Person: GENÇ, SEVAL
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GENÇ
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SEVAL
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Publication Open Access Phosphate recovery from sewage sludge supernatants using magnetic nanoparticles(ELSEVIER, 2021-04) SEMERCİ, NESLİHAN; Gulyas, Anett; Genc, Seval; Can, Zehra Semra; Semerci, NeslihanPhosphorus removal and recovery from synthetic solutions and sewage sludge supernatants by using magnetic nanoparticles (MNP) were investigated through batch adsorption experiments. The adsorption kinetics and isotherms on the removal of phosphate have been studied using different MNP doses, contact time, pH, and initial P concentrations. Reusability of the MNP and the enrichment of phosphate in desorption solution from dewatering supernatants were tested in a series of adsorption-desorption cycles. The removal efficiency was between 29 and 97 % after 24 h depending on the P concentrations and adsorbent concentrations. This efficiency was detectable in pH similar to 3-5 but decreased in case of increased pH levels. Intra particle (IP) diffusion model kinetic tests demonstrated that the adsorption process was controlled by a multi-step mechanism and the reaction equilibrium was reached after 120 min. Besides phosphate, ammonium, magnesium and calcium ions were adsorbed on MNP to a lesser extent. Surface characterization and adsorption mechanism were discussed based on XRD, SEM and FTIR analyses. MNP can be very effective for both ammonia and phosphate removal and recovery from dewatering supernatant solutions.Publication Metadata only Adsorptive removal of bisphenol A from aqueous solutions using phosphonated levan(ELSEVIER, 2019) HACIOSMANOĞLU, GÜL GÜLENAY; Haciosmanoglu, Gul Gulenay; Dogruel, Tugce; Genc, Seval; Oner, Ebru Toksoy; Can, Zehra SemraIn this study, the potential use of phosphonated Halomonas Levan (PhHL) as a natural and cost effective adsorbent for Bisphenol A (BPA), was systematically investigated via the study of the adsorption equilibrium, kinetics, and reuse potential as well as the interpretation of adsorption mechanism. The effects of pH and temperature on the adsorption were also evaluated. The maximum amount of BPA adsorbed on the unit weight of PhHL was determined as 104.8 (-/+ 5.02) mg/g (at 298 K) and the maximum adsorption capacity was calculated as 126.6 mg/g by Sips model. FTIR and XPS studies were conducted to elucidate the adsorption mechanism. Based on the obtained results OH-pi and CH-pi interactions were found to be effective in the adsorption mechanism. The reuse ability was studied with three cycles of adsorption-desorption, and the results showed that the BPA adsorbed per gram of the PhHL decreased 28.6% after the third cycle. This study has shown that PhHL can be used as an effective adsorbent for the removal of BPA from aqueous solutions. The obtained results may be useful in the development of PhHL based adsorption systems for the removal of EDCs with similar chemical properties to BPA.Publication Metadata only Efficient removal of methyl orange from aqueous solutions using ulexite(ELSEVIER, 2021) HACIOSMANOĞLU, GÜL GÜLENAY; Haciosmanoglu, Gill Gillenay; Genc, Seval; Can, Zehra SemraUlexite, a natural boron mineral was used as an adsorbent for methyl orange (MetO) removal from aqueous solutions. SEM/EDS, IEP, BET, XPS and FTIR analyses were used for the characterization of ulexite. The adsorption characteristics of MetO by ulexite were investigated using batch adsorption experiments with varying contact time, pH, initial dye concentration and temperature. Batch adsorption experiments showed that the equilibrium time was 90 min and the reaction kinetics followed pseudo-first-order model. Equilibrium adsorption data were best fitted by the Liu isotherm and the maximum amount of MetO adsorbed per unit weight of ulexite was 1477.6 mg/g (experimental) at 298 K. The equilibrium experiments were repeated for different temperatures (288, 298 and 308 K) and the obtained data were used to calculate the thermodynamic parameters. Based on the results, the adsorption process was exothermic, spontaneous and thermodynamically favourable under the experimental conditions. The adsorption mechanism was elucidated by SEM/EDS, BET, XPS and FTIR analyses of ulexite before and after MetO adsorption. These results suggested that adsorption mechanism includes pi-p bonding, electrostatic attraction, hydrogen bonding and OH-pi bonding. The reuse experiments demonstrated a 14.17 % reduction in the adsorbed amount of MetO per unit weight of ulexite, after the fifth adsorption-desorption cycle. The obtained results indicate that ulexite is potentially an efficient adsorbent for MetO, especially for high initial concentrations. (c) 2021 Elsevier B.V. All rights reserved.Publication Metadata only Halomonas smyrnensis as a cell factory for co-production of PHB and levan(ELSEVIER SCIENCE BV, 2018) KASAVİ, CEYDA; Tohme, Souha; Haciosmanoglu, Gul Gulenay; Eroglu, Mehmet Sayip; Kasavi, Ceyda; Genc, Seval; Can, Zehra Semra; Oner, Ebru ToksoyLevan is a fructan type polysaccharide that has long been considered as an industrially important biopolymer however its limited availability is mainly due to the bottlenecks associated with its large-scale production. To overcome such bottlenecks in the commercialization of this very promising polysaccharide, co-production of levan with polyhydroxyalkanoates (PHAs) by halophilic Halomonas smyrnensis cultures has been proposed in this study for the first time. After in silico and in vitro assessment of PHA accumulation, fermentation profiles for levan and PHA concentrations were obtained in the presence of sucrose and glucose and the PHA granules observed by TEM were found to be poly(3-hydroxybutyrate) (PHB) after detailed structural characterization by GC-MS, DSC, FTIR and NMR. Six nutrient limitation strategies based on nitrogen (N) and phosphorus (P) were tested but highest levan and PHB yields were obtained under unlimited conditions. H. smyrnensis is proved to co-produce PHB and levan while using inexpensive carbon sources which is a commercially successful microbial cell factory system showing a great potential in lowering manufacturing costs and aiming for a zero waste policy within the biorefinery concept. (C) 2018 Elsevier B.V. All rights reserved.