نتایج جستجو برای: active metals

تعداد نتایج: 500875  

Journal: :Chemical Society reviews 2015
Alfons Baiker

In view of the importance of optically pure chiral products there is ample reason to develop methods that facilitate their efficient production. Compared to the mostly applied homogeneous catalysts based on transition metals coordinated to suitable chiral ligands, heterogeneous chiral catalysts could offer several features that are beneficial for practical application such as stability, ease of...

ژورنال: مواد پرانرژی 2018

Ammonium Perchlorate (AP) is one of the most important oxidizer in composite solid propellants. Therefore, synthesis and application of nanoparticles as catalyst for improving thermal decomposition of AP is an important issue in catalysis research. There are a great many nanomaterials for the thermal decomposition of AP such as nano metal particles, metal oxides, metals salts, metallic composit...

In the present study, a field study was performed on some herbaceous plants growing in thesoutheast of Ahvaz, where some metal producing industries are active. The aim of this studywas to investigate and compare manganese (Mn) and zinc (Zn) accumulation in seven dominantherbaceous plants in this area. Plant samples were collected randomly. Associated soils weresampled from the same sites next t...

Recent advances in nanoscience have led to the development of numerous methodologiesfor controlled synthesis of mono dispersed nanoparticles and/or nanoclusters via surface stabilization by organic capping ligands. The application of these nanoparticles in catalysis and other fields often requires the removal of organic ligands. It is known that the removal of organic capping agents or or...

2014
E.M. da Fonseca J.A. Baptista Neto J.J. McAlister B.J. Smith M.A.C. Crapez

Processes involving heavy metals and other contaminants continue to present unsolved environmental questions. To advance the understanding of geochemical processes that involve the bioavailability of contaminants, cores where collected in the Rodrigo de Freitas lagoon, and analyzed for bacterial activity and metal concentrations. Results would suggest an extremely reducing environment where org...

Journal: :محیط شناسی 0
سیده مریم خرازی کارشناس ارشد مهندسی منابع طبیعی، محیط زیست، دانشگاه تربیت مدرس حبیب یونسی دانشیار گروه محیط زیست، دانشکدۀ منابع طبیعی پردیس نور، دانشگاه تربیت مدرس جواد عابدینی طرقبه 3- سازمان مدیریت پسماند شهرداری مشهد، دانشجوی دکتری شیمی آلی، دانشگاه فردوسی مشهد

introduction the problem of solid waste management is one of the most critical environmental issues because of rapid population and economic growth, urbanization, and industrialization. furthermore, global attitudes are bent on accessing sustainable agriculture and conserving a clean and green environment. vermicomposting is a process to convert organic waste by the use of earthworms to produce...

2014
Nabraj Bhattarai Subarna Khanal Daniel Bahena

The synergetic combination of two metals in bimetallic (BM) nanoparticle (NP) significantly changes the optical, catalytic, electronic and magnetic properties. The possible reason for synergetic effects is the heterometallic bond between two metals, dilution of active site, the combination of two kinds of metals and their fine structures. The enhanced catalytic properties of BM nanoparticles ar...

2008
Emiko Harada Yong-Eui Choi

Tobacco (Nicotiana tabacum) was recently shown to detoxify heavy metals by exudation of metals as a metalsubstituted calcite (calcium carbonate) through leaf trichomes. In this paper, we describe the applications of the variablepressure scanning electron microscopy (VP-SEM) system to investigate tobacco trichomes exudates after heavy metal treatment. An energy-dispersive X-ray analysis (EDX) sy...

Journal: :Angewandte Chemie 2014
Hristiyan A Aleksandrov Sergey M Kozlov Swetlana Schauermann Georgi N Vayssilov Konstantin M Neyman

Heterogeneous catalysis is commonly governed by surface active sites. Yet, areas just below the surface can also influence catalytic activity, for instance, when fragmentation products of catalytic feeds penetrate into catalysts. In particular, H absorbed below the surface is required for certain hydrogenation reactions on metals. Herein, we show that a sufficient concentration of subsurface hy...

2003
M. Fernández-García A. Martínez-Arias

This paper provides a review of recently obtained spectroscopic results, ab-initio calculations and catalytic activity tests from the authors ́ laboratory of factors affecting the performance of materials used as automobile catalysts. Issues addressed include the preparation of (Ce,Zr)Ox/Al2O3 (CZA) mixed oxide supports and the use of new active metals, such as Pd and Cu, for three-way catalysts...

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