Thallium adsorption onto polyacryamide–aluminosilicate composites: A Tl isotope tracer study

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 162; no. 1; pp. 97 - 105
• Main Authors: Şenol, Zeynep Mine, Ulusoy, Ulvi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.08.2010; Elsevier
• Subjects: Adsorption; Aluminosilicate; Applied sciences; Bentonite; Chemical engineering; Composite; Entropy; Exact sciences and technology; Extraction; Ion exchange; Isotope tracer; Natural water pollution; Pollution; Polymer matrix composites; Reusable; Sea water; Seawaters, estuaries; Sorption; Thallium; Water treatment and pollution; Thallium; B; Aluminosilicate; PAAm–B/Z; Adsorption; Composite; Isotope tracer; PAAm; Z; DR; Second order; Enthalpy; Adsorption capacity; Entropy; Zeolite; Composite material; Sorption; Ionic strength; Kinetics; Thermodynamic properties; Compatibility; Ion exchange; Seawater; Tracers
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2010.05.005

Adsorptive features of the composites of polyacrylamide (PAAm) and bentonite (B), and zeolite (Z) were investigated for Tl + and Tl 3+. Langmuir monolayer adsorption capacities for the corresponding ions were 1.85 and 0.97 mol kg −1 for PAAm–Z and 0.36 and 0.16 mol kg −1 for PAAm–B. The values of enthalpy and entropy changes were positive for both composites and ions. The compatibility of the second order adsorption kinetics implied that the rate-controlling step was concentration dependent; the sorption process was ion exchange. High adsorption rate was found for both composites; the time required for adsorption of half of Tl + concentrations was 7 min. In the presence of both ions, PAAm–B was more selective for Tl 3+ than PAAm–Z. The reusability tests for Tl + for five uses proved that the composites were reusable after complete recovery of the loaded ion. The values of Tl + adsorption onto PAAm–Z from solutions containing Fe 3+, Pb 2+, Zn 2+ confirmed that the effect of the presence of these ions on Tl + extraction was not significant. Although Tl + sorption decreased with increasing ionic strength (CaCl 2) of the medium, the results of adsorption from sea water containing 5 × 10 −6 mol L −1 (1 mg L −1) of Tl + ascertained that the composites still adsorbed about 10% of Tl.