Potential bioavailability of mercury in humus-coated clay minerals

It is well-known that both clay and organic matter in soils play a key role in mercury biogeochemistry, while their combined effect is less studied. In this study, kaolinite, vermiculite, and montmorillonite were coated or not with humus, and spiked with inorganic mercury (IHg) or methylmercury (MeHg). The potential bioavailability of mercury to plants or deposit-feeders was assessed by CaCl₂ or bovine serum albumin (BSA) extraction. For uncoated clay, IHg or MeHg extraction was generally lower in montmorillonite, due to its greater number of functional groups. Humus coating increased partitioning of IHg (0.5%–13.7%) and MeHg (0.8%–52.9%) in clay, because clay-sorbed humus provided more strong binding sites for mercury. Furthermore, humus coating led to a decrease in IHg (3.0%–59.8% for CaCl₂ and 2.1%–5.0% for BSA) and MeHg (8.9%–74.6% for CaCl₂ and 0.5%–8.2% for BSA) extraction, due to strong binding between mercury and clay-sorbed humus. Among various humus-coated clay particles, mercury extraction by CaCl₂ (mainly through cation exchange) was lowest in humus-coated vermiculite, explained by the strong binding between humus and vermiculite. The inhibitory effect of humus on mercury bioavailability was also evidenced by the negative relationship between mercury extraction by CaCl₂ and mercury in the organo-complexed fraction. In contrast, extraction of mercury by BSA (principally through complexation) was lowest in humus-coated montmorillonite. This was because BSA itself could be extensively sorbed onto montmorillonite. Results suggested that humus-coated clay could substantially decrease the potential bioavailability of mercury in soils, which should be considered when assessing risk in mercury-contaminated soils.     

锅炉省煤器H型鳍片管局部泄漏机理研究

本文以某电厂的#1机组锅炉炉省煤器H型鳍片管为研究对象,设计对比试验,从宏观分析和微观分析两方面,对鳍片管局部泄漏的原因进行了深入研究,最终推断发生泄漏是局部点蚀所致.在锅炉运行过程中,沟槽内灰分沉积致使S、Cl元素在沟槽底部富集而发生点蚀,减薄管壁,直至局部区域管壁不足以承压而发生泄漏.本文研究贴近工程实际,具有实际...     

连续紫外扫描光谱法快速测定废水的化学需氧量

探讨了紫外扫描光谱最佳吸收波段内的吸光度集合所组成的峰面积与被测定废水的COD含量的相关性,同时进行了精密度和标准方法的比对实验,取得较好效果.该方法适用于多成分有机混合物的快速测定.     

The Boiling Liquid Expanding Vapour Explosion (BLEVE): A bibliometric review and futur trends

The phenomenon “Boiling Liquid Expanding Vapor Explosion” (BLEVE) is one of the most common accidental events in the chemical industry and in the transport of dangerous goods. A bibliographic search in the Web of Science Core Collection reported 375 publications related to BLEVEs from 1979 to the present (August 10, 2022). A bibliometric analysis was conducted using the VOSviewer tool to allow a better understanding of the scientific knowledge on this phenomenon. A comprehensive overview of BLEVE research is presented in terms of annual publication, top journals, countries/regions with the highest productivity, authors and their cooperation networks, key terms, and co-citation analysis. The 375 publications cover 691 authors, 83 journals, 44 countries or territories and 290 institutions. The key publication (highest number of citations and co-citations) for understanding the BLEVE phenomenon is. The results obtained constitute a snapshot of the current state of the art on BLEVEs and can be applied to improve the understanding of research on this topic and establish new trends of research.     

Inherent safety concept based proactive risk reduction strategies: A review

The growing scale and complexity of process industries have brought safety, health, and environmental issues to the forefront. As a result, proactive risk reduction strategies (RRSs) are commonly employed to address these issues by reducing the frequency or mitigating the consequences of potential incidents. Among these strategies, inherent safety, which is a proactive measure of loss prevention and risk management, is considered to be the most effective method. This review aims to provide a comprehensive analysis of RRSs for achieving inherency, as well as techniques for evaluating the performance of inherent safety, health, and environmental aspects. Background information is presented, including the development and implementation of the inherently safer process design, as well as the approaches for achieving inherently healthier and environmentally friendlier processes. Subsequently, the execution approaches and practical applications of other RRSs are discussed to highlight the distinctiveness and benefits of inherent safety. Next, this study examined the characteristics of inherency assessment tools (IATs) based on available information at different process stages. Furthermore, the evaluation methods and historical development of IATs are investigated from the perspectives of safety, occupational health, and environmental considerations, followed by a statistical analysis of IATs. It is concluded that the no-chemical hazards-based IATs have not been extensively studied yet, which may improve the safety level of process plants from the perspective of comprehensive inherency risk reduction. As a way forward, future research opportunities are proposed to promote the implementation of greater optimized risk management.