tobit model and then addresses.     

序言

<正>A model organism is a non-human species that is extensively studied to understand particular biological phenomena,with the expectation that discoveries made in the organism model will provide insight into the workings of other organisms.模式生物是一类为了揭示特殊生物学现象而广泛采用的非人类种属,通过对模式生物物种进行的科学研究可以类推到同类或其他类别生物的某种具有普遍规律的生命现象。如今,模式生物的研究     

Impact of cleaner production on business performance

Extensive research has examined the relationship between environmental management/performance and business performance but yielded no conclusive results. This paper makes two contributions to the literature. First, instead of focusing on one aspect, we try to compare using various types of cleaner production activities: low- and high-cost activities. Second, the study complements the existing literature which focuses on firms in developed countries with an analysis of firms in the Chinese manufacturing industry. In this paper, the relationship between cleaner production and business performance was analyzed using Structure Equation Model (SEM). We find an overall positive impact of cleaner production on firm's business performance. We also found that the cleaner production activities of low-cost scheme have a bigger contribution to financial performance compared to non-financial performance, while cleaner production activities of high-cost scheme have a greater contribution to non-financial performance, compared to financial performance. This study should be useful for firms that consider adopting cleaner production as well as stakeholders who aim to promote cleaner production.     

浅议现代企业安全管理需要法治

简述了现代企业安全管理必须加强法制建设。只有逐步形成以法治为保障的安全管理模式，企业才能不断自我完善和发展。     

电子废弃物回收处置及再循环利用——基于在校大学生的问卷调查

随着现代科技的迅猛发展和人们消费水平的日益提高，越来越多的电子产品被时尚性淘汰，其次是功能性淘汰，而由于耐久性淘汰的电子废弃物所占比例越来越低。问卷调查结果表明，体验消费、追求时尚和更多功能是在校大学生消费电子产品的主要特征；大多数被调查者不满意目前的电子废弃物回收途径，期待能有所改善；接近三成的在校大学生不知道如何合理处置电子废弃物；消费者、生产者和废品回收者的环保意识水平较低，市场不规范和政府在法律法规及监管上的疏漏，是造成目前电子废弃物回收市场秩序混乱的主要原因。     

建立优质种苗示范基地，加快发展海南椰子产业

通过对海南椰子生产现状的分析，本文指出了建立优质良种椰子种苗生产示范基地的必要性和重要性，并针对一些需要解决的问题，提出了加快海南椰子产业发展的建议。