Influence Of Chelating Agents Research Articles

The role of chelating agent in the self-assembly of amphoteric surfactants

Hypothesis: Limited research has been conducted on the influence of chelating agents on the self-assembly process in surfactant solutions. The traditional approach assumes the chelating agent only interferes as a salting-out ion, therefore promoting surfactant separation. However, the opposite behavior has been observed for iminodipropionate based surfactants, in which the presence of chelating agents of the aminopolycarboxylate type increases solubility of nonionic ethoxylated surfactants in mixed micellar systems. Specific interaction between chelating agents-surfactants can be an important parameter in the self-assembly processes.Experiments: Physicochemical properties of solutions containing amphoteric surfactant and tetrasodium glutamatediacetate have been investigated. Macroscopic properties, such as viscosity and cloud point, were evaluated in the presence of a non-water-soluble alkyl ethoxylated surfactant. Interactions between amphoteric surfactant and chelating agent were monitored by NMR spectroscopy, including 13C chemical shift and lineshape analysis as well as 1H diffusometry.Findings: The study reveals that there is an interaction between the head group of the surfactant and the chelating agent forming oligomeric surfactant analogues with larger hydrophilic moieties, which results in smaller, more spherical micelles. The combined interactions provide possibilities for tuning the aggregation behavior of systems containing surfactants and chelating agents, and with that, the macroscopic properties of the system.

Electrodeposition of Silver in Cyanide-Free Solution Containing Pyrimidine Derivative as a Complexing Agent

Pyrimidine derivatives, for example, 2,4-pyrimidinedione (uracil), 1-methyluracil and 5-methyluracil (thymine) can bind with metal ions in alkaline solution. 5-methyluracil (thymine) as complexing agent in electroplating solution has not been investigated due to low solubility in water. The aims of this study were to determine the potential of 5-methyluracil (thymine) as complexing agent for cyanide-free silver electroplating solution. The influence of complexing agent and polyethyleneimine on the silver electrodeposition reaction were studied. Several methods which are electrochemical quartz crystal microbalance (EQCM) and electrochemical impedance spectroscopy (EIS) have been used to study the electrochemical behavior of cyanide-free silver electroplating solution. The surface morphology and brightness of silver deposits obtained from each cyanide-free silver electroplating solution were evaluated. A semi-bright deposit was obtained from thymine and uracil-complexing silver solution while matte deposit from 5,5-dimethylhydantoin-complexing silver solution. A bright silver deposit could be obtained in the presence of polyethyleneimine. The reduction current value decreases as the amount of polyethyleneimine added increases due to inhibition effect on the silver electrodeposition reaction. The results of electrochemical quartz crystal microbalance measurement showed that the addition of polyethyleneimine in thymine-complexing silver solution does not significantly affect the resonance frequency change.

Influence of chelating agent on structural, magnetic, and dielectric properties of CoNd0.075Fe1.925O4-nanosized spinels ferrites derived from sol–gel auto-combustion method

Influence of chelating agent on structural, magnetic, and dielectric properties of CoNd0.075Fe1.925O4-nanosized spinels ferrites derived from sol–gel auto-combustion method

Chelating agent size effect on thermal decomposition, phase formation and morphology characteristics of Y3+ doped Ba(Ce,Zr)O3 ceramics powder prepared by a sol-gel process

This present work reports the facile sol-gel synthesis of Y 3+ doped Ba(Ce,Zr)O 3 with composition of BaCe 0.54 Zr 0.36 Y 0.10 O 2.95 (BCZY). Series of six samples were prepared using various chelating agents namely citric acid (denoted as S1, 210 g/mol), tartaric acid (S2, 150 g/mol), glycolic acid (S3, 70 g/mol), nitriloacetic acid (S4, 191 g/mol), ethylenediaminetetraacetic acid (S5, 292 g/mol) and triethylenetetramine (TETA) (S6, 146 g/mol). The influence of chelating agents’ molecular weight ( M w ) and functional group on thermal decomposition, phase formation and morphology of BCZY were explored. The reaction products obtained after heat treatment were characterized by Thermal Gravimetric Analyzer (TGA), Fourier Transform Infrared (FTIR) spectrometer, X-ray diffractometer (XRD) and Scanning Electron Microscope (SEM) equipped with Energy Dispersive X-ray (EDX) spectrometer. TGA along with FTIR analysis confirmed that the thermal decomposition of all samples achieved almost completion at processing temperature below 1000 °C. TGA verified the weight loss of intermediate compounds increased with an increase in the M w of the chelating agents in the following trend: S3 (28%) < S6 (35%) < S2 (40%) < S4 (90%) < S1 (93%) < S5 (95%). At calcination temperature of 1100 ° C, XRD pattern of all samples excluding S4 showed successful formation of single-phase BCZY crystals. The highest percentage (99.5%) of BCZY perovskite phase was achieved for S6. In contrast, S4 exhibited 57.5% secondary phase of BaCeO 3 and 42.5% BCZY, suggesting incomplete formation of the required perovskite phase. SEM revealed all calcined powders have similar morphology of clump-like network structure. The use of different types of chelating agents interacts with different atomic radius of metal cations resulted in the formation of Zr-cluster and Ce-cluster, suggesting the possible cause for the fluctuations observed in the EDX elemental composition of the calcined powders. • Six chelating agents were used to prepare BCZY composite using sol-gel method. • Amino-based chelating agent is effectively retarded the BaCO 3 formation. • TETA showed the highest total weight loss and perovskite phase percentage. • N -donor chelating agent favors a complete substitution of Zr 4+ at Ce 3+ sites.

The influence of chelating agents on clays in geothermal reservoir formations: Implications to reservoir acid stimulation

Acid stimulation to enhance the permeability of geological reservoirs is the oldest technique still in use. Acid stimulation sometimes fails due to either poor stability of the acid or due to an undesirable influence on clay minerals in the reservoir formation. Among others, clay minerals in a reservoir formation govern the permeability of the reservoir. The interaction is investigated of biodegradable chelating agents (BCA1, BCA2 and BCA3) and clay minerals kaolinite-natural (KN) and montmorillonite-K10 (MM) in a hydrothermal reactor in which the conditions of a geothermal reservoir are simulated under a CO2 environment with temperature of 230 οC and pressure of 85 bars. The porisimetry, ATR-FTIR and infrared reflectance spectroscopy show changes on surface properties and structure of MM and KN which in turn suggest chemical interaction to take place. However, XRD results show insignificant changes on structure of MM and KN. The ICP-OES, pH, conductivity and salinity results show the chemical interactions (dissolution reactions) to take place on both KN and MM and therefore strongly support the results of the earlier techniques. The results show that BCA1 and BCA3 cause greater dissolution with lower precipitation as compared to BCA2 and no-BCA. Further, the R -values from multiple linear regression show that pH and BCAs’ function groups have strong influence on the normalized concentration of dissolved ions though the p-values are insignificant. The coefficient values show that the BCAs’ functional groups have more influence than pH. BCA1 and BCA 3 would therefore be useful acids for reservoir stimulation in improving permeability especially in geothermal reservoir formations which contain clay minerals.

The influence of chelating agents on cerium oxide decorated on graphite synthesized by the hydrothermal route

Morphology features of cerium oxide nanoparticles, such as size and agglomeration, are important as a coating that improves corrosion resistance and as reinforcement in mechanical applications. In this work, the influence of two heat treatments (160° and 190 °C) in combination with three different chelating agents in the preparation of CeO2 and CeO2 decorated on graphite (CeO2_Gr) nanoparticles is studied. The novelty of this work is that CeO2_Gr was successfully prepared using the hydrothermal method. All the samples evaluated by X-ray diffraction exhibit a single fluorite-type structure in the cubic phase and Fm3m space group. The spherical harmonics method using the Fullprof Suite program was used to determine the average crystallite sizes, which were 9 nm for CeO2 and 7 nm for CeO2_Gr. Transmission electron micrographs for the prepared samples with citric acid showed non-agglomerate particles with homogeneous particle sizes and a quasi-spherical shape distribution. Raman spectra show a band centre at 600 cm-1 associated with the presence of Frenkel-type oxygen vacancies that induced the reduction of Ce4+ to Ce3+. The analysis of X-ray photoelectron spectra corroborates the coexistence of Ce3+ and Ce4+ species for CeO2 and CeO2_Gr nanoparticles. This work forms new perspectives in the development of CeO2 decorated on graphite prepared by the hydrothermal method to obtain composites not only for sensing applications and wastewater treatment but also for corrosion resistance and reinforcement materials.

Influence of tartaric acid concentration on structural and optical properties of CuSe nanoparticles synthesized via microwave assisted method

The influence of chelating agent on structural and optical properties of copper selenide nanoparticle has been the subject of ongoing debate in copper selenide based material research. In this project we developed a straightforward microwave irradiation technique for the synthesis of copper selenide nanoparticles. Copper selenide nanoparticles were successfully synthesized using CuCl2·2H2O and Na2SeO3 as copper and selenium sources respectively while, the reducing and chelating agents were hydrazine hydrate and tartaric acid respectively. The effect of concentration of tartaric acid on structural and optical properties of CuSe NPs were investigated. The as-prepared product were characterized by means of an X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron spectroscopy (FESEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), UV–visible absorption spectroscopy (UV–Vis.), Raman spectroscopy and photoluminescence spectroscopy (PL). XRD results reveal a hexagonal (Klockmannite) crystal structure with size in the range between 73.10 nm and 16.10 nm. The band gap of the as-prepared CuSe NPs were found to increase between 1.80 eV and 2.10 eV. The wavelength of the maximum PL emission was at 600 nm with 400 nm excitation wavelength. Three characteristics vibrational modes belonging to CuSe NPs were detected in the Raman spectra. Therefore, the results obtained in this study provide a new pathway of understanding the effect of tartaric acid concentration on structural and optical properties of CuSe NPs and can explain the use of this novel product as a potential candidate for optoelectronic and solar cell applications.

CO2 Hydrogenation to Methanol via In‐situ Reduced Cu/ZnO Catalyst Prepared by Formic acid Assisted Grinding

AbstractMethanol is an essential chemical raw material and potential alternative energy source. In this paper, Cu based catalyst was prepared by the noble solid phase grinding method for CO2 hydrogenation to methanol. The influence of chelating agent, heating rate, calcination temperature and calcination period of the precursor on catalyst performance were studied in depth. The catalyst precursor with formic acid as a chelating agent was reduced in‐situ when calcined in nitrogen (N2) at 573 K. The formic acid was decomposed, releasing the reducing agents, CO and H2, resulting in continuous in‐situ CuO reduction to metallic Cu0. XRD, XPS, BET, TG‐DSC, H2‐TPR and other characterization techniques were employed to analyze the catalyst properties. Results revealed that CuO was successfully reduced in‐situ to Cu0 during calcination process in a nitrogen atmosphere without further reduction. The catalyst prepared by formic acid grinding (F/I−Cu/ZnO) showed highest catalytic activity compared with the conventional catalyst which was further reduced by 5% H2 (F/H−Cu/ZnO). CO2 conversion and methanol selectivity reached 33.44% and 84.26%respectively.

Ni tolerance and its distinguished amelioration by chelating agents is reflected in root radius of B. napus cultivars

The negative effect of excess nickel (Ni) on plants is well investigated but there is only little information on its influence on root anatomy and a possible amelioration by chelating agents. In this study, we utilized light microscopy to observe anatomical changes in canola (Brassica napus) roots and investigated the element content by X-ray microanalysis. Ni-tolerant (Con-II) and Ni-sensitive cultivars (Oscar) were selected for this purpose. The plants were treated with 30 ppm NiSO4. Then, citric acid and ethylene-diamine-tetra-acetic acid (EDTA) (alone or in combination) were applied to observe the influence of chelating agents in metal stress amelioration. Ni treatment led to significant swelling of the roots in the Con-II variety as compared to the cultivar Oscar. Application of EDTA reduced the root radius of Con-II plants and this effect for Ni tolerance is discussed. According to X-ray microanalyses, Ni ions were more dispersed in the sensitive cultivar as indicated by metal adsorption to the cell wall. We investigate the hypothesis that an enhanced capacity of binding metals to the cell wall allows the plants to tolerate more heavy metals.

The Effects of Chelating Agents on CoMo/TiO2–Al2O3 Hydrodesulfurization Catalysts

A series of CoMo/TiO2–Al2O3 catalysts with different chelating agents were prepared by co-impregnation method. The influence of chelating agents on dispersions of active phase, textural properties, and hydrodesulfurization (HDS) activity for CoMo/TiO2–Al2O3 catalysts was studied. XRD characterization demonstrates that the addition of chelating agents can promote the dispersion degree of active components. TPR experiments exhibit an important effect of chelating agents on the catalysts. CoMo/TiO2–Al2O3 catalysts prepared with different chelating agents shows different HDS activity, and the addition of EDTA results in a remarkable improvement in both thiophene and DBT HDS conversions compared with others.

Effect of chelating agents on catalytic performance of Cr/γ-Al2O3 dehydrogenation catalysts

Chromia/alumina (Cr2O3/γ-Al2O3) catalysts with addition of chelating agents (citric acid or oxalic acid) were prepared by the incipient impregnation method. The resulting catalysts with different citric acid (CA) or oxalic acid (OA) contents were applied to the dehydrogenation of isobutane to isobutene. The influence of chelating agents on the catalysts was investigated by means of BET, SEM, H2-TPR, NH3-TPD, and TG-DTG. The results showed that the Cr2O3/γ-Al2O3 catalysts with addition of CA or OA exerted slightly increase on specific surface area. The addition of the chelating agents as expected, determined a general decrease in the surface acidity. The catalysts with CA or OA have a better anti-coking ability by inhibiting the side reaction of cracking and carbon formation. The addition of CA or OA for preparing these catalysts resulted in a beneficial effect on the reducibility of the Cr species to diminish the reduction temperature. The appropriate content of chelating agents could improve dispersion of metal species in the γ-Al2O3 support. The catalytic activity showed an important enhancement when the metal species was impregnated in the presence of CA or OA.

Reductive leaching of jarosites by Aeromonas hydrophila

The mineral industry has suffered in recent years two significant impacts: the raise on energy cost and more strict environmental regulations. In parallel to the above restrictions, the depletion of high grade mineral resources leads the mining industry to search for alternative processes to avoid the high energy consumption and exploit low grade mineral deposits. Jarosite is a common product in mining and industrial operations. This basic sulfate mineral incorporates several metals by substitution and the dissolution of jarosite by dissimilatory iron-reducing bacteria influences the mobility of many heavy metals present in the mineral structure.In this work, the anaerobic bioreduction of three ferric solids (a biogenic mixture of ammonium and potassium jarosites, synthetic silver jarosite and natural gossan ore from RioTinto, Spain) by an isolated strain of Aeromonas hydrophila has been investigated. The release of ferrous ion indicated that the microbial reduction of jarosite takes place using lactate as electron donor. This process was accompanied by the subsequent secondary mineralization, leading to the formation of various iron-bearing minerals such as siderite, vivianite or magnetite. In addition, the influence of chelating agents (citrate and EDTA) and humic substances’ analogue (AQDS) as electron shuttling molecule were studied. While the chelants increased iron reduction and dissolution rate, the humic substances had no effect in the process. These results suggest that direct contact between A. hydrophila and minerals is required for the reduction of Fe(III).

403 水溶性油剤中のスラッジ生成に対するキレート剤の影響(GS4,11 接触問題・材料加工,研究討論セッション)

403 水溶性油剤中のスラッジ生成に対するキレート剤の影響(GS4,11 接触問題・材料加工,研究討論セッション)

Influence of chelating agents on the tribocorrosion of tungsten in sulphuric acid solution

The corrosion and tribocorrosion of tungsten in 0.01 M H 2SO 4, without and with the presence of lactic acid and phosphoric acid as chelating agents was studied here. The passive behaviour was characterised using potentiostatic polarization and potential step techniques combined with rotating disk electrodes. Surface analysis techniques (XPS, AES) were used to assess surface chemistry. The tribocorrosion of tungsten was investigated using a tribometer equipped with an electrochemical cell operating at applied passive potentials of 0.2 V and 1.0 V. Under static corrosion conditions chelating agents were found to enhance passive film dissolution and to decrease the passive film thickness. Despite this, the effect of the investigated chelating agents was limited under tribocorrosion conditions. Indeed, only lactic acid at the most anodic potential lead to significant differences in material removal by impeding the formation of protective tungsten oxide tribolayers. The discrepancy on the effect of chelating agents in corrosion and tribocorrosion was explained in terms of the different involved time constants.

Influence of chelating agent and reaction time on the swelling process for preparation of porous TiO 2 particles

This study aimed to describe the preparation and characterization of porous titanium oxide particles of narrow particle size distribution by a single-step swelling process of polystyrene template microspheres. In this research, different specific surface areas, porous structures and densities of porous titanium oxide particles had been synthesized with various experimental parameters. Two main parameters were tested and discussed: (1) acetylacetone amount (from 0 to 1 ml) and (2) reaction time (from 2 to 32 h). Polystyrene template particles were polymerized by emulsifier free-emulsion polymerization (a kind of polymerization method). For the swelling process to be successful, a chelating agent (acetylacetone) was added to delay the aqueous hydrolysis of titanium (IV) isopropoxide in the water phase. The influences of various reaction parameters on size, morphology, composition, specific surface area, porous structure and density of particles were investigated. The properties of particles were analyzed by scanning electron microscope, Brunauer–Emmett–Teller, Fourier transform infrared analysis, thermogravimetric analysis, powder X-ray diffraction, and specific gravity meter.

Structural and morphological characteristics of polycrystalline BaTiO3:Er3+, Yb3+ ceramics synthesized by the sol–gel route: influence of chelating agents

The preparation of a co-doped BaTiO3:Er, Yb compound was investigated using alkoxide precursors. The complex alkoxide was hydrolyzed under specific conditions using chelating agents [(AcAc)H and H–(OAc)], and nano-size powders and films of perovskite compounds were obtained. The nanostructure materials were formed through nucleation-aggregation growth. Through a comparison of co-doped BaTiO3:Er, Yb compounds (with and without chelating agents), important differences in shape and size of the particles were found. In addition, the use of chelating agents during the sol–gel process allowed us to obtain optical BaTiO3:Er, Yb thin films. The results suggest that the particle size and shape can be tailored in the current system by manipulating the simultaneous use of chelating agents and the crystallization temperature. Consequently, a wide range of particle size has an effect on the crystal structures.

Influence of chelating agents on the growth and photoelectrochemical responses of chemical bath-synthesized AgIn 5S 8 film electrodes

An aqueous method for the deposition of silver–indium–sulfide ternary semiconductor film electrodes is presented. Various deposition parameters, such as reaction temperature and molar ratios of different chelating agents, were changed in order to grow uniform and adherent films on indium–tin–oxide glass substrates. With a reaction temperature higher than 65 °C, a film composed of AgIn 5S 8 was grown on the substrates in our experimental conditions. The direct and indirect energy band gaps of samples prepared in this study varied from 1.70 to 1.97 eV and 1.61 to 1.72 eV, respectively. The maximum photocurrent density of samples in this study reached 3.0 mA/cm 2 at an external potential of +1.0 V vs. a Pt electrode under illumination using a 300 W Xe lamp system with the light intensity set at 100 mW/cm 2.

FT-IR study of the effect of lead and the influence of chelating agents, DMSA and D-Penicillamine, on the biochemical contents of brain tissues of Catla catla fingerlings

The goal of this study was to investigate the effect of lead and the influence of chelating agents,meso 2, 3-dimercaptosuccinic acid (DMSA) and D-Penicillamine, on the biochemical contents of the brain tissues of Catla catla fingerlings by Fourier Transform Infrared Spectroscopy. FT-IR spectra revealed significant differences in absorbance intensities between control and lead-intoxicated brain tissues, reflecting a change in protein and lipid contents in the brain tissues due to lead toxicity. In addition, the administration of chelating agents, DMSA and D-Penicillamine, improved the protein and lipid contents in the brain tissues compared to lead-intoxicated tissues. Further, DMSA was more effective in reducing the body burden of lead. The protein secondary structure analysis revealed that lead intoxication causes an alteration in protein profile with a decrease in α-helix and an increase in β-sheet structure of Catla catla brain. In conclusion, the study demonstrated that FT-IR spectroscopy could differentiate the normal and lead-intoxicated brain tissues due to intrinsic differences in intensity.

Bioaccumulation of lead and the influence of chelating agents in Catla catla fingerlings

Lead is a widespread element and one of the persistent and cumulative pollutants of the environment. The present study deals with the bioaccumulation of lead and the influence of chelating agents, meso 2,3-dimercaptosuccinic acid (DMSA), D-Penicillamine and CaNa2EDTA in reducing the concentration of lead on the selected organs of Catla catla fingerlings for both acute and chronic exposures by using ICP-AES. It is inferred from the present findings that there was a correlation between environmental conditions and the heavy metal contents of the fish. The highest concentration of lead is found in kidney tissues and the lowest in muscle tissues. The accumulation pattern of lead in the selected organs of Catla catla is: kidney > liver > gill > brain > muscle. Also, it has been found that the treatment of chelating agents, DMSA, D-Penicillamine and CaNa2EDTA reduces the concentration of lead significantly for both acute and chronic exposures. The results also show that DMSA is the most effective chelator of lead in reducing the body burden of C. catla fingerlings. The observed data further indicate that C. catla could be suitable for monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.

Influence of chelating agents on the photopolymerization of hybrid Ti-based waveguides

Sol–gel derived inorganic–organic hybrid materials (HYBRIMERs) have shown a great potential for planar and channel waveguides due to their high photosensitivity, low-cost processing and good suitability for doping. These materials have been synthesized with a high content of titanium (40%) and with three different chelating agents: acetylacetone, methacrylic acid and trifluoroacetic acid. The degree of photopolymerization of the methacrylate part changes with the nature of the chelating agent. Trifluoroacetic acid and methacrylic acid are the chelating agents showing the highest photopolymerization conversion. All coatings were crack free (thickness ∼1 μm), transparent in the visible spectra range with refractive indexes from 1.54 to 1.58. Simple confined structures based on trifluoroacetic acid with well-defined shapes, smooth surfaces (RMS = 0.28 nm) and good optical properties were synthesized. Straight and bent channel waveguides and beam splitters were patterned by UV exposure and wet etching, and light confinement effects into the different channel waveguides were shown.