Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Citation - WoS: 6Citation - Scopus: 9The Effect of Military Conflict Zone in the Middle East on Atmospheric Persistent Organic Pollutant Contamination in Its North(Elsevier, 2023) Ayrı, İlknur; Genişoğlu, Mesut; Sofuoğlu, Aysun; Kurt Karakuş, Perihan B.; Birgül, Askın; Sofuoğlu, Sait CemilThis study aimed to investigate long-range atmospheric transport of selected POPs released due to the effects of mili-tary conflicts in regions to the south of Turkey's borders. Ten locations were selected to deploy passive air samplers at varying distances to the border on a southeast-west transect of the country, proximity-grouped as close, middle, and far. Sampling campaign included winter and transition months when desert dust transport events occur. Hypothesis of the study was that a decreasing trend would be observed with increasing distance to the border. Group comparisons based on statistical testing showed that PBDE-183, E45PCB, and dieldrin in winter; PBDE-28, PBDE-99, PBDE-154, p,p '-DDE, E14PBDE, and E25OCP in the transition period; and PBDE-28, PBDE-85, PBDE-99, PBDE-154, PBDE-190, PCB-52, E45PCB, p,p '-DDE, and E25OCP over the whole campaign had a decreasing trend on the transect. An analysis of concen-tration ratio to the background showed that long-range atmospheric transport impacted the study sites, especially those of close group in comparison to the local sources. Back-trajectory analyses indicated that there was transport from the conflict areas to sites in the close-proximity group, while farther sampling locations mostly received air masses from Europe, Russia, and former Soviet Union countries, followed by North Africa, rather than the military con-flict areas. In consequence, decrease in concentrations with distance and its relation to molecular weight through pro-portions, diagnostic ratios, analysis of concentration ratio to the background, and back-trajectory analyses support the effect of transport from the military-conflict area to its north.Article Citation - WoS: 10Citation - Scopus: 12Novel Hybrid Adsorption-Electrodialysis (aded) System for Removal of Boron From Geothermal Brine(American Chemical Society, 2022) Altınbaş, Bekir Fırat; Orak, Ceren; Ökten, Hatice Eser; Yüksel, AslıA novel hybrid adsorption-electrodialysis (AdED) system to remove environmentally harmful boron from geothermal brine was designed and effective operating parameters such as pH, voltage, and flow rate were studied. A cellulose-based adsorbent was synthesized from glycidyl methacrylate (GMA) grafted cellulose and modified with a boron selective n-methyl-d-glucamine (NMDG) group and characterized with SEM-EDX, FT-IR, and TGA analyses. Batch adsorption studies revealed that cellulose-based adsorbent showed a remarkable boron removal capacity (19.29 mg/g), a wide stable operating pH range (2-10), and an adsorption process that followed the Freundlich isotherm (R2= 0.95) and pseudo-second-order kinetics (R2= 0.99). In the hybrid AdED system, the optimum operating parameters for boron removal were found to be a pH of 10, a voltage of 10 V, a flow rate of 100 mL/min, and an adsorbent dosage of 4 g/L. The presence of the adsorbent in the hybrid system increased boron removal from real geothermal brine (containing 199 ppm boron) from 7.2% to 73.3%. The results indicate that the designed AdED system performs better than bare electrodialysis for boron removal from ion-rich real geothermal brine while utilizing environmentally friendly cellulose-based adsorbent.Article Citation - WoS: 4Citation - Scopus: 5Continuous Treatment of Diethyl Hexyl and Dibutyl Phthalates by Fixed-Bed Reactor: Comparison of Two Esterase Bionanocomposites(Elsevier, 2022) Sanroman, Maria Angeles; Balcı, Esin; Rosales, Emilio; Pazos, Marta; Sofuoğlu, AysunThe removal of Diethyl hexyl phthalate (DEHP) and Dibutyl phthalate (DBP) is of great importance due to their potential adverse effects on the environment and human health. In this study, two bionanocomposites prepared by immobilization of Bacillus subtilis esterase by crosslinking to halloysite and supported in chitosan and alginate beads were studied and proposed as a green approach. The esterase immobilization was confirmed by physical-chemical characterization. Bionanocomposite using chitosan showed the best degradation levels in batch tests attaining complete degradation of DBP and around 90% of DEHP. To determine the operational stability and efficiency of the system, two fixed bed reactors filled with both bionanocomposites were carried out operating in continuous mode. Chitosan based bionanocomposite showed the best performance being able to completely remove DBP and more than 85% of DEHP at the different flowrates. These results proved the potential of these synthesized bionanocomposites to effectively remove Phthalic Acid Esters.Article Citation - WoS: 31Citation - Scopus: 35Electrochemical Degradation of Methylene Blue by a Flexible Graphite Electrode: Techno-Economic Evaluation(American Chemical Society, 2022) Gören, Ayşegül Yağmur; Recepoğlu, Yaşar Kemal; Edebali, Özge; Şahin, Çağrı; Genişoğlu, Mesut; Ökten, Hatice EserIn this study, electrochemical removal of methylene blue (MB) from water using commercially available and low-cost flexible graphite was investigated. The operating conditions such as initial dye concentration, initial solution pH, electrolyte dose, electrical potential, and operating time were investigated. The Box-Behnken experimental design (BBD) was used to optimize the system's performance with the minimum number of tests possible, as well as to examine the independent variables' impact on the removal efficiency, energy consumption, operating cost, and effluent MB concentration. The electrical potential and electrolyte dosage both improved the MB removal efficiency, since increased electrical potential facilitated production of oxidizing agents and increase in electrolyte dosage translated into an increase in electrical current transfer. As expected, MB removal efficiency increased with longer operational periods. The combined effects of operating time-electrical potential and electrical potential-electrolyte concentration improved the MB removal efficiency. The maximum removal efficiency (99.9%) and lowest operating cost (0.012 $/m3) were obtained for initial pH 4, initial MB concentration 26.5 mg/L, electrolyte concentration 0.6 g/L, electrical potential 3 V, and operating time 30 min. The reaction kinetics was maximum for pH 5, and as the pH increased the reaction rates decreased. Consequent techno-economic assessment showed that electrochemical removal of MB using low-cost and versatile flexible graphite had a competitive advantage.Article Citation - WoS: 56Citation - Scopus: 64Carbonaceous Materials for Removal and Recovery of Phosphate Species: Limitations, Successes and Future Improvement(Pergamon-Elsevier Science Ltd, 2022) Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur; Orooji, Yasin; Khataee, AlirezaThe carbonaceous materials have gained significant interest for the phosphorus species remediation and recovery in the last decade. Carbonaceous materials present many unique features, such as cost effective, availability, environmentally friendly, and high removal efficiency that make them a promising adsorbent. In this review, the recent application of carbonaceous materials including activated carbon (AC), graphene and graphene oxide (GO), lignin, carbon nanotubes (CNTs), and gC(3)N(4) for phosphate removal and recovery were comprehensively summarized. The kinetics and isotherm models, removal mechanisms, and effects of operating parameters are reported. The reusability, lifetime of carbonaceous materials, and impact of modification were also considered. The modified carbonaceous materials have significantly high phosphate adsorption capacity compared to unmodified adsorbents. Namely, MgO-functionalized lignin-based bio-charcoal exhibited a 906.8 mg g(-1) of capacity as the highest one among other reviewed materials. The modification of carbonaceous materials with various elements has been presented to improve the surface functional groups, surface area and charge, and pore volume and size. Among these loaded elements, iron has been effectively used to provide a prospect for magnetic recovery of the adsorbent as well as increase phosphate adsorption. Furthermore, the phosphate recovery methods, phosphate removal efficiency of carbonaceous materials, the limitations, important gaps in the literature, and future studies to enhance applicability of carbonaceous materials in real scale are also discussed.Article Citation - WoS: 12Citation - Scopus: 13Selected Persistent Organic Pollutants in Ambient Air in Turkey: Regional Sources and Controlling Factors(American Chemical Society, 2021) Güngörmüş, Elif; Sofuoğlu, Aysun; Çelik, Halil; Gedik, Kadir; Mulder, Marie D.; Lammel, Gerhard; Sofuoğlu, Sait CemilAs a result of its unique location, Turkey receives air masses from Europe, Russia, Middle East, and Africa, making it an important place in terms of long-range atmospheric transport (LRT) of contaminants. Atmospheric levels of 22 organochlorine pesticides (OCPs), 45 polychlorinated biphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) were measured in two metropolitan cities, Istanbul and Izmir, on a weekly basis from May 2014 to May 2015. Dichlorodiphenyltrichloroethane (DDT) and its derivatives were dominant OCP species, followed by isomers of hexachlorocyclohexane (HCH) at both sites. The annual mean concentration of Sigma DDX (sum of o,p'-DDT, p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE, and p,p'-DDE) was 82 pg/m(3) for Istanbul and 89 pg/m(3) for Izmir, while these levels were about 46 pg/m(3) for Sigma HCHs (sum of alpha-, beta-, gamma-, and delta-HCH) at both of the sites. At both stations, tri- and tetra-PCBs and tetra- and penta-PBDEs were dominant congeners. The temperature dependence indicates that both LRT and local contaminated areas contribute to the elevated levels. A Lagrangian particle dispersion model (FLEXPART) showed a few potential source regions in northern Africa and Middle East, southern-southwestern and eastern Europe including Russia, as well as from local domestic metropolitan areas.Article Citation - WoS: 20Citation - Scopus: 25Indoor Air Partitioning of Synthetic Musk Compounds: Gas, Particulate Matter, House Dust, and Window Film(Elsevier, 2020) Balcı, Esin; Genişoğlu, Mesut; Sofuoğlu, Sait Cemil; Sofuoğlu, AysunDue to diversity of contaminants indoors and complexity in the physical structure of particulate matter, partition process of chemicals affects indoor concentration distribution. Synthetic Musk Compounds (SMCs) are ubiquitously found in household and personal care products, thus, in the environment. Exposure to SMCs is important for human health, therefore, their partitioning in indoor environmental media is a key issue. In this study, gas particle, house dust, andwindowfilm partitioning of SMCs were investigated in an indoor micro-environment. In a sealed and unoccupied room, a polycyclic and nitro musk mixture was left for volatilization for an hour. Then, samples were collected using XAD-2 sandwiched between two PUF plugs, glass-fiber filter, and wipes for gas, PM10, window-film, house dust phases, respectively, for 145 h. Collected samples were analyzed using a GC-MS. Results demonstrated that MC concentrations decreased over time, non-linearly. Six of the SMCs partitioned to PM10 with at least 10% at beginning of the experiment, whereas the number of compounds dropped to two at the end, showing that SMCs may partition well between the two phases but they tend to be in the gas phase. They were also detected in the film and dust phases but a decrease pattern similar to gas-particle was not observed. Spearman correlations indicate that the dust and film-associated concentrations were governed by similar processes but PM-associated concentrations were not. SMCs may be found in all phases, mainly in house dust in terms of mass among the studied media and unaccounted surface reservoirs. Therefore, their partitioning between indoor media has key implications for human exposure. (C)20 Elsevier B.V. All rights reserved.Article Citation - WoS: 15Citation - Scopus: 19Brominated Flame Retardants in a Computer Technical Service: Indoor Air Gas Phase, Submicron (pm1) and Coarse (pm10) Particles, Associated Inhalation Exposure, and Settled Dust(Elsevier Ltd., 2019) Genişoğlu, Mesut; Sofuoğlu, Aysun; Kurt Karakuş, Perihan Binnur; Birgül, Aşkın; Sofuoğlu, Sait CemilBrominated flame retardants (BFRs) are found in multi-media indoors, therefore, may pose serious risks to human health. This study investigated the occurrence of BFRs in particulate matter (PM1 and PM10) and gas phase by active and passive sampling, and settled dust to estimate potential exposure in a computer technical service. Polybrominated diphenyl ethers (PBDEs) and their alternatives (novel BFRs, NBFRs) were studied. PM and gas phase were collected on glass fiber filters and polyurethane foam plugs, respectively, and analyzed with a GC/MS after extraction, clean-up, and concentration. Inhalation exposure of the staff was estimated based on the measured concentrations using Monte Carlo simulation. BDE-209 was the dominating PBDE congener in all media while bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate and 1,2-bis(2,4,6-tribromophenoxy)ethane were those of NBFRs. Submicron particulate matter (PM1) BFR levels constituted about one half of the PM10-associated concentrations, while average PM10 mass concentration (69.9 μg m−3) was nine times that of PM1 (7.73 μg m−3). Calculated log10 dust-gas and PM-gas partitioning coefficients ranged from −5.03 to −2.10, −2.21 to −0.55, and −2.26 to −1.04 for settled dust, PM10, and PM1, respectively. The indoor/outdoor concentration ratios were >1 for all compounds indicating the strength of indoor sources in the service. The estimated potential inhalation exposures, for future chronic-toxic and carcinogenic risk assessments, indicated that the levels of gas-phase and PM1-associated exposures were similar at approximately one half of PM10-associated levels. Results of this study indicate that the occurrence of BFRs in all studied media should be taken into consideration for occupational health mitigation efforts.Article Citation - WoS: 27Citation - Scopus: 28Fast Formation of Nitro-Pahs in the Marine Atmosphere Constrained in a Regional-Scale Lagrangian Field Experiment(American Chemical Society, 2019) Mulder, Marie D.; Dumanoğlu, Yetkin; Efstathiou, Christos; Kukucka, Petr; Matejovicova, Jana; Maurer, Christian; Pribylova, Petra; Prokes, Roman; Sofuoğlu, Aysun; Sofuoğlu, Sait Cemil; Wilson, Jake; Zetzsch, Cornelius; Wotawa, Gerhard; Lammel, GerhardPolycyclic aromatic hydrocarbons (PAHs) and some of their nitrated derivatives, NPAHs, are seemingly ubiquitous in the atmospheric environment. Atmospheric lifetimes may nevertheless vary within a wide range, and be as short as a few hours. The sources and sinks of NPAH in the atmosphere are not well understood. With a Lagrangian field experiment and modeling, we studied the conversion of the semivolatile PAHs fluoranthene and pyrene into the 2-nitro derivatives 2-nitrofluoranthene and 2-nitropyrene in a cloud-free marine atmosphere on the time scale of hours to 1 day between a coastal and an island site. Chemistry and transport during several episodes was simulated by a Lagrangian box model i.e., a box model coupled to a Lagrangian particle dispersion model, FLEXPART-WRF. It is found that the chemical kinetic data do capture photochemical degradation of the 4-ring PAHs under ambient conditions on the time scale of hours to 1 day, while the production of the corresponding NPAH, which sustained 2-nitrofluoranthene/fluoranthene and 2-nitropyrene/pyrene yields of (3.7 ± 0.2) and (1.5 ± 0.1)%, respectively, is by far underestimated. Predicted levels of NPAH come close to observed ones, when kinetic data describing the reactivity of the OH-adduct were explored by means of theoretically based estimates. Predictions are also underestimated by 1-2 orders of magnitude, when NPAH/PAH yields reported from laboratory experiments conducted under high NOx conditions are adopted for the simulations. It is concluded that NPAH sources effective under low NOx conditions, are largely underestimated.Article Citation - WoS: 91Citation - Scopus: 95Source Apportionment and Carcinogenic Risk Assessment of Passive Air Sampler-Derived Pahs and Pcbs in a Heavily Industrialized Region(Elsevier Ltd., 2018) Çetin, Banu; Yurdakul, Sema; Güngörmüş, Elif; Öztürk, Fatma; Sofuoğlu, Sait CemilCancer has become the primary reason of deaths in Dilovasi probably due to its location with unique topography under the influence of heavy industrialization and traffic. In this study, possible sources and carcinogenic health risks of PAHs and PCBs were investigated in Dilovasi region by Positive Matrix Factorization (PMF) and the USEPA approach, respectively. PAHs and PCBs were measured monthly for a whole year at 23 sampling sites using PUF disk passive samplers. Average ambient air concentrations were found as 285 ± 431 ng/m 3 and 4152 ± 6072 pg/m 3 , for Σ 15 PAH and Σ 41 PCB, respectively. PAH concentrations increased with decreasing temperature especially at urban sites, indicating the impact of residential heating in addition to industrial activities and traffic. On the other hand, PCB concentrations mostly increased with temperature probably due to enhanced volatilization from their sources. Possible sources of PAHs were found as emissions of diesel and gasoline vehicles, biomass and coal combustion, iron and steel industry, and unburned petroleum/petroleum products, whereas iron-steel production, coal and biomass burning, technical PCB mixtures, and industrial emissions were identified for PCBs. The mean carcinogenic risk associated with inhalation exposure to PAHs and PCBs were estimated to be >10 −6 and >10 −5 , respectively, at all sampling points, while the 95th percentile was >10 −5 at 15 of 23 and >10 −4 at 8 of 23 sampling locations, respectively. Probabilistic assessment showed, especially for PCBs, that a majority of Dilovasi population face significant health risks. The higher risks due to PCBs further indicated that PCBs and possibly other pollutants originating from the same sources such as PBDEs and PCNs may be an important issue for the region.