Iron Oxide Hydroxide Research Articles

Performance of FeOOH-brick based composite for Fe(II) removal from water in fixed bed column and mechanistic aspects

A new composite adsorbent – HCl-activated brick coated with iron oxihydroxide – was employed for the removal of iron(II) from aqueous solution using fixed bed column. The effects of various experimental conditions such as: bed depth, flow rate and column diameter on Fe(II) adsorption were examined. Kinetic Thomas model was used in describing column performance and prediction of breakthrough curves. The bed depth service time (BDST) model was tested in an attempt to obtain a mathematical description of the Fe(II) adsorption on to the modified brick and to assess column capacity. The saturated column was regenerated by a bleach solution and the resulting material could be re-used efficiently for Fe(II) removal. A mechanistic interpretation of iron(II) adsorption on to this composite was also addressed in the present work by investigating the evolution of ions contents versus elution time in column effluents using ICP-AES, and by detecting chemical modifications at the brick surface during the course of the adsorption process by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Our findings showed clearly that the sorption of iron(II) proceeded via an ions-exchange mechanism implicating the Na+ and H+ ions and two-line ferrihydrite (which was identified by X-ray diffraction) present at the brick surface and leading to the generation of a bi-dentate complex, (S)2Fe, with the following stoechiometric balance: [Na+]released+[H+]released≅2[Fe2+]adsorbed. Adsorbed iron was further found to be preferentially associated with iron oxide hydroxide in relatively stable chemical forms which were assigned to solid phases: (Fe2+)x(Fe3+)yOOH.

Facile synthesis of nanocomposite materials by intercalating an optically active poly(amide-imide) enclosing (l)-isoleucine moieties and azobenzene side groups into a chiral layered double hydroxide

The use of layered inorganic solids as host materials for the creation of inorganic–organic host–guest supramolecular structures is of increasing interest. In the present investigation, the nanocomposites of chiral poly(amide-imide) (PAI) and different amount of modified layered double hydroxide (LDH) were prepared via solution intercalation method for the first time. Chiral organically-modified chiral LDH was prepared via ion exchange reaction of LDH in a solution of N,N′-(pyromellitoyl)-bis-l-isoleucine diacid in distilled water. Novel diamine with azo side group was synthesized from the reaction of 4-aminoazobenzene and 3,5-dinitrobenzoyl chloride followed by reduction of dinitro with iron oxide hydroxide catalyst and hydrazine monohydrate. An optically active PAI was prepared by direct polyamidation of the chiral diacid with azo diamine under green condition using molten tetra-n-butylammonium bromide with good yield and moderate inherent viscosity. The obtained polymer and organically-modified chiral LDH were used to prepare chiral and high performance hybrid materials. The effect of LDH contents on thermal, physicomechanical, and morphological properties of PAI was investigated by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy techniques. Thermogravimetric analysis results confirmed that the heat stability of the prepared nanoparticle-reinforced composites was improved.

Enhanced Adsorption of Fluoride from Aqueous Solution Using an Iron‐Modified Attapulgite Adsorbent

Attapulgite modified with iron was used as an adsorbent for fluoride removal from aqueous solutions. The pristine attapulgite and the iron-modified attapulgite composite were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) techniques, and the pH point of zero charge measurement. The XRD analysis indicates the existence of iron oxide hydroxide (FeO[OH]) in the iron-modified attapulgite composite. The FT-IR spectra of the iron-modified attapulgite composite before and after adsorption indicate that the involvement of the hydroxide radical in the fluoride adsorption. The effects of pH, contact time, initial concentration, and temperature on fluoride adsorption by the adsorbent were studied in a batch system. Kinetics studies show that the fluoride adsorption kinetics over the adsorbent is well-described by the pseudo-second-order kinetic model. The fluoride adsorption isotherm is well-fitted by the Langmuir model. Desorption studies show that the iron-modified attapulgite adsorbent can be easily regenerated at pH 12.5. The adsorption mechanism is discussed in detail.

One-pot green synthesis of silver/iron oxide composite nanoparticles for 4-nitrophenol reduction

Silver/iron oxide composite nanoparticles have been synthesized successfully via a facile one-pot green route by the use of l-arginine, which created an aqueous solution of about pH 10 and acted as a reducing agent for the successive formation of iron oxide and Ag nanoparticles. The product was characterized to be silver-coated iron oxide and iron oxide hydroxide composite nanoparticles with a mean diameter of about 13.8±3.0nm and 8.53% of Ag in weight. It exhibited good catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. The reduction reaction followed the pseudo-first-order kinetics. The corresponding rate constants increased with the increases of temperature and catalyst amount but decreased with the increase of initial 4-NP concentration, revealing an activation energy of 28.2kJ/mol and a diffusion controlled mechanism. In addition, this product had quite good stability. No significant activity loss was observed after reuse for 5 cycles.

Catalytic degradation of microcystin-LR using bentonite supported bimetallic Fe/Pd nanoparticles

In this paper,bentonite supported bimetallic Fe/Pd nanoparticles(B-Fe/Pd) was explored to use for degradation of microcystin-LR(MC-LR).96.86% of MC-LR was degraded after 180 min with an initial MC-LR concentration of 5mg L-1(pH 6.86) using 0.1g B-Fe/Pd.UV-Vis and HPLC-UV showed that the peak of MC-LR at 238 nm was disappeared after B-Fe/Pd react with MC-LR.SEM-EDS,XRD,FTIR and XPS used for characterization of B-Fe/Pd before and after reaction with MC-LR revealed the formation of iron oxide and iron hydroxides after degradation of MC-LR.The degradation of MC-LC using B-Fe/Pd fitted well the pseudo-first kinetic order model with an activation energy was 12.77 kJ mol-1.Degradation mechanism of MC-LR was proposed,which was based on firstly MC-LR adsorded in the surface of bentonite and iron nanoparticles-palladium particles,secondly iron nanoparticles reacted with water to produce hydrogen,and the formation of hydrogen radical by the Pd catalysis,finally MC-LR was reduced by hydrogen radical,where the most toxic conjugated double bond of MC-LR was broken by the reduction.

Kinetics of Zero Valent Iron Nanoparticle Oxidation in Oxygenated Water

Zero valent iron (ZVI) nanoparticles are versatile in their ability to remove a wide variety of water contaminants, and ZVI-based bimetallic nanoparticles show increased reactivity above that of ZVI alone. ZVI nanoparticles degrade contaminants through the reactive species (e.g., OH*, H(2(g)), H(2)O(2)) that are produced during iron oxidation. Measurement and modeling of aqueous ZVI nanoparticle oxidation kinetics are therefore necessary to optimize nanoparticle design. Stabilized ZVI and iron-nickel nanoparticles of approximately 150 nm in diameter were synthesized through solution chemistry, and nanoparticle oxidation kinetics were determined via measured mass change using a quartz crystal microbalance (QCM). Under flowing aerated water, ZVI nanoparticles had an initial exponential growth behavior indicating surface-dominated oxidation controlled by migration of species (H(2)O and O(2)) to the surface. A region of logarithmic growth followed the exponential growth which, based on the Mott-Cabrera model of thin oxide film growth, suggests a reaction dominated by movement of species (e.g., iron cations and oxygen anions) through the oxide layer. The presence of ethanol or a nickel shell on the ZVI nanoparticles delayed the onset of iron oxidation and reduced the extent of oxidation. In oxygenated water, ZVI nanoparticles oxidized primarily to the iron oxide-hydroxide lepidocrocite.

Poly(amide-imide)s obtained from 3,5-diamino-N-(thiazol-2-yl)-benzamide and dicarboxylic acids containing various amino acid units

This study reports a green approach toward the synthesis of novel optically active poly(amide-imide)s (PAI)s bearing thiazole moiety, which was formed by the polycondensation reaction of 3,5-diamino- N-(thiazol-2-yl)benzamide and various diacids containing natural amino acids in molten tetrabutylammonium bromide. Diamine monomer was synthesized by the reduction of 3,5-dinitro- N-(thiazol-2-yl)benzamide in methanol using iron oxide hydroxide as a catalyst. This catalyst can rapidly reduce the sulfur and azo-containing aromatic nitro compounds to the corresponding amines in high yield by employing hydrazine hydrate as a hydrogen donor. Chiral diacid monomers were synthesized in high yield through the reaction of pyromellitic dianhydride and amino acids (l-isoluecine, S-valine, S-methionine, and l-phenylalanine) in acetic acid. The direct polymerization reactions of these monomers provided a series of new optically active PAIs with inherent viscosities in the range of 0.20–0.28 dL g−1. The obtained polymers were characterized by Fourier-transformed infrared spectroscopy, specific rotation measurements, and the representative of them by proton nuclear magnetic resonance and elemental analysis techniques.

Quantification of extraction of colloid iron oxide hydroxides by Di-(2-ethylhexyl)phosphoric acid

A mathematical model of extraction is proposed based on the concept of the adsorption of an extractant by nanosized colloid particles. The composition and structure of extractable species are discussed.

바이오매트 형성에 의한 산성광산배수 내 중금속 유출질량 제거효율

This research investigated to reduce mass of heavy metals in AMD(acid mine drainage) by microbial mats formed on the channel bed. As, Cd, Cu, Fe, Mn and Zn components were monitored in water and microbial mats, at three points (AMD1, AMD2 and AMD3), in a total of six times. Average daily discharge mass of heavy metals was highest in July, Fe component contained more than 76% of total discharge mass. Discharge mass of heavy metals of AMD and heavy metal contents in microbial mats decreased with downstream at channel. Heavy metal components that average daily discharge mass is over 0.5 kg were Fe, Cu and Zn, and they were highest in July. Average removal efficiency of heavy metals in AMD was highest about 21% in Fe, this microbial mats were due to form from precipitation of Fe component in AMD by aerobic iron bacteria. Relative content for As component in microbial mats than AMD was over 16 times, this As components were due to absorb at iron oxide and iron hydroxide on the surface of microbial mats.

Removal of Fluoride from Water Using Iron Oxide-Hydroxide Nanoparticles

A novel and facile method for the synthesis of uniform stoichiometric powder form of non-magnetic iron oxide-hydroxide nanoparticles with spherical morphology and its application for defluoridation of drinking water is reported. X-ray powder diffraction analysis (XRD), BET surface area, FTIR, field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) images were used to characterize nanoscale iron oxide-hydroxide. Transmission electron microscopy (TEM) image revealed the formation of iron oxide-hydroxide nanoparticles with spherical morphology. The iron oxide-hydroxide nanoparticles showed an excellent ability to remove fluoride (F-) from contaminated water over a wide range of pH. The influences of temperature, stirring speed, pH, adsorbent dose and contact time were studied. The equilibrium data were tested with various isotherm models and finally, a calculation procedure was reported for the calculation of adsorbent requirement. The fluoride adsorbed nanoparticles was regenerated upto 70% using sodium hydroxide or hydrochloric acid solution. The iron oxide-hydroxide nanoparticles can be used as an effective and replicable adsorbent media for defluoridation of water in presence of competing anions like chloride, iodate, iodide and sulphate.

Preparation and Electrocatalytic Activity of WC/W<sub>2</sub>C Nanocomposite with Core-Shell Structure

A monotungsten carbide (WC)/bitungsten carbide (W2C) nanocomposite having a core-shell structure was prepared through a combination of surface coating and in situ reduction-carbonization, using ammonia meta-tungsten as tungsten source and iron oxide hydroxide as a hard support. The crystal phase, morphology, microstructure, and chemical components of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray energy dispersion spectroscopy (EDS). The results show that after calcination, the morphology, the crystal phases of the support, and the coating layer around the support are changed. After acid dissolution, reduction, and carbonization, the crystal phase of the final product is composed of WC and W2C; the microstructure of the sample particle is a core-shell structure in which WC forms the core and W2C forms the shell. Based on the characterization results, the formation mechanism of the core-shell structure is discussed. The electrocatalytic activities of the samples for methanol electrooxidation were investigated by cyclic voltammetry with a three-electrode system in acidic, neutral, alkaline aqueous solutions. The results show that the electrocatalytic activity of the sample for methanol oxidation is higher than that of tungsten carbide particles and hollow microsphere

Estudo petrográfico e geoquímico dos ironstones da base da Formação Pimenteiras, Borda Oeste da Bacia do Parnaíba, Tocantins

Ironstones that occur at the base of the Devonian Pimenteiras Formation (northwestern border of the Parnaíba basin) were investigated along the Xambioá-Vanderlândia and Colinas do Tocantins-Couto Magalhães sections. The ironstones consist of discontinuous decimeter-thick layers intercalated in sandstones and shales that underlie rocks of the Neoproterozoic Araguaia belt. The Xambioá-Vanderlândia ironstones are texturally and chemically quite distinct from those of the Colinas do Tocantins-Couto Magalhães area. Besides the presence of oolites, the former shows smaller amounts of terrigenous material (especially quartz) and higher iron oxide-hydroxides proportions. They also are more enriched in V, Sr, Zr and ΣREE, and poorer in Al2O3 and Rb. The North American Shale Composite (NASC) normalized REE distribution pattern is also different, especially concerning the IREE N values, which, being higher in the oolithic ironstones, display convex curves and, being lower in the non-oolithic ironstones, display concave ones. In the field, spatial relationships could not be defined between both ironstone types. It is then suggested that they represent different lithological facies of the same iron formation. Probably, the deposition of the non-oolithic facies occurred in deeper and quieter waters away from the continental border, where larger amounts of detrital sediments were discharged, whereas the deposition of the oolithic facies took place in shallower and more agitated waters, with less supply of terrigenous material. Iron was largely derived from the erosion of continental areas where reduced environments favored its mobilization and transport by rivers as suspended particles, colloids, and organic complexes.

Systematic comparison of the size, surface characteristics and colloidal stability of zero valent iron nanoparticles pre- and post-grafted with common polymers

This study systematically examines the effect of four common polymers on the size, surface chemistry, colloidal stability, and sedimentation behaviour of nanoparticles of zero valent iron (NZVI). The mean diameters of NZVI ranged from 5 to 189 nm, depending on the synthesis conditions. The influence of the pre- or post-grafting of the polymers on the above parameters was also investigated. The four polymers are carboxymethyl cellulose (CMC), poly(styrenesulfonate) (PSS), poly(acrylic acid) (PAA) and polyacrylamide (PAM). The molecular weight of these polymers range over three orders of magnitude, from 1.8 × 103 to 5000 × 103 g mol −1 and they are all negatively charged with the exception of the non-ionic PAM. All NZVI samples were synthesized by sodium borohydride reduction of ferrous sulfate solutions. For pre-grafting, the NZVI was synthesized in the presence of the different polymers and identical synthesis conditions were maintained which allowed for an unbiased and direct comparison of the characteristics of the different particles. ATR-FTIR analyses revealed that both pre- and post-grafted polymers were bound to the iron nanoparticle surface with polar bonds between carboxylate groups of CMC and PAA, sulfonate groups of PSS, and with hydrogen bonds with the amine groups of the non-ionic PAM. TEM images and nanoparticle tracking analysis revealed that iron nanoparticles synthesised in the presence of the polymers were larger in diameter, with TEM mean diameters ranging from 84.5 to 189 nm, than the bare-NZVI (59.1 nm), when synthesized with the same initial Fe 2+ concentration. Altering the CMC or Fe 2+ concentration during synthesis allowed synthesis of relatively monodisperse, colloidally stabilized CMC-NZVI with defined average diameters ranging from 5 nm to 129 nm. XPS studies indicated that all pre-grafted polymer-stabilized NZVI had a polymer coating covering a core–shell structure with a shell of iron oxide–hydroxides and a core of Fe 0. Pre-grafted CMC was found to be the most efficient in colloidally stabilizing NZVI. Sedimentation tests demonstrated that after 60 min pre-grafted CMC-NZVI were slightly more stable than pre-grafted PAA-NZVI, but at least two-times more stable than pre-grafted PSS- or PAM-NZVI and 13 times more stable than bare-NZVI. The colloidal stability of all post-grafted NZVI was lower than the corresponding pre-grafted particles by 1.3 to 6 times, with the exception of PSS. The nature of polymer–Fe interactions were further explored by ATR-FTIR spectra of pre- and post-grafted particles. These results highlight the relevance of the extent and the nature of the polymer–Fe interactions during synthesis of polymer-stabilized NZVI.

Synthesis, characterization and kinetics of bentonite supported nZVI for the removal of Cr(VI) from aqueous solution

Bentonite supported nanoscale zero-valent iron (B-nZVI) was synthesized by the sodium borohydride reduction method, characterized with SEM, and used for aqueous Cr(VI) removal. Bentonite decreased nano-Fe0 aggregation and thus increase Cr(VI) removal efficiency. At 35°C and 250rmin−1, 99% Cr(VI) removal was achieved from aqueous solution containing 50mgL−1 of Cr(VI) by B-nZVI, while only 66% removal was achieved with unsupported nZVI after an experimental duration of 3h when the Fe0 loadings were 1.5gL−1. XRD indicated the existence of iron oxide and iron-chromium hydroxide coprecipitation on the surface of B-nZVI after exposure to an aqueous solution of Cr(VI). Kinetics studies under a series of different conditions showed that reduction of Cr(VI) to Cr(III) could be expressed by pseudo first-order reaction kinetics, with initial Cr(VI) and B-nZVI concentrations, pH and temperature as variables. The apparent activation energy of Cr(VI) remediation by B-nZVI was 21kJmol−1, which was characteristic of a chemically controlled reaction. These results demonstrated that B-nZVI could potentially be used as a new material for use in situ remediation.

Pigmentų įtakos savaime sutankėjančio betono savybėms tyrimai

Darbe aprašomas geležies oksido pigmento įtakos savaime sutankėjančio betono savybėms tyrimai. Tyrimo metu pigmento į betono mišinius buvo pridedama nuo 3 iki 6 % cemento masės. Taip pat atlikti kelių (chromo oksido, geležies oksido hidroksido ir geležies oksido) pigmentų įtakos normalaus tirštumo cementinei tešlai gauti tyrimai. Straipsnyje parodome, kad geležies oksido pigmentas sumažina vandens poreikio normalaus tirštumo cemento tešlai gauti. Pridedamas pigmentas mažina betono stiprį gniuždant iki 20 %. Bandiniai buvo testuojami po 1 paros ir 28 parų kietėjimo, išlaikant juos vandenyje 20±2 ºC. Dalis bandinių, siekiant paspartinti cemento hidratacijos procesą bei įvertinti pelenuose esančio aktyvaus SiO2 poveikį savaime sutankėjančio betono savybėms, buvo apdorota termiškai šutinimo kameroje 60 ºC temperatūroje. Naudojant geležies oksido pigmentą savaime sutankėjančiam betono mišiniui gaminti, pasklidimas padidėja iki 5 %. Sukietėjusio betono tyrimų duomenys parodė, kad geležies oksidas sumažina vandens įgeriamumą (iki 6 %) bei atvirą betono poringumą. Tai daro jį atsparesnį šalčiui.

Formation of Nucleobases from Formamide in the Presence of Iron Oxides: Implication in Chemical Evolution and Origin of Life

Simple compounds like HCN, which have one C and one N, are proposed as the probable precursors for biomonomers. Formamide, a hydrolysis product of HCN, is known as the precursor of various biologically important compounds, for example, nucleobases (purines and pyrimidines). In this paper, we report our results on the synthesis of nucleobases, adenine, cytosine, purine, 9-(hydroxyacetyl) purine, and 4(3H)-pyrimidinone from formamide, using iron oxide (hematite) and oxide hydroxides (goethite and akaganeite) as a catalyst. Goethite and hematite produced purine in higher yield. The products formed were characterized by high-performance liquid chromatography and electrospray ionization mass spectrometry techniques. Results of our study reveal that iron oxides might have worked as efficient prebiotic catalysts.

Characterization and fluoride uptake studies of nano-scale iron oxide-hydroxide synthesized by microemulsion method

In the present study nano scale iron oxide hydroxide was synthesized by water in oil microemulsion method. A non-ionic surfactant span 80, hexanol and FeCl3 were chosen as starting materials. The prepared sample was characterized by XRD, TEM, TGA and FT-IR. X-ray diffraction pattern showed it be 2- line ferrihydrite like structure. TEM showed aggregated particles in the range of 5-10 nm size. The fluoride adsorption efficiency of the nano powder was determined with respect to contact time, initial F- concentration and pH of the solution. The batch adsorption data revealed that the fluoride adsorption efficiency was highly influenced by the studied factors. Equilibrium was attained within one hour of contact time indicating fast kinetics. The adsorption data followed second order kinetic model. The isothermic data fitted to both Langmuir and Freundlich models and maximum loading capacity as estimated by Langmuir model was 62.89 mg/g for the studied concentration range of 10-30 mg/L. The high loading capacity points towards the potential of this adsorbent for fluoride removal from aqueous streams. Keywords: Fluoride, nano-iron oxide hydroxide, adsorption, kinetics, isotherm study International Journal of Engineering, Science and Technology, Vol. 2, No. 8, 2010, pp. 1-12

Bioconstructions in ochreous speleothems from lava tubes on Terceira Island (Azores)

The ochreous speleothems examined here were obtained from a lava tube on Terceira Island (Azores) and show compact mineralized areas intermixed with zones in which bacterial structures are evident. Bacterial layers of filament-like structures are common throughout the deposits but differences in microstructure among the different speleothems were observed, reflecting a broad morphological range of deposits. The structures and minerals detected in the speleothems betray their biogenic origin. Gallionella and Leptothrix were the two most frequently observed morphotypes and probably the main contributors to speleothem formation. However, DGGE analysis indicated the presence of another bacterial population (with a predominance of proteobacteria) that could also contribute to iron hydroxide–oxide precipitation. The sheaths of Leptothrix cells and stalks of Gallionella cells were associated with large amounts of extrapolymeric substances (EPS), which play a role in biomineralization processes. Independently of the taxa present, mineral deposits were composed of poorly ordered Si-rich ferrihydrite, a typical mineral phase of biogenic Fe precipitates. In this microscopy study of interrelationships between mineral precipitates and associated microorganisms and their structures, we attribute bacteria to have an important role in constructing these speleothems. Through their metabolic activity, these bacteria cause the precipitation of ferrihydrite but their mineral structures could also act as nucleation points for passive mineral precipitation. Finally, the build-up of bacterial mineral structures and later cementation processes seems responsible for the formation of mineral layers that confer consistency to the speleothem. Our findings point to bacterial activity as the main factor determining speleothem structure and formation.

Iron-rich Oklahoma clays as a natural source of chromium in monitoring wells

Water samples, drawn from groundwater monitoring wells located southeast of Oklahoma City, OK, were found to contain elevated concentrations of total chromium with an apparent source localized to the area surrounding each well. Since these monitoring wells are located in areas with no historic chromium usage, industrial sources of chromium were ruled out. Water testing was performed on twelve monitoring wells in the area that historically had elevated total chromium concentrations ranging from 10-4900 micrograms per litre. Filtered water samples were found to be free of chromium contamination, indicating that the source of the chromium is the suspended solids. Analysis of these solids by acid digestion and a sequential extraction technique revealed that the chromium was primarily associated with iron-containing solids. X-ray diffraction identified goethite, an iron oxide hydroxide, as the dominant iron-containing phase in the suspended solids. The mineralogy in this region is dominated by interbedded red-bed sandstone and mudstone whose mineral content includes mixed-layer illite-smectite, hematite, goethite, gypsum and dolomite. Elemental analysis of soil samples collected as a function of depth in the locale of the monitoring wells indicated that the iron rich clays contain a natural source of chromium. The elevated levels of total chromium are most likely due to the dissolution of silica and alumina from the chromium containing iron clays in the basic well water, resulting in the release of fine suspended solids that naturally have high chromium concentrations. These results should be applicable to other areas containing iron-rich clays.

Formation of cobalt ferrites from aqueous solutions of metal nitrates containing PVA: effects of the amount of PVA and annealing temperature

Controlling magnetic properties of sol–gel synthesized cobalt ferrites (CoFe2O4) have been studied by variations in amount of polyvinyl alcohol (PVA) and annealing temperature. PVA of 24, 32, 40 and 48 g in 10% w/v aqueous solutions was used in the reaction between 10.592 g of Co(NO3)2·6H2O and 29.407 g of Fe(NO3)3·9H2O. The decrease in PVA led to the reductions in coercive field and squareness. However, X-ray diffraction peaks indicated that iron oxide (α-Fe2O3) and iron oxide hydroxide [FeO(OH)] were also formed when the PVA was less than 48 g. The optimized amount for obtaining single phase CoFe2O4 was therefore 48 g which was used for studies of heat treatment effect. Both coercive field and squareness were increased with the increase in annealing temperature from 280 to 680°C and then reduced with the further increasing temperature up to 900°C as a result of particles agglomeration.