Sorption recovery of metal ions using silica gel modified with salicylaldoxime

Trace metals in water were preconcentrated with silica gel modified with salicylaldoxime and determined by AAS. Optimum conditions for the maximum recovery of metal ions, viz. Cu(II), Ni(II), Co(II), Zn(II) and Fe(III), for both batch and column methods were developed. The efficiency of the adsorbent with respect to different experimental conditions was established.     

Sorption behavior of gamma-irradiated silica gel

The effect of Pb(II) and non-ionic surfactants (oxyethylate alcohols OS-10 and ALM-10) on the rate of intraparticle diffusion and on to the equilibrium sorption on Purolite C 106 cation exchanger in hydrogen form was investigated. The sorption of Pb(II) cations and in free state and bonded to the surfactant was measured. The coefficients of intraparticle diffusion were also calculated.     

Novel one-pot synthesis of 4H-chromene derivatives using amino functionalized silica gel catalyst

A simple, efficient, and environmentally benign method for the synthesis of 4H-chromene derivatives was developed using well ordered and recoverable amino functionalized silica gel as a base catalyst. The 4H-chromene derivatives were obtained in short time and excellent yield(87%–96%) by three component reaction of aldehydes, malononitrile and cyclic 1,3-diketones in water at 70 8C.     

Sorption and preconcentration of copper and cadmium on silica gel modified with 3-aminopropyltriethoxysilane

3-Aminopropyltriethoxysilane, (C₂H₅O)₃ Si(CH₂)₃NH₂, loaded on silica gel was used as a pre-concentration sorbent for copper and cadmium prior to their determination by flame atomic absorption spectrometry (FAAS). Both batch and column methods were used for the separation of the above metals. The analytes are quantitatively retained on the proposed adsorbent at pH 6.5. The complexation capacity of the collector is 0.032 mmol Cu/g silica. In the batch method, the effects of shaking time and the ratio of metal/silica on the retention by the asorbent were investigated. Columns filled with the collector provided quantitative recovery of the above metals from standardized samples as well as from sodium chloride solutions.     

Sorption of traces of strontium ions on silica gel containing crown ether

This paper is concerned with the synthesis of silica gel sorbents by the sol method. A sorbent selective for trace amounts of Sr ions has been prepared. This method of synthesis is shown to be preferable to the tradition of impregnating the carrier.L. V. Pisarzhevskii Institute of Physical Chemistry, Ukrainian Academy of Sciences, Ukraine, 252039 Kiev, Science Prosp., 31. Translated from Teoreticheskiya i Éksperimental'naya Khimii, Vol.32, No. 4, pp. 258–260, July–August, 1996. Original article submitted October 17, 1995.     

Solid phase extraction using silica gel functionalized with Sulfasalazine for preconcentration of uranium(VI) ions from water samples

Silica gel surface was chemically functionalized by reaction the silanol from the silica surface with 3-chloropropyltrimethoxysilane followed by reaction with Sulfasalazine. This new sorbent has been used for the preconcentration of low levels of U(VI) ions from an aqueous phase. Parameters involved in extraction efficiency such as pH, weight of the sorbent, volume of sample and eluent were optimized in batch and column methods prior to determination by spectrophotometry using arsenazo(III) reagent. The results showed that U(VI) ions can be sorbed at pH range of 5.0–6.0 in a minicolumn and quantitative recovery of U(VI) (>98.0?±?1.6%) was achieved by stripping with 2.5 mL of 0.1 mol L^?1 HCl. The sorption capacity of the functionalized silica gel was 1.15 mmol g^?1 of U(VI). A linear calibration graph was obtained over the concentration range of 0.02–27.0 μg mL^?1 with a limit of detection of 1 μg L^?1 in treatment with 1000 mL of the U(VI) solution in which the preconcentration factor was as high as 400. The method was employed to the preconcentration of U(VI) ions from spiked ground water and synthetic sea water samples.     

Sorption of the peroxocomplex of titanium on silica gel and its analytical use

Summary Sorption of the titanium peroxocomplex on silica gel was studied in dependence on the pH and on the presence of various complexing substances, especially tartaric and citric acids. The distribution coefficients for the titanium peroxocomplex and for some other components were determined. Optimum conditions were established for the separation of small amounts of titanium from a number of accompanying cations and anions on a column and under static conditions.     

Sorption behavior of vanadium on silica gel modified with tetrakis(4-carboxyphenyl)porphyrin.

Tetrakis(4-carboxyphenyl)porphyrin (TCPP) has been loaded on aminopropyl-silica gel by physical adsorption and by direct immobilization through formation of an amide bond to obtain chelating sorbents. These sorbents have been studied for preconcentration and separation of vanadium prior to its determination by atomic absorption spectrometry. Several parameters, such as sorption capacity of the chelating resin, pH for retention of V(IV) and V(V), volume of sample and eluent, were evaluated. Both vanadium species sorbed on TCPP-modified resin could be eluted using 2 mol L(-1) nitric acid solution. The recovery values were > 94% and preconcentration factor of 160 was obtained. For speciation analysis, cyclohexane-1,2-diaminetetraacetic acid (CDTA) was added to the sample for complexation of vanadium(IV), which was not retained on the microcolumn. The proposed method was examined for reference standard materials (TM-25.2 and CAAS-3) as well as for river water samples.     

Sorption and preconcentration of metal ions in ethanol solution with a silica gel surface chemically modified with benzimidazole

The adsorption isotherms of MCl(2) (M Mn, Ni, Cu, Zn and Cd) and FeCl(3) by silica gel chemically modified with benzimidazole molecules ( Si(CH(2))(3)NC(7)H(5)N) were studied in ethanol solution at 298 K. A column made of modified silica was used to adsorb and preconcentrate the above metal ions from ethanol solution. Elution was done with 0.1 M hydrochloric acid in an ethanol/water mixture having a mole fraction of water of 0.8. The material was applied in the preconcentration of metal ions from commercial ethanol normally used as engine fuel.     

Synthesis of quaternary ammonium salt functionalized large-particle silica gel for removal of uranium

Journal of Radioanalytical and Nuclear Chemistry - Quaternary ammonium salt functionalized silica gel (QA/SiO2) was synthesized and used to remove uranium from the alkaline solution. Batch...     

Diethylenetriamine functionalized silica gel for adsorption of uranium from aqueous solution and seawater

Journal of Radioanalytical and Nuclear Chemistry - The diethylenetriamine (DETA) organic moiety was anchored covalently on the surface of silica gel to obtain a surface-modified adsorbent...     

Extraction of copper ions using silica gel with chemically modified surface

The applicability of silica gels for the application in solid-phase extraction was tested. Silica was modified with ketoimine groups. Surface characteristics of the modified silica were determined by elemental analysis, NMR spectra of solid phases (²⁹Si CP MAS NMR), analysis of pore size distribution of the silica support, and nitrogen adsorption-desorption. Newly proposed sorbents with ketoimine groups were applied in the preconcentration of trace amounts of the Cu (II) ions from lake water, post-industrial water, and demineralized water unburdened back to the lake. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

Determination of tricyclic antidepressants using silica gel with a reversed-phase eluent

Summary Five common tricyclic antidepressants are separated on a silica column using an aqueous eluent. The tricyclics are concentrated from serum using an adsorption procedure on a solid phase Sep Pak^TM C₁₈ cartridge. The method appears to be adequate for monitoring therapeutic levels of these drugs.Dedicated to Professor Dr. István Halász for his 60th birthday.     

Sorption behaviour of some actinides on silica gel from mineral acids and alcoholic solutions

Sorption of Th, Pa, U, Np and Pu on silica gel from HNO₃, HCl and HCl−ROH solutions was investigated. Equilibrium studies indicated sorption behaviour to vary greatly with the acid used. In mixtures of HCl with different alcohols, distribution coefficints were found to depend on alcohol percentage as well as on acidity. Results were discussed and conditions for possible separations were indicated.     

Sorption of uranium and thorium from sulphuric acid using TVEX-PHOR resin

Summary Solid-liquid extraction has been used to study the uptake of uranium(VI) and thorium(IV) from sulphuric acid using a TVEX-PHOR resin. The experimental results were found to fit the BET isotherm and show a higher affinity of the TVEX-PHOR resin towards the extraction of uranium than thorium under similar experimental conditions. The best separation of uranium from thorium is obtained from 3M sulphuric acid at V/m ratio of 20 ml/g. Elution of loaded uranium and thorium was carried out with 1M sodium carbonate and 0.075M sulphuric acid, respectively. After the elution of both elements, the regenerated resin could be reused with high efficiency.     

Sorption of transition metals by silica gel with fixed amide of maleic acid and polyhexamethyleneguanidine on the surface

The possibility was determined for covalent binding of amide of maleic acid and polyhexamethyleneguanidine to a silica gel surface previously activated with cyanur chloride. Adsorption of Zn(II), Cd(II), Pb(II), Cu(II), Mn(II), Ni(II), Fe(III), and Co(II) cations from aqueous solution with a modified silica obtained was studied. The possibility of subsequent formation on the surface of mixed ligand complexes