title: Comparative study of tributyltin adsorption onto mesoporous silica functionalized with calix[4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix[4]arene.
abstract: The adsorption of tributyltin (TBT), onto three mesoporous silica adsorbents functionalized with calix[4]arene, p-tert-butylcalix[4]arene and p-sulfonatocalix[4]arene (MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively) has been compared. Batch adsorption experiments were carried out and the effect of contact time, initial TBT concentration, pH and temperature were studied. The Koble-Corrigan isotherm was the most suitable for data fitting. Based on a Langmuir isotherm model, the maximum adsorption capacities were 12.1212, 16.4204 and 7.5757 mg/g for MCM-TDI-C4, MCM-TDI-PC4 and MCM-TDI-C4S, respectively. The larger uptake and stronger affinity of MCM-TDI-PC4 than MCM-TDI-C4 and MCM-TDI-C4S probably results from van der Waals interactions and the pore size distribution of MCM-TDI-PC4. Gibbs free energies for the three adsorption processes of TBT presented a negative value, reflecting that TBT/surface interactions are thermodynamic favorable and spontaneous. The interaction processes were accompanied by an increase of entropy value for MCM-TDI-C4 and MCM-TDI-C4S (43.7192 and 120.7609 J/mol K, respectively) and a decrease for MCM-TDI-PC4 (-37.4704 J/mol K). It is obviously observed that MCM-TDI-PC4 spontaneously adsorbs TBT driven mainly by enthalpy change, while MCM-TDI-C4 and MCM-TDI-C4S do so driven mainly by entropy changes.
authors.affiliation: Department of Chemistry, Faculty of Science, University Malaya, Kuala Lumpur 50603, Malaysia. so2002na@yahoo.com.
authors.forename: Sana
authors.initials: S
authors.lastname: Alahmadi
authors.affiliation: Department of Chemistry, Faculty of Science, University Malaya, Kuala Lumpur 50603, Malaysia. sharifahm@um.edu.my.
authors.forename: Sharifah
authors.initials: S
authors.lastname: Mohamad
authors.affiliation: Department of Chemistry, Faculty of Science, University Malaya, Kuala Lumpur 50603, Malaysia. mjamil@um.edu.my.
authors.forename: Mohd Jamil
authors.initials: MJ
authors.lastname: Maah
mesh_terms: D000327:Adsorption; D047250:Calixarenes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014220:Trialkyltin Compounds / Q000737:chemistry*
chemical_list: D014220:Trialkyltin Compounds; D047250:Calixarenes; C011559:tributyltin; D012822:Silicon Dioxide
references.citation: J Hazard Mater. 2008 Jun 15;154(1-3):337-46
references.pmid: 18035483
references.citation: J Hazard Mater. 2009 Oct 30;170(2-3):744-53
references.pmid: 19539425
references.citation: Chemosphere. 2005 Apr;59(5):743-52
references.pmid: 15792672
references.citation: J Colloid Interface Sci. 2011 Aug 1;360(1):86-92
references.pmid: 21549384
references.citation: J Colloid Interface Sci. 1998 Dec 15;208(2):379-387
references.pmid: 9845681
references.citation: Mar Pollut Bull. 2002 Jun;44(6):480-6
references.pmid: 12146831
references.citation: Bioresour Technol. 2008 May;99(8):2766-77
references.pmid: 17698354
references.citation: J Colloid Interface Sci. 2003 Aug 15;264(2):307-12
references.pmid: 16256645
references.citation: Int J Mol Sci. 2012 Oct 23;13(10):13726-36
references.pmid: 23202977
references.citation: J Hazard Mater. 2011 Feb 28;186(2-3):1696-703
references.pmid: 21216532
references.citation: Environ Toxicol Chem. 2009 Mar;28(3):503-8
references.pmid: 18937536
references.citation: J Hazard Mater. 2010 Sep 15;181(1-3):1059-65
references.pmid: 20579808
references.citation: Spectrochim Acta A Mol Biomol Spectrosc. 2006 Jan;63(1):207-12
references.pmid: 15978870
references.citation: J Colloid Interface Sci. 2003 Apr 15;260(2):273-9
references.pmid: 12686175
references.citation: Environ Toxicol Chem. 2002 Jul;21(7):1390-7
references.pmid: 12109738
references.citation: Environ Pollut. 2003;123(2):217-27
references.pmid: 12628201
references.citation: Langmuir. 2011 Oct 4;27(19):11990-8
references.pmid: 21861473
references.citation: Environ Sci Technol. 2004 Dec 15;38(24):6694-700
references.pmid: 15669329
references.citation: J Hazard Mater. 2006 May 20;133(1-3):304-8
references.pmid: 16297540
references.citation: Environ Pollut. 2010 Dec;158(12):3642-9
references.pmid: 20828900
references.citation: Environ Int. 2008 Feb;34(2):292-308
references.pmid: 17959247
references.citation: J Hazard Mater. 2010 Jun 15;178(1-3):680-5
references.pmid: 20185235