Authors:Y. Inoue, O. Tochiyama, H. Yamazaki, and A. Sakurada
A model for treating the sorption of metal ions on hydrous metal oxides was established based on the assumptions that these materials are weakly acidic cation exchangers and have a discrete exchanger phase. The experimental results of the sorption of metal ions on the hydrous niobium(V) and tin(IV) oxides are found to be consistent with the formulas derived from the model by considering that the charge balance and the mass action law hold in the exchanger phase and cations are sorbed by the distribution between this phase and the bulk aqueous phase.
structure, interlayer spacing, water content, absorption ability, and thermal stability [ 23 – 32 ].
In this study, alkaline and alkaline earth metalions exchange with Na-montmorillonites (NaM) and Ca-montmorillonites (CaM) have been investigated
Pure species of Bacilluslicheniformis was used to remove ions from aqueous and simulated waste solutions. Metal ion accumulation on B. licheniformis was fast. Maximum uptake occurred at pH 4±0.5 and at 25±3 °C. One gram of dry B. licheniformis was found to accumulate 115 mg cerium, 34 mg copper and 11 mg cobalt from aqueous solutions. The presence of certain foreign ions such as calcium, sodium and potassium decreased the uptake of ions by B. licheniformis, while citrate and EDTA prevent the uptake. Electron microscopic investigations showed that cerium (III), copper (II) and cobalt (II) accumulated extracellulary around the surface wall of B. licheniformis cells. A bio-adsorption mechanism between the metal ions and B. licheniformis cell wall was proposed.
Adsorption behavior of zinc, cadmium and mercury ions on hydrous titanium oxide in aqueous solution has been studied as a
function of concentration of the metal ion (10−2−10−7M), temperature (303–333 K) and pH 3–10 by applying radiotracer technique. The kinetics of adsorption follows the first order
rate law and agrees well with the classical Freundlich isotherm. The removal was found to increase with increasing pH but
was suppressed in the presence of EDTA. The overall process is endothermic and irreversible in nature.
Authors:C. Kozlowski, W. Walkowiak, W. Pellowski, and J. Koziol
The paper gives a short overview of application of polymer inclusion membranes (PIMs) for separation and removal of metal ions. Investigation of the selective removal of toxic metal ions, i.e. Cr(VI), Cd(II), Zn(II) from acidic chloride aqueous solutions, as well as trace radionuclides, i.e., 137Cs, 90Sr and 60Co from wastewaters using transport across polymer inclusion membranes was studied. The carriers, i.e., tri-n-octylamine for anionic metal species, as well as dibenzo-21-crown-7, tertbutyl-dibenzo-21-crown-7, and dinonylnaphtalenesulfonic acid for metal cations were incorporated into polymer inclusion membranes composed of cellulose triacetate as a support and o-nitrophenyl pentyl ether as a plasticizer. Selective transport of chromium(VI) over zinc(II) and cadmium(II) chloride complexes through PIMs was observed. Competitive transport of trace radionuclide ions, i.e., 137Cs, 90Sr, and 60Co from NaNO3 aqueous solutions across polymer inclusion membranes containing a mixture of dinonylnaphtalenesulfonic acid, and dibenzo-21-crown-7 as the carrier provide the selectivity order Cs(I)>Sr(II)>Co(II).
Authors:Ali Mohammad, Inamuddin, Arshi Amin, Mu. Naushad, and Gaber E. Eldesoky
radius ∼125 μm (50–70 mesh) in H + form were used to evaluate various kinetic parameters. The rate of exchange was determined by limited batch technique as follows:
A total of 20-mL fractions of the 0.03 M metalion solutions (Ni, Cu, Mn, and
This paper describes some experimental results obtained at the extraction of sulfate solutions of U(VI), Mo(VI), V(V), Ce(IV), Zr(IV), Fe(III), Al(III) with a benzene solution of Primene JMT. The aqueous solutions consist of metal sulfates (or other metal salts) in the presence of sulfuric acid with a concentration range of 0–2.1 mol·dm–3, the concentration of amine in the organic phase being 0.1–0.3 mol·dm–3. The presence of various species of metal ions in the aqueous phase is considered and the equilibrium concentration of substances extracted in the organic phase is determined. On the basis of the results of chemical analysis (concentration of metals and sulfate ions) the composition of the prevailing complexes in the organic phase is proposed.