Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 79Citation - Scopus: 90Hydrophobically-Associating Cationic Polymers as Micro-Bubble Surface Modifiers in Dissolved Air Flotation for Cyanobacteria Cell Separation(Elsevier Ltd., 2014) Yap, R.K.L.; Bulmuş Zareie, Volga; Diao, M.; Stuetz, R. M.; Jefferson, B.; Bulmuş, Volga; Peirson, W. L.; Nguyen, A. V.; Henderson, R. K.; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyDissolved air flotation (DAF), an effective treatment method for clarifying algae/cyanobacteria-laden water, is highly dependent on coagulation-flocculation. Treatment of algae can be problematic due to unpredictable coagulant demand during blooms. To eliminate the need for coagulation-flocculation, the use of commercial polymers or surfactants to alter bubble charge in DAF has shown potential, termed the PosiDAF process. When using surfactants, poor removal was obtained but good bubble adherence was observed. Conversely, when using polymers, effective cell removal was obtained, attributed to polymer bridging, but polymers did not adhere well to the bubble surface, resulting in a cationic clarified effluent that was indicative of high polymer concentrations. In order to combine the attributes of both polymers (bridging ability) and surfactants (hydrophobicity), in this study, a commercially-available cationic polymer, poly(dimethylaminoethyl methacrylate) (polyDMAEMA), was functionalised with hydrophobic pendant groups of various carbon chain lengths to improve adherence of polymer to a bubble surface. Its performance in PosiDAF was contrasted against commercially-available poly(diallyl dimethyl ammonium chloride) (polyDADMAC). All synthesised polymers used for bubble surface modification were found to produce positively charged bubbles. When applying these cationic micro-bubbles in PosiDAF, in the absence of coagulation-flocculation, cell removals in excess of 90% were obtained, reaching a maximum of 99% cell removal and thus demonstrating process viability. Of the synthesised polymers, the polymer containing the largest hydrophobic functionality resulted in highly anionic treated effluent, suggesting stronger adherence of polymers to bubble surfaces and reduced residual polymer concentrations.Master Thesis Preconcentration of Heavy Metals in Environmental Samples by Biosorption and Determination by Atomic Spectrometry(Izmir Institute of Technology, 2007) Şeker, Ayşegül; Eroğlu, Ahmet Emin; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn the assessment of environmental quality, one of the priorities must be given to the determination of heavy metals. In the present study, Spirulina platensis, a cyanobacteria (or blue-green alga) was suggested to be used as a biosorbent prior to the atomic spectrometric determination of Pb, Cd and Ni in some environmental samples. For this purpose, the parameters which might be effective on the biosorption were investigated such as pH, time, initial metal ion concentration, biosorbent amount, temperature, kinetics of sorption, repetitive reactivity and ionic competition. According to the sorption kinetics, results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. Thermodynamic parameters (.G0, .H0 and .S0) were calculated and the sorption process was found to be largely driven towards the products and it had an endothermic nature. Faster adsorption kinetics was observed for Pb2+ ions in comparison to Cd2+ and Ni2+ ions. Based on kinetic modeling, the apparent activation energy, Ea, was calculated to be 44 kJmol-1, -16 kJmol-1 and 54 kJmol-1 for Pb2+, Cd2+and Ni2+, respectively. The measurements of the repetitive reusability of Spirulina platensis indicated a large capacity towards the three metal ions. Sorption activities in a three metal ion system were studied and at an initial metal concentration of 100.0 mgL-1, % Pb2+ was found to be still high (85%).However, it decreased to less than 20% for Cd2+ and Ni2+ indicating the relative selectivity of the biosorbent towards Pb2+. Finally, the use of Spirulina platensis, in its natural form or after be immobilized onto various matrices (alginate, silicate, carboxymethylcellulose and polysulfone) was planned for the separation of heavy metals from the sample matrix.