Hasil untuk "Chemical technology"

S. Linic, P. Christopher, David B. Ingram

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.

E. Coronado

M. R. Dunn, Randi M. Jimenez, J. Chaput

Eric Singh, M. Meyyappan, H. Nalwa

P. Mosier-Boss

The SERS effect was initially discovered in the 1970s. Early research focused on understanding the phenomenon and increasing enhancement to achieve single molecule detection. From the mid-1980s to early 1990s, research started to move away from obtaining a fundamental understanding of the phenomenon to the exploration of analytical applications. At the same time, significant developments occurred in the field of photonics that led to the advent of inexpensive, robust, compact, field-deployable Raman systems. The 1990s also saw rapid development in nanoscience. This convergence of technologies (photonics and nanoscience) has led to accelerated development of SERS substrates to detect a wide range of chemical and biological analytes. It would be a monumental task to discuss all the different kinds of SERS substrates that have been explored. Likewise, it would be impossible to discuss the use of SERS for both chemical and biological detection. Instead, a review of the most common metallic (Ag, Cu, and Au) SERS substrates for chemical detection only is discussed, as well as SERS substrates that are commercially available. Other issues with SERS for chemical detection have been selectivity, reversibility, and reusability of the substrates. How these issues have been addressed is also discussed in this review.

A. Bogaerts, E. Neyts

A. Hoffman

Karin Ackermann

N. V. van Dam, H. Bouwmeester

Z. Xiong, Heng Zhang, Wenchao Zhang et al.

Abstract This review intends to provide an overview of chemical redox degradation of nitrophenols (NPs) and their derivatives. The main scientific focus is on the degradation of NPs by advanced oxidation processes (AOPs, such as microwave assisted catalytic oxidation, ultrasound-enhanced oxidation, electrochemical oxidation, catalytic ozonation, photocatalytic oxidation, persulfate and peroxymonosulfate oxidation, etc.), advanced reduction processes (ARPs, such as zero valent iron, bimetals and NaBH4 with precious metal catalysts), and their synergistic processes. The strengths and weaknesses of various treatment technologies are described. The degradation mechanisms of NPs by chemical redox treatment are proposed and summarized. Other aspects such as mechanism of chemical redox, and degradation pathways of NPs, are also discussed in detail. Furthermore, pretreatment of real industrial wastewater containing NPs was introduced according to the reports. The combination of chemical redox and biological treatments for the real industrial wastewater was finally evaluated and discussed significantly.

Raoul Meys, F. Frick, S. Westhues et al.

Abstract Plastic packaging waste faces increasingly stringent sustainability targets such as recycling rates of 55% imposed by the European Commission. To realize the vision of a circular economy, chemical recycling is advocated as a large-scale avenue to decrease fossil resource depletion and greenhouse gas (GHG) emissions. In this work, we develop a theoretical model for chemical recycling technologies assuming ideal performance. The theoretical model allows us to compute the minimal environmental impacts for chemical recycling technologies and compare them to real-case benchmark waste treatments. Thereby, we robustly identify chemical recycling technologies that will not result in environmental benefits, since their minimal environmental impacts are already higher than those of current benchmark waste treatments. In this way, we show that PET, HDPE, LDPE, PP and PS should not be recycled chemically to refinery feedstock or fuel products and rather be treated by mechanical recycling and energy recovery in cement kilns in order to reduce global warming impacts. In contrast, chemical recycling to monomers or value-added products could potentially reduce global warming impacts compared to all benchmark waste treatments by up to 4.3 kg CO2-eq per kg treated PET packaging waste. By analyzing 75 waste treatment scenarios for 5 environmental impacts, our analysis offers guidance to stakeholders involved in chemical recycling to identify the most promising as well as the least promising chemical recycling technologies.

S. Pankaj, Hu Shi, K. Keener

Z. Schiffer, Karthish Manthiram

Yufei Zhao, Geoffrey I N Waterhouse, Guangbo Chen et al.

The discovery of improved chemical processes for CO and CO2 hydrogenation to valuable hydrocarbon fuels and alcohols is of paramount importance for the chemical industry. Such technologies have the potential to reduce anthropogenic CO2 emissions by adding value to a waste stream, whilst also reducing our consumption of fossil fuels. Current thermal catalytic technologies available for CO and CO2 hydrogenation are demanding in terms of energy input. Various alternative technologies are now being developed for COx hydrogenation, with solar-driven processes over two-dimensional (2D) and 2D-related composite materials being particularly attractive due to the abundance of solar energy on Earth and also the high selectivity of defect-engineered 2D materials towards specific valuable products under very mild reaction conditions. This review showcases recent advances in the solar-driven COx reduction to hydrocarbons over 2D-based materials. Optimization of 2D catalyst performance demands interdisciplinary research that embraces catalyst electronic structure manipulation and morphology control, surface/interface engineering, reactor engineering and density functional theory modelling studies. Through improved understanding of the structure-performance relationships in 2D-related catalysts which is achievable through the application of modern in situ characterization techniques, practical photo/photothermal/photoelectrochemical technologies for CO and CO2 reduction to high-valuable products such as olefins could be realized in the not-too-distant future.

Ke Wang, A. Dowling

The design of chemical-based products and functional materials is vital to modern technologies, yet remains expensive and slow. Artificial intelligence and machine learning offer new approaches to leverage data to overcome these challenges. This review focuses on recent applications of Bayesian optimization (BO) to chemical products and materials including molecular design, drug discovery, molecular modeling, electrolyte design, and additive manufacturing. Numerous examples show how BO often requires an order of magnitude fewer experiments than Edisonian search. The essential equations for BO are introduced in a self-contained primer specifically written for chemical engineers and others new to the area. Finally, the review discusses four current research directions for BO and their relevance to product and materials design.

Li-Zhen Deng, A. Mujumdar, Z. Pan et al.

Abstract With a growing demand for safe, nutritious, and fresh-like produce, a number of disinfection technologies have been developed. This review comprehensively examines the working principles and applications of several emerging disinfection technologies. The chemical treatments, including chlorine dioxide, ozone, electrolyzed water, essential oils, high-pressure carbon dioxide, and organic acids, have been improved as alternatives to traditional disinfection methods to meet current safety standards. Non-thermal physical treatments, such as UV-light, pulsed light, ionizing radiation, high hydrostatic pressure, cold plasma, and high-intensity ultrasound, have shown significant advantages in improving microbial safety and maintaining the desirable quality of produce. However, using these disinfection technologies alone may not meet the requirement of food safety and high product quality. Several hurdle technologies have been developed, which achieved synergistic effects to maximize lethality against microorganisms and minimize deterioration of produce quality. The review also identifies further research opportunities for the cost-effective commercialization of these technologies.

Petar Kassal, M. Steinberg, Ivana Murković Steinberg

Abstract Parallel advances in chemical sensing and wireless communication technologies have sparked the development of wireless chemical sensors (WCSs). These hybrid devices enable wireless determination, collection and distribution of (bio)chemical analytical information in a way that is significantly impacting the Sensor Internet of Things with applications in healthcare, defence, sport, the environment, and agriculture. Challenges and examples for each of the major chemical sensor and major radio technologies related to different application areas are reviewed, including the latest trends emerging from wearable sensors. The review focuses on radio-based WCSs, and finds that ubiquitous wireless technologies such as Bluetooth, ZigBee, radio-frequency identification (RFID) and near-field communication (NFC) are helping make analytical (bio)chemical sensing appropriate and realistic for mass market adoption, in particular for two major classes of chemical sensor – electrochemical and optical. The review provides an in-depth analysis of academic WCS research publications over the ten year period 2007–2017.

Qin Li, Yinzhu Chen, Hongmei Zhao et al.

Abstract Background Phenolic acid decarboxylase (PAD) is an enzyme capable of catalyzing the nonoxidative decarboxylation of phenolic acids, yielding the corresponding 4-vinyl derivatives. This enzymatic process holds considerable promise for converting naturally abundant phenolic acid substrates into high-value compounds. Results The PAD gene from Bacillus subtilis J6 was cloned to yield the BJ6PAD enzyme, and its mutant BJ6PAD-N was generated by introducing an N-terminal substitution. Compared with BJ6PAD, BJ6PAD-N demonstrated not only higher specific enzyme activity but also increased alkaline resistance. The N-terminal region of BJ6PAD-N exhibited increased flexibility, leading to a looser structure. This change improved the catalytic efficiency for sinapic acid (SA) with bulky side chains. After its immobilization, the application potential of BJ6PAD-N was significantly enhanced, demonstrating reusability and storage stability that were superior to those of BJ6PAD. After 10 repeated uses, the residual enzyme activity remained above 80%. When stored at 4 °C for 60 days, 61.15% of the enzyme activity was retained. These characteristics are crucial for facilitating the industrial application of enzymes. Conclusions Replacing the N-terminal of phenolic acid decarboxylase BJ6PAD (resulting in BJ6PAD-N) made the enzyme structure more flexible. While this reduced substrate binding stability, it increased specific enzyme activity. Notably, the enzyme showed improved catalytic efficiency for sinapic acid, which has a bulky side chain. After being immobilized, the performance stability of the enzyme has been further enhanced.

Ayelén A. Hugo, María Delos Ángeles Serradell, Pablo L. Peri et al.

Nothofagus antarctica (NA) is a native tree of Patagonia. Since ancient times, NA leaves were used in infusions for medical and food purposes, but there are no deep insights on its toxicity. The aim of this work was to assess the safety and antioxidant activity of NA leaves infusion. Mice were used to determine acute and subacute oral toxicity. Total polyphenols, flavonoids and the antioxidant activity of the infusion were assessed, as well as the antioxidant activity in biological samples. Toxicity tests revealed no death or signs of toxicity. No significant differences in biochemical parameters/histological structure were registered. NA infusion exhibited a high content of polyphenols and flavonoids, contributing to its remarkably antioxidant activity. The periodic administration of NA infusion could increase the antioxidant capacity in mice at intestinal level. The results support the safe of consuming NA leaves infusion and suggest their contribution for modulating the intestinal oxidative stress.