title: Copper removal using bio-inspired polydopamine coated natural zeolites.
abstract: Herein, for the first time, natural clinoptilolite-rich zeolite powders modified with a bio-inspired adhesive, polydopamine (PDA), have been systematically studied as an adsorbent for copper cations (Cu(II)) from aqueous solution. Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) revealed successful grafting of PDA onto the zeolite surface. The effects of pH (2-5.5), PDA treatment time (3-24h), contact time (0 to 24h) and initial Cu(II) ion concentrations (1 to 500mgdm(-3)) on the adsorption of Cu(II) ions were studied using atomic absorption spectroscopy (AAS) and neutron activation analysis (NAA). The adsorption behavior was fitted to a Langmuir isotherm and shown to follow a pseudo-second-order reaction model. The maximum adsorption capacities of Cu(II) were shown to be 14.93mgg(-1) for pristine natural zeolite and 28.58mgg(-1) for PDA treated zeolite powders. This impressive 91.4% increase in Cu(II) ion adsorption capacity is attributed to the chelating ability of the PDA on the zeolite surface. Furthermore studies of recyclability using NAA showed that over 50% of the adsorbed copper could be removed in mild concentrations (0.01M or 0.1M) of either acid or base.
authors.affiliation: Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA, Australia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA, Australia.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Shapter
authors.affiliation: School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA, Australia.
authors.forename: Rachel
authors.initials: R
authors.lastname: Popelka-Filcoff
authors.affiliation: Centre for Nuclear Applications, Australian Nuclear Science and Technology Organisation, Lucas Heights 2234, NSW, Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Bennett
authors.affiliation: Flinders Centre for Nanoscale Science & Technology, School of Chemical and Physical Sciences, Flinders University, Sturt Road, Bedford Park, Adelaide 5042, SA, Australia. Electronic address: Amanda.Ellis@flinders.edu.au.
authors.forename: Amanda V
authors.initials: AV
authors.lastname: Ellis
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013499:Surface Properties; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D007211:Indoles; D011108:Polymers; D014874:Water Pollutants, Chemical; C568283:polydopamine; D017641:Zeolites; D003300:Copper
keywords: Copper adsorption; Natural zeolites; Neutron activation analysis; Polydopamine