title: Combined cation-exchange and solid phase extraction for the selective separation and preconcentration of zinc, copper, cadmium, mercury and cobalt among others using azo-dye functionalized resin.
abstract: A facile synthesis of an ion exchange material (FSG-PAN) has been achieved by functionalizing silica gel with an azo-dye. Its composition and structure are well assessed by systematic analysis. Extractor possesses high BET surface area (617.794m(2)g(-1)), exchange capacity and break-through capacity (BTC) (Q0 Zn(II): 225; Cd(II): 918; Hg(II): 384, Cu(II): 269 and Co(II): 388μMg(-1)). The sorption process was endothermic (+ΔH), entropy-gaining (+ΔS) and spontaneous (-ΔG) in nature. Preconcentration factor has been optimized at 172(Zn(II)); 157.2(Cd(II)); 193.6(Hg(II)); 176(Cu(II)); 172.4(Co(II)). Density functional theory calculation has been performed to analyze the sorption pathway. BTC (μMg(-1)) of FSG-PAN was found to be the product of its frontier orbitals and state of sorbed metal ion species, x (at x=1, mononuclear and x>1, a polynuclear species; i.e., BTC=[amount of HOMO]×x). FSG-PAN is used for the selective separation and preconcentration of Zn(II), Cd(II), Hg(II), Cu(II),Co(II) from large volume sample (800mL) of low concentration (0.017-0.40mML(-1)) in presence of foreign ions (50-300mML(-1)) at optimum conditions (pH: 7.0±1.5, flow rate: 2.5mLmin(-1), temperature: 27°C, equilibration-time: 5min). The method was found to be effective for real samples also.
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, India.
authors.forename: Mousumi
authors.initials: M
authors.lastname: Chatterjee
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, India.
authors.forename: Bhavya
authors.initials: B
authors.lastname: Srivastava
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, India.
authors.forename: Milan K
authors.initials: MK
authors.lastname: Barman
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, India. Electronic address: bhabatosh_mandal@yahoo.co.in.
authors.forename: Bhabatosh
authors.initials: B
authors.lastname: Mandal
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002411:Cation Exchange Resins / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D007474:Ion Exchange; D019216:Metals, Heavy / Q000737:chemistry / Q000302:isolation & purification*; D052616:Solid Phase Extraction
chemical_list: D001391:Azo Compounds; D002411:Cation Exchange Resins; D019216:Metals, Heavy
keywords: BTC is function of both frontier orbital and state of metal ion species; Composition and structure of FSG–PAN; Facile synthesis; Metal sorption escorted by ligand electron density; Optimization of preconcentration factor; Selective separation of congeners