Ethylenediaminetriacetic Acid Research Articles

Voltammetric Sensor Modified by EDTA-immobilized Graphene-like Carbon Nitride Nanosheets: Preparation, Characterization and Selective Determination of Ultra-Trace Pb (II) in Water Samples

A voltammetric sensor for selective determination of ultra-trace Pb (II) was prepared based on EDTA-immobilized graphene-like carbon nitride nanosheets (EDTA-CN-NS), which has been designed to improve the accumulation performance for Pb (II) onto the electrode surface. The EDTA-CN-NS was prepared through pre-oxidation by K2S2O8 and silanization by N-(trimethoxysilylpropyl) ethylene-diamine triacetic acid sodium salt. The crystalline structure, morphology and the added functional groups of EDTA-CN-NS were characterized by XRD, SAED, TEM, STEM mapping and FT-IR, which are quite in accord with the catalysis action in cyclic voltammetry test generated by improved accumulation performance of the immobilized EDTA for Pb (II). The detection limit of EDTA-CN-NS/Nafion modified sensor reached 5.7×10−13molL−1 with two linear ranges from 2.1×10−12∼1.3×10−9molL−1 and 1.3×10−9∼1.7×10−6molL−1. The sensor behaves acceptable immunity from common interferences in Pb (II) determination and was employed for analyzing the Pb (II) concentration in different water samples. This work gives new instructions in designing ultra-high sensitive sensors for determination of heavy metal ions using 2D functional materials.

Determination of sunset yellow in soft drinks based on fluorescence quenching of carbon dots

Fluorescent carbon dots was prepared by heating N-(2-hydroxyethyl)ethylene diaminetriacetic acid in air. The carbon dots were not only highly soluble in water but also uniform in size, and possessed strong blue fluorescence and excitation wavelength-dependent emission properties with the maximum excitation and emission wavelength at 366nm and 423nm, respectively. Food colorant sunset yellow whose excitation and emission wavelength at 303nm and 430nm could selectively quench the fluorescence of carbon dots, efficient fluorescent resonance energy transfer between the carbon dots and sunset yellow is achieved. This was exploited to design a method for the determination of sunset yellow in the concentration range from 0.3 to 8.0μmolL−1, with a limit of detection (3σ/k) of 79.6nmolL−1. Furthermore the fluorimetric detection method was established and validated for sunset yellow in soft drinks samples with satisfactory results.

Synthesis, characterization, and functionalization of ZnO nanoparticles by N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (TMSEDTA): Investigation of the interactions between Phloroglucinol and ZnO@TMSEDTA

The use of semiconductor oxides, such as chemical or biological sensors, requires their functionalization with appropriate molecules displaying specific interaction with the substance to be detected.Generally, the support materials used are TiO2 or SiO2. In the present work, zinc oxide nanoparticles (ZnO NPs), known for its reactivity and high specific area, were used. The synthesis of nanoscale ZnO was advantageously performed by precipitation at low temperature (60°C). To our knowledge, it was the first time that this material was synthesized at such a low temperature, therefore lowering production cost. Moreover, the surface functionalization of ZnO was performed with N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (TMSEDTA) in ethanol. This allowed shortening the functionalization reaction duration as compared to previously published literature in the field. The samples obtained were analyzed by XRD, TEM, DLS, FTIR, TGA and XPS, which all concur with the successful synthesis of ZnO nanoparticles as well as the efficiency of TMSEDTA grafting on ZnO.Then, the interactions of this functionalized material, ZnO@TMSEDTA, with the Phloroglucinol (drug) were evaluated by using cyclic voltammetry measurements in solution. The cyclic voltammograms showed an intense cathodic peak which was correlated to the initial concentration of free Phloroglucinol. This cathodic peak was degraded upon addition of ZnO@TMSEDTA particles due to the drug interactions with free available carboxylic groups on the functionalized NPs. Based on a calibration curve, the drug concentration uptake can be therefore quantified. Thus, these results establish a big step to develop a Phloroglucinol sensor.

Thermal Stability of Oilfield Aminopolycarboxylic Acids/Salts

Summary Chelating agents are used to remove various inorganic scales, including sulfates and carbonates. They are also used as standalone stimulation fluids and as iron-control agents during acidizing treatments. The main chelating agents used in the oil field include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), and glutamic acid diacetic acid (GLDA). (Note that the abbreviations for these chelating agents will be used throughout the rest of the paper.) One of the concerns with these chelants is their thermal stability at elevated temperatures. Chelant solutions (0.7 to 0.8 M) of HEDTA, GLDA, NTA, EDTA, and their mono-/disalts were prepared. The aqueous solutions of these chelants were heated at various temperatures (300 to 400°F) and times (2 to 12 hours). The concentration of chelant was measured with a titration method that uses FeCl3 solutions. The products of thermal decomposition of chelants were determined with mass spectrometry (MS) and gas-chromatography/MS techniques. Most chelants decomposed at temperatures greater than 350°F. At 400°F and after 12 hours of heating, diammonium salt of GLDA degraded more quickly than diammonium salt of EDTA chelant. Analyses of NH4H3GLDA with MS techniques after heating highlighted that the decomposition products included iminodiacetic acid, hydroxyacetic acid, and α-hydroxyglutaric acid. Studying the kinetics of aqueous solutions of NaH3GLDA, NaH2HEDTA, and (NH4)2H2EDTA showed that their thermal-degradation kinetics followed a pseudofirst-order reaction. The Arrhenius equation can be used to predict the activation energy that is necessary for the degradation mechanisms of chelants.

Multifunctional nanocomposites Fe3O4@SiO2-EDTA for Pb(II) and Cu(II) removal from aqueous solutions

In this study, EDTA-functionalized Fe3O4 (Fe3O4@SiO2-EDTA) was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (EDTA-silane) and hydroxyl groups for Pb(II) and Cu(II) removal from aqueous solutions. Fe3O4@SiO2-EDTA composites were characterized using SEM, TEM, EDX, FTIR, XPS, TGA and saturated magnetization techniques. Maximum Pb(II) adsorption capacity was found to be 114.94mgg−1 with SiO2/EDTA molar ratio of 2.5:1. The adsorption rate was significantly fast and the equilibrium was reached within 10min. The optimum pH was recorded to be 5.0. The maximum adsorption capacity of the studied heavy metal ions calculated by Langmuir model followed the order: Cu(II) (0.58mmolg−1)>Pb(II) (0.55mmolg−1)≈Ni(II) (0.55mmolg−1)>Cd(II) (0.45mmolg−1). Moreover, Pb(II) and Cu(II) adsorption capacities were not significantly affected by co-existing cations and NOM. These results suggested that this adsorbent can be considered as a promising adsorbent to remove Pb(II) and Cu(II) from wastewaters.

Plant-Available Phosphorus after Application of Synthetic Chelating Agents

ABSTRACTFertilizer phosphorus (P) can become immobilized in acidic soils through bonds with iron (Fe) and aluminum (Al). Two chelating agents, ethylenediamine tetraacetic acid disodium salt (EDTA) and hydroxyethyl ethylenediamine triacetic acid (HEEDTA), were tested in a greenhouse study for efficiency at increasing plant-available P to corn (Zea mays L.). Fertilizer P was added with or without chelate to the center of pots, simulating a starter band of P. Without the presence of chelates, biomass above and below ground increased linearly as P fertilizer rates increased at 0, 9.6, 19.3, 28.9, and 38.5 kg P ha−1. Applications of EDTA and HEEDTA did not significantly increase water-soluble P (WSP), Mehlich 1 P, and Mehlich 3 P compared to soils without chelates. Applications of EDTA increased P uptake in the belowground biomass. Despite previous research showing that chelates increased WSP in soils, a decrease in P sorption was not observed with the additions of chelating agents to soils.

Reaction of Np(VI) with N-(2-Hydroxyethyl)ethylenediaminetriacetic acid in perchloric acid solutions

The stoichiometry of the reaction Np(VI) + H3hedta [hedta is N-(2-hydroxyethyl)ethylenediaminetriacetate, HEDTA, anion] in a 0.05 M HClO4 solution was studied by spectrophotometry. With Np(VI) in excess, 1 mol of HEDTA reduces 4 mol of Np(VI) to Np(V). In 0.125–1.0 M HClO4 solutions (the ionic strength of 1.0 was maintained constant by adding LiClO4), containing 3–29.2 mM HEDTA, at 20–45°С Np(VI) at a concentration of 0.4–3.5 mM is consumed in accordance with a first-order rate law until approximately 40% of Np(VI) remains. Then, the reaction decelerates. The reaction rate has first order with respect to [HEDTA] and the order of–1.6 with respect to [Н+]. The activated complex arises with the loss of one and two Н+ ions. The activation energy is 88.4 ± 5.3 kJ mol–1.

Complexation of NpO2+with (2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) in aqueous solutions: thermodynamic studies and structural analysis

The complexation of Np(v) with HEDTA in aqueous solutions was investigated by spectrophotometry, microcalorimetry and EXAFS. Thermodynamic parameters were determined and coordination modes also discussed.

Sepiolite functionalized with N-[3-(trimethoxysilyl)propyl]-ethylenediamine triacetic acid trisodium salt. Part II: Sorption of Ni2+ from aqueous solutions

sorption of Ni2+ on the sepiolite functionalized by covalent grafting of N-[3-(trimethoxysilyl)propyl]ethylenediamine triacetic acid trisodium salt, MSEAS, was studied in batch experiments as a function of the initial metal concentration, the equilibration time, pH value, and temperature. The modification of sepiolite resulted in an enhanced Ni2+ retention with a capacity of 0.261 mmol/g at 298 K. The retention of Ni2+ ions occurred dominantly by specific sorption and exchange of Mg2+ ions from the sepiolite structure. The sorption process followed pseudo-second-order kinetics. The sorption equilibrium results were best described by the non-linear form of the Langmuir Sorption Equation. The values of the thermodynamic parameters (enthalpy, free energy and entropy) were calculated from temperature dependent sorption isotherms and these values showed that the sorption of Ni2+ onto modified sepiolite was endothermic.

Facile Synthesis of Fe3O4-N-[(3-Trimethoxysilyl)propyl]ethylenediamine Triacetic-acid Trisodium Salt and Adsorption of Sr 2+

Fe3O4-N-[(3-Trimethoxysilyl)propyl]ethylenediamine triaceticacid trisodium (Fe3O4-TMS) has been synthesized by TMS adsorb to the surface of Fe3O4. Energy dispersive spectrometer (EDS) was used to characterize Fe3O4-TMS. The results of EDS indicate that TMS is modified on the surface of Fe3O4 successfully. The effects of initial concentration, pH, and coexist ions on the equilibrium adsorption capacities of strontium ion were investigated comprehensively. Removal of Sr2+ could reach 100% when initial concentration of Sr2+ is 1.0 mmol/L. The effect of pH conforms to S curve. Equation of the curve is qSr = 0.08104 – 0.09012/(1 + exp((pH – 2.92707)/0.2995)). Correlation coefficient is equal to 0.9987. Sodium and calcium ions suppress the adsorption of strontium ion. Complexation and ion exchange maybe main adsorption mechanism.

Investigation of the Impacts of Gamma Radiolysis on an Advanced TALSPEAK Separation

The advanced TALSPEAK process is a selective solvent extraction that utilizes 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) to separate lanthanide elements from trivalent actinides, which are held back in the aqueous phase by N-hydroxylethyl-N,N’,N’-ethylenediamine triacetic acid (HEDTA) buffered by citric acid. Gamma irradiation of an experiment containing Eu(III) and Am(III) as representative lanthanide and actinide elements resulted in higher distribution ratios of both and separation factors which decreased in an exponential fashion with increasing dose. Analysis of the reagents showed that the HEDTA concentration also decreased in an exponential fashion, strongly suggesting that degradation was correlated with loss of separation selectivity. In contrast, the concentration of citrate was unaffected, and while the concentration of HEH[EHP] did decrease, its dose-dependent kinetic profile indicated that it was not limiting partitioning. A second set of experiments were conducted using a citrate concentration that was 7.5 X higher, with the expectation that citrate would protect the HEDTA by scavenging radiolytically formed OH radicals. HEDTA degradation was significantly mitigated at higher gamma doses, but the Eu-Am separation was worse than in the low citrate experiments, presumably because at the high citrate concentrations, the Eu-citrate complexes formed in abundances competitive with the Am complexes, and are more effectively held back in the aqueous phase.

Enhanced accumulation of Cd in castor (Ricinus communis L) by soil-applied chelators

ABSTRACTPhytoextraction has been identified as one of the most propitious methods of phytoremediation. This pot experiment were treated with varying amounts of (ethylenediamine triacetic acid) EDTA 3–15, (Nitriloacetic acid) NTA 3–10, (Ammonium citrate) NH4 citrate 10 – 25 mmol and one mg kg–1Cd, filled with 5 kg soil. The addition of chelators significantly increased Cd concentration in soil and plant. The results showed that maximum Cd uptake was noted under root, shoot and leaf of castor plant tissue (2.26, 1.54, and 0.72 mg kg–1) under EDTA 15, NTA 10, and NH4 citrate 25 mmol treatments respectively, and in soil 1.08, 1.06 and 0.52 mg kg–1 pot–1 under NH4 citrate 25, NTA 10 and EDTA 15 mmol treatments respectively, as against to control (p < 0.05). Additions of chelators reduction biomass under the EDTA 15 mmol as compared to other treatments, However, Bioconcentration factor (BCF), translocation factor (TF) and remediation factor (RF) were significantly increased under EDTA 15 and NH4 citrate 25 mmol as against control. Our results demonstrated that castor plant proved satisfactory for phytoextraction on contaminated soil, and EDTA 15 and NH4 citrate 25 mmol had the affirmative effect on the Cd uptake in the artificial Cd-contaminated soil.

Mixed Monofunctional Extractants for Trivalent Actinide/Lanthanide Separations: TALSPEAK-MME

The basic features of an f-element extraction process based on a solvent composed of equimolar mixtures of Cyanex-923 (a mixed trialkyl phosphine oxide) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) extractants in n-dodecane are investigated in this report. This system, which combines features of the TRPO and TALSPEAK processes, is based on co-extraction of trivalent lanthanides and actinides from 0.1 to 1.0 M HNO3 followed by application of a buffered aminopolycarboxylate solution strip to accomplish a Reverse TALSPEAK selective removal of actinides. This mixed-extractant medium could enable a simplified approach to selective trivalent f-element extraction and actinide partitioning in a single process. As compared with other combined process applications in development for more compact actinide partitioning processes (DIAMEX-SANEX, GANEX, TRUSPEAK, ALSEP), this combination features only monofunctional extractants with high solubility limits and comparatively low molar mass. Selective actinide stripping from the loaded extractant phase is done using a glycine-buffered solution containing N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) or triethylenetetramine-N,N,N’,N’’,N’’’,N’’’-hexaacetic acid (TTHA). The results reported provide evidence for simplified interactions between the two extractants and demonstrate a pathway toward using mixed monofunctional extractants to separate trivalent actinides (An) from fission product lanthanides (Ln).

Determination of aminopolycarboxylic acids at ultra-trace levels by means of online coupling ion exchange chromatography and inductively coupled plasma-mass spectrometry with indirect detection via their Pd2+-complexes

A new indirect IC-ICP-MS method for the determination of aminopolycarboxylic acids in water samples is described. It is based on the addition of an excess of Pd(II) to water samples. The analytes are forced into very strong and negatively charged palladium complexes, separated by ion exchange chromatography and detected by their palladium content, utilizing an on-line coupled ICP-MS. This method is suitable to determine the concentration of 8 aminopolycarboxylic acids (nitrilotriacetic acid (NTA), (2-carboxyethyl) iminodiacetic acid (β-ADA), methylglycinediacetic acid (MGDA), 2-hydroxyethyl) ethylenediamine triacetic acid (HEDTA), diethylene triamine pentaacetic acid (DTPA), ethylendiamine tetraacetic acid (EDTA), 1,3-diaminopropane tetraacetic acid (1,3-PDTA) and 1,2-diaminopropane tetraacetic acid (1,2-PDTA) at the ngkg−1 level. The method is faster and easier than the established gas chromatography (GC)-method ISO 16588:2002 [1] and up to two orders of magnitude more sensitive than the ion pair chromatography based method of DIN 38413-8. Analytic performance is superior to ISO 16588:2002 and the comparability is good.

Advanced TALSPEAK Separations Using a Malonate Buffer System

The extraction behavior of lanthanides and americium has been evaluated under Advanced TALSPEAK (Trivalent Actinide Lanthanide Separation by Phosphorus-reagent Extraction from Aqueous Komplexes) conditions using malonic acid as the aqueous buffering agent. The extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) was used as an organic phase liquid cation exchanger in n-dodecane diluent, while N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) served as a selective aqueous holdback reagent. Extractions conducted from malonate media exhibit a pH profile that flattens as the concentration of malonate is increased up to 1.0 M malonate. This relatively flat extraction behavior from pH 2.5–4.0 is reminiscent of previous studies on Advanced TALSPEAK in lactate media. The extraction kinetics with other carboxylic acid buffers as well as the effects of varying HEDTA, HEH[EHP], and malonate concentration are compared.

Determination of Ti, Zr, Nb, V, W and Mo in seawater by a new online-preconcentration method and subsequent ICP–MS analysis

We present a new method for the determination of Ti, Zr, Nb, V, W and Mo in seawater by adapting the online-preconcentration procedure with the system SeaFAST and subsequent analysis by ICP–MS to these metals. The trace elements Ti, Zr, Nb and W are present in seawater in ultratrace concentrations in the range of pmolkg−1, whereas Mo and V, which are biologically essential elements, are present in the concentration range of nmolkg−1. The online-preconcentration system we used consists of an autosampler, a sample loop, a preconcentration column and two valves controlling the sample loop and the preconcentration processes. The pre-packed preconcentration column contains a chelating resin with two functional groups, ethylenediamine triacetic acid (EDTriA) and iminodiacetic acid (IDA), immobilized on a polymer backbone. The preconcentration process was optimized for loading the sample and subsequent rinsing to remove residues of seawater matrix prior to elution with the optimized elution acid (0.5M HNO3–0.002M HF). We used acidified North Sea seawater (0.02M HCl–0.002M HF) for the method development. Samples and calibration standards were loaded onto the preconcentration column and after elution directly transferred to the quadrupole ICP–MS and measured immediately. Best results were achieved with matrix-matched calibration standards (0.6M NaCl–0.02M HCl–0.002M HF) simulating acidified seawater samples. Titanium, Zr, Nb and W are measured simultaneously in one run, whereas V and Mo are determined simultaneously in a separate run. Low procedure blanks were calculated for Ti, Zr, Nb, W (635, 14.5, 1.35, 10.2pmolkg−1) and for V and Mo, 9.79 and 5.61nmolkg−1, respectively. Very good spike recoveries achieved with spiked North Sea water demonstrate the applicability for all six elements. Analysis of the seawater standard NASS-6 gave recoveries of 97–99% (0.9–2.2% standard deviation, SD) for Mo and V. We also provide Zr, Nb and W data for this reference standard. The applicability of the on-line preconcentration method was demonstrated for samples collected during a GEOTRACES cruise in the Atlantic. Due to the low limit of quantification, LOQ, and SD, this method enables the determination of ultratrace concentration levels for Ti, Zr, Nb and W as well as the detection of small variations in concentration for all six elements. The required sample volume of only 50mL, the fast determination within 1h for all elements and the principle of a closed system are a clear advantage of the analytical procedure compared to many other methods and facilitates sample logistics for the determination of Ti, Zr, Nb, V, W and Mo in seawater.

An off-line automated preconcentration system with ethylenediaminetriacetate chelating resin for the determination of trace metals in seawater by high-resolution inductively coupled plasma mass spectrometry

A novel automated off-line preconcentration system for trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater was developed by improving a commercially available solid-phase extraction system SPE-100 (Hiranuma Sangyo). The utilized chelating resin was NOBIAS Chelate-PA1 (Hitachi High-Technologies) with ethylenediaminetriacetic acid and iminodiacetic acid functional groups. Parts of the 8-way valve made of alumina and zirconia in the original SPE-100 system were replaced with parts made of polychlorotrifluoroethylene in order to reduce contamination of trace metals. The eluent pass was altered for the back flush elution of trace metals. We optimized the cleaning procedures for the chelating resin column and flow lines of the preconcentration system, and developed a preconcentration procedure, which required less labor and led to a superior performance compared to manual preconcentration (Sohrin et al. [5]). The nine trace metals were simultaneously and quantitatively preconcentrated from ∼120g of seawater, eluted with ∼15g of 1M HNO3, and determined by HR-ICP-MS using the calibration curve method. The single-step preconcentration removed more than 99.998% of Na, K, Mg, Ca, and Sr from seawater. The procedural blanks and detection limits were lower than the lowest concentrations in seawater for Mn, Ni, Cu, and Pb, while they were as low as the lowest concentrations in seawater for Al, Fe, Co, Zn, and Cd. The accuracy and precision of this method were confirmed by the analysis of reference seawater samples (CASS-5, NASS-5, GEOTRACES GS, and GD) and seawater samples for vertical distribution in the western North Pacific Ocean.

Modeling Flow of Chelating Agents During Stimulation of Carbonate Reservoirs

Chelating agents such as ethylenediaminetetraacetic acid (EDTA) and hydroxy ethylene diamine triacetic acid (HEDTA) have been used as stand-alone stimulation fluids. These fluids can be used to stimulate water injectors, oil, or gas producers. In this study, an analytical model was developed to describe the flow of HEDTA and EDTA chelating agents and propagation inside calcite formations. The analytical model can be used as a pre-design tool before the treatments. The developed model can be used to predict the volume of the chelant required to create wormholes in calcite formations at different temperatures. The temperature affects the diffusion coefficient of the chelating agent, wormholing rate, and wormhole shape and size. The dissolving power of different forms of HEDTA can be determined using the model. The optimum injection rate based on optimum wormholing conditions was identified. Also, the model can be used to predict the wormholing rate of different chelating agents in calcite formations. The analytical model can be used to predict the performance of the chelating agent in calcite stimulation. The volume of chelating agent required to stimulate calcite formation per foot thickness was determined using the developed model. The optimum injection rate was determined for different chelating agents using the model, and the results were compared with experimental results from previous work and there was a good agreement between the measured and the predicted values. The model can be used to determine the best stimulation fluid based on the temperature and fracture pressure of the target zones.

Folic Acid-Conjugated MnO Nanoparticles as aT1Contrast Agent for Magnetic Resonance Imaging of Tiny Brain Gliomas

Detection of brain gliomas at the earliest stage is of great importance to improve outcomes, but it remains a most challenging task. In this study, oleic acid capped manganese oxide (MnO) nanoparticles (NPs) were prepared by the thermal decomposition of manganese oleate precursors and then transformed to water-dispersible MnO NPs by replacing oleic acid with N-(trimethoxysilylpropyl) ethylene diamine triacetic acid (TETT) silane. The covalently bonded TETT silane offers MnO NPs colloidal stability and abundant carboxylic functional groups allowing the further conjugation of the glioma-specific moiety, folic acid (FA). Moreover, the thin layer of TETT silane ensures a short distance between external Mn ion and water proton, which endows the FA-conjugated, TETT modified MnO (MnO-TETT-FA) NPs a longitudinal relaxivity as high as 4.83 mM(-1) s(-1). Accordingly, the in vivo magnetic resonance (MR) images demonstrated that MnO-TETT-FA NPs could efficiently enhance the MRI contrast for tiny brain gliomas. More importantly, due to the specificity of FA, MnO-TETT-FA NPs led to a clearer margin of the tiny glioma. This together with the good biocompatibility discloses the great potential of MnO-TETT-FA NPs as effective MRI contrast agents for the early diagnosis of brain gliomas.

Effects of Surface Modification on the Stability of Suspension and Thermal Conductivity Enhancement of Composite Fe Nanofluids

Composite Fe nanoparticles (CINPs) were synthesized by surface modification of Fe nanoparticles with silicon alkyl ethylenediamine triacetic acid, and the silicone oil-based composite Fe nanofluids (CINPs nanofluids) were prepared with the as-synthesized CINPs and silicone oil. The surface molecular structure, magnetic properties, and surface morphology of the CINPs were characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscope, and vibrating sample magnetometer. The stability and thermal conductivity enhancement of the CINPs nanofluids were characterized via a thermal conductivity method and using a thermal property analyzer. Results show that the suspension stability of the CINPs nanofluids was greatly improved by the surface modification of the Fe nanoparticles. The thermal conductivity enhancement became more stable, and further, it was demonstrated that thermal conductivity could be tuned by applying magnetic field.