Hasil untuk "Chemical industries"

Shuke Wu, R. Snajdrova, Jeffrey C. Moore et al.

Abstract Biocatalysis has found numerous applications in various fields as an alternative to chemical catalysis. The use of enzymes in organic synthesis, especially to make chiral compounds for pharmaceuticals as well for the flavors and fragrance industry, are the most prominent examples. In addition, biocatalysts are used on a large scale to make specialty and even bulk chemicals. This review intends to give illustrative examples in this field with a special focus on scalable chemical production using enzymes. It also discusses the opportunities and limitations of enzymatic syntheses using distinct examples and provides an outlook on emerging enzyme classes.

Jonathan Hwang, Reshma R. Rao, L. Giordano et al.

L. T. Mika, Edit Cséfalvay, Á. Németh

Fergal P Byrne, Saimeng Jin, Giulia Paggiola et al.

Driven by legislation and evolving attitudes towards environmental issues, establishing green solvents for extractions, separations, formulations and reaction chemistry has become an increasingly important area of research. Several general purpose solvent selection guides have now been published with the aim to reduce use of the most hazardous solvents. This review serves the purpose of explaining the role of these guides, highlighting their similarities and differences. How they can be used most effectively to enhance the greenness of chemical processes, particularly in laboratory organic synthesis and the pharmaceutical industry, is addressed in detail.Graphical abstractThis review assesses the advances made in green solvent selection using tabular guides and related tools.

N. M. Dowell, P. Fennell, N. Shah et al.

Furkan H. Isikgor, R. Becer

The demand for petroleum dependent chemicals and materials has been increasing despite the dwindling of their fossil resources. As the dead-end of petroleum based industry has started to appear, today's modern society has to implement alternative energy and valuable chemical resources immediately. Owing to the importance of lignocellulosic biomass being the most abundant and bio-renewable biomass on earth, this critical review provides insights into the potential of lignocellulosic biomass as an alternative platform to fossil resources. In this context, over 200 value-added compounds, which can be derived from lignocellulosic biomass by various treatment methods, are presented with their references. Lignocellulosic biomass based polymers and their commercial importance are also reported mainly in the frame of these compounds. This review article aims to draw the map of lignocellulosic biomass derived chemicals and their synthetic polymers, and to reveal the scope of this map in today's modern chemical and polymer industry.

L. Mohammed, M. Ansari, G. Pua et al.

Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs) and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.

R. Jayaraj, Pankajshan Megha, P. Sreedev

Abstract Organochlorine (OC) pesticides are synthetic pesticides widely used all over the world. They belong to the group of chlorinated hydrocarbon derivatives, which have vast application in the chemical industry and in agriculture. These compounds are known for their high toxicity, slow degradation and bioaccumulation. Even though many of the compounds which belong to OC were banned in developed countries, the use of these agents has been rising. This concerns particularly abuse of these chemicals which is in practice across the continents. Though pesticides have been developed with the concept of target organism toxicity, often non-target species are affected badly by their application. The purpose of this review is to list the major classes of pesticides, to understand organochlorine pesticides based on their activity and persistence, and also to understand their biochemical toxicity.

Song Guo, Min Hu, M. Zamora et al.

Agnieszka Kołodziejczak-Radzimska, T. Jesionowski

Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide.

G. Fine, L. Cavanagh, A. Afonja et al.

Metal oxide semiconductor gas sensors are utilised in a variety of different roles and industries. They are relatively inexpensive compared to other sensing technologies, robust, lightweight, long lasting and benefit from high material sensitivity and quick response times. They have been used extensively to measure and monitor trace amounts of environmentally important gases such as carbon monoxide and nitrogen dioxide. In this review the nature of the gas response and how it is fundamentally linked to surface structure is explored. Synthetic routes to metal oxide semiconductor gas sensors are also discussed and related to their affect on surface structure. An overview of important contributions and recent advances are discussed for the use of metal oxide semiconductor sensors for the detection of a variety of gases—CO, NOx, NH3 and the particularly challenging case of CO2. Finally a description of recent advances in work completed at University College London is presented including the use of selective zeolites layers, new perovskite type materials and an innovative chemical vapour deposition approach to film deposition.

Song Jin, Zhimeng Hao, Kai Zhang et al.

Electrochemical carbon dioxide reduction reaction (CO2RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the different CO2RR pathways, CO2 conversion to carbon monoxide (CO) is considered as one of the most promising candidate reactions in the chemical industry due to its high technologically and economically feasibility. Integrating catalyst and electrolyte design with understanding of catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we review recent advances and challenges for selective CO2 conversion to CO. The intelligent multidimensional catalyst and electrolyte engineering for CO2RR are comprehensively summarized. Furthermore, recent efforts on large-scale production of CO are provided so as to facilitate the industrialization of electrochemical CO2 reduction. To conclude, the remaining technological challenges and future direction of industrialized application of CO2RR to CO are put forward.

Arun Mittal

Biological treatment is an important and integral part of any wastewater treatment plant that treats wastewater from either municipality or industry having soluble organic impurities or a mix of the two types of wastewater sources. The obvious economic advantage, both in terms of capital investment and operating costs, of biological treatment over other treatment processes like chemical oxidation; thermal oxidation etc. has cemented its place in any integrated wastewater treatment plant.

D. Herbert, P. Phipps, R. Strange

Miaomiao Zhou, Binghua Yan, J. Wong et al.

Zihe Liu, Kai Wang, Yun Chen et al.

Faheem Uddin

Juan Carlos Fariñas

A simple, fast and energy efficient microwave-assisted hydrothermal method was developed for the preparation of nanocrystalline zirconia from commercially available ZrOCl2·8H2O and KOH. The synthesis was conducted at 180 °C for 20 min by two ways: direct decomposition of ZrOCl2·8H2O (sample Z), and precipitation of ZrOCl2·8H2O with KOH and dehydration of hydroxides (sample ZK). The as-synthesized powders were calcined at 500 °C, and all the resulting products were characterized by XRD, FE-SEM, HR-TEM and SAED. Both the as-synthesized and calcined nanoparticles were highly crystalline. A single monoclinic phase was obtained for sample Z, while for sample ZK a tetragonal phase was achieved as the main phase with a minor fraction of monoclinic. The particles of the as-synthesized sample Z showed irregular and semi-hexagonal shapes, although they changed to spherical or ellipsoidal shapes during heat treatment. The particles of the sample ZK, both as-synthesized and calcined, exhibited nearly spherical or ellipsoidal shapes. The average crystallite size for the as-synthesized samples Z and ZK were 3.2 ± 0.8 and 5.5 ± 0.9 nm, respectively, while for the calcined ones the values were 8.5 ± 1.2 and 7.6 ± 1.2 nm, respectively. Resumen: Se ha desarrollado un método hidrotermal asistido por microondas, simple, rápido y eficiente energéticamente, para la preparación de circona nanocristalina a partir de ZrOCl2·8H2O y KOH comercialmente disponibles. La síntesis se ha realizado a 180 °C durante 20 min por dos caminos: descomposición directa de ZrOCl2·8H2O (muestra Z), y precipitación de ZrOCl2·8H2O con KOH y deshidratación de hidróxidos (muestra ZK). Los polvos sintetizados fueron calcinados a 500 °C, y todos los productos resultantes fueron caracterizados por XRD, FE-SEM, HR-TEM y SAED. Tanto las nanopartículas sintetizadas como las calcinadas fueron altamente cristalinas. En el caso de la muestra Z, se obtuvo únicamente fase monoclínica, mientras que, en el caso de la muestra ZK, se obtuvo fase tetragonal como fase principal con una pequeña fracción de monoclínica. Las partículas de la muestra Z sintetizada mostraron formas irregulares y semihexagonales, aunque durante el tratamiento térmico cambiaron a formas esféricas o elipsoidales. Las partículas de la muestra ZK, tanto sintetizada como calcinada, presentaron formas prácticamente esféricas o elipsoidales. El tamaño medio de los cristales de las muestras sintetizadas Z y ZK fue 3.2 ± 0.8 y 5.5 ± 0.9 nm, respectivamente, mientras que el de las muestras calcinadas fue 8.5 ± 1.2 and 7.6 ± 1.2 nm, respectivamente.

Lexin Ding, Eduard Matito, Christian Schilling

Chemical bonding is a nonlocal phenomenon that binds atoms into molecules. Its ubiquitous presence in chemistry, however, stands in stark contrast to its ambiguous definition and the lack of a universal perspective for its understanding. In this work, we rationalize and characterize chemical bonding through the lens of an equally nonlocal concept from quantum information, the orbital entanglement. We introduce maximally entangled atomic orbitals (MEAOs) whose entanglement pattern is shown to recover both Lewis (two-center) and beyond-Lewis (multicenter) structures, with multipartite entanglement serving as a comprehensive index of bond strength. Our unifying framework for bonding analyses is effective not only for equilibrium geometries but also for transition states in chemical reactions and complex phenomena such as aromaticity. It also has the potential to elevate the Hilbert space atomic partitioning to match the prevalent real-space partitioning in the theory of atoms in molecules. Accordingly, our work opens new pathways for understanding fuzzy chemical concepts using rigorous, quantitative descriptors from quantum information.

Raghvendra Kumar Mishra, Jayati Sarkar, Kartikey Verma et al.

MXenes, a rapidly growing family of two-dimensional (2D) transition metal carbides, nitrides, or carbonitrides (Mn+1XnTx, where M is a transition metal, X is carbon, nitrogen, or both, and T represents surface functional groups), have captured the scientific community's interest due to their exceptional physicochemical properties and diverse technological applications. This comprehensive review explores the latest breakthroughs in MXene synthesis and characterisation, emphasising their multifaceted applications in energy storage, catalysis, sensing, and other cutting-edge domains. This review examines the most widely used MXene synthesis strategies, including selective etching and delamination, and highlight recent advancements in controlling surface terminations, composition, and morphology. The influence of these synthetic parameters on MXene properties is discussed in detail. Characterisation techniques, ranging from spectroscopic methods to electron microscopy, are essential for elucidating MXenes' structure-property relationships. Research into energy storage leverages MXenes' high electrical conductivity, large surface area, and chemical tunability. This has led to significant progress in the field. This paper presents research efforts focused on optimising MXenes for both battery and supercapacitor applications. Additionally, the catalytic prowess of MXenes, particularly in electrocatalysis and photocatalysis, is explored, emphasising their role in green energy technologies and environmental remediation. MXenes' remarkable sensitivity and selectivity make them promising candidates for sensing various gases, biomolecules, and ions, offering exciting possibilities in healthcare and environmental monitoring. Importantly, this review underscores the need for continued optimisation of MXene synthesis protocols to achieve large-scale production, enhanced stability, and precise control over properties across various fields.