Chemistry / Kimya

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

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  • Article
    Citation - WoS: 21
    Citation - Scopus: 23
    Adsorption of Methylene Blue From Aqueous Solution on High Lime Fly Ash: Kinetic, Equilibrium, and Thermodynamic Studies
    (Taylor and Francis Ltd., 2012) Keleşoğlu, Serkan; Kes, Mürşide; Sütçü, Leman; Polat, Hürriyet
    Kinetic, equilibrium, and thermodynamic studies were performed for the batch adsorption of methylene blue (MB) on the high lime fly ash as a low cost adsorbent material. The studied operating variables were adsorbent amount, contact time, dye concentration, and temperature. The kinetic data were analyzed using the pseudo-first order and pseudo-second order kinetic models and the adsorption kinetic was followed well by the pseudo-second order kinetic model. The equilibrium data were fitted with the Freundlich, Langmuir, and Dubinin Radushkevich (D-R) isotherms and the equilibrium data were found to be well represented by the Freundlich and D-R isotherms. Based on these two isotherms MB is taken by chemical ion exchange and active sites on the high lime fly ash have different affinities to MB molecules. Various thermodynamic parameters such as enthalpy of adsorption (ΔH°), free energy change (ΔG°), and entropy change (ΔS°) were investigated. The positive value of ΔH° and negative value of ΔG° indicate that the adsorption is endothermic and spontaneous. The positive value of ΔS° shows the increased randomness at the solid-liquid interface during the adsorption. A single-stage batch adsorber was also designed based on the Freundlich isotherm for the removal of MB by the high lime fly ash. © 2012 Copyright Taylor and Francis Group, LLC.
  • Article
    Citation - WoS: 45
    Citation - Scopus: 55
    Incorporation of Iron Nanoparticles Into Clinoptilolite and Its Application for the Removal of Cationic and Anionic Dyes
    (Korean Society of Industrial Engineering Chemistry, 2015) Nairat, Muath; Shahwan, Talal; Eroğlu, Ahmet Emin; Fuchs, Harald
    This study reports the preparation of composite sorbents of iron nanoparticles (nZVI) and clinoptilolite at various iron/clinoptilolite ratios. The composites were characterized using various characterization techniques. The material was used for the removal of methylene blue (MB) and methyl orange (MO) as model cationic and anionic dyes. The experiments investigated the effects of time, loading, initial pH, reusability, and temperature on the removal process. According to the results, Cl-nZVI showed fast and quantitative removal over a wide range of concentrations. The removal process was endothermic in nature, and the composite demonstrated reusability for several trials.
  • Article
    Citation - WoS: 654
    Citation - Scopus: 786
    Green Synthesis of Iron Nanoparticles and Their Application as a Fenton-Like Catalyst for the Degradation of Aqueous Cationic and Anionic Dyes
    (Elsevier Ltd., 2011) Shahwan, Talal; Abu-Sirriah, Sadieh; Nairat, Muath; Boyacı, Ezel; Eroğlu, Ahmet Emin; Scott, Thomas B.; Hallam, Keith R.
    Iron nanoparticles were produced using extracts of green tea leaves (GT-Fe NPs). The materials were characterized using TEM, SEM/EDX, XPS, XRD, and FTIR techniques and were shown to contain mainly iron oxide and iron oxohydroxide. The obtained nanoparticles were then utilized as a Fenton-like catalyst for decolorization of aqueous solutions containing methylene blue (MB) and methyl orange (MO) dyes. The related experiments investigated the removal kinetics and the effect of concentration for both MB and MO. The concentrations of dyes in aqueous solution were monitored using ultraviolet–visible (UV–vis) spectroscopy. The results indicated fast removal of the dyes with the kinetic data of MB following a second order removal rate, while those of MO were closer to a first order removal rate. The loading experiments indicated almost complete removal of both dyes from water over a wide range of concentration, 10–200 mg L−1. Compared with iron nanoparticles produced by borohydride reduction, GT-Fe nanoparticles demonstrated more effective capability as a Fenton-like catalyst, both in terms of kinetics and percentage removal.