Hasil untuk "Chemical industries"

J. Hahladakis, C. Velis, R. Weber et al.

Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as "additives") contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times.

Coby J. Clarke, Wei-Chien Tu, Oliver Levers et al.

H. Slama, Ali Chenari Bouket, Zeinab Pourhassan et al.

Natural dyes have been used from ancient times for multiple purposes, most importantly in the field of textile dying. The increasing demand and excessive costs of natural dye extraction engendered the discovery of synthetic dyes from petrochemical compounds. Nowadays, they are dominating the textile market, with nearly 8 × 105 tons produced per year due to their wide range of color pigments and consistent coloration. Textile industries consume huge amounts of water in the dyeing processes, making it hard to treat the enormous quantities of this hazardous wastewater. Thus, they have harmful impacts when discharged in non-treated or partially treated forms in the environment (air, soil, plants and water), causing several human diseases. In the present work we focused on synthetic dyes. We started by studying their classification which depended on the nature of the manufactured fiber (cellulose, protein and synthetic fiber dyes). Then, we mentioned the characteristics of synthetic dyes, however, we focused more on their negative impacts on the ecosystem (soil, plants, water and air) and on humans. Lastly, we discussed the applied physical, chemical and biological strategies solely or in combination for textile dye wastewater treatments. Additionally, we described the newly established nanotechnology which achieves complete discharge decontamination.

Hao Chen, M. Ling, Luke Hencz et al.

Tremendous efforts have been devoted to the development of electrode materials, electrolytes, and separators of energy-storage devices to address the fundamental needs of emerging technologies such as electric vehicles, artificial intelligence, and virtual reality. However, binders, as an important component of energy-storage devices, are yet to receive similar attention. Polyvinylidene fluoride (PVDF) has been the dominant binder in the battery industry for decades despite several well-recognized drawbacks, i.e., limited binding strength due to the lack of chemical bonds with electroactive materials, insufficient mechanical properties, and low electronic and lithium-ion conductivities. The limited binding function cannot meet inherent demands of emerging electrode materials with high capacities such as silicon anodes and sulfur cathodes. To address these concerns, in this review we divide the binding between active materials and binders into two major mechanisms: mechanical interlocking and interfacial binding forces. We review existing and emerging binders, binding technology used in energy-storage devices (including lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, and supercapacitors), and state-of-the-art mechanical characterization and computational methods for binder research. Finally, we propose prospective next-generation binders for energy-storage devices from the molecular level to the macro level. Functional binders will play crucial roles in future high-performance energy-storage devices.

C. Kwiatkowski, David Q. Andrews, L. Birnbaum et al.

This commentary presents a scientific basis for managing as one chemical class the thousands of chemicals known as PFAS (per- and polyfluoroalkyl substances). The class includes perfluoroalkyl acids, perfluoroalkylether acids, and their precursors; fluoropolymers and perfluoropolyethers; and other PFAS. The basis for the class approach is presented in relation to their physicochemical, environmental, and toxicological properties. Specifically, the high persistence, accumulation potential, and/or hazards (known and potential) of PFAS studied to date warrant treating all PFAS as a single class. Examples are provided of how some PFAS are being regulated and how some businesses are avoiding all PFAS in their products and purchasing decisions. We conclude with options for how governments and industry can apply the class-based approach, emphasizing the importance of eliminating non-essential uses of PFAS, and further developing safer alternatives and methods to remove existing PFAS from the environment.

Arne Kätelhön, Raoul Meys, S. Deutz et al.

Significance Carbon dioxide (CO2) drives climate change when released to the atmosphere. Alternatively, CO2 could be captured and utilized as carbon source for chemicals. Here, we provide a global assessment of the technical climate change mitigation potential of carbon capture and utilization (CCU) in the chemical industry. We develop an engineering-level model of the global chemical industry representing 75% of current greenhouse gas (GHG) emissions. The model allows us to analyze the potential disruptive changes through large-scale CO2 utilization and resulting emission reductions. Our study shows that CCU has the technical potential to lead to a carbon-neutral chemical industry and decouple chemical production from fossil resources. This transition, however, would cause largely increased mass flows and demand for low-carbon electricity. Chemical production is set to become the single largest driver of global oil consumption by 2030. To reduce oil consumption and resulting greenhouse gas (GHG) emissions, carbon dioxide can be captured from stacks or air and utilized as alternative carbon source for chemicals. Here, we show that carbon capture and utilization (CCU) has the technical potential to decouple chemical production from fossil resources, reducing annual GHG emissions by up to 3.5 Gt CO2-eq in 2030. Exploiting this potential, however, requires more than 18.1 PWh of low-carbon electricity, corresponding to 55% of the projected global electricity production in 2030. Most large-scale CCU technologies are found to be less efficient in reducing GHG emissions per unit low-carbon electricity when benchmarked to power-to-X efficiencies reported for other large-scale applications including electro-mobility (e-mobility) and heat pumps. Once and where these other demands are satisfied, CCU in the chemical industry could efficiently contribute to climate change mitigation.

Tariq Alsawy, Emanne Rashad, Mohamed El-Qelish et al.

The chemical regeneration process has been extensively applied to reactivate biochar, supporting its reusability and leading to significant operating cost reduction. However, no recent review discusses the effectiveness of biochar chemical regeneration. Thus, this article comprehensively reviews the chemical regeneration of biochar contaminated with organic and inorganic pollutants. Performance of the chemical regeneration depends on adsorption mechanism, functional groups, adsorbent pore structure, and changes in active adsorbent sites. Secondary contamination is one of the challenges facing the sustainable adaptation of the chemical regeneration process in the industry. The paper discusses these challenges and draws a roadmap for future research to support sustainable wastewater treatment by biochar.

P. Gabrielli, M. Gazzani, M. Mazzotti

This contribution provides a conceptual analysis and a quantitative comparative assessment of three technology chains that enable a carbon neutral chemical industry in a net-zero-CO2 world. These a...

Jianlin Han, L. Kiss, Haibo Mei et al.

Over the last 100–120 years, due to the ever-increasing importance of fluorine-containing compounds in modern technology and daily life, the explosive development of the fluorochemical industry led to an enormous increase of emission of fluoride ions into the biosphere. This made it more and more important to understand the biological activities, metabolism, degradation, and possible environmental hazards of such substances. This comprehensive and critical review focuses on the effects of fluoride ions and organofluorine compounds (mainly pharmaceuticals and agrochemicals) on human health and the environment. To give a better overview, various connected topics are also discussed: reasons and trends of the advance of fluorine-containing pharmaceuticals and agrochemicals, metabolism of fluorinated drugs, withdrawn fluorinated drugs, natural sources of organic and inorganic fluorine compounds in the environment (including the biosphere), sources of fluoride intake, and finally biomarkers of fluoride exposure.

D. Mallapragada, Y. Dvorkin, M. Modestino et al.

The chemical industry is a major source of economic productivity and employment globally and among the top 3 industrial sources of greenhouse gas (GHG) emissions, along with steel and cement. As global demand for chemical products continues to grow, there is an urgency to develop and deploy sustainable chemical production pathways and re-consider continued investment in current emission-intensive production technologies. This Perspective describes the challenges and opportunities to decarbonize the chemical industry via electrification powered by the low-emission electric power sector, both in the near-term and long-term, and discusses four technological pathways ranging from the more mature direct substitution of heat with electricity and use of hydrogen to technologically less mature, yet potentially more selective approaches based on electrochemistry and plasma. Finally, we highlight the key elements of integrating an electrified industrial process with the power sector to leverage process flexibility to reduce energy costs of chemical production and provide valuable power grid support services. Unlocking

Paolo Gabrielli, L. Rosa, M. Gazzani et al.

P. Chowdhary, R. Bharagava, Sandhya Mishra et al.

Fanran Meng, Andreas Wagner, Alexandre B. Kremer et al.

Significance The chemical industry underpins modern society across manufactured goods, food production and energy security via the production of plastics, solvents, fertilizers and more. However, it simultaneously presents multiple threats to the planetary boundaries that will undermine the industry's license to operate, requiring major and rapid system transformation. Our study presents seven planet-compatible pathways for transitioning the industry towards net-zero, employing both demand- and supply-side interventions to chemicals representing over 70% of the sector’s emissions. The pathways rely on circular strategies and suggest that the chemical industry has the option to become a carbon steward ultimately providing much-needed negative emissions to society. Imminent action and implementation are required globally to enable this radical transformation and unlock the presented pathways.

Katrin E. Daehn, R. Basuhi, J. Gregory et al.

Luis Itza Vazquez-Salazar, Markus Meuwly

Machine learning (ML) has become a standard tool for the exploration of chemical space. Much of the performance of such models depends on the chosen database for a given task. Here, this aspect is investigated for "chemical tasks" including the prediction of hybridization, oxidation, substituent effects, and aromaticity, starting from an initial "restricted" database (iRD). Choosing molecules for augmenting this iRD, including increasing numbers of conformations generated at different temperatures, and retraining the models can improve predictions of the models on the selected "tasks". Addition of a small percentage of conformers (1 % ) obtained at 300 K improves the performance in almost all cases. On the other hand, and in line with previous studies, redundancy and highly deformed structures in the augmentation set compromise prediction quality. Energy and bond distributions were evaluated by means of Kullback-Leibler ($D_{\rm KL}$) and Jensen-Shannon ($D_{\rm JS}$) divergence and Wasserstein distance ($W_{1}$). The findings of this work provide a baseline for the rational augmentation of chemical databases or the creation of synthetic databases.

Eugene V. Stepanov, Alexander F. Gutsol

A theoretical approach to describing transport of an entire ensemble of clusters with different sizes as a single species in gas has been developed. The major assumption is an existence of local partial chemical equilibrium between the clusters. It is shown that thermal diffusion emerges in the collective description as a significant factor even if it is negligible when transport of the original molecular species is considered. Analytical expressions for the effective diffusion and thermal diffusion coefficients at temperature, pressure, and chemical composition gradients have been derived. The theory has been applied to a technology of H2S conversion in a centrifugal plasma-chemical reactor and has made it possible to account for sulfur clusters in numerical process modeling.

Xin Xie, Tangbing Cui

The efficiency of polycyclic aromatic hydrocarbon (PAH) removal by indigenous microorganisms is often suboptimal, resulting in constraints on its practical application. To enhance the degradation efficiency of benzo[a]pyrene (B[a]P) in contaminated soil, an effective microbial fermented product (EMF) was employed as a biostimulant. Our findings demonstrated that when 1‱ or 1‰ (<i>w</i>/<i>w</i>) of the EMF was applied to the B[a]P-contaminated soil for 21 days, the biodegradation rates of the B[a]P were 59.37% and 100%, respectively, which is much higher than that by the natural attenuation (18.79%). The abundance of the 16S rDNA and PAH-RHDα GP genes were both significantly increased due to the applied EMF. Soil enzymatic activities were also affected, to different degrees, by the addition of the EMF. The diversity, composition, and functionality of the soil microbial community also changed to varying degrees. These results suggest that the use of the EMF to enhance the biodegradation of the B[a]P in soil may hold promise for the microbial remediation of PAH-contaminated soils.

Yongqiang Chen, Mao Chen, Haoyuan Lei et al.

One-dimensional tantalum carbide (TaC) nanorods are considered promising candidates for high-temperature electromagnetic wave (EMW) absorption because of their intrinsically high electrical conductivity and exceptional thermal stability. However, conventional synthesis approaches typically yield products with low quality and poor efficiency, limiting their practical applicability. Here, we report the rapid and scalable synthesis of high-quality TaC nanorods via a molten salt-assisted carbothermal reduction strategy integrated with microwave heating. The formation of well-defined one-dimensional TaC nanorods was achieved within 20 min at 1300 °C by precisely tuning the precursor composition (Ta2O5 : C : NaCl : Ni = 1 : 8 : 2 : 0.08). The resulting TaC nanorods exhibit notable EMW absorption properties, with a maximum effective absorption bandwidth (EABmax) of 3.0 GHz at a simulated thickness of 1.0 mm and a minimum reflection loss (RLmin) of −30.5 dB. Off-axis electron holography reveals pronounced charge accumulation at the Ta2O5 shell/TaC core interface, indicative of interfacial polarization effects. Furthermore, radar scattering cross-section (RCS) simulations demonstrate substantial attenuation of the backscattered signal from a perfect electric conductor (PEC) substrate coated with the TaC layer, with the strongest electromagnetic energy dissipation observed at a coating thickness of 1.0 mm. These results underscore the viability of microwave-assisted synthesis as an efficient and sustainable route for producing high-performance TaC nanorods for EMW absorption applications under extreme thermal conditions.

Yuan Yao, Kai Lan, Thomas E. Graedel et al.

Various technologies and strategies have been proposed to decarbonize the chemical industry. Assessing the decarbonization, environmental, and economic implications of these technologies and strategies is critical to identifying pathways to a more sustainable industrial future. This study reviews recent advancements and integration of systems analysis models, including process analysis, material flow analysis, life cycle assessment, techno-economic analysis, and machine learning. These models are categorized based on analytical methods and application scales (i.e., micro-, meso-, and macroscale) for promising decarbonization technologies (e.g., carbon capture, storage, and utilization, biomass feedstock, and electrification) and circular economy strategies. Incorporating forward-looking, data-driven approaches into existing models allows for optimizing complex industrial systems and assessing future impacts. Although advances in industrial ecology-, economic-, and planetary boundary-based modeling support a more holistic systems-level assessment, more effects are needed to consider impacts on ecosystems. Effective applications of these advanced, integrated models require cross-disciplinary collaborations across chemical engineering, industrial ecology, and economics. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering , Volume 15 is June 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Joseph M. Cavanagh, Kunyang Sun, Andrew Gritsevskiy et al.

Here we show that a general-purpose large language model (LLM) chatbot, Llama-3.1-8B-Instruct, can be transformed via supervised fine-tuning of engineered prompts into a chemical language model (CLM), SmileyLlama, for molecule generation. We benchmark SmileyLlama by comparing it to CLMs trained from scratch on large amounts of ChEMBL data for their ability to generate valid and novel drug-like molecules. We also use direct preference optimization to both improve SmileyLlama's adherence to a prompt and to generate molecules within the iMiner reinforcement learning framework to predict new drug molecules with optimized 3D conformations and high binding affinity to drug targets, illustrated with the SARS-Cov-2 Main Protease. This overall framework allows a LLM to speak directly as a CLM which can generate molecules with user-specified properties, rather than acting only as a chatbot with knowledge of chemistry or as a helpful virtual assistant. While our dataset and analyses are geared toward drug discovery, this general procedure can be extended to other chemical applications such as chemical synthesis.