Ezzat M. Soliman

Activated carbon immobilized dithizone phase for selective adsorption and determination of gold(III)

Abstract A simple method for selective adsorption and determination of gold(III) based on activated carbon immobilized dithizone (AC-DTZ) phase combined with inductively coupled plasmaoptical emission spectrometry was developed. Surface properties of the new hemically modified AC-DTZ phase were confirmed by Fourier transform infrared spectroscopy. The effect of pH on the selectivity of AC-DTZ towards eight metal ions, including Au(III), Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II), was investigated. Based on the pH study, it was found that the selectivity of AC-DTZ phase was the most towards Au(III). For a deeper mechanistic understanding of the analytical potential of the AC-DTZ phase towards Au(III), other factors influencing the maximum uptake of Au(III) on AC-DTZ were also investigated. The results showed that the adsorption capacity for Au(III) was improved by 64.07% with the AC-DTZ phase as compared to the carboxylic acid derivative of activated carbon after only 1 h contact time. Adso...

Selective Adsorption and Determination of Hexavalent Chromium in Water Samples by Chemically Modified Activated Carbon with Tris(hydroxymethyl)aminomethane

This study introduces a sensitive and simple method for selective adsorption of hexavalent chromium, Cr(VI), from water samples prior to its determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The method utilized activated carbon modified with tris(hydroxymethyl)aminomethane (AC-TRIS) as an adsorbent. Surface properties of the new chemically modified AC-TRIS phase were confirmed by Fourier transform infrared (FTIR) spectroscopy. Seven metal ions, including Co(II), Cu(II), Ni(II), Pb(II), Cr(III), Cr(VI), and Fe(III) were evaluated and determined at different pH values (1.0–8.0), except for Fe(III) at pH values (1.0–4.0). Based on the results of the effect of pH on adsorption of these metal ions on AC-TRIS, Cr(VI) was selected for the study of other parameters controlling its maximum uptake on AC-TRIS under batch conditions and at the optimum pH value 1.0. The maximum static adsorption capacity of Cr(VI) onto the AC-TRIS was found to be 43.30 mg g−1 at this pH and after 1 hour contact time. The adsorption data of Cr(VI) were modeled using both Langmuir and Freundlich classical adsorption isotherms. Results demonstrated that the adsorption of Cr(VI) onto AC-TRIS followed a pseudo second-order kinetic model. In addition, the efficiency of this methodology was confirmed by applying it to real environmental water samples.

Removal of 2-chlorophenol from aqueous solutions using activated carbon-impregnated Fe(III)

AbstractThis manuscript combines both the advantages of the high surface area of activated carbon (AC) and the strong high affinity of Fe(III) for reacting with phenolic compounds. So, AC, activated carbon-impregnated Fe(III) (AC-Fe), activated carbon-immobilized Eriochrome Blue Black as a complexing agent (AC-EBB) and its impregnated Fe(III) form (AC-EBB-Fe) were prepared and characterized using Fourier transform infrared spectroscopy and Scanning electron microscope. Batch experiments were conducted at 25°C, at pH values 3, 6, 9, and 12, with 50 mg/L 2-Chlorophenol (2-CP) concentration, 25 mg adsorbent mass and a 1 h shaking time to evaluate and compare their efficiency for the removal of 2-CP. Generally, the impregnated Fe(III) adsorbents were better than the non impregnated ones. Moreover, AC-Fe adsorbent was the best according to the order AC-Fe (97.0%) > AC (89.9%) > AC-EBB-Fe (79.0%) > AC-EBB (65.9%) judging from values of percentage extraction at pH 9. So, the optimization of 2-CP removal using AC...