Colloids iron oxide

Nechaev, E. A., Nikolenko, N. V. (1986). Adsorption of chloride complexes of gold(III) on iron-oxides. Colloid Journal of the USSR, 48(6), 992-996. 

Kretzschmar R., and H. Sticher. 1997. Transport of humic-coated iron oxide colloids in a sandy soil Influence of Ca2+ and trace metals. Environmental Science Technology 31 3497-3504. 

Breulmann, M., Colfen, H., Flentze, FI.-P Antonietti, M., Walsh, D. and Mann, S. (1998) Elastic Magnets Template controlled mineralization of iron oxide colloids in a sponge-like gel matrix. Advanced Materials 10 237-241. 

Biotite K(MB,Fe)3Si3A10ifl(0H)2 > 5 Kaolinite or mont-morillonite, iron oxides, colloidal silica, MgC03, K2CO3... 

Larpent C. and Patia H. (1992) Oxidation of alkanes with hydrogen peroxide catalyzed by iron salts or iron oxide colloids in reverse microemulsions, J. Mol. Catal. 72,315-329. 

Reactions of Colloidal Iron Oxide. — Colloidal iron oxides obtained from the acetate are turbid in reflected light and clear in transmitted. Sulfuric acid or its salts coagulate the hydrosol immediately, and the precipitate is not soluble in concentrated acid in contradistinction to the precipitate from Graham s solutions. When the hydrosol is poured into concentrated acid a precipitate is formed that is again dissolved by water. There exist several analogies between the hydrosol of meta-stannic acid and those of these ferric acetate hydrosols this accounts for the name, inetairon oxide. The hydrosol deserves more elaborate investigation the apparent isomerism of the two modifications is probably due to the difference in the size of the particles. 

Pretreatment For most membrane applications, particularly for RO and NF, pretreatment of the feed is essential. If pretreatment is inadequate, success will be transient. For most applications, pretreatment is location specific. Well water is easier to treat than surface water and that is particularly true for sea wells. A reducing (anaerobic) environment is preferred. If heavy metals are present in the feed even in small amounts, they may catalyze membrane degradation. If surface sources are treated, chlorination followed by thorough dechlorination is required for high-performance membranes [Riley in Baker et al., op. cit., p. 5-29]. It is normal to adjust pH and add antisealants to prevent deposition of carbonates and siillates on the membrane. Iron can be a major problem, and equipment selection to avoid iron contamination is required. Freshly precipitated iron oxide fouls membranes and reqiiires an expensive cleaning procedure to remove. Humic acid is another foulant, and if it is present, conventional flocculation and filtration are normally used to remove it. The same treatment is appropriate for other colloidal materials. Ultrafiltration or microfiltration are excellent pretreatments, but in general they are... 

Most commercial liquid ammonia contains up to several ppm of colloidal iron compounds, possibly the iron oxide catalyst commonly used in manufacturing ammonia. Reduction converts these compounds to colloidal iron which strongly catalyzes the reaction between alcohols and sodium and potassium. The reaction of lithium with alcohols is also catalyzed by iron but to a markedly lesser degree. The data in Table 1-4 illustrate the magnitude of these catalytic effects. The data of Table 1-5 emphasize how less than 1 ppm... 

Some acrylic acid copolymers are promoted as having a very wide range of functions that permit them to act as calcium phosphate DCAs, barium sulfate antiprecipitants, particulate iron oxides dispersants, and colloidal iron stabilizers. One such popular copolymer is acrylic acid/sulfonic acid (or acrylic acid/ 2-acrylamido-methylpropane sulfonic acid, AA/SA, AA/AMPS). Examples of this chemistry include Acumer 2000 (4,500 MW) 2100 (11,000 MW) Belclene 400, Acrysol QR-1086, TRC -233, and Polycol 43. 

Acrylic acid terpolymers have appeared on the market in recent years. With their broad spectrum of functions, they offer the potential for excellent waterside conditions. In particular, the terpolymers have proved to be very effective particulate iron oxides dispersants and colloidal iron stabilizers. Examples include acrylic acid/sulfonic acid/sodium styrene sulfonate (AA/SA/SSS), such as Good-Rite K781, K797, K798. A further example is acrylic acid/ sulfonic acid/substituted acrylamide (AA/SA/NI), such as Acumer 3100. 

Consequently, when selecting and blending the various raw materials used in all-polymer/all-organic formulations, the questions of thermal and hydrolytic stability and ability to transport or otherwise control colloidal iron oxides (in addition to possible adverse effects such as copper corrosion) become increasingly important at higher boiler temperatures and pressures. 

The foregoing results demonstrate that the thickness of the capsule wall can be controlled at the nanometer level by varying the number of deposition cycles, while the shell size and shape are predetermined by the dimensions of the templating colloid employed. This approach has recently been used to produce hollow iron oxide, magnetic, and heterocomposite capsules [108], The fabrication of these and related capsules is expected to open up new areas of applications, particularly since the technology of self-assembly and colloidal templating allows unprecedented control over the geometry, size, diameter, wall thickness, and composition of the hollow capsules. This provides a means to tailor then-properties to meet the criteria of certain applications. 

Sonoelectrochemistry has also been used for the efficient employment of porous electrodes, such as carbon nanofiber-ceramic composites electrodes in the reduction of colloidal hydrous iron oxide [59], In this kind of systems, the electrode reactions proceed with slow rate or require several collisions between reactant and electrode surface. Mass transport to and into the porous electrode is enhanced and extremely fast at only modest ultrasound intensity. This same approach was checked in the hydrogen peroxide sonoelectrosynthesis using RVC three-dimensional electrodes [58]. 

Aslant M, Schultz EA, Sun T, Meade T, Dravid VP (2007) Synthesis of amine-stabilized aqueous colloidal iron oxide nanoparticles. Cryst Growth Design 7(3) 471 175... 

The use of nanoscale materials in the dean-up of hazardous waste sites is termed nanoremediation. Remediation of soil contaminated with pentachloro phenol using NZVI was studied [198]. In a separate study, soils contaminated with polychlorinated biphenyls was treated using iron nanopartides [194], NZVI and iron oxide have been suggested to be used as a colloidal reactive barrier for in situ groundwater remediation due to its strong and spedfic interactions with Pb and As compounds [199]. 

Hongshao Z, Stanforth R (2001) Competitive adsorption of phosphate and arsenate ongoethite. Environ Sci Technol 35 4753—4757 Hsia TH, Lo SL, Lin CF, Lee DY (1994) Characterization of arsenate adsorption on hydrous iron oxide using chemical and physical methods. Colloid Surface A 85 1-7... 

As pointed out by Sposito (1984) this equation initiated the surface chemistry of naturally occurring solids. Maarten van Bemmelen published this equation (now referred to as the Freundlich isotherm) more than 100 years ago and distilled from his results, that the adsorptive power of ordinary soils depends on the colloidal silicates, humus, silica, and iron oxides they contain. 

Simple electrolyte ions like Cl, Na+, SO , Mg2+ and Ca2+ destabilize the iron(Hl) oxide colloids by compressing the electric double layer, i.e., by balancing the surface charge of the hematite with "counter ions" in the diffuse part of the double... 

Waite, T. D., and F. M. M. Morel (1984), "Photoreductive Dissolution of Colloidal Iron Oxide Effect of Citrate," J. Colloid Interface Sci. 102, 121-137. 

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