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Hexavalent Chromium Removal and Reduction to Cr (III) by Polystyrene Tris(2-aminoethyl)amine

American Journal of Analytical Chemistry 2015年第1期6卷 26-37页

作者： Lina odeh imad odeh Mustafa Khamis Mahmoud Khatib Mohannad Qurie Ziad Shakhsher Mutaz Qutob Department of Chemistry and Chemical Technology Al-Quds University Jerusalem Palestine Center for Chemical and Biological Analysis Al-Quds University Jerusalem Palestine Department of Earth and Environmental Studies Al-Quds University Jerusalem Palestine

A commercially available chelating polymer, polystyrene tris(2-aminoethyl)amine, was used for the removal of chromium from aqueous solution. The influence of pH, contact time, adsorbent dosage and initial Cr (VI) concentration on adsorption was studied. The optimum pH for the removal of Cr (VI) was at pH 5, while optimum contact time and adsorbent dosage were 120 minutes and 10 g/L, respectively. Total chromium and Cr (VI) concentrations were analyzed by ICP-MS and UV-Visible. Adsorption isotherms using Langmuir and Freundlich isotherm models revealed that the data fitted Langmuir isotherm model better than Freundlich with a maximum adsorption capacity of 312.27 mg/g. FTIR spectroscopy, Scanning electron microscopy (SEM) and Energy Dispersive Spectrometry (EDS) analyses were performed on the adsorbent before and after binding Cr (VI). All analyses confirmed the complexation of Cr (VI) to the adsorbent. Desorption experiments using KCl solution indicated 89.3% release of chromium, rendering this method of high potential for adsorbent regeneration.

关键词： Adsorption of Cr (VI) Polystyrene Tris(2-aminoethyl)amine ICP-MS SEM EDS

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An Optical Sensor Based on Polyvinyl Benzyl Malonate Cross-Linked with Divinyl Benzene Dispersed in a Hydrogel Membrane for Detection of Some Heavy Metals

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American Journal of Analytical Chemistry 2012年第4期3卷 283-287页

作者： imad odeh Ziad Shakhsher Suha Jaber Mahmood Khateeb Fuad Al-Rimawi Faculty of Science and Technology Al-Quds University East Jerusalem Palestine

In previous work we have developed a dicarboxylate functionalized polymer that demonstrated chemical sensing. It showed good response to pH changes as well as to varying concentrations of copper and calcium ions. Our recent in-vest- tigations showed interesting results upon testing the functionalized sensing polymer on heavy metals. This sensor is composed of microspheres of polyvinyl benzyl malonate lightly-cross-linked with divinyl benzene dispersed in a hydrogel membrane. The response of the optical sensor is based on the interaction between the metal cations with the deprotonated functional group. The polymer, thus, undergoes shrinking as a result of neutralization of adjacent negative charges on the back-bone of the polymer. This causes significant changes in the optical properties of the sensing element. The optical changes were measured as absorbance vs. wavelength as the sensing membrane is exposed to solutions of varying concentrations of heavy metal ions. The sensor showed significant increase in absorbance up to a concentration of 5 × 10-3 M to the following metal ions: Ni2+, Zn2+, and Cd2+. Furthermore, the studied capacity of the derivatized microspheres showed close values to Ni2+, Zn2+, Cd2+ (1.20, 1.09, 1.08 mmol/g respectively). These kinds of properly functionalized polymers appear to be suitable, versatile sensing elements for the detection of low concentrations of heavy metal ions. In addition, all of the tested heavy metals showed a similar value of the equilibrium formation constant, (log Kf1 is 2.63). In contrast, the sensor showed no significant response to varying concentrations of K+ and Mg2+ metal ions.

关键词： Shrinking Microsphere Polymer Polyvinylbenzylmalonate Optical Chemical Sensors Heavy Metal Sensing Equilibrium Formation Constant

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Polyvinylbenzyl Tris-Aminodicarboxylate Microspheres for the Optical Sensing of Cu<sup>2+</sup>Ions

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American Journal of Analytical Chemistry 2014年第2期5卷 122-127页

作者： Ziad M. Shakhsher Ibrahim Abu Shqair Hanin R. Qasim imad odeh Department of Chemistry and Chemical Technology Al-Quds University Jerusalem Palestine Department of Chemistry An-Najah National University Nablus Palestine

In this work, a tris(2-aminoethyl)aminodicaboxylate functionality was substituted for the chloride of polyvinyl-benzyl chloride (PVBC) which was lightly cross-linked (2%) with divinyl benzene. The resulting derivatized polymer microspheres were embedded in a hydrogel matrix of poly vinyl alcohol cross-linked with glutaraldehyde to produce a sensing membrane. The latter responded selectively to Cu2+ solutions of different concentration ranges (1 × 10-4 M to 1 × 10-6 M). The response is based on the interaction between the metal cations and the negatively charged deprotonated dicarboxylate functional group, which led to neutralization of the charges. As a result, an increase in the turbidity of the sensing membrane occurred which is attributed to a change in the refractive index of the derivatized polymer microspheres relative to that of the hydrogel. The change in the turbidity of the sensing membrane was measured as absorbance using a conventional spectrophotometer. It was found that Cu2+ ions bind to the aminodicarboxylated-polymer with a formation constant, Kf, of 1 × 105 M-1. SEM, Eds and IR analyses were performed on the aminodicarboxylated microspheres and their Cu2+ complex.

关键词： Tris(2-aminoethyl)aminodicarboxylate-Polymer Optical Sensing Refractive Index SEM Eds

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