Ferric Salts Research Articles

EDTA-Fe(III) sodium complex–derived bubble-like nitrogen-enriched highly graphitic carbon nanospheres as anodes with high specific capacity for lithium-ion batteries

Bubble-like nitrogen-enriched graphitic carbon was prepared using EDTA-Fe(III) sodium complex (ethylenediaminetetraacetic acid ferric sodium salt) as the precursor. The complex was carbonized at 700 °C for 2 h in argon atmosphere, and then, the product was washed with diluted hydrochloric acid and distilled water to remove iron and iron compounds so as to achieve the hollow carbon nanospheres. The as-prepared bubble-like carbon material exhibits excellent energy storage capability as the anode for lithium-ion batteries. A maximal reversible specific capacity of about 505 mAh g−1 can be achieved at a current density of 100 mA g−1, and 150 mAh g−1 can still be retained at a high current density of 1600 mA g−1, demonstrating superior cycling performance and excellent rate capability mainly due to the unique porous architecture and improved conductivity.

Characterization and Evaluation of Zeolite A/Fe3O4Nanocomposite as a Potential Adsorbent for Removal of Organic Molecules from Wastewater

In this work, zeolite (Z) and Z-Fe3O4nanocomposite (Z-Fe3O4NC) have been synthesized. The Fe3O4nanoparticles were synthesized using the extract from maize leaves and ferric and ferrous chloride salts and encapsulated into the zeolite framework. The nanocomposite (Z-Fe3O4NC) was characterized using X-ray diffractometer (XRD), Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The potential of Z-Fe3O4NC as an adsorbent for removing methylene blue molecules (MB) from solution was examined using UV-Vis and kinetic and equilibrium isotherm models. The adsorption data fitted best with the pseudo-second-order model and Weber and Morris model, indicating that the adsorption process was chemisorption, while the Weber and Morris described the rate-controlling steps. The intraparticle diffusion model suggests that the adsorption processes were pore and surface diffusion controlled. The Langmuir isotherm model best describes the adsorption process indicating homogeneous monolayer coverage of MB molecules onto the surface of the Z-Fe3O4NC. The maximum Langmuir adsorption capacity was 2.57 mg/g at 25°C. The maximum adsorption efficiency was 97.5%. After regeneration, the maximum adsorption efficiency achieved at a pH of 7 was 82.6%.

Fabrication of Strong Solid Base FeO–MgO for Warm CO2 Capture

A strong solid base, FeO–MgO, is synthesized using magnesium acetate and ferrous acetate in order to meet the requirement of capturing CO2 in flue gas at a temperature higher than 423 K. After the two salts are ground and carbonized at 823 K, the ferric MgO composite with a surface area exceeding 160 m2 g−1 is obtained, where ferric oxide species are wrapped by magnesia particles. The influence of ferric salt on the structure and adsorption properties of the strong solid bases is investigated to determine the optimal amount, and the distribution of ferric additive is assessed with X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). With a mass ratio of ferrous oxide of about 3%, the basic sorbent could capture 35 mg g−1 CO2 at 473 K and the ratio of strong base sites increases to 91%. Both the CO2 adsorption capacity and the ratio of strong basic sites are higher than those of the other MgO sorbents, which is beneficial for warm CO2 capture. Additionally, the function of strong basic sites in the ferric MgO sorbent is explored in the instantaneous adsorption of warm CO2. The capability in the cycled warm CO2 adsorption is found to be related to the desorption temperature of CO2. Different forms of CO2 injections are used in adsorption and the influence on the performance of the strong basic sorbent is also studied.

Different ferric dosing strategies could result in different control mechanisms of sulfide and methane production in sediments of gravity sewers

Ferric salt dosing is widely used to mitigate sulfide and methane emissions from sewers. In gravity sewers with sediments, responses of sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) residing in different zones to Fe3+ dosing strategies still remain unknown. In this study, we investigated the changes in behavior of SRB and MA in different depths of sewer sediment using laboratory-scale sewer sediment reactors with different Fe3+ dosing strategies (different instant dosages and frequencies). All Fe3+ dosing strategies examined efficiently suppressed sulfide concentration for a short time, but the control mechanisms were different. When a low-dosage, high-frequency Fe3+ dosing strategy was employed, Fe3+ could not penetrate into the sewer sediment, therefore, the abundances of SRB and MA in all zones of sewer sediment did not change substantially. As a result, the active sulfide-producing and methane-producing zones kept unchanged. Sulfide was controlled mainly via chemical sulfide oxidation and precipitation, and methane formation was not influenced. In contrast, when a high-dosage, low-frequency Fe3+ dosing strategy was used, the SRB activity in the upper layer of the sewer sediment was nearly fully suppressed according to the down moving zones of sulfide production (from 0-5 mm to 20–25 mm) and lower sulfate reduction, in which sulfate reduction decreased by 56% in the long-term trial. The generated sulfide was further removed via chemical sulfide oxidation and precipitation. This strategy also significantly suppressed MA activity (21% reduction in methane production). However, considering a long-term satisfactory sulfide control, a low operational cost and less sediments deposited in gravity sewers, a low-dosage, high-frequency Fe3+ dosing strategy would be a more cost-effective solution for sulfide control in gravity sewers with thin (<20 mm) or thick (>20 mm) sediments if methane mitigation does not need to be taken into account.

Modelling the effects of ferric salt dosing for chemical phosphorus removal on the settleability of activated sludge

There is a growing utilisation of ferric salts (Fe3+) for precipitation of phosphorus from wastewater due to tighter regulatory limits for wastewater effluent discharge. The effect of Fe3+dosing on activated sludge settleability indicators; zone settling velocity (ZSV) and stirred specific volume index (SSVI) were examined in laboratory-based batch settleability tests over a three years period. The experimental data revealed that ZSV increased with increasing dose of ferric salt as SSVI decreased with the highest changes obtained at a dose rate of 50 mgL-1. Fe3+ facilitated the agglomeration of the activated sludge flocs, thereby improving settleability. At >50 (mgL-1) of Fe3+, there was a slight breakdown in sludge settleability due mainly to surface charge reversals. The modelling of the settleability of ferric sludge in recent wastewater engineering practice for design and improvement purposes is presently based on conventional empirical sludge settleability models. This paper proposed a new activated sludge settleability model that describes the effects of Fe3+ dosing on the ZSV and SSVI of activated sludge. The exponential form of the Vesilind equation was optimised and validated to include ferric chemical dosing parameters. The proposed ferric settleability equations were found to effectively describe the settling characteristics of ferric sludge.

Treatment of high-strength olive mill wastewater by combined Fenton-like oxidation and coagulation/flocculation

The efficiency of Fenton/Fenton-like processes on the oxidation of organic matter from real olive mill wastewater (OMW) is described. Tests were performed in lab-scale batch reactors and the influence of different operational parameters was evaluated, namely: type of iron salt, effect of pH readjustments during the reaction, reactants addition method and Fe/H2O2 mass ratio. For the Fenton-like system (Fe3+/H2O2) it was found that H2O2 consumption and consequently total organic carbon (TOC) degradation rate are significantly affected by the reagents addition method, especially in earlier stages of the reaction, although the overall extent of TOC removal is not. Results showed that the gradual addition of H2O2 along with pH readjustments during the process led to better chemical oxygen demand (COD) and total phenolic content (TPh) reduction. Operating at pH0 = 3.0, T0 = 25 °C, [Fe3+] = 1.0 g·L−1 and Fe/H2O2 = 0.04, 34.9% of TOC, 55.7% of COD and 81.4% of TPh were removed after 180 min. The same conditions were applied with the assistance of artificial radiation (photo-Fenton-like process) with slight organic matter degradation improvement (41.8% of TOC, 63.2% of COD and 83.8% of TPh removals). The catalyst’s (ferric chloride salt) ability to act as a coagulant/flocculant after the oxidative process was also checked, being reached a global reduction of 76.7% for COD and 96.4% for TPh after 1 h of sedimentation and no further pH adjustments. Moreover, the effluent’s biodegradability (BOD5:COD ratio) after the combined process improved from the initial value of 0.11 to 0.33, and toxicity against the bioluminescent Vibrio fischeri bacteria decreased from 53% to 4%, putting into evidence the possibility of coupling downstream a biological unit so that the final effluent meets legal discharge limits.

Clusters of superparamagnetic iron oxide nanoparticles capped with palm shell extract and modified with chitosan: Catalytic applications for degradation of cationic and anionic dyes and their binary mixtures

Heterogeneous regenerative iron oxide nanocatalyst capped with palm shell extract(IO) and IO modified with chitosan has been developed by simple coprecipitation of ferrous and ferric salts for degradation of single and binary mixture of dyes in aqueous phase. The iron oxide nanoparticles were characterized using IR, UV, TEM, XRD, Raman, VSM and Mossbauer techniques. The obtained results suggest the presence of Fe3O4, γ-Fe2O3 and α-Fe2O3 in IO and CIO though to different extents. The degradation process was carried out at room temperature and at near neutral pH which led to complete degradation and multicyclic use of the nanocatalyst for environmental applications without loss in efficiency. CIO was observed to be more efficient as compared to IO during catalytic degradation of binary mixture of dyes.

Material inter-recycling for advanced nitrogen and residual COD removal from bio-treated coking wastewater through autotrophic denitrification

For wastewaters containing high strength sulfide and nitrogen (e.g. coking wastewater), sulfide might be precipitated and recovered using ferrous salt. This study systematically investigated the feasibility of recovered and precipitated FeS (comparing to commercial FeS minerals) to support autotrophic denitrification for advance nitrogen removal from bio-treated coking wastewater in fluidized bed reactors. The reactor with precipitated FeS could achieve simultaneous removal of NO3−-N and inert COD with high efficiencies of around 96.3% and 30.5%, at NO3−-N and COD loading rates of 4.18 mg·L−1·h−1 and 8.06 mg·L−1·h−1, respectively. Whereas, the performance of commercial FeS reduced gradually and irreversibly after two days, which became completely ineffective after 40 days. Thiobacillus and Rhodanobacter dominated the biomass, which played a key role in the FeS-based denitrification process. This material inter-recycling concept benefits an advance and more sustainable treatment of wastewaters with high strength sulfide and nitrogen.

Fabrication of Polymer@α-FeOOH Core–Shell Particles for the Photocatalytic Degradation of Organic Pollutant

α-FeOOH nanocrystals were grown on the surface of polymeric spheres through in situ hydrothermal synthesis. The polymer with the surface amine groups was composed of styrene, divinylbenzene and 2-(dimethylamino)ethyl methacrylate via emulsion polymerization, which abbreviated it as PSDM. The structure and component of PSDM@α-FeOOH composites were investigated by Fourier transform infrared, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy. It was observed that the crystal structure, morphology and dispersion of α-FeOOH depended on different factors, i.e., temperature, reactant concentration and ferric salt types. A plausible formation mechanism of PSDM@α-FeOOH composites was revealed based on the systematic investigations of the assembly process. Additionally, it was possible for this method to be extended to synthesis the composite particles for other metal ions. The photocatalytic activity of the composites had been discussed by testing the degradation of rhodamine B as well as methylene blue and neutral red in the presence of H2O2. The measurements demonstrated that PSDM@α-FeOOH composites catalyst exhibited excellent photocatalytic ability and superior stability.

Rapid and Reliable Qualitative Methods for Identification of Iron Fortificants in Wheat Flour (P13-015-19)

ObjectivesFortification is a common strategy to reduce the prevalence of iron deficiency anemia (IDA). Currently, manufacturers are able to fortify wheat flour with cheaper iron compounds with lower bioavailability, leading to less of an impact on IDA. Therefore, a method is needed for government agencies to monitor the type of iron added to flour. The objective was to develop a quick and simple method to qualitatively determine iron compounds commonly used for fortifying wheat flour. MethodsUnfortified wheat flour was fortified with 40 ppm using these salts: ferric pyrophosphate (FePP), ferrous sulfate (FeSO4), ferrous citrate (FeC), ferrous fumarate (FeF), and sodium iron EDTA (NaFeEDTA), except for electrolytic iron (EFe) where 60 ppm was added. Iron salts were identified based on their magnetic property, solubility in water or acid, and oxidation state. EFe was identified by passing a magnet through the flour. Ferrous and ferric salts were identified using potassium thiocyanate (KSCN) in 3 N hydrochloric acid (HCl) with and without hydrogen peroxide (H2O2). Ferric salts (NaFeDTA and FePP) were identified using Ferrozine and ascorbic acid. Poor solubility of FeF in weak acid with KSCN was used to differentiate it from FeSO4 and FeC. Acidity testing with phenolphthalein and sodium hydroxide (NaOH) further differentiated FeC from FeSO4. Flour samples were tested in triplicates and blinded samples were tested independently. ResultsEFe from flour was visible on the magnet. In addition to producing red specks with KSCN, NaFeEDTA in water produced strong color with Ferrozine and ascorbic acid, unlike FePP. Using KSCN and H2O2, FeF did not produce pink color with 0.1 N HCl, unlike FeSO4 and FeC. Acidity testing differentiated FeSO4 and FeC; FeSO4 produced pink color with less NaOH than FeC. Blinded flour samples were independently and correctly identified to confirm the validity of the methods. ConclusionsThese quick, inexpensive, and reliable qualitative methods will be useful for agencies to identify the type of iron added to flour to monitor the quality of iron fortification strategies. Funding SourcesSupported by Nutrition International through a grant from Global Affairs Canada.

Optimization of process parameters influencing the sustainable construction of iron oxide nanoparticles by a novel tropical wetlands Streptomyces spp.

A Streptomyces strain isolated from the soil sediments of tropical freshwater wetlands in Malaysia demonstrated promising attributes to be developed into a versatile microbial nanofactory for the sustainable synthesis of ferric oxide nanoparticles (IONP). Process parameters such as temperature, ferric salt precursor concentration, cell free extract (CFE) concentration and biomass harvesting times are serious players in the extracellular generation of metallic nanoparticles. A statistical approach using One-Variable-At-A-Time (OVAT) Analysis followed by Response Surface Methodology (RSM) was employed towards the optimization of the microbial bioprocess and modulation of nanoparticle size dimensions. OVAT revealed that IONP production increased with increasing temperature, precursor concentration, harvesting time and CFE concentration with highest yield at 65 °C, 2 mM precursor concentration, 68 h harvesting time and 100% CFE concentration. A detailed statistical analysis using RSM (RSM) showed significantly strong negative interactive effects between temperature and CFE concentration (p = 0.0037), temperature and precursor concentration (p = 0.0093) and mild interactive effects between CFE and precursor concentration (p = 0.0301). Taking into account the interactive influence of these variables, numerical analysis using RSM proposed that for optimal generation of microbial mediated IONP, a CFE concentration of 55.58%, temperature of 55.75 °C and precursor concentration of 2.46 mM FeCl3.6H2O would be required.

Sequential electrocoagulation-electrooxidation for virus mitigation in drinking water

Electrochemical water treatment is a promising alternative for small-scale and remote water systems that lack operational capacity or convenient access to reagents for chemical coagulation and disinfection. In this study, the mitigation of viruses was investigated using electrocoagulation as a pretreatment prior to electrooxidation treatment using boron-doped diamond electrodes. This research is the first to investigate a sequential electrocoagulation-electrooxidation treatment system for virus removal. Bench-scale, batch reactors were used to evaluate mitigation of viruses in variable water quality via: a) electrooxidation, and b) a sequential electrocoagulation-electrooxidation treatment train. Electrooxidation of two bacteriophages, MS2 and ΦX174, was inhibited by natural organic matter and turbidity, indicating the probable need for pretreatment. However, the electrocoagulation-electrooxidation treatment train was beneficial only in the model surface waters employed. In model groundwaters, electrocoagulation alone was as good or better than the combined electrocoagulation-electrooxidation treatment train. Reduction of human echovirus was significantly lower than one or both bacteriophages in all model waters, though bacteriophage ΦX174 was a more representative surrogate than MS2 in the presence of natural organic matter and turbidity. Compared to conventional treatment by ferric salt coagulant and free chlorine disinfection, the electrocoagulation-electrooxidation system was less effective in model surface waters but more effective in model groundwaters. Sequential electrocoagulation-electrooxidation was beneficial for some applications, though practical considerations may currently outweigh the benefits.

Conditioning for excess sludge and ozonized sludge by ferric salt and polyacrylamide: Orthogonal optimization, rheological characteristics and floc properties

Effects of molecular weight (MW), charge density (CD) and structure of polyacrylamide (PAM) on conditioning of excess sludge (ES) and ozonized sludge (OS) with/without ferric salt pretreatment (FSP) were investigated by orthogonal experiment. Rheological and morphological analyses were conducted to elucidate conditioning mechanism of ES and OS. OS had smaller particle size, worse filterability, lower flowability and more evident thixotropy than ES, and required FSP before conditioning. Orthogonal experiment showed that the optimal conditioner was PAM with medium MW and cross-linked structure for ES, and high MW and linear structure for OS after FSP, respectively. The specific resistance of filtration and capillary suction time were reduced to (1.2 ± 0.1) × 1012 m/kg and 25.8 ± 1.9 s for OS after FSP and optimized PAM conditioning, and particle size increased from 30.3 for OS to 269.7 μm after conditioning. The limiting viscosity, structural strength and thixotropy of conditioned OS were lower than conditioned ES, but greatly enhanced by FSP. Morphological analyses confirmed that ozonation cracked microbial cells of sludge, and FSP obtained more porous structure and reinforced floc strength of PAM conditioned OS.

Removal of Pharmaceuticals and Illicit Drugs from Wastewater Due to Ferric Dosing in Sewers.

Ferric (Fe3+) salt dosing is an efficient sulfide control strategy in the sewer network, with potential for multiple benefits including phosphorus removal in the biological reactors and sulfide emission control in the anaerobic digesters of wastewater treatment plant (WWTP). This paper extends the knowledge on the benefit of iron dosing by exploring its impact on the fate of organic micropollutants (MPs) in the wastewater using sewer reactors simulating a rising main sewer pipe. The sulfide produced by the sewer biofilms reacted with Fe3+ forming black colored iron sulfide (FeS). Among the selected MPs, morphine, methadone, and atenolol had >90% initial rapid removal within 5 min of ferric dosing in the sewer reactor. The ultimate removal after 6h of retention time in the reactor reached 93-97%. Other compounds, ketamine, codeine, carbamazepine, and acesulfame had 30-70% concentration decrease. The ultimate removal varied between 35 and 70% depending on the biodegradability of those MPs. In contrast, paracetamol had no initial removal. The rapid removal of MPs was likely due to adsorption to the FeS surface, which is further confirmed by batch tests with different FeS concentrations. The results showed a direct relationship between the removal of MPs and FeS concentration. The transformation kinetics of these compounds in the reactor without Fe3+ dosing is in good agreement with biodegradation associated with the sewer biofilms in the reactor. This study revealed a significant additional benefit of dosing ferric salts in sewers, that is, the removal of MPs before the sewage enters the WWTP.

Effect of the point mutation H54N on the ferroxidase process of Rana catesbeiana H′ ferritin

Human H and Rana catesbeiana H′ subunits in vertebrate ferritin protein cages catalyze the Fe(II) oxidation by molecular oxygen and promote the ferric oxide biomineral synthesis. By depositing iron biomineral, ferritins also prevent potentially toxic reactions products from Fe(II)-based Fenton chemistry. Recent work from our laboratory was aimed to describe the iron pathways within ferritin, from entrance into the cage to the ferroxidase site, and to understand the role played by amino-acid residues in iron trafficking and catalysis. Our approach exploits anomalous X-ray diffraction from ferritin crystals, exposed to a ferrous salt, to track transient iron binding sites along the path towards a well-defined di-iron site where they get oxidized by oxygen. Coupling structure determination with solution kinetic measurements on selected variants, allows validating the role played by key residues on the catalytic iron oxidation. Our previous studies on H′ ferritin indicated the regulatory role played by His54, and by its human counterpart Gln58, on guiding Fe(II) ions to the catalytic site. Here, we have investigated the effects induced by substituting the wild type His54 with Asn54, having different iron coordination properties. We have obtained a series of atomic-resolution crystal structures that provide time-dependent snapshots of iron bound at different locations in the H′ ferritin H54N variant. The comparison with H′ ferritin and H′ ferritin H54Q variant leads to identify a new iron binding site. Our kinetic and structural data support the role of H′ ferritin residue 54 in regulating the access of Fe(II) ions to the catalytic site.

PdAu-catalyzed oxidation through in situ generated H2O2 in simulated produced water

Abstract Most wastewater recovered from hydraulically fractured oil and gas wells (i.e. produced water) is transported to government-permitted, salt-water disposal units (SWDs) and discarded via downhole injection. However, there is a limited availability of disposal wells in some states and growing interest over future options for beneficial reuse. One alternative to using SWD facilities is to recycle the water for further use in oilfield operations. Residual oil and grease are one contaminant class in produced water where cost-effective treatment technologies are lacking. In this work, we studied the ability of alumina-supported bimetallic PdAu to degrade organic compounds at room temperature and atmospheric pressure via the catalytic formation of H2O2. Similar to monometallic Pd and Au catalysts, the PdAu catalyst produced H2O2 and hydroxyl radicals in the presence of oxygen and formic acid. The bimetallic catalyst was the most active in terms of initial OH formation rate, and when phenol was present, PdAu showed the highest rate of phenol degradation. We assessed the promotional and inhibitory effects of other species present in produced water including ferrous ion concentration, pH and salt concentration on catalytic phenol oxidation. PdAu was catalytically active for phenol degradation in simulated produced water at salinities as high as ˜0.3 M (˜16,000 ppm). The combination of air-formic acid-bimetallic catalyst is an intriguing approach for the degradation of organics in contaminated water at low pH and moderate salinity.

Effectiveness of Trihalomethane (THM) Precursors Removal in Groundwater Using Coagulant-Disinfectant

Trihalomethanes (THMs) is a disinfection byproduct (DBP) which forms when disinfectants react with natural organic matter (NOM) in treated drinking water. The coagulation process using ferric salts was able to remove NOM, a DBP precursor, effectively. This study method included the combination of coagulants (ferric-based) with disinfectant(s), to speed up the treatment process in emergency applications. Groundwater samples were treated using either ferric sulphate or ferric chloride, and chlorine in a series of jar tests. Ferric sulphate application showed a good turbidity removal (50.51%) while UV254 removal using ferric chloride was as high as 80.76%. Most conditions at pH 5.5 formed lower THMs compared to other pH levels, although the THM level at this pH still exceeded the limit set by authorities.

Effect of metal salts on the decomposition characteristics of Mengdong lignite

ABSTRACTIn this study, the apparent activation energy of coal samples during pyrolysis with NiCl2, FeCl3, Ni(NO3)2 and Fe(NO3)3 in-situ loaded on was calculated. The results show that metal salts promote the devolatilization process with the activation energy decreased by 24.28%, 13.27%, 38.61%, and 41.53%, corresponding to NiCl2, FeCl3, Ni(NO3)2 and Fe(NO3)3 respectively. And the catalytic effect on the evolution of H2 and CH4 was also studied via TG-MS test. Except Fe(NO3)3, the adding of other metal salts made activation energy of CH4 and H2 descend. NiCl2-coal sample has the least activation energy of CH4, which indicates a closer interaction with coal matrix compared with Ni(NO3)2. However, the activation energy of H2 for NiCl2-coal sample and Ni(NO3)2-coal sample varies little. To further investigate the catalytic effect during pyrolysis, hydrogen distribution in solid residues was analyzed according to the FTIR spectrums. The relatively abundant hydrogen content in aromatic structure when ferric salts were added indicates the hydrogen transfer to aromatic rings under the effect of Fe element. And FeCl3 has a superior effect compared with Fe(NO3)3. The difference in the catalytic effect between metal nitrates and metal chlorides could be ascribed to the different behaviors during the decomposition process.

Electro-oxidation and chemical oxidation treatment of sugar industry wastewater with ferrous material: An investigation of physicochemical characteristic of sludge

The growth of any nation depends upon the contribution of industrialization. Sugarcane industry is among one of them. It required a large quantity of fresh water for processing and release the large quantity of wastewater. This discharge has a major effect on the Environment and receiving bodies. To protect the surrounding environment an attempt has been made to treat the sugar industry wastewater by electrocoagulation and coagulation process. The result shows that treatment with electrocoagulation could achieve 85% chemical oxygen demand (COD) reduction and 89% color reduction at initial pH of sample 6.5, electrode distance 20 mm, current density 156 Am−2 and electrolyte concentration 0.5 M (NaCl). Addition of ferric salt as chemical coagulant after electrocoagulation treatment shows an overall 98% COD reduction and 99.7% color reduction at same pH with 5 mM coagulant mass loading. The sludge generated after treatments are found suitable for the alternative application.

Effect of annealing on phase formation, microstructure and magnetic properties of MgFe2O4 nanoparticles for hyperthermia

In this study the effect of annealing time is confirmed to alter the morphology (shape and size) of magnesium ferrite nanoparticles (MgFe2O4) synthesized by autoclave route, employing ferric and magnesium nitrate salts as precursors. Annealing was applied at 1000 °C for different durations (2, 30 and 60 h) and Rietveld refinements of X-ray diffraction patterns confirm the formation of pure spinel phase and show that the annealing time has a dominant effect on the crystallite size as it increases from 29 up to 89 nm for 2 to 60 h, respectively. Scanning electron microscopy observations confirm that longer annealing time enhances particle growth, in agreement with the crystallite size obtained by X-ray diffraction analysis. Room temperature magnetic measurements reveal a ferromagnetic behavior with a saturation magnetization (Ms) ranging from 25.84 emu/g for annealing at 2h and 29.49 emu/g at 60 h. Self-heating characteristics under an alternating current (AC) magnetic field of 17mT and frequency of 331 kHz were investigated for hyperthermia applications using Magnetherm from Nanotherics. Temperature-time curves indicate that the as-prepared MgFe2O4 nanoparticles show a considerable heating rate, with a maximum temperature of 48 °C in a very short period of time of 15 min and specific absorption rate (SAR) of 19.23 W/g, when annealed for 60 h.