Preconcentration and determination of copper and cadmium ions with 1,6-bis(2-carboxy aldehyde phenoxy)butane functionalized Amberlite XAD-16 by flame atomic absorption spectrometry

A new chelating resin, covalently linked 1,6-bis(2-carboxy aldehyde phenoxy)butane with the Amberlite XAD-16 was synthesized and used for preconcentration of Cu(II) and Cd(II) prior to their determination by flame atomic absorption spectrometry (FAAS). It was characterized by elemental analyses and Fourier Transform Infrared Spectroscopy (FT-IR). Cu(II) and Cd(II) ions were quantitatively preconcentrated on minicolumn loaded with synthesised resin at pH 4.00 and 6.00, respectively. They were eluated with 5 mL of 0.5 mol L(-1) HCl. Recoveries of Cu(II) and Cd(II) were found to be 100±2.15, 100±1.40 (N=5), the limits of detection of Cu(II) and Cd(II) in the determination by FAAS (3s, N=20) were found to be 0.33 and 1.19 μg L(-1), respectively. The effect of foreign ions on the recovery has been investigated. The proposed method has been applied for the determination of Cu(II) and Cd(II) ions to the real samples collected from Tigris river water in Diyarbakir and Elaziğ cities in Turkey. Standard addition method and analysis of the certified reference material (NCS-DC 73350) was employed to check the accuracy of the method.

Studies on the Removal of Malachite Green Dyes by Adsorption onto Activated Carbons – A Comparative Study

Malachite Green is an organic compound that is used as a dyestuff for the materials like silk, leather and paper. As a part of removal of malachite green dye from textile and leather industrial wastes, using activated carbon as adsorbents namely, commercial activated carbon (CAC), rose apple carbon (RAC), coconut shell carbon (CSC) and saw dust carbon (SDC). The percentage of malachite green adsorbed increases with decrease in initial concentration and particle size of adsorbent and increased with increase in contact time, temperature and dose of adsorbent. The pH is highly sensitive for dye adsorption process. The adsorption process followed first order kinetics and the adsorption data with Freundlich and Langmuir isotherm models. The first order kinetic equations like Natarajan Khalaf, Lagergren, Bhattacharya and Venkobhachar and intra particle diffusion were found to be applicable. A comparative account of the adsorption capacity of various carbons has been made. These activated carbons are alternative to commercial AC for the removal dyes in General and MG is particular. These results are reported highly efficient and effective and low cost adsorbent for the MG. The thermodynamics parameters are also studied and it obeys spontaneous process. The results are confirmed by before and after adsorption process with the help of the following instrumental techniques viz., FT-IR, UV-Visible Spectrophotometer and SEM photos.

Synthesis of malonic acid-functionalized Amberlite XAD-4 and its use in solid phase extraction/preconcentrative separation of thorium(IV)

A new chelating polymer has been developed wherein Amberlite XAD-4 has been functionalized by coupling it with diethylmalonate after acetylation. The resulting resin has been characterized by IR spectral and microanalysis studies and has been used for preconcentrative separation of thorium(IV) in the presence of alkali, alkaline earth, transition elements and lanthanides. Various physico-chemical parameters influencing the sorption of thorium(IV) onto the polymeric matrix was investigated and optimized by both batch and column methods. Quantitative extraction of thorium(IV) was obtained in the pH range 6.0–8.0. The sorption capacity of the malonic acid functionalized resin is 19.28 mg per g of polymer with an enrichment factor of 500. Moreover, the system showed faster exchange kinetics for extraction of thorium(IV) thus resulting in quantitative enrichment at flow rates as high as 16.0 cm3/min using 0.2 g of resin packed column (7 mm dia). Five replicate determinations of 10 μg of thorium(IV) present in 2.5 dm3 of sample solution gave a mean absorbance of 0.160 with a relative standard deviation of 2.54%. The detection limit corresponding to 3 times the standard deviation of the blank was found to be 0.2 μg dm3. The developed procedure has been successfully utilized for the estimation of thorium(IV) content of pure rare earth chloride solution collected from Indian Rare Earths Limited, Alwaye, India.

Removal and recovery of mercury(II) from hazardous wastes using 1-(2-thiazolylazo)-2-naphthol functionalized activated carbon as solid phase extractant

As a part of removal of toxic heavy metals from hazardous wastes, solid phase extraction (SPE) of mercury(II) at trace and ultra trace levels was studied using 1-(2-thiazolylazo)-2-naphthol (TAN) functionalized activated carbon (AC). The SPE material removes traces of mercury(II) quantitatively in the pH range 6.0 +/- 0.2. Other parameters that influence quantitative recovery of mercury(II), viz. percent concentration of TAN in AC, amount of TAN-AC, preconcentration time and volume of aqueous phase were varied and optimized. The possible means of removal of Hg(II) from other metal ions that are likely to be present in the wastes of the chloroalkali industry is discussed. The potential of TAN-functionalized AC SPE material for decontaminating mercury from the brine sludge and cell house effluent of a chloralkali plant has been evaluated.