Chemistry / Kimya

Permanent URI for this collectionhttps://hdl.handle.net/11147/4072

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Author: search.filters.author.Shahwan, TalalInstitution Author: search.filters.institutionAuthor.Yılmaz, Sinan

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  • Article
    Citation - WoS: 120
    Citation - Scopus: 127
    Equilibrium, Thermodynamic and Kinetic Studies for the Biosorption of Aqueous Lead(ii), Cadmium(ii) and Nickel(ii) Ions on Spirulina Platensis
    (Elsevier Ltd., 2008) Şeker, Ayşegül; Shahwan, Talal; Eroğlu, Ahmet Emin; Yılmaz, Sinan; Demirel, Zeliha; Conk Dalay, Meltem
    The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as ΔG°, ΔH°and ΔS° calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb2+ ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 18
    Effect of Magnesium Carbonate on the Uptake of Aqueous Zinc and Lead Ions by Natural Kaolinite and Clinoptilolite
    (Elsevier Ltd., 2005) Shahwan, Talal; Zünbül, Banu; Eroğlu, Ahmet Emin; Yılmaz, Sinan
    Adsorption behavior of Zn2+ and Pb2+ ions on kaolinite and clinoptilolite, originating from natural resources, was studied as a function of contact time and concentration. Zn2+ and Pb2+ ions are quickly adsorbed on both minerals and the uptake of the latter is more favored. The uptake of both ions was then examined on kaolinite–MgCO3 and clinoptilolite–MgCO3 mixtures over a metal ions range from 1 to 10 000 mg/L. The sorption behavior of Zn2+ and Pb2+ on pure MgCO3 was also studied. MgCO3 is much more effective in the retention of Zn2+ and Pb2+ ions, in particular at higher concentrations. The large increase in the retarded amounts of both ions was associated with formation of the hydroxy-carbonate phases; namely hydrozincite for Zn2+, and cerussite and hydrocerussite in the case of Pb2+.