Equilibrium, kinetics and thermodynamic studies for the removal of arsenic from water using newly synthesized amino resin supported hydrous ferric oxide nano composite.

Arsenic (III) was treated by newly synthesized ferric oxide nano composite supported on amino resin (NXHFO). Amberlite XAD-4 was converted to amino derivative (NX) and HFO particles were prepared on its surface. Batch study was conducted to study the removal of arsenic from aqueous media. Uptake of ∼98.5% was recorded at pH 4 using 50 mg of NXHFO while the agitation time was 30 min. Monolayer sorption capacity of NXHFO resin calculated from Langmuir sorption isotherm for As(III) ions was 32.3 mg g-1. The sorption energy (E) calculated was 15 kJ mol-1, suggesting that the uptake of arsenite onto the NXHFO surface was due to ion-exchange.

Equilibrium, kinetic and thermodynamic studies of removal of phenol from aqueous solution using surface engineered chemistry.

Iron impregnated activated carbon has been used as a new adsorbent for the adsorptive removal of phenol from waste water. Impregnation of iron was confirmed by Fourier transform infrared spectroscopy and scanning electron microscope and energy dispersive spectroscopy. Different parameters affecting the adsorption capacity of Iron impregnated activated carbon such as Iron impregnated activated carbon dosage, contact time, pH of solution, initial concentration of phenol and agitation speed were optimized. The residual concentration of phenol was determined by UV-Vis spectroscopy. Maximum adsorption efficiency was calculated 98.5% at optimized parameters: concentration of phenol 25 mg L-1, Iron impregnated activated carbon dose 75 mg, pH 7.0 and agitation time 90 min. The experimental data was fitted to different adsorption isotherms and adsorption capacities obtained were 20 and 15 mg g-1, respectively. Adsorption energy was found to be 1.54 kJ mol-1 which predicts that phenol was adsorbed onto the Iron impregnated activated carbon through physisorption.

Solid Phase Extraction of Trace Elements in Waterand Tissue Samples on a Mini Column with Diphenylcarbazone Impregnated Nano-TiO2 and Their Determination by Inductively Coupled Plasma Optical Emission Spectrometry.

This study presents a simple, robust and environmentally friendly solid phase preconcentration procedure for multielement determination by inductively coupled plasma optical emission spectrometry (ICP-OES) using diphenylcarbazone (DPC) impregnated TiO2 nanopowder (n-TiO2). DPC was successfully impregnated onto n-TiO2 in colloidal solution. A number of elements, including Co(II), Cr(III), Cu(II), Fe(III), Mn(II) and Zn(II) were quantitatively preconcentrated from aqueous solutions between pH 8 and 8.5 at a flow rate of 2 mL min-1, and then eluted with 2 mL of 5% (v/v) HNO3. A mini-column packed with 0.12 g DPC impregnated n-TiO2 retained all elements quantitatively from up to 250 mL multielement solution (2.5 µg per analyte) affording an enrichment factor of 125. The limits of detection (LOD) for preconcentration of 50 mL blank solutions (n = 12) were 0.28, 0.15, 0.25, 0.22, 0.12, and 0.10 µg L-1 for Co, Cr, Cu, Fe, Mn, and Zn, respectively. The relative standard deviation (RSD) for five replicate determinations was 0.8, 3.4, 2.6, 2.2, 1.2 and 3.3% for Co, Cr, Cu, Fe, Mn and Zn, respectively, at 5 µg L-1 level. The method was validated with analysis of Freshwater (SRM 1643e) and Lobster hepatopancreas (TORT-2) certified reference materials, and then applied to the determination of the elements from tap water and lake water samples by ICP-OES.

Preconcentration of trace elements from water samples on a minicolumn of yeast (Yamadazyma spartinae) immobilized TiO2 nanoparticles for determination by ICP-AES.

A trace element preconcentration procedure is described utilizing a minicolumn of yeast (Yamadazyma spartinae) immobilized TiO(2) nanoparticles for determination of Cr, Cu, Fe, Mn, Ni and Zn from water samples by inductively coupled plasma atomic emission spectrometry. The elements were quantitatively retained on the column between pH 6 and 8. Elution was made with 5% (v/v) HNO(3) solution. Recoveries ranged from 98 ± 2 (Cr) to 100 ± 4 (Zn) for preconcentration of 50 mL multielement solution (50 µg L(-1)). The column made up of 100mg sorbent (yeast immobilized TiO(2) NP) offers a capacity to preconcentrate up to 500 mL of sample solution to achieve an enrichment factor of 250 with 2 mL of 5% (v/v) HNO(3) eluent. The detection limits obtained from preconcentration of 50 mL blank solutions (5%, v/v, HNO(3), n=11) were 0.17, 0.45, 0.25, 0.15, 0.33 and 0.10 µg L(-1) for Cr, Cu, Fe, Mn, Ni and Zn, respectively. Relative standard deviation (RSD) for five replicate analyses was better than 5%. The retention of the elements was not affected from up to 500 µg L(-1) Na(+) and K(+) (as chlorides), 100 µg L(-1) Ca(2+) (as nitrate) and 50 µg L(-1) Mg(2+) (as sulfate). The method was validated by analysis of freshwater standard reference material (SRM 1643e) and applied to the determination of the elements from tap water and lake water samples.

Simultaneous generation of hydrides of bismuth, lead and tin in the presence of ferricyanide and application to determination in biominerals by ICP-AES.

Performance of potassium ferricyanide, K(3)(Fe(CN)(6), for simultaneous generation of hydrides of Bi, Pb and Sn in dilute HCl is investigated for determination by ICP-AES. On-line addition of K(3)Fe(CN)(6) to sample solution was essential to achieve optimum signals and stability in generation of BiH(3) and SnH(4). Off-line addition caused instability for Bi(III) and Sn(IV) that resulted in substantial loss in hydride generation efficiency within 24 h. Lead hydride (PbH(4)) generation, however, was not influenced from on-line or off-line addition of [Fe(CN)(6)](3-), nor did it show any instability under the same conditions indicating that [Fe(CN)(6)](3-) affects generation of PbH(4) differently from those of BiH(3) and SnH(4). The effects of transition metals and hydride forming elements were not significant, except Cr(VI) and Cu(II) that suppressed the signals of Bi and Sn, and Pb, respectively, at and above 1.0 µg mL(-1). The detection limits (3s, n = 11) were 0.20, 0.13 and 0.10 µg L(-1) for Bi, Pb and Sn, respectively. The method was applied to the analysis of calcium-rich biominerals - fish otoliths and NIST bone ash certified reference material (SRM 1400).

Penicillium digitatum immobilized on pumice stone as a new solid phase extractor for preconcentration and/or separation of trace metals in environmental samples.

This study presents a column solid phase extraction procedure based on column biosorption of Cu(II), Zn(II) and Pb(II) ions on Penicillium digitatum immobilized on pumice stone. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions such as: pH values, amount of solid phase, elution solution and flow rate of sample solution were evaluated for the quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes has also been investigated. The recoveries of copper, zinc and lead under the optimum conditions were found to be 97+/-2, 98+/-2 and 98+/-2%, respectively, at 95% confidence level. For the analytes, 50-fold preconcentration was obtained. The analytical detection limits for Cu(II), Zn(II) and Pb(II) were 1.8, 1.3 and 5.8 ng mL(-1), respectively. The proposed procedure was applied for the determination of copper, zinc and lead in dam water, waste water, spring water, parsley and carrot. The accuracy of the procedure was checked by determining copper, zinc and lead in standard reference tea samples (GBW-07605).

Determination of lead and nickel in environmental samples by flame atomic absorption spectrometry after column solid-phase extraction on Ambersorb-572 with EDTA.

Lead and nickel were preconcentrated as their ethylenediaminetetraacedic acid (EDTA) complexes from aqueous sample solutions using a column containing Ambersorb-572 and determined by flame atomic absorption spectrometry (FAAS). pH values, amount of solid phase, elution solution and flow rate of sample solution have been optimized in order to obtain quantitative recovery of the analytes. The effect of interfering ions on the recovery of the analytes has also been investigated. The recoveries of Pb and Ni under the optimum conditions were 99 +/- 2 and 97 +/- 3%, respectively, at 95% confidence level. Seventy-five-fold (using 750 mL of sample solution and 10 mL of eluent) and 50-fold (using 500 mL of sample solution and 10 mL of eluent) preconcentration was obtained for Pb and Ni, respectively. Time of analysis is about 4.5 h (for obtaining enrichment factor of 75). By applying these enrichment factors, the analytical detection limits of Pb and Ni were found as 3.65 and 1.42 ng mL(-1), respectively. The capacity of the sorbent was found as 0.17 and 0.21 mmol g(-1) for Pb and Ni, respectively. The interferences of some cations, such as Mn2+, Co2+, Fe3+, Al3+, Zn2+, Cd2+, Ca2+, Mg2+, K+ and Na+ usually present in water samples were also studied. This procedure was applied to the determination of lead and nickel in parsley, green onion, sea water and waste water samples. The accuracy of the procedure was checked by determining Pb and Ni in standard reference tea leaves sample (GBW-07605). The results demonstrated good agreement with the certified values.

The use of Agrobacterium tumefacients immobilized on Amberlite XAD-4 as a new biosorbent for the column preconcentration of iron(III), cobalt(II), manganese(II) and chromium(III).

A microorganism Agrobacterium tumefacients as an immobilized cell on a solid support was presented as a new biosorbent for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to flame atomic absorption spectrometric analysis. Amberlite XAD-4 was used as a support material for column preconcentration. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of sample solution, volume of sample solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH for the sorption of above mentioned metal ions were about 6, 8, 8 and 6, respectively. The loading capacity of adsorbent for Co(II) and Mn(II) were found to be 29 and 22mumolg(-1), respectively. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III), under the optimum conditions were found to be 99 +/- 3, 99 +/- 2, 98 +/- 3 and 98 +/- 3%, respectively, at the 95% confidence level. The limit of detection was 3.6, 3.0, 2.8 and 3.6ngml(-1) for Fe(III), Co(II), Mn(II) and Cr (III), respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied for metal ion determination from water samples, alloy samples, infant foods and certified samples such as whey powder (IAEA-155) and aluminum alloy (NBS SRM 85b). The analytes were determined with a relative error lower than 10% in all samples.

Application of silica gel 60 loaded with Aspergillus niger as a solid phase extractor for the separation/preconcentration of chromium(III), copper(II), zinc(II), and cadmium(II).

Sorption properties of silica gel 60 loaded with fungi cells characterized as Aspergillus niger were evaluated for trace enrichment of Cr(III), Cu(II), Zn(II), and Cd(II) from various water samples prior to the description of flame atomic absorption spectrometric analysis. The proposed SPE method is cheap, simple, highly sensitive, accurate, and selective for enrichment of analytes. The effect of experimental parameters, such as pH of sample solution, amount of solid phase, eluent type, and volume of sample solution on the recovery of the metal ions has been investigated. The effect of diverse ions was also investigated. The recoveries of Cr(III), Cu(II), Zn(II), and Cd(II) under the optimum experimental conditions were 98 +/- 2, 98 +/- 3, 99 +/- 2, 100 +/- 2%, respectively, at the 95% confidence level. The analytical detection limits were found to be 3.1, 1.6, 1.1, and 1.4 microg/L for Cr(III), Cu(II), Zn(II), and Cd(II), respectively. The proposed enrichment method was applied to the determination of analytes in Atatürk Dam, Egirdir Lake, and tap-water samples. The analytes were determined with a relative error lower than 8% in various water samples. The method has been validated by analyzing spiked water samples.

Use of Escherichia coli immobilized on amberlite XAD-4 as a solid-phase extractor for metal preconcentration and determination by atomic absorption spectrometry.

A sensitive solid-phase extraction technique (SPE) for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to atomic absorption spectrometric analysis is described. Escherichia coli immobilized on Amberlite XAD-4 was used as a solid-phase extractor. The effects of the pH, amount of solid-phase, eluent type and volume of the sample solution on the recovery of the metal ions were investigated. The effect of diverse ions was also investigated. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III) under the optimum conditions were found to be 99 +/- 2, 99 +/- 3, 98 +/- 2, 98 +/- 3%, respectively, at the 95% confidence level. The detection limits of the metal ions were found as to be 2.4, 3.8, 1.3 and 1.7 ng ml(-1) for Fe(II), Co(II), Mn(II) and Cr(III) respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied to the determination of analytes in Atatürk Dam water samples, and alloy samples (RSD < 5%). The accuracy of the method was verified on certified alloy samples (NBS SRM 85b and NBS SRM 59a). The analytes were determined with a relative error lower than 5% in water and alloy samples.