首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
Based on recent examples and initiatives reported in the literature, this concept article discusses how chemistry can contribute to the circular economy approach in order to improve our current and future economical, societal, and environmental system. Through five proposed levels of contribution, chemists can take a significant part in this global approach via the consideration of green chemistry principles, the simplification of syntheses, the limitation of complex products preparation, the efficient utilization of resources but also the novel ways of waste valorization. A more systematic and generalized environmental and economic assessment from the lab-scale is also recommended. At last, chemists have to work even more collaboratively and in a multidisciplinary way, within chemistry and beyond.  相似文献   

3.
Pyrolysis and hydrocracking of plastic waste can produce valuable products with manageable effects on the environment as compared to landfilling and incineration. This research focused on the process simulation and life cycle assessment of the pyrolysis and hydrocracking of high-density polyethylene. Aspen Plus was used as the simulator and the Peng-Robinson thermodynamic model was employed as a fluid package. Additionally, sensitivity analysis was conducted in order to optimize product distribution. Based on the simulation, the hydrocracking process produced value-added fuels, i.e., gasoline and natural gas. In contrast, pyrolysis generated a significant quantity of pyrolysis oil with a high number of cyclo-compounds and char, which are the least important to be utilized as fuels. Moreover, in the later part of the study, life cycle assessment (LCA) was adopted in order to investigate and quantify their impact upon the environment using simulation inventory data, which facilitates finding a sustainable process. Simapro was used as a tool for LCA of the processes and materials used. The results demonstrate that hydrocracking is a better process in terms of environmental impact in 10 out of the 11 impact categories. Overall, the present study proposed a promising comparison based on energy demands, product distribution, and potential environmental impacts, which will help to improve plastic waste management.  相似文献   

4.
戚万友 《化学教育》2016,37(21):67-68
在实证分析、理论证据的基础上,设计了白磷还原氧化铜的实验,得出白磷可以夺取部分金属氧化物(如氧化铜)中的氧,具有一定的还原性。  相似文献   

5.
Extracting valuable products from wastewaters with nitrogen-selective adsorbents can offset energy-intensive ammonia production, rebalance the nitrogen cycle, and incentivize environmental remediation. Separating nitrogen (N) as ammonium from other wastewater cations (e.g., K+, Ca2+) presents a major challenge to N removal from wastewater and N recovery as high-purity products. High selectivity and capacity were achieved through ligand exchange of ammonia with ammine-complexing transition metals loaded onto polymeric cation exchange resins. Compared to commercial resins, metal–ligand exchange adsorbents exhibited higher ammonia removal capacity (8 mequiv g−1) and selectivity (N/K+ equilibrium selectivity of 10.1) in binary equimolar solutions. Considering optimal ammonia concentrations (200–300 mequiv L−1) and pH (9–10) for metal–ligand exchange, hydrolyzed urine was identified as a promising candidate for selective TAN recovery. However, divalent cation exchange increased transition metal elution and reduced ammonia adsorption. Ultimately, metal–ligand exchange adsorbents can advance nitrogen-selective separations from wastewaters.  相似文献   

6.
生态生命周期评价(Eco-LCA)作为常规生命周期评价的拓展,提供了一种对工业过程生态影响及可持续性分析评价的方法.但目前Eco-LCA中尚缺失生态累积耗(ECEC)指标的完整模型.本文探讨了工业过程中自然资源消耗、社会经济投入和环境污染危害三种主要影响因素.通过构建囊括资源、经济、环境三要素的工业过程生态累积耗模型,完善了Eco-LCA方法应用于工业过程可持续分析的理论框架.最后,以此生态累积耗模型对中国原油生产进行了示例性分析讨论.  相似文献   

7.
Verbenone and carvone are allylic monoterpenoid ketones with many applications in the fine chemicals industry that can be obtained, respectively, from the allylic oxidation of α-pinene and limonene over a silica-supported iron hexadecachlorinated phthalocyanine (FePcCl16-NH2-SiO2) catalyst and with t-butyl hydroperoxide (TBHP) as oxidant. As there are no reported analyses of the environmental impacts associated with catalytic transformation of terpenes into value-added products that include the steps associated with synthesis of the catalyst and several options of raw materials in the process, this contribution reports the evaluation of the environmental impacts in the conceptual process to produce verbenone and carvone considering two scenarios (SI-raw-oils and SII-purified-oils). The impact categories were evaluated using ReCiPe and IPCC methods implemented in SimaPro 9.3 software. The environmental impacts in the synthesis of the heterogeneous catalyst FePcCl16-NH2-SiO2 showed that the highest burdens in terms of environmental impact come from the use of fossil fuel energy sources and solvents, which primarily affect human health. The most significant environmental impacts associated with carvone and verbenone production are global warming and fine particulate matter formation, with fewer environmental impacts associated with the process that starts directly from turpentine and orange oils (SI-raw-oils) instead of the previously extracted α-pinene and limonene (SII-purified-oils). As TBHP was identified as a hotspot in the production process of verbenone and carvone, it is necessary to choose a more environmentally friendly and energy-efficient oxidizing agent for the oxidation of turpentine and orange oils.  相似文献   

8.
The agri-food sector produces a huge amount of agri-food wastes and by-products, with a consequent great impact on environmental, economic, social, and health aspects. The reuse and recycling of by-products represents a very important issue: for this reason, the development of innovative recovery and extraction methodologies must be mandatory. In this context of a circular economy, the study of green extraction techniques also becomes a priority in substitution of traditional extraction approaches. This review is focused on the recovery of chlorogenic acids from agri-food wastes, as these compounds have an important impact on human health, exhibiting several different and important healthy properties. Novel extraction methodologies, namely microwave and ultrasound-assisted extractions, supercritical fluid extraction, and pressurized-liquid extraction, are discussed here, in comparison with conventional techniques. The great potentialities of these new innovative green and sustainable approaches are pointed out. Further investigations and optimization are mandatory before their application in industrial processes.  相似文献   

9.
黄卫清  李瀚 《化学教育》2023,44(2):85-91
将化工流程模拟Aspen Plus软件与环境影响评估领域常用的生命周期评价(LCA)进行集成应用,围绕环境工程原理教学中有关化工过程质量能量衡算与环境污染防治内容的协同应用与拓展,构建化工流程模拟-环境风险评估科研案例“苯酐生产流程模拟及环境风险研究”,并将其作为环境工程原理的综合教学案例。教学实践经验表明,通过引入工程相关综合教学案例,不仅使得抽象的理论知识更加生动具体,而且在深化学生对课程理论知识理解的同时,提高学生应用专业知识分析和解决化工生产环境污染工程问题的综合能力和素质,为学生将来步入相关领域工作奠定扎实的基础。  相似文献   

10.
11.
提出了一种基于电洗脱原理的核酸纯化回收芯片, 通过对芯片上电极进行适当的切换操作, 可一次完成核酸样品分离和纯化回收. 同时采用数值模拟的方法对纯化回收芯片管道的几何形状及电场分布进行了优化设计, 并进行了实验验证. 实验结果与模拟分析非常吻合, 证明优化设计达到了预期的效果.  相似文献   

12.
Over the last several years, the number of concepts and technologies enabling the production of environmentally friendly products (including materials, consumables, and services) has expanded. One of these ways is cradle-to-cradle (C2C) certifiedTM. Life cycle assessment (LCA) technique is used to highlight the advantages of C2C and recycling as a method for reducing plastic pollution and fossil depletion by indicating the research limitations and gaps from an environmental perspective. Also, it estimates the resources requirements and focuses on sound products and processes. The C2C life cycle measurements for petroleum-based poly (ethylene terephthalate) (PET) bottles, with an emphasis on different end-of-life options for recycling, were taken for mainland China, in brief. It is considered that the product is manufactured through the extraction of crude oil into ethylene glycol and terephthalic acid. The CML analysis method was used in the LCIA for the selected midpoint impact categories. LCA of the product has shown a drastic aftermath in terms of environmental impacts and energy use. But the estimation of these consequences is always dependent on the system and boundary conditions that were evaluated throughout the study. The impacts that burden the environment are with the extraction of raw material, resin, and final product production. Minor influences occurred due to the waste recycling process. This suggests that waste degradation is the key process to reduce the environmental impacts of the production systems. Lowering a product’s environmental impact can be accomplished in a number of ways, including reducing the amount of materials used or choosing materials with a minimal environmental impact during manufacture processes.  相似文献   

13.
The disposal of food waste is a current and pressing issue, urging novel solutions to implement sustainable waste management practices. Fish leftovers and their processing byproducts represent a significant portion of the original fish, and their disposal has a high environmental and economic impact. The utilization of waste as raw materials for the production of different classes of biofuels and high-value chemicals, a concept known as “biorefinery”, is gaining interest in a vision of circular economy and zero waste policies. In this context, an interesting route of valorization is the extraction of omega-3 fatty acids (ω-3 FAs) for nutraceutical application. These fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have received attention over the last decades due to their beneficial effects on human health. Their sustainable production is a key process for matching the increased market demand while reducing the pressure on marine ecosystems and lowering the impact of waste production. The high resale value of the products makes this waste a powerful tool that simultaneously protects the environment and benefits the global economy. This review aims to provide a complete overview of the sustainable exploitation of fish waste to recover ω-3 FAs for food supplement applications, covering composition, storage, and processing of the raw material.  相似文献   

14.
The title γ-P4N6(NH) polymorph is obtained by high-temperature high-pressure synthesis using P3N5 and NH4Cl in the molar ratio of 4:1 (multianvil cell, 14 GPa, 1200 °C, 3 h).  相似文献   

15.
16.
Herein we present the first superbase MHPN with two interacting P‐ylide entities. Unlike classical proton sponges, this novel compound class has carbon atoms as basicity centers which are forced into close proximity by a naphthalene scaffold. The bisylide exhibits an experimental pK BH+ value of 33.3±0.2 on the MeCN scale and a calculated gas‐phase proton affinity of 277.9 kcal mol−1 (M062X/6‐311+G**//M062X/6‐31G*+ZPVE method) exceeding that of the corresponding monoylide by nearly 15 kcal mol−1. The origin of the unexpectedly high basicity of the new bisylide was investigated by NMR spectroscopic methods, single‐crystal X‐ray diffraction as well as theoretical calculations and can be partly attributed to the rapid exchange of the “acidic” proton between the two basic carbon atoms after protonation.  相似文献   

17.
18.
In this work, a heterostructure obtained by vacuum evaporation of a strong molecular n-dopant, [RuCp*(mes)]2, onto black phosphorus (BP) is reported, along with the systematic investigation of the interfacial structure and properties by various in situ characterization techniques. Ultraviolet photoelectron spectra (UPS) showed a large decrease in the work function of BP and a new peak within the bandgap, which is attributed to electron transfer from dopants to the underlying BP. The electrons trapped at the interface act as hole traps and induce photogating effect so that a photodetector based on BP–organoruthenium complex heterostructure demonstrates a photoresponsivity of 5.5 mA W−1 and an EQE of 1.3 % at 515 nm, a tenfold improvement compared to the pristine BP device.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号