Hydrolysis Of Ferric Chloride Research Articles

Geochemical Behavior of Ferric Hydroxide Nanodispersion Under the Influence of Weak Magnetic Fields

The change of geochemical properties of ferric hydroxide nanoparticles under the influence of a weak magnetic field was investigated. Ferric hydroxide nanoparticles formed as a result of the interaction of iron-containing minerals with natural aqueous solutions are of importance for geochemical processes, especially hypergenesis, sedimentation, and soil formation. The hydrolysis of ferric chloride in hot water (t = 70-75°С) was used to obtain ferric hydroxide nanoparticles under laboratory conditions. The nanodispersion (colloidal solution) was exposed to a weak pulsed magnetic field. The spectrophotometric properties of the colloidal solution of ferric hydroxide were determined using an SF-46 spectrophotometer in the wavelength range of 320-610 nm. The size of colloidal particles was calculated by a method based on the theory of Rayleigh light scattering. The size of colloidal particles depended on the exposure duration of a pulsed magnetic field on the colloidal solution. The size of colloidal particles was due to a change in the magnitude of the diffuse ionic atmosphere under the influence of a pulsed magnetic field. The kinetic stability of the colloidal solution was evaluated by the coagulation threshold, which was determined visually by the appearance of the turbidity of ferric hydroxide colloid when adding NaCl solution. The kinetic stability of a colloidal system was determined by the size of colloidal particles. These results can be used to better understand certain hypergenesis, sedimentation, and soil formation processes.

Understanding the Interaction Mechanism between Elemental Selenium and Ferric Hydroxide in Wastewater Treatment

The conversion of selenium oxyanions to elemental selenium (Se0) of low solubility and bioavailability is an effective industrial approach for selenium management in wastewater treatment. The generated Se0 particles require further treatment with coagulants such as ferric ions to facilitate the precipitation of Se0 particles. In this work, the settling of Se0 particles in simulated wastewater was investigated with amorphous ferric hydroxide (Fe(OH)3) as a coagulant prepared from hydrolysis of ferric chloride. The effects of ferric ion dosage, water composition, and pH on the Se0 removal percentage were investigated. The surface properties, i.e., ζ potential and morphology, were characterized, which influenced the interactions between Se0 and Fe(OH)3. The forces acting between Se0 and Fe(OH)3 surfaces were directly measured, for the first time, using atomic force microscopy (AFM). The water composition and pH had a significant effect on the adhesion force. In simulated wastewater, the adhesion force generally increased with pH, suggesting that the adsorption of Ca2+ and Mg2+ on Fe(OH)3 surface increased with pH, which enhanced the adhesion. Interestingly, long-range pull-off forces and sawtooth patterns were observed on the retraction force–separation curves, which were attributed to the stretching of Fe(OH)3 particle aggregates or chains during separation. Bulk settling tests showed that the best Se0 removal performance of Fe(OH)3 was found to be around pH 8, which was because the largest amount of Fe(OH)3 precipitates was found around this pH. The results indicate that the Fe(OH)3 solubility as well as the related intermolecular and surface forces play the predominant role in determining the Se0 removal performance of the ferric coagulant. This work, for the first time, revealed the interaction mechanisms of Se0 particle and amorphous Fe(OH)3, providing useful insights on the performance of ferric coagulants on Se0 particle removal from wastewater under various solution conditions. The experimental approach used in this work can be readily extended to other water treatment systems and processes such as polymer flocculation.

Characterization and quantification of chromate adsorption by layered porous iron oxyhydroxide: An experimental and theoretical study

The inner structure of iron oxyhydroxide agglomerates (IOAs) prepared from hydrolysis of ferric chloride was characterized and correlated to surface complexation of hexavalent chromium, Cr(VI), in a broad range of pH (3–12) and ionic strengths (0.0–5.0M). Evolution of particle size, morphology, and surface activity, combined with density functional theory (DFT) calculations, support the condensation reaction initiated formation of IOAs in three levels: iron nanoparticles to nanolayers to agglomerates. This agglomeration process led to a layered porous structure for aqueous-phase IOAs resulting in a rapid and high removal of Cr(VI) in batch tests. By integrating adsorption results, thermodynamic modeling, and quantum chemical calculations for the adsorption reactions, a quantitative distribution profile for each surface coordination of Cr(VI) ions (i.e., monodentate, bidentate, and hydrogen-bonding) was established. Results of this study are important to understand the fundamental mechanism of IOAs formation in aqueous phase and the intrinsic nature of surface complexations at the mineral-water interface for optimal Cr(VI) removal in hypersaline waste streams.

Structural, optical, and photocatalytic properties of ZnS/α-Fe2O3 core shell nano particles

Core shell ZnS/α-Fe2O3 nanoparticles were produced by the two-step method. In the first step uniform α-Fe2O3 particles were synthesized by hydrolysis of ferric chloride at 80°C. In the second step ZnS particles were added to α-Fe2O3 particles via hydrothermal rout at ca 90°C. The α-Fe2O3 and ZnS phases were identified by XRD and energy dispersive X-ray analysis (EDX). Crystal structure and morphology were studied by high resolution TEM. Photoreactivity of ZnS/α-Fe2O3 core shell nanoparticles was quantified by degradation of formaldehyde under UV irradiation.

Synthesis and growth of hematite nanodiscs through a facile hydrothermal approach

This study reports a facile hydrothermal method for the synthesis of monodispersed hematite (α-Fe2O3) nanodiscs under mild conditions. The method has features such as no use of surfactants, no toxic precursors, and no requirements of high-temperature decomposition of iron precursors in non-polar solvents. By this method, α-Fe2O3 nanodiscs were achieved with diameter of 50 ± 10 nm and thickness of ~6.5 nm by the hydrolysis of ferric chloride. The particle characteristics (e.g., shape, size, and distribution) and functional properties (e.g., magnetic and catalytic properties) were investigated by various advanced techniques, including TEM, AFM, XRD, BET, and SQUID. Such nanodiscs were proved to show unique magnetic properties, i.e., superparamagnetic property at a low temperature (e.g., 20 K) but ferromagnetic property at a room temperature (~300 K). They also exhibit low-temperature (<623 K) catalytic activity in CO oxidation because of extremely clean surfaces due to non-involvement of surfactants, compared with those spheres and ellipsoids capped by PVP molecules.

Surfactant-Resisted Assembly of Fe-Containing Nanoparticles for Site-Specific Growth of SWNTs on Si Surface

This paper describes a facile approach to the site-specific growth of single-walled carbon nanotubes (SWNTs) on silicon surfaces by chemical vapor deposition (CVD). The approach is based on the use of a surfactant as a resist to define patterns of silicon oxide nanodomains onto which nanoparticles of iron hydroxide (Fe(OH)3), 1-5 nm diameter, could be deposited. In base growth mode, the SWNTs can grow from the oxide nanodomains. By controlling the location of oxide nanodomains, site-specific growth could be obtained. The iron hydroxide nanoparticles were prepared by hydrolysis of ferric chloride (FeCl3). Patterned hydroxylated silicon oxide nanodomains were created by scanning probe oxidation (SPO) of silicon substrates modified with aminopropyltrimethoxysilane (APTMS, H2N(CH2)3Si(OCH3)3). Due to electrostatic interaction, Fe(OH)3 nanoparticles can be selectively deposited on hydroxyl groups present on silicon oxide nanodomains. To inhibit the assembly of the nanoparticles on a APTMS-coated silicon surface, sodium dodecyl sulfate (SDS) was introduced, which restricted deposition to the hydroxylated nanodomains. A model mechanism for the selective deposition mechanism has been proposed. It was possible to convert the patterned Fe(OH)3 nanoparticles to iron oxide, which served as a catalyst for the site-specific growth of SWNTs. Raman spectroscopy and AFM were used to characterize the nanotubes on the Si substrate. This will offer the possibility for future integration with conventional microelectronics as well as the development of novel devices.

Ferric hydrous oxide sols. IV. Preparation of uniform cubic hematite particles by hydrolysis of ferric chloride in alcohol—water solutions

Ferric hydrous oxide sols. IV. Preparation of uniform cubic hematite particles by hydrolysis of ferric chloride in alcohol—water solutions

The role of ferric chloride in the polymerization of vinyl butyl ether

The mechanism of polymerization of vinyl alkyl ethers has been discussed in Shostakovskii's monograph [1]. According to the monograph the polymerization of vinyl alkyl ethers is brought about by the action of an electrophilic agent, usually hydrogen chloride, and always involves the formation of an oxonium-ion complex. Shostakovskii used ferric chloride as a catalyst for the polymerization of vinyl butyl ether but even in this case he considered that polymerization is brought about by hydrogen chloride, which in his opinion is formed by the hydrolysis of ferric chloride [2]. This interpretation is not in accord with the facts and does not explain the extremely small expenditure of catalyst. For this reason an attempt was made in the present investigation to define by experimental means the role of ferric chloride in the polymerization of vinyl butyl ether and the effect of hydrogen chloride on this reaction.

The Effect of Temperature, of Colloidal Ferric Hydrate, and of a Magnetic Field on the Hydrolysis of Ferric Chloride

The Effect of Temperature, of Colloidal Ferric Hydrate, and of a Magnetic Field on the Hydrolysis of Ferric Chloride