Nanosized Iron Oxyhydroxide: Properties, Application, Preparation

Abstract

Nanoparticles are increasingly in demand in such rapidly developing types of human activity as microelectronics, catalysis, biosensors, etc. The mild neutralization process is desirable to obtain a high-quality product due to forming a great amount of nucleation centers. The advantage of carbamide application is its capability to dissolve in the reaction volume without interacting with it, and evenly distribute in volume, slowly hydrolyzing with ammonium ions formation. At the same time, a very mild neutralization regime is realized without local pH value excess. Method of iron oxyhydroxide obtaining by carbamide precipitation is illustrated below. The aim of investigation was to obtain nanoscale precipitate, to study the properties of the obtained material and to describe the precipitation process. The study of the iron (III) oxyhydroxide precipitation kinetics from the iron (III) sulphate solution, and a mathematical model of the process are presented in the article. A mathematical model of the precipitation process allows to take into account the influence of the substances concentration and the process temperature to the rate of precipitate production. The precipitate was characterized by X-ray and DTA analysis, as well as by Raman spectroscopy and scanning electron microscopy methods.

Features of the Formation of Surface Layers on Metals

“…Сучасний стан розвитку мікро-та макротехніки стимулює пошук можливості використання нових високоефективних матеріалів [7,8], у тім числі аморфних металевих сплавів, які, наприклад, за рівнем магнітних властивостей перевищують у кілька разів кристалічні аналоги. Використання наноматеріалів [9][10][11][12][13] у складі композитів для підвищення ефективності захисного покриття від впливу електромагнітного випромінювання (ЕМВ), або з підвищеною каталітичною здатністю термостабільністю перевершують властивості кристалічних прецизійних сплавів. Наприклад, магнітопроводи з нанокристалічного сплаву Fe73,6Cu1,0Nb2,4Si15,8B1,2 використовують для виготовлення електролічильників, індукційних магнітометрів у геології та для досліджень космічного простору.…”

Soft synthesis and characterization of goethite-based nanocomposites as promising cyclooctene oxidation catalysts

“…Moreover, since their properties are affected by all these factors, they also need to be precisely tuned depending on the requirements of particular applications. 38,39 Usually, goethite is mainly obtained by the wet-chemical precipitation process starting from water-soluble iron salts (chloride, nitrate, or sulfate) by adding either caustic soda or ammonia in the presence of air as oxidizing agent. 40 Parameters like pH, salt concentration, temperature, and stirring velocity are involved in the particle size and geometry, which control the properties.…”

“…40 Parameters like pH, salt concentration, temperature, and stirring velocity are involved in the particle size and geometry, which control the properties. 38,39 However, the attention in this eld is now focused on the development of some non-conventional methods such as plasma treatment, 24,25 electrodeposition, 27,30,31,34 chemical deposition, 29,32 or chemical deposition assisted by a magnetic eld. 33 Moreover, all these methods are eco-friendly and control both the nano-dimension of the particles and the substitution degree.…”

“…Moreover, since their properties are affected by all these factors, they also need to be precisely tuned depending on the requirements of particular applications. 38,39 …”

“…40 Parameters like pH, salt concentration, temperature, and stirring velocity are involved in the particle size and geometry, which control the properties. 38,39 …”