ABSTRACT LEAD(II) AND AMMONIUM EXCHANGE on Na-FORM of G&Ouml / RDES CLINOPTILOLITE ASiroglu, Sedat M.S., Department of Chemical Engineering Supervisor Prof. Dr. Hayrettin Y&uuml / cel September 2006, 89 pages Natural zeolites, especially clinoptilolite, have the ability of removing certain cations from wastewater by utilizing ion exchange and adsorption. In this study, ion exchange behaviour of G&ouml / rdes clinoptilolite at particle size range (0.5-0.25 mm) for lead and ammonium removal was investigated to establish the conditions under which clinoptilolite may be used in an economical and effective manner. Experiments were divided into two parts. Batch and continuous (column) experiments were carried out. In the batch experiments, experimental isotherms of NH4+-Na+, Pb2+-Na+ binary systems and NH4+-Pb2+-Na+ ternary system were obtained as the graphs of equivalent fractions of exchanging cation in solution versus equivalent fractions of cation in zeolite. It was determined that clinoptilolite has affinity for Pb2+ and NH4+ ions. Finally, the selectivity sequence of G&ouml / rdes clinoptilolite in the presence of Pb2+ and NH4+ together was determined as Pb2+ &gt / NH4+ &gt / Na+. In the column studies, removal of lead, ammonium and simultaneous removal of lead-ammonium solutions were investigated. The loading flow rates were selected as 8, 15, and 30 mL/min. The ion exchange capacity of clinoptilolite for lead and ammonium removal showed good performance. Flow rates at 8, 15, 30 mL/min, breakthrough capacities were found as 0.398 meq/g (Pb2+) and 0.337 meq/g (NH4+), 0.299 meq/g (Pb2+) and 0.297 meq/g (NH4+), 0.197 meq/g (Pb2+) and 0.198 meq/g (NH4+) for lead-ammonium-sodium system and corresponding column efficiencies were 63.36%, 51.38%, 34.05%, respectively.

Zeolites are crystalline, hydrated aluminosilicate minerals that are characterized by their ability to exchange some of their constituent cations with cations in aqueous solutions, without a major change in their crystalline structure. Clinoptilolite is the most abundant ype of zeolite and it has received extensive attention due to its favorable selectivity for mmonium and certain heavy metal cations. The aim of this study is to investigate the binary and ternary (multicomponent) ion xchange behavior of sodium form of G&ouml / rdes type clinoptilolite for ammonium,cadmium and sodium ions. For this purpose, NH4 +-Na+,Cd2+-Na+ binary systems and NH4 +-Cd2+-Na+ multicomponent system were investigated both in batch and column systems at 0.1 and 0.01 constant total normality respectively and at 250C constant temperature. As a result of binary and ternary experiments, clinoptilolite&rsquo / s affinity for both ions but greater affinity to NH4+ ion than Cd2+ ion was observed and the selectivity sequence of G&ouml / rdes clinoptilolite was determined as NH4+&gt / Cd2+&gt / Na+ in binary and multicomponent batch and column operations. Additionally, total ion exchange capacities and maximum exchange levels of G&ouml / rdes clinoptilolite for both ions were determined in batch systems whereas breakthrough capacities and column efficiencies (for three different flow rates) were determined in column systems. Finally, it was concluded that the increase of the flow rate reduced the breakthrough capacities and column efficiencies of G&ouml / rdes clinoptilolite for ammonium and cadmium ions in multicomponent column systems involving more than one cation.

Wastewaters resulted from anthropogenic influence can encompass a wide range of potential contaminants and concentrations. There are numerous procedures that can be used to clear out wastewaters depending on the type and extent of contamination, however / disposal of pollutants from wastewaters in industrial scale is a difficult and costly problem. In this study, the use of ion exchange theory utilizing natural Turkish clinoptilolite zeolite from G&ouml / rdes-Manisa as ion exchange resins in down-flow column mode is investigated. The clinoptilolite with particle size range of 0.25-0.50 mm is used in the removal of lead Pb2+ and ammonium NH4+ ions from aqueous solutions. The aim of the study is to set up the conditions under which clinoptilolite may be used in an economical and efficient approach in the removal process. Experiments were divided into two sets: binary studies, and ternary studies, and the effects of conditioning clinoptilolite with NaCl solution, flow rate, and initial concentration of the solutions on the removal behavior were investigated. In binary studies, results showed that increasing the loading volumetric flow rate resulted in decreasing the breakthrough capacity and the column efficiency, while the total capacity remained constant. The maximum total capacity was determined as 1.16 meq/g of zeolite for NH4+, and 1.1 meq/g of zeolite for Pb2+ and these values were close to each other and to the sodium content of Na-form of pretreated clinoptilolite (1.16 meq/g of zeolite). In addition, by decreasing the initial contaminant concentration, an increase in breakthrough capacity and column efficiency was observed. In ternary studies, the results showed that the removal of Pb2+ and NH4+ ions are dependent on the flow rate, in which at moderately low flow rate, a higher ion exchange capacity is yielded. That was explained as at higher flow rates, the retention time was insufficient for the ion exchange process to take place completely between clinoptilolite and lead and ammonium ions. Thus, a competition between Pb2+ and NH4+ ions for the exchange sites on clinoptilolite was observed and this competition was in favor of lead ions. Consequently, it was observed that the clinoptilolite zeolite has affinity for both Pb2+ and NH4+ ions. However, the affinity of clinoptilolite for lead ions is higher than that for ammonium ions. Therefore, the cations selectivity for clinoptilolite according to their affinity is determined as the following sequence: NH4+ &gt / Pb2+ &gt / Na+.

Anaerobic ammonium oxidation (anammox) by anammox bacteria contributes significantly to the global nitrogen cycle and plays a major role in sustainable wastewater treatment. To date, autotrophic nitrogen removal by anammox bacteria is the most efficient and environmentally friendly process for the treatment of ammonium in wastewaters; its application can save up to 60% of the energy input, nearly 100% elimination of carbon demand and 80% decrease in excess sludge compared to conventional nitrification/denitrification process. In the anammox process, ammonium (NH4+) is directly oxidized to dinitrogen gas (N2) using intracellular electron acceptors such as nitrite (NO2–) or nitric oxide (NO). In the absence of NO2– or NO, anammox bacteria can couple formate oxidation to the reduction of metal oxides such as Fe(III) or Mn(IV). Their genomes contain homologs of Geobacter and Shewanella cytochromes involved in extracellular electron transfer (EET). However, it is still unknown whether anammox bacteria have EET capability and can couple the oxidation of NH4+ with transfer of electrons to extracellular electron acceptors. In this dissertation, I discovered by using complementary approaches that in the absence of NO2–, freshwater and marine anammox bacteria couple the oxidation of NH4+ with transfer of electrons to carbon-based insoluble extracellular electron acceptors such as graphene oxide (GO) or electrodes poised at a certain potential in microbial electrolysis cells (MECs). Metagenomics, fluorescence in-situ hybridization and electrochemical analyses coupled with MEC performance confirmed that anammox electrode biofilms were responsible for current generation through EET-dependent oxidation of NH4+. 15N-labelling experiments revealed the molecular mechanism of the EET-dependent anammox process. NH4+ was oxidized to N2 via hydroxylamine (NH2OH) as intermediate when electrode was used as the terminal electron acceptor. Comparative transcriptomics analysis supported isotope labelling experiments and revealed an alternative pathway for NH4+ oxidation coupled to EET when electrode was used as electron acceptor. The results presented in my dissertation provide the first experimental evidence that marine and freshwater anammox bacteria can couple NH4+ oxidation with EET, which is a significant breakthrough that is promising in the context of implementing EET-dependent anammox process for energy-efficient treatment of nitrogen using bioelectrochemical systems.

Microbial fuel cell (MFC) has become one of the energy-sustainable technologies for wastewater treatment purpose in the recent years. It combines wastewater treatment and electricity generation together so as to achieve energy balance. By inoculating microorganism in the anode chamber and filling catholyte in the cathode chamber, and also with the help of a proton exchange membrane (PEM) between them, the MFC can transfer protons and produce power. Microbial desalination cells (MDC) are based on MFC’s structure and can fulfill desalination function by the addition of a middle chamber and anion exchange membrane (AEM). This study focuses on ammonium removal and electricity generation in MDC system. Mainly two types of liquid were tested, a solution of Hjorthorn Salt and filtrated supernatant. The experiments were performed at Hammarby Sjöstad research station and laboratory of Land and Water Resources department, Stockholm. It consists of a preparation stage, a MFC stage and a MDC stage. Until the end of MFC stage, biofilm in the anode chamber had been formed and matured. After that, solutions of different initial concentrations (1.5, 2.5, 5, 15 g/L) of Hjorthorn Salt and also filtrated supernatant have been tested. Ammonium removal degree can be obtained by measuring the initial concentration and cycle end concentration, while electricity generation ability can be calculated by voltage data which was continuously recorded by a multimeter. Results showed that this MDC system is suitable for ammonium removal in both of Hjorthorn Salt solutions and supernatant. The removal degrees in Hjorthorn Salt solution at desalination chamber were 53.1%, 52.7%, 60.34%, and 27.25% corresponding to initial NH4+ concentration of 340.7, 376, 376 and 2220 mg/L. The ammonium removal degrees in the supernatant were up to 53.4% and 43.7% under 21 and 71 hours operation, respectively. In power production aspect, MDC produced maximum voltage when potassium permanganate was used in the cathode chamber (217 mV). The power density in solutions of Hjorthorn Salt was relative low (46.73 - 86.61 mW/m3), but in the supernatant it showed a good performance, up to 227.7 and 190.8 mW/m3.

Struvite is a salt that is formed out of  Mg2+,NH4+ and PO43- and it crystallizes in form of MgNH4PO4.6H2O. Struvite‟s (magnesium ammonium phosphate or MAP) precipitation has recently been regarded as an interesting technique to remove phosphate and ammonium from waste water. The high elimination rates and the possibility of recycling the struvite as a direct slow release fertilizer make this process feasible and appealing. However, the costs due to the raw chemicals needed are drawbacks that leave aside the application of the process in some facilities. The MAP biological dissolution makes possible a recycling of magnesium and phosphate, a fact that reduces the process‟s costs and will help making it even more feasible and environmentally friend. This thesis goes also through the parameters, reactions and different techniques that optimize the struvite precipitation process.