Hydrogen Ion In Aqueous Phase Research Articles

Synthesis of crown ether functionalized polyacrylamide gel beads and their extraction behaviour for strontium ions

ABSTRACT 4-acrylamidobenzo-18-crown-6(ABCE) functionalized polyacrylamide (PAAm) gel beads have been synthesized using an indigenously developed sedimentation polymerization setup. The extraction of Sr2+ ions by ABCE functionalized PAAm gel beads was monitored by batch extraction experiments in different concentrations of nitric acid and sodium nitrate solutions. With the aid of atomic absorption spectroscopy (AAS), the concentration of Sr2+ ions in aqueous phase before and after extraction was measured. In nitric acid, the extraction efficiency is found to be high (> 80%) when the number of hydrogen ions in aqueous phase is less than that of ABCE molecules attached to hydrogel backbone. A sudden drop in extraction efficiency was observed when the number of hydrogen ions present in the aqueous phase is greater than that of ABCE molecules attached to hydrogel backbone. Our results indicate that the number of hydrogen ions present in the aqueous phase play an important role in deciding the extraction effici...

Liquid-liquid distribution of metals in systems with trioctylmethylammonium dinonyl naphthalenesulfonate

The extraction of copper, nickel, cobalt, zinc, and iron chlorides by the solutions of trioctylmethylammonium dinonyl naphthalenesulfonate in toluene depending on the acidity of aqueous phase was studied. In the range of relatively high acidity (from 3 to 1 M HCl), an increase in the DM values is observed with a growth in the concentration of hydrogen ions in aqueous phase; that corresponds to the principles of the binary extraction of chloro complex metal-containing acids. With a decrease in the acidity of aqueous phase, an increase in the distribution coefficients of metals is observed due to the change in the extraction mechanism and increase in the fraction of the complexes extracted as metal dinonyl naphthalenesulfonates. In the acidic range, the extractability of metals is mainly determined by the stability of complex metal-containing anions and qualitatively corresponds to the following order: Fe(III) > Cu(II) > Co(II) > Ni(II).

Extraction and separation of gallium, indium and thallium with several carboxylic acids from chloride media

A method is proposed for the extraction and individual separation of trivalent gallium, indium and thallium with sec-octylphenoxy acetic acid (CA-12), sec-nonylphenoxy acetic acid (CA-100) and naphthenic acid (NA) from chloride media. The distribution equilibria of gallium (III), indium (III), thallium (III) and thallium (I) between carboxylic acids (CA-12, CA-100 and NA) dissolved in kerosene and acidic aqueous chloride media has been investigated as a function of the concentration of extractants and the concentration of hydrogen ion in aqueous phase. A possible mechanism of the extraction is discussed. The method permits rapid and precise individual separation of gallium (III), indium (III) and thallium (III), and is applicable to the analysis of alloy samples.

LIQUID–LIQUID EXTRACTION OF GALLIUM(III) FROM CHLORIDE MEDIA WITH CARBOXYLIC ACIDS IN KEROSENE

The extraction behavior and mechanism of gallium(III) with Naphthenic Acid (NA), Sec-octylphenoxy acetic Acid (CA-12) and Sec-nonylphenoxy acetic Acid (CA-100) from hydrochloric acid solution was studied. The distribution equilibria of gallium (III) between carboxylic acids (NA, CA-12 and CA-100) dissolved in kerosene and acidic aqueous chloride media has been investigated as a function of the concentration of extractants in organic phase and concentration of hydrogen ion in aqueous phase. To get further information, we compared the extraction characteristics among NA, CA-12 and CA-100. The stoichio metry of the extracted species is determined on the basis of slope analysis and IR spectra. Gallium is extracted by a cation exchange mechanism as Ga(OH)R2·2HR by NA and as GaR3·HR by CA-12 and CA-100.

Dissociation‐association sorption on ion exchangers. I. Experimental study of dependence of equilibrium function of acidity in ion exchanger on activity of hydrogen ions in aqueous phase

AbstractEquilibrium coloring of crystal violet, methyl violet, and dimethyl yellow sorbed on ion exchanger Dowex‐50‐WX4 was studied by a spectrophotometric method as a function of the pH of the aqueous phase. From the data obtained, the function of acidity in a ion exchanger was calculated corresponding to individual equilibriums of the exchange reaction. A simple relationship between H̄0′ in a ion exchanger and the pH of the aqueous phase was found.