Browsing by Subject "Adsorption experiment"

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    Removal of nickel(II) ions by histidine modified chitosan beads
    (2012) Eser A.; Nüket Tirtom V.; Aydemir T.; Becerik S.; Dinçer A.
    In order to increase the nickel adsorption capacity of raw chitosan beads (CB), they were chemically modified with histidine (HIS-ECH-CB) by using crosslinking agent, epichlorohydrine (ECH). The nature and morphology of the sorbent were characterized using FTIR, TGA and SEM analysis. For optimization of adsorption conditions, sorption experiments were performed by varying contact time, pH, temperature and initial nickel concentration. Based on the adsorption experiment, the HIS-ECH-CB showed the significant adsorption capacity of 55.6mg/g under the optimal adsorption condition. Nickel adsorption isotherms data were fitted to Freundlich isotherm. Thermodynamic parameters namely ΔG°, ΔH° and ΔS° of the Ni(II) adsorption process were calculated. The negative values of Gibbs free energy of adsorption (ΔG°) indicated the spontaneity of the adsorption of Ni(II) ions on the histidine modified chitosan. Desorption of Ni(II) ions from HIS-ECH-CB could be done rapidly by using 0.1M HCl, HNO 3 and EDTA solutions and the beads could be used again to adsorb Ni(II) ions. © 2012 Elsevier B.V..
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    Determination of adsorption capacities of NaX Nano-particles against heavy metals and dyestuff; [NaX Nano-taneciklerin ağır metal ve boyar maddelere karşı adsorpsiyon kapasitelerinin belirlenmesi]
    (Gazi Universitesi Muhendislik-Mimarlik, 2019) Yürekli Y.
    Adsorption is an effective method for the removing of heavy metals in the industrial waste water. Improvement of the efficiencies of the adsorbents can be possible by reduction of the particle size into nano scale. Therefore, in this study, zeolite nano-particles were synthesized by classical and microwave heating methods and then determined their adsorption capacities for the lead and nickel cations during batch adsorption processes carried out at 25C with different adsorbent loading and initial metal concentrations. Results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis revealed that the synthesized zeolite nanoparticles was pure NaX with ultrafine and uniform particle sizes around 170 nm and Si/Al ratio of 1.24. Batch adsorption studies at 25C revealed that, NaX nanoparticles have high affinities against lead, nickel and methylene blue dye. As the initial metal and dye concentrations were increased, sorption capacity of the NaX was increased and reached the maximum value of 0.99, 1.33, 2.11, 1.89 and 0.15 mmol /g for the lead, nickel, copper, silver and methylene blue cations respectively. Sips model equation successfully described the equilibrium adsorption data of all adsorbates. Adsorption experiments of NaX for heavy metals from a real wastewater indicates that although the solution contains calcium and potassium ions in huge concentrations, the adsorbent is capable to adsorb lead and nickel even if they are low in concentrations. © 2019 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.
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    Determination of adsorption characteristics of synthetic NaX nanoparticles
    (Elsevier B.V., 2019) Yurekli Y.
    Zeolite nanoparticles were synthesized by means of a hydrothermal method and the sorption performances were tested in batch experiments using single and binary components of Pb2+, Ni2+ and Cu2+ synthetic solutions. Fast adsorption was observed and the majority of sorption occurred within the first 5 min for each case of metal cations. Percentage metal removal increased with the adsorbent dosage and it was adversely affected by the initial metal concentrations. XRD, FTIR-ATR and XPS analyses revealed that the removal of metal ions occurred mainly on the basis of ion-exchange. Equilibrium sorption data were best described by Sips isotherm model and the maximum attainable metal amount on the NaX were estimated as 1.23, 1.76 and 2.20 mmol/g for the Pb2+, Ni2+, and Cu2+ cations, respectively. A single step desorption process conducted in NaCl solution seemed to be practically applicable for regeneration and after three adsorption/desorption cycles, 79, 76 and 48% of initial sorption capacity of NaX were preserved for lead, nickel and copper ions, respectively. Single isotherm parameters used for the prediction of binary equilibrium data were satisfactory. Binary sorption experiments for Pb2+-Ni2+, Pb2+-Cu2+ and Ni2+-Cu2+ couples reflected that the presence of secondary ions decreased the uptake of the primary one. Lead exhibited greater inhibition of the sorption of nickel and copper, demonstrating the stronger affinity of NaX for Pb2+. Extended Freundlich model best described all the three binary metal systems. Adsorption experiments carried out in real wastewater demonstrated that NaX nanoparticle has a high affinity for all the cations except copper. © 2019 Elsevier B.V.