Master Degree / Yüksek Lisans Tezleri
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Master Thesis Preparation of Natural Zeolite Supported Tio2 Composites for Removal of Terephthalic Acid(Izmir Institute of Technology, 2014) Deliismail, Özgün; Deliismail, Özgün; Özkan, Seher Fehime; Çakicioğlu Özkan, Seher Fehime; Helvacı, Şerife Şeref; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study focuses on the preparation of natural zeolite supported TiO2 composites for the removal of model pollutant, terepththalic acid (TPA) via sorption. Natural zeolite was purified and used to prepare natural zeolite supported TiO2 adsorbents. Prior to sorption, the adsorbents were characterized by Scanning Electron Microscopy, Volumetric Adsorption Instrument, X-ray Diffractometer, Fourier Transformer Infrared, Induced Coupled Plasma Atomic Emmision Spectroscopy, and Thermal Gravimetric Analyzer. It was deduced that natural zeolite was clinoptilolite rich low (Ca) silicate. The sorption studies of TPA on adsorbents were applied in dark conditions at room temperature by altering adsorbent amount (0.2-1.5 g/l) and initial TPA concentration (20-60 ppm). It was observed that the amount of adsorbed TPA per unit mass of adsorbent decreased with increasing adsorbent amount, and sorption percent was unchanged (about 72%). This can be explained by the affinity of adsorbents to water molecules more than TPA molecules. Much more number of TPA molecules was allocated on the clinoptilolite than TiO2 composites. Sorption mechanism was identified by fitting the kinetic data to diffusion (Weber-Morris model, intraparticle/external diffusion) and reaction models (First order and pseudo second order model). First order reaction model was well correlated to experimental data for sorption process. Comparing pore size of the adsorbents to molecular size of TPA indicates that main contribution to intraparticle diffusion was the intercrystalline diffusion. Intraparticle diffusion was not the sole rate-limiting step due to the existence of external resistance. Biot and Weber-Morris calculations corroborated these results. In the future, photocatalytic performance of these adsorbents will also be tested.Master Thesis Ion exchange in natural zeolite packed column(Izmir Institute of Technology, 2004) Can, Özge; Ülkü, Semra; Can, Özge; Ülkü, Semra; 03.01. Department of Bioengineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyTurkish natural clinoptilolites were examined to evaluate their ion exchange performance for the removal of copper, nickel and cobalt ions by performing both batch and packed column experiments.Initial metal solutions were prepared using metal nitrate solutions at various concentrations.All of the experiments were carried out at 29oC.Before performing the ion exchange experiments zeolites were characterized and their clinoptilolite contents were determined quantitatively as 80 and 64 % for zeolites named as CP1 and CP2, respectively.The copper exchange capacities of CP1 and CP2 were determined from equilibrium studies as 10.01 mg (0.32 meq) Cu2+ / g CP1 and 8.33 mg (0.262 meq) Cu2+ / g CP2. Ion exchange capacity of CP2 zeolite was determined as 6.64 mg (0.226 meq) Ni2+ / g and 4.55 mg (0.154 meq) Co2+ / g.The equilibrium behaviour of the system was best described by Langmuir model.Experiments were designed to investigate the optimum parameters and significance of the interactions between these parameters.In column studies, the parameters such as packing height, inlet metal concentration and flow rate were investigated.The concentration of the metals in the sample solutions which were taken from the exit of the ion exchange column at specific time intervals were analyzed by using Optical Emission Spectrometry (ICP-OES).Afterwards, by making use of the data obtained from ICP-OES, breakthrough curves were constructed.By the help of these curves, breakthrough capacity and ion exchange capacity of natural zeolites were calculated.The ion exchange capacity of CP2 zeolite was calculated as 8.04 mg Cu2+/g CP2, which was consistent with the capacity calculated from batch experiments, 8.33 mg Cu2+/g CP2.Also, breakthrough points were determined. Furthermore, solid phase was also analysed for determining its crystal structure and chemical composition using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) devices (Philips XL 30S FEG).In addition to these, natural zeolite particles which have been ion exchanged throughout this process were regenerated using 0.2M and 1.7M of NaCl solutions.According to regeneration studies, it was determined that 94 and 95% of copper were recovered within the first 100 minutes for both experiments.After the experiments were performed, model equations were applied to the system in order to be able to investigate the dynamic behavior of the system.As a result of this simulation, breakthrough was well predicted.Master Thesis Synergistic Effect of Zinc Stearate and Natural Zeolite on Pvc Thermal Stability(Izmir Institute of Technology, 2004) Atakul, Sevdiye; Balköse, Devrim; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAt high temperatures (about 100 °C), PVC decomposes by the removal of hydrogen chloride (HCl) gas and the decomposition is accompanied by polymer discoloration going from yellow to orange, brown and black. In order to prevent decomposition of PVC, thermal stabilizers are added to PVC. The synergistic effect of zinc stearate (ZnSt2) and/or natural zeolite (clinoptilolite) on PVC thermal stability was investigated in this project. For this purpose PVC plastisol was prepared by mixing poly(vinyl chloride) (PVC) and dioctyphthalate (DOP) and stabilized with different amounts of metal soaps and zeolite.The materials and the prepared PVC plastisols were characterized by spectroscopic and thermal analysis techniques. The gelation of the plastisols was observed by optical microscopy and the photographs were taken by a digital camera. The complete gelation was observed at 185 °C. The morphology of PVC plastigel films were studied by scanning electron microscope (SEM). SEM with energy dispersive X-ray (EDX) analysis was used to obtain elemental compositions in polymer and particle phases. The thermal stability of PVC plastigels in terms of color were obtained by heating them in a static vaccum oven. When zeolite was used as a primary stabilizer it prevented the early blackening of the film. Kinetic study of dehydrochlorination was determined by 763 PVC Thermomat equipment for unstabilized and stabilized PVC plastigels. When PVC plastigels were heated in PVC Thermomat in the presence of nitrogen gas, the conductivity of water which nitrogen gas was passed due to the evolved HCl, changed with respect to time. The period when conductivity starts to increase is called as induction time, and the period when the conductivity value reaches to 50 uS/cm is called as stability time. The induction and stability time values of unstabilized and stabilized PVC plastigel films were obtained at 140 and 160 °C. The stabilizing effect of zeolite on the increase in the induction period of the sample was considered the result from the absorption of HCl which was thought to reduce the autocatalytic effect of HCl evolved at the initial stages of dehydrochlorination. Since the induction time of the sample having 0.53% ZnSt2 and 0.53% zeolite was higher than the PVC plastigels having only ZnSt2 or zeolite the synergistic effect on thermal stability was observed at low levels of them.Master Thesis Investigation of Fuel Oxygenate Adsorption on Clinoptilolite Rich Natural Zeolite(Izmir Institute of Technology, 2006) Yetgin, Senem; İnal, Fikret; İnal, Fikret; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe wide use of fuel oxygenates in gasoline as anti-knocking and emission reduction agent have recently led to serious environmental concerns due to their detection in groundwater and surface water. Among the various gasoline additives, methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE) are the most frequently used fuel oxygenates worldwide. Due to the physical and chemical properties of fuel oxygenates, the conventional treatment technologies are generally ineffective for their removal from contaminated water. Adsorption is a common process frequently used to remove fuel oxygenates from water. The use of natural zeolites as adsorbent have increased significantly because of their availability and low cost. Clinoptilolite is one of the most abundant zeolites in nature, and Turkey has very large clinoptilolite reserves. In this project the adsorption properties of clinoptilolite rich natural zeolites for use in the removal of MTBE and ETBE from water have been investigated using batch equilibrium and fixed-bed column experiments. The adsorption properties have been compared with those of two activated carbons (i.e., Powdered Activated Carbon (PAC) and Granulated Activated Carbon (GAC)). In addition, bisolute (i.e., benzene and oxygenate) adsorption experiments were also carried out to determine the effectiveness of these adsorbents in the presence of other gasoline hydrocarbons. All the experiments were performed at 25 °C with initial oxygenate and benzene concentrations of 2000 ppb and 400 ppb, respectively. In batch equilibrium experiments, it has been found that the powdered and granulated activated carbons had higher adsorption capacities for MTBE and ETBE than clinoptilolite. The highest capacity for the amount of MTBE adsorbed per unit mass of adsorbent was achieved using GAC while that of ETBE was obtained using PAC. The presence of benzene decreased the adsorption capacities of GAC and PAC. However, the effect of benzene was not clear and was dependent on the adsorbent loading for clinoptilolite. In fixed-bed column experiments, GAC and clinoptilolite were tested as adsorbents. The column breakthrough curves for clinoptilolite were steep indicating fast adsorption and narrow mass transfer region. For GAC, mass transfer regions were wider due to the relatively flat breakthrough curves. There was no significant effect of benzene on the breakthrough curves for GAC and clinoptilolite.Master Thesis Preparation and Characterization of Polypropylene Based Composite Films(Izmir Institute of Technology, 2001) Pehlivan, Hilal; Tıhmınlıoğlu, Funda; Tıhmınlıoğlu, Funda; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn the scope of this study, preparation of silver . natural zeolite reinforced polypropylene (PP) composite system possessing antibacterial properties via ion exchange process and characterization by means of different techniques (FTIR, TGA, DSC, mechanical tests, optical microscopy) were aimed. It has been established that zeolites are suitable for removing Ag ions from silver containing solutions and that silver zeolites are increasingly investigated as germicidal, bactericidal, antifungal, and antiseptic components in different compositions (Hagiwara 1990, Kawahara 2000, Klasen 2000).In the present study, prior to the ion exchange studies, water sorption behavior of PP . clinoptilolite rich natural zeolite composites was investigated, since the ion exchange process was to be conducted in aqueous media. It was observed that a hydrophobic polymer, PP attained the property of water sorption due to the porous structure of the composite films. The effective diffusivity of liquid water in the PP-zeolite composites prepared by hot press and extrusion techniques varied in the range of 0.3- 9.9 x10-10 and 0.1 - 3.3 x10-12 cm2/s, respectively. Silver loading to PP - zeolite composites was provided by means of two different methods. In Method I, PP - zeolite composite films were treated with a variety of silver ion containing solutions (5 to 50 ppm AgNO3 solution), whereas in Method II silver exchanged zeolite minerals (prepared with initial AgNO3 concentrations of 50, 500, and 5000 ppm) were molded with PP in the presence of DOP (Dioctyl Phthalate). The amounts of Ag+ loaded per gram of zeolite for initial AgNO3 concentrations of 50, 500, and 5000 ppm were determined as 4.36, 27.85, and 183.78 mg, respectively. Antibacterial activity tests against E.coli indicated that the samples obtained in Method II were superior to those prepared by Method I since the penetration of silver ions to the zeolite phase was limited by the PP phase in the case of Method I. However, the discoloring effect of silver ion was readily observed for the samples prepared by Method II as indicated by the discoloration parameters. The release of Ag+ to water was found to be negligible as reported in literature leading to long . term antibacterial activity.The thermal characterization studies showed that the addition of the zeolite increased the crystallinity of the structure acting as a nucleating agent in PP crystallization as well as retarded the degradation temperature of PP. At low silver concentrations, the zeolite behaved as a decelerating agent in PP, however at higher silver concentrations, the composites degraded at a faster rate than pure PP. Yet the activation energy values for the thermal decomposition reactions of Method II was considerably lower indicating that the decomposition has been accelerated by the presence of silver.It was found that the addition of the zeolite into the PP matrix decreased the density of pure PP (0.89 g/cm3) due to the formation of voids. However, a systematic approach was not observed with the increasing zeolite content as a consequence of the uneven zeolite distribution. On the other hand, a considerable enhancement was noticed for the tensile tested film densities changing between 0.58 - 0.78 g/cm3, which are in a better agreement with the commercially desired range (0.6 - 0.65 g/cm3) for packaging applications of PP composites. Mechanical tests indicated that the addition of the zeolite tended to decrease the yield stress values while a slight decrease was observed for Young moduli. The effect of silver on the Young Modulus values of the composites is not quite significant, however the yield stress values increased from 23.6 to 29.5 MPa with the increasing silver concentration.Consequently, of all the composite films prepared by Method II, the ones loaded with 4.36 (mg Ag+/g zeolite) containing 2, and 4 % wt zeolite were selected to be the most appropriate, considering the thermal, mechanical, and structural characteristics as well as the discoloring actions.Master Thesis Co2, N2 and Ar Adsorption on Modified Zeolites(Izmir Institute of Technology, 2004) Ertan, Aslı; Özkan, Seher Fehime; Özkan, Seher Fehime; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, CO2 and N2 adsorption on synthetic zeolites namely, 5A and 13X, and acid treated natural zeolites was investigated by using volumetric adsorption device, ASAP 2010. The natural zeolites and its acid treated forms with HCl (1M, 3M and 5M), HNO3 (2 M), and H3PO4 (1.1 M) solutions at 60 oC for 6 or 3 hours were used as adsorbent. The effect of the acid treatment and temperature on the adsorption properties of the zeolites for the CO2 and N2 gases at 5 and 25 oC was studied. Langmuir, Sips, Vrial and Dubinin-Astakhov model equations were applied to the adsorption data in order to determine the affinity and the heterogeneity of the adsorbents.Calorimetric properties of the zeolites were also studied using CO2, N2 and Ar gases through a Tian-Calvet calorimeter, Setaram C80 at 25 oC. Isosteric heat of adsorption of the gases adsorbed on the adsorbents under investigation was determined at 5 oC and 25 oC using Clasius- Clapeyron equation. These results were compared with the heat of adsorptions obtained from the calorimetric studies directly.The zeolite treated with 1.1 M H3PO4, P1 has the highest adsorption capacity (2.24 mmol/g and 0.67 mmol/g) for CO2 and N2 while the natural zeolite has only 2.08 mmol/g and 0.51 mmol/g respectively at 5 oC. Synthetic zeolites 13X and 5A have higher CO2 (6.82 mmol/g and 5.46 mmol/g respectively) and N2 adsorption capacities (0.31mmol/g and 0.91 mmol/g respectively) than natural zeolites at 5 oC. Langmuir b parameter called the affinity constant decreased as adsorption temperature increased for CO2 and N2 adsorption. The Sips model t parameter characterizing the system heterogeneity is higher for CO2 adsorption than N2 adsorption and decreases with increasing temperature. This indicates that the CO2 molecules give more specific interactions than N2 molecules. The pure component selectivities of CO2 over N2 calculated from Langmuir equation, are the highest for NCW zeolite as 408 at 25 oC. This value follows by P1 zeolite which is 151 at the same temperature.The highest differential heat of adsorption value (80.29 kJ/mol) at zero coverage for CO2 also belongs to P1 sample. The heterogeneity parameters of the model equations applied also indicated that P1 sample is more heterogeneous when compared to other acid treated natural zeolites. Finally as expected, for both N2 and CO2 as temperature increased from 5 to 25 oC, the adsorbed amounts decreased when fresh samples were used at each run in the experiments. The temperature difference had a greater effect on N2 adsorption rather than CO2.Master Thesis Effects of Metal Cation on the Skeletal Isomerization of N-Butene Over Zsm-5 and Ferrierite(Izmir Institute of Technology, 2005) Birsoy, Öniz; Yılmaz, Selahattin; Yılmaz, Selahattin; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe effects of metal cation on the skeletal isomerization of 1-butene to isobutene was investigated. H-ZSM-5 was sythesized with the initial SiO2/Al2O3 ratio of 30. MFI-50, MFI-90 and Ferrrierite zeolite catalysts were commercially supplied. The zeolites were ion exchanged with cobalt, nickel, zinc, cupper (magnesium and manganese only for synthesized ZSM-5) salts, impregnated with cobalt, in order to change their acidity.The H-ZSM-5 zeolite was additionally ion exchanged with cobalt using different metal loading amounts. Then, the catalysts were tested for their activity in a fixed bed tubular quartz reactor at 375°C at weight hourly space velocity (WHSV) of 22 h-1.Scanning Electron Microscopy images and X-Ray Powder Diffraction patterns of the zeolites showed that their crystallinity was not affected with ion exchange, even with the increase in the loading amount (2.68 w%). But with the impregnation method, the intensity of the characteristic peaks for zeolites were decreased. Impregnating the zeolite also resulted in a decrease in the surface area.The acidity measurements of the catalysts were made by IR spectroscopy with pyridine adsorption method. The tests showed that acidities of the catalysts were changed with ion exchange and impregnation of metal ions.The catalytic tests for H-ZSM-5 showed that different metal loadings with ion exchange lowered the yield for isobutene. H-ZSM-5 showed a conversion of 59 % and 33.2 % yield for isobutene. The lowest yield was obtained from magnesium and manganese with 12.2 % and 9.6 %, respectively. The H-ZSM-5 zeolite catalysts were also tested for Co ion exchanged with different amounts (2.68, 1.45, 0.63 and 0.23 w%).1.45 w% loaded catalyst showed the best activity for the reaction with a conversion of 59.1 %, and yield for isobutene 24.5 %. Both increased and decreased loading decreased yield 17.8 %, 2.5 % and 0.48 %, respectively. H-MFI-50 and its modified forms showed high conversions compared to H-ZSM-5. But low yields and selectivities were obtained. H-MFI-50 showed the highest conversion with 82.7 % and yield of 21.5 %. Co-MFI-50 showed similar conversion as the parent zeolite with 82.7 %, and yield of 17.9 %. The lowest conversion is obtained by Cu-MFI-50 with 76.5 % and yield for isobutene was 21 %. H-MFI-90 and its modified samples showed alike conversions around 76.1 %, but Cu loading decreased conversion as low as 65.9 %. Like MFI-50, the yield of isobutene was also affected by the metal ion exchanging. H-MFI-90 showed 24.8 % yield of isobutene. However, Co-MFI-90 had a yield of 27.6 %. The worst yield was obtained from cupper loaded catalyst with 20.4 %. As would be expected, changing the metal ion loaded to ferrierite also changed the activity of the catalyst. The highest conversion was obtained by H-FER with 57 % and a yield of 39 %. Co-FER and Ni-FER showed similar conversions 52 % and 53 %, respectively. Zn-FER and Cu-FER showed the lowest conversions with 47 % and 45 %, respectively. Yields for the metal loaded catalysts lowered to 27 %.Impregnation with Co, severely decreased the activity of the catalysts both compared to H form and ion exchanged form of the catalysts. Impregnated H-ZSM-5, H-MFI-50, H-MFI-90 and ferrierite showed conversions of 48.1 %, 66.8 %, 60.7 % and 45.4 %, respectively. The yields for isobutene were 11 %, 13.8 %, 15.5 % and 13.7 %, respectively.Master Thesis Investigation of Catalytic Activity and Selectivity of Pd and Ni Loaded Clinoptilolite Rich Natural Zeolite for Citral Hydrogenation(Izmir Institute of Technology, 2002) Uçar, Şule; Yılmaz, Selahattin; Yilmaz, Selahattin; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe preparation of active and selective clinoptilolite rich natural zeolite supported palladium and nickel catalysts for the liquid phase hydrogenation of citral was investigated. The catalysts were prepared by impregnation and ion exchange methods. Catalytic activity and selectivity tests were performed in a semi-batch reactor for different calcination temperatures, pressures, stirring rates, reaction temperatures, amount of catalysts, ethanol sources, catalyst metal loadings and catalysts preparation methods. Catalyst deactivation was also investigated. The characterization results showed that clinoptilolite was the major mineral in natural zeolite used as catalyst and catalyst support. It was thermally stable up to 440°C and its stability improved with Pd and Ni loading. Catalysts with loading of 0.72, 2.42, 5.63 % Pd and 3.12 % Ni were prepared by impregnation method. One catalyst was prepared by Pd ion exchange (5.66 %). Surface areas of the catalyst samples changed with calcination temperature, method of metal loading, amount of metal loading. A calcination temperature of 430°C and catalyst metal loading of 2.42 % Pd provided the largest surface area (38.96 m2/g) among the catalysts prepared by impregnation. The catalyst prepared by ion exchange had a much more larger surface area (49.46 m2/g) than those prepared by impregnation. The product distribution changed with catalysts prepared by different methods, catalyst metal loadings, catalyst calcination temperatures and reaction temperatures. The results showed that the Pd catalyst prepared by impregnation favoured the hydrogenation of the conjugated double bond of citral, giving citronellal as the primary hydrogenation products, whereas the amounts of unsaturated alcohols were very minor. High selectivity to citronellal was obtained for the catalyst calcined at 430°C containing 2.42 % Pd. The product distribution and the reaction rates were affected significantly by the reaction temperature (80, 100 and 120°C). The highest selectivity to citronellal (88 %) and the yield of citronellal (87 %) were obtained at 120°C. Higher reaction rates were observed as temperature increased. Increasing the amount of the catalyst in the reaction medium (150, 250 and 400 mg/100mL) affected the reaction rates, selectivity and the yield of citronellal. The highest amount of citronellal yield (91 %) was obtained when the reaction was carried out in the presence of the largest amount of the catalyst (400 mg/100 mL) used in this study. Different product distributions were obtained with various ethanol sources. Higher yields and selectivities were obtained with more pure solvent. Product distribution changed with catalyst metal loading. First increased significantly by changing catalyst loading from 0.72 to 2.42 % Pd and then rised slowly when metal loading changed from 2.42 to 5.63 % Pd. This was attributed to active metal surface area and its dispersion. Impregnated Pd catalysts regained their activities and selectivities upon regeneration. Ni impregnated catalyst showed a different product distribution. It showed a lower activity for a given temperature. Overall selectivities of the best Pd catalyst and Ni catalysts were similar. Pd catalyst prepared by ion exchange gave different products and its selectivity to citronellal was the lowest. This was attributed to the metal and catalyst surface interactions.Master Thesis The Production of Thymoquinone From Thymol and Carvacrol by Using Zeolite Catalysts(Izmir Institute of Technology, 2005) Güneş, Alev; Bayraktar, Oğuz; Bayraktar, Oğuz; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this thesis study, by using general flexible ligand method, Cr(III), Fe(III),Bi(III), Ni(II) and Zn(II) complexes of N,Nbis(salicylidene)propane-1,3-diamine (H2salpn) encapsulated in NaY-zeolite were prepared. All catalyst were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) analyses to confirm the complex encapsulation. Activities of all prepared catalysts for the decomposition of hydrogen peroxide and oxidation of carvacrol were tested. Leaching test or heterogeneity test was also performed. The performances of all catalysts were compared based on the leaching test results and carvacrol conversion. Thymohydroquinone and benzoquinones were observed as by-products at high conversions of carvacrol. No product was formed in the absence of a catalyst. Fe(salpn)-NaY catalyst has shown the highest carvacrol conversion of 27.6% with a yield of 22.0% which was followed by Cr(salpn)-NaY catalyst with 23.5% carvacrol conversion with a yield of 17.6%. Other catalysts have shown relatively lower performances in terms of carvacrol conversion and leaching. The Cr(salpn)-NaY catalyst was found to be a more efficient catalyst than others based on leaching and activity tests. Selected catalyst was extra characterized by Brunauer Emmett and Teller (BET) and Thermal gravimetric (TGA) analyses. With selected catalyst Cr (salpn)-NaY, temperature, catalyst amount, reactant carvacrol to hydrogen peroxide molar ratio effects were investigated in carvacrol oxidation reactions. Increasing the temperature from 40 to 60C caused the increment of thymoquinone yield from 6.2 to 16.0%. In addition to that the yield of thymoquinone was increased from 7.4 to 20.7% by increasing catalyst amount from 0.05 to 0.2 g. And also thymoquione yield was increased from 3.7 to 23.0% by decreasing carvacrol to hydrogen peroxide molar ratio from 1 to 3. Moreover, Cr (salpn)-Y catalyst was also tested in thymol and essential oil oxidation reactions.Master Thesis Treatment of Domestic Wastewater With Natural Zeolites(Izmir Institute of Technology, 2004) Cansever, Beyhan; Ülkü, Semra; Ülkü, Semra; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, the use of Gördes natural zeolite for removing NH4+ ion from wastewater effluent and from NH4Cl solution was investigated under various conditions. The effect of the solid:solution ratio, initial concentration of the solution, presence of competing cation, particle size of the clinoptilolite sample on ammonium ion removal capacity were studied. Highest amount of ammonium removal per gram zeolite was found in the solution having 1% solid: solution ratio. The experimental results indicate that the NH4+ exchange capacity is not dependent on the particle size of the clinoptilolite sample. Increasing the initial concentration increases the NH4+ uptake capacity. NH4+ removal decreases with increasing the initial ammonium concentration. For instance, the higher NH4+ ion concentrations show the 30.5-55 % removal and lower NH4+ ion concentrations lead to 87-95 % removal for pure ammonium chloride solution. The presence of potassium ion had the most significant effect upon ammonium ion uptake, followed by calcium ion. Magnesium ion had the least effect.Equilibrium data obtained have been found to fit both Langmuir and Freundlich models. The Langmuir model provided excellent equilibrium data fitting (R2>0.995). From the plateau of the isotherms maximum exchange capacities were determined as 9.03, 8.76, 8.695 and 7.84 mg NH4+/gr for NH4+, NH4+-Mg+2, NH4+-Ca+2and NH4+-K+, respectively. As a consequence of this result, the ammonium capacity of Gördes clinoptilolite was approximately 0.51meq/gr for pure ammonium chloride solution. When comparing the removal of NH4+ ion from wastewater effluent and from NH4Cl, the percent removal and the uptake capacity were lower for wastewater than for NH4Cl for same solid: solution ratio and the same initial concentration. It is expected that in domestic wastewater, where the complexity of the system is high, several matter could influence the removal of specific target cations. The decreased ammonium removal for wastewater may be attributed to by the existence of several matters (suspended solid, organic matter) in the wastewater effluent samples, which reduce the ammonium exchange capacity.experimental results indicate a significant potential for the Gördes clinoptilolite rich mineral as an ion exchange material for wastewater treatment and water reuse application.