Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Master Thesis An Investigation of Dye-Surfactant Intetactions in Aqueous Solutions for Elucidating the Mechanisms of Ultrafiltration(Izmir Institute of Technology, 2014) Olcay, Aybike Nil; Polat, Hürriyet; Polat, Mehmet; Polat, Mehmet; Polat, Hürriyet; 04.01. Department of Chemistry; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyLow Molecular Weight Contaminants (LMWCs) in waters are serious environmental concern due to removal problems with classical techniques such as chemical coagulation, biological treatments and adsorption. LMWCs are usually copresent with surface active agents in contaminated waters. Though such advanced removal techniques as ultrafiltration and micelle enhanced ultrafiltration are said to perform better, no systematic study is present for elucidating how the contaminantsurfactants interactions affect removal efficiency. In this study, methylene blue (MB), a dye widely employed in textile, paper and chemical industries, was chosen as the model contaminant. Surfactants selected were anionic sodium dodecyl sulfate (SDS), cationic hexadecyltrimethyl ammonium bromide (CTAB) and non-ionic ethoxylated octylphenol (TX-100). Surface tension, size, charge and contact angle measurements were conducted to investigate dye-surfactant interactions. Cellulose nitrate filters were employed to determine the effect of these interactions in filtration efficiency. It was found that significant amount of MB was removed from solution since it attached on the negatively charged cellulose nitrate filter. Though presence of surfactants generally decreased MB removal efficiency, MB-SDS interaction created large-loose aggregates at low SDS concentrations which cannot pass the filter paper. The MB-CTAB/TX-100 interactions created positively charged MB-surfactant pairs which can attach to the filter surface causing a decrease in the removal. At concentrations above Critical Micelle Concentration (CMC), the efficiency of MB removal is low due to the formation of surfactant-micelles that are smaller than the pores of the filter. Detailed size distribution experiments suggest that MB molecules are within the micelles structure, not in the core as believed in literature and do not increase the size of the micelle.Master Thesis Removal of Phenol From Industrial Wastewaters Using Lignitic Coals(Izmir Institute of Technology, 2004) Molva, Murat; Polat, Hürriyet; Polat, Hürriyet; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyPhenol adsorption capacity of lignitic coals which were obtained from Soma and Yataan / Turkey was investigated under different operational conditions such as solid-liquid ratio (S/L), reaction time, initial phenol concentration and temperature. Based on batch adsorption studies, it was observed that the phenol was completely adsorbed by coal depending on time of adsorption and the S/L ratio. From these results, the maximum adsorption values on the time axis at various S/L ratios were used and the fractions of phenol receptive adsorption sites on coal surfaces were calculated as 60 % and 43 % for Soma and Yataan coals, respectively. Freundlich adsorption isotherm was found to describe the adsorption of phenol on lignitic coals well. The Langmuir model did not describe the system as good as Freundlich model most probably due to the monolayer coverage assumption on this model. Activation energy and the maximum heat of adsorption calculated using adsorption data at different temperatures by the Arrhenious and Van.t Hoff equations were 10.3 and -20.2 kJ/mol, respectively. The low energies suggest that the adsorption of phenol on these lignitic coals were through physical interactions. An adsorption mechanism of phenol on lignite was discussed based on these findings. Residual water quality following adsorption in terms of major elements and heavy metals was within acceptable limits defined for wastewaters. The amount of organic matters dissolved from coals were also negligable. The presence of heavy metals as Cu, Zn etc. in water as a contaminant was also found to affect the removal of phenol by about 10-20 %.Master Thesis Removal of Heavy Metals From Wastewaters by Ion Flotation(Izmir Institute of Technology, 2005) Erdoğan, Demet; Polat, Hürriyet; Polat, Hürriyet; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, ion flotation experiments were performed to investigate the removal of heavy metals (copper, zinc, silver and chromium) from wastewaters.Various parameters such as pH, surfactant and frother concentrations and airflow rate values were tested to determine the optimum flotation conditions. Sodium dodecyl sulfate and Hexadecyltrimethyl ammonium bromide were used as collectors. Ethanol /MIBC were used as frothers.For 10 mg/L initial concentrations of copper, zinc, silver and chromium (III), the highest recoveries obtained were 90%, 71%, 73% and 97%, respectively. When the initial concentration of metals increased the recovery decreased. This proves the attachment of metal ions on surfactant molecules.The presence of Na+, Mg2+, Ca2+ ions in solution reduced the recoveries in case of all the metals since the presence of excess Na, Mg, Ca ions compete with metals and the metal ions can not find enough surfactant molecules to attach to.Selective flotation experiments were conducted in the presence of metal ion mixture solutions. It was possible to separate copper and chromium from zinc and silver, and also possible to separate chromium from zinc and copper and zinc from copper and chromium under suitable conditions.The classical first order equation fitted the results on flotation. Zinc and chromium floated not only more in an amount but also floated faster than copper.Surface tension measurements were conducted to investigate both the collector surfactants and the frothers at air/water interface since air bubbles carry the surfactant-metal ion complexes to the froth and separate from solution.Master Thesis Removal of Boron From Waters Using Fly Ash(Izmir Institute of Technology, 2005) Sütçü, Leman; Polat, Hürriyet; Polat, Hürriyet; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, various operational parameters were tested in order to determine the feasibility of using fly ash to remove boron from aqueous solutions. Studied parameters include time of reaction, material type, solid-liquid ratio, temperature and boron concentration. Preliminary studies revealed that the ability of Yeniköy fly ash to remove boron is similar to that achieved by amberlite under certain conditions. Therefore, Yeniköy ash was selected for sorption studies which aimed at elucidating some of the thermodynamic and kinetic profiles of the sorption process. Experiments were performed using the batch technique at six different initial boron concentrations (10, 30, 50, 100, 250, 500 mg/L), three different temperatures (298, 308, 318 K) and time period ranging from 2 minutes up to 48 hours. The experimental results revealed that the percentage sorption of boron on Yeniköy fly ash can reach up to 100% under appropriate conditions. Results showed that sorption of boron on Yeniköy fly ash followed pseudo-second-order kinetics. The activation energies Ea, were obtained as -90.3, -57.8 and -6.1 kJ/mole for the initial concentrations of 10, 30 and 50 mg/L, respectively. Negative .Ho values were obtained for lower initial concentrations of boron (10, 30, 50 mg/L) indicating that the processes are exothermic. On the contrary, at high concentrations, positive .Ho values were obtained for boron sorption on fly ash indicating that the uptake process becomes endothermic. The entropy change of the sorption process was found in the range of (-234)-(158) J/mole-K.