Selection Of Chelating Agents Research Articles

Rapid Synthesis of Pure Phase Bismuth Ferrite through Modified Sol‐gel Auto‐ignition Method: Impact of Different Chelating Agents

AbstractPure phase bismuth ferrite has been successfully prepared in this research using a modified method of sol‐gel auto‐ignition. This method is a fast and economical synthesis technique since it can produce fine as‐synthesis powder for less than 4 hours. Also, the influences of diverse chelating agents on the physicochemical properties of the synthesized samples were examined using various characterization techniques. XRD revealed that pure bismuth ferrite nanoparticles with rhombohedral perovskite structure were produced by using ascorbic acid (AA) as a chelating agent. From the UV spectra, a blue shift observed in the presence of AA and citric acid (CA). Moreover, the specific surface area of the as‐prepared BFO‐EDTA, BFO‐AA and BFO‐CA samples was 1.694, 1.134 and 1.627 m2/g, respectively, consistent with the XRD findings. Raman analysis shows that the synthesized BFO samples exhibit 4 A1 and 8E modes confirming Rhombohedral R3c geometry of bismuth ferrite nanoparticles. Finally, FTIR spectra depicted three absorption peaks at 410, 450, and 548 cm−1 corresponding to Fe−O stretching and bending, respectively, which is a characteristic of FeO6 octahedral in perovskite. The findings of this study would assist the researcher in the selection of chelating agents in the auto‐combustion method for the processing of nanoparticles for particular applications.

Chemically synthesized phase-pure BiFeO3 nanoparticles: Influence of agents on the purity

Single-phase BiFeO3 (BFO) nanoparticles with an average size of ∼64 nm were synthesized using formic acid and ethylene glycol as agents through a modified Pechini type sol–gel method. The present work highlights the synthesis of phase-pure BFO that lies on the right selection of chelating agent and complexing agent. Thermal and Fourier transform infrared (FTIR) studies revealed the temperature at which the metal oxide forms. X-ray diffraction patterns showed a gradual phase evolution as calcined temperature increased from 400 to 600 °C. The values of Rietveld refinement parameters (Rwp=5.42%, Rp=4.2%, Goodness of fit (S)=1.29) confirmed the single-phase BFO corresponding to rhombohedral perovskite structure with the space group R3c. Selected area electron diffraction pattern displayed the polycrystalline nature of the synthesized particles. The M–H loop measured at room temperature for the sample calcined at 500 °C revealed a ferromagnetic-like component with a coercivity of ∼907 Oe, whereas the sample calcined at 600 °C exhibited the typical antiferromagnetism.

Supercritical Fluid Extraction of Hazardous Metals from Urban Total Suspended Particles

This paper describes the procedure for supercritical fluid extraction (SFE) of hazardous metals (Cu, Pb, Zn, Cd, Cr, and Ni) from urban total suspended particles (TSP) with supercritical CO2 and several different types of chelating agents, under optimum extraction conditions of 20MPa, 60°C, and surfactant‐methanol modified supercritical CO2. Efficient extraction of metal ions from simulate samples was achieved. Only trifluoracetylacetone (TFA) is a general chelating agent to efficiently extract all of the target metal ions from TSP (83.2–99.3%). Sodium diethyldithiocarbamate (NaDDTC) can extract Cu, Pb, Zn, and Cd effectively (80.6–94.9%). 8‐Hydryquinoline (8‐HOx) can selectively extract Cu and Zn, with recoveries of 90.1% and 78.7%, respectively. Dithizone (H2Dz) is capable of extracting Cu, Zn, and Cr with recoveries of 93.8, 79.8, and 94.5%, respectively. The results showed that, under optimized extraction conditions, and with suitable selection of chelating agent, SFE for pretreating metals in TSP can yield results comparable to chemical digestion methods much more quickly and conveniently.

Electroless pure nickel plating process with continuous electrolytic regeneration system

We have developed an electroless nickel plating solution in which titanium ion redox system, Ti 3+→Ti 4++e −, was used as a reducing agent. The stability of the solution has been improved by the selection of chelating agents and their ratio to nickel and titanium ion, and by the addition of an amino acid and a sulfur-containing compound. A pure nickel film containing no phosphorus was obtained from the new electroless plating solution. Any other elements except nickel were not detected by inductively coupled plasma analysis. Electrolytic regeneration system of the solution has been also developed. Continuous running test for more than 100 h has been achieved in a pilot plant and the bath is believed to be stable enough to apply to a commercial production line.