Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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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: 15Citation - Scopus: 19Immobilization of Esterase From Bacillus Subtilis on Halloysite Nanotubes and Applications on Dibutyl Phthalate Degradation(Elsevier, 2023) Rosales, Emilio; Pazos, Marta; Sanroman, Maria Angeles; Balcı, Esin; Sofuoğlu, AysunDibutyl phthalate (DBP) is one of the listed phthalic acid esters (PAEs) known as the priority toxicants which exhibit carcinogenic and teratogenic properties and is responsible for endocrine disruption. Therefore, its removal has become a matter to tackle with. In this work, the feasibility of DBP degradation by esterase and lipase enzymes obtained from various microorganisms and the immobilization of the most effective in a clayey material were investigated. Esterase from Bacillus subtilis exhibited the highest degradation efficiency reaching a complete degradation. Its immobilization onto halloysite nanotubes (HNTs) by adsorption method was studied by response surface methodology using a central composite design face-centered. The four selected factors that affect the HNT-enzyme composite generation were: pH, adsorption time, enzyme/HNT (E/H) ratio, and adsorption temperature, and the optimal conditions were determined (pH 7, time 360 min, E/H ratio 0.2, temperature 30oC). Consequently, the activity did not significantly decrease by immobilization, and the adsorption efficiency and relative activity were determined to be 73.15% and 82.7%, respectively. Besides, the immobilization enhanced thermal and storage stability. As for enzyme reusability, after 7 continuous cycles, the composite maintained almost 75% of its initial activity. Both the free enzyme (1 mg/mL) and the composite degraded 100 mg/L DBP with 100% efficiency and several byproducts were detected. Moreover, the composite could be reused for 7 cycles keeping a remarkable catalytic activity. Overall, this study indicated that the HNT-enzyme composite may be used as an effective candidate for remediation of the environmental media contaminated with DBP and other PAEs.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Research Project Yakıt oxygenate'lerin klinoptilolitçe zengin doğal zeolite adsorpsiyonunun incelenmesi(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2006) İnal, Fikret; Sofuoğlu, Aysun; Yılmaz, Selahattin; Yetgin, Senem[No Abstract Available]Research Project Tarihi yapılarda mermer yüzeylerinin bio-bozunur polimer ile korunması(2007) Böke, Hasan; Ocak, Yılmaz; Sofuoğlu, Aysun; Tıhmınlıoğlu, Funda; İpekoğlu, BaşakHava kirliliği, tüm dünyada ve ülkemizde kültür varlıklarımızın hızlı ve buna bağlı olarak artan bir şekilde bozulmasına yol açan önemli bir çevre faktörünü oluşturmaktadır. Bu bozulma, en fazla kalkerli taşlardan yapılmış (mermer, traverten, v.b) anıtlarda ve eserlerde gözlenmektedir. Kirli havada bulunan kükürt dioksit gazı (SO2) kalkerli taşları oluşturan kalsiyum karbonat (CaCO3) ile suyun varlığında reaksiyona girerek ara reaksiyon ürünü olan kalsiyum sülfit hemihidrat (CaSO3 . 0.5 H2O) ve bu ürünün oksitlenmesi sonucunda alçı taşını oluşturmaktadır (CaSO4 . 2 H2O) (ELFVING 1994; BÖKE 1999; GAURI 1999) . Oluşan alçı taşının sudaki çözünürlüğünün kalsit’den daha fazla olması yağmura açık bölgelerde bulunan mermer yüzeylerin erozyonunu hızlandırmaktadır (Şekil 1a). Eğer mermer yüzeyleri yağmurdan korunan bir bölgede ise bu oluşum, yüzeylerin bir süre sonra kabuklanmasına ve giderek dökülmesine yol açmaktadır (Şekil 1b). Tarihi anıtların ve arkeolojik alanlarda bulunan eserlerin büyük çoğunluğu kalsit kristallerinden oluşan kireç taşlarından oluşmaktadır.Research Project İlköğretim okullarında bina-içi çevresel kalitenin değerlendirilmesi(2010) Sofuoğlu, Sait C.; İnal, Fikret; Sofuoğlu, Aysun; Odabaşı, Mustafaİzmir’de, ikisi kentsel biri yarı kentsel alanda yer alan üç ilköğretim okulunda, bina‐içi hava uçucu organik madde, yarı‐uçucu organik madde, partikül madde, partikül maddede element ve inorganik gaz kirletici derişimleri ölçülmüştür. Anket uygulaması yapılarak, bina ile ilgili semptomların yaygınlığı çalışılmıştır. Bina‐içi konfor değişkenlerinden sıcaklık ve nispi nem kullanılarak hesaplanan Bina‐içi Rahatsızlık Göstergesi çok yüksek değerler almamıştır. Bina‐içi hava CO2 derişimleri ölçülerek dersliklerde havalandırmanın yeterli olmadığı görülmüştür. Uçucu organik bileşiklerden formaldehit, benzen, naftalin, toluen ve 1,3‐diklorobenzenin yüksek bina‐içi derişimlere ulaşabildiği görülmüş, ve formaldehit ve benzenin birincil düzeyde, naftalin ve toluenin de ikincil düzeyde önemli sağlık riski yaratabileceği değerlendirilmiştir. Yarı‐uçucu organik bileşiklerden poliklorlu bifeniller (PCB) ve polibromlu difenil eterler (PBDE) grubu kirleticilerin bina‐içi havada bulundukları ve içeride kaynakları olabileği görülürken, sentetik koku bileşiklerinin bir derslikte yapılan çalışma ile okul binalarında hem gaz hem de partikül fazda bulunabildikleri ve gaz fazda önemli düzeyde derişimlere eriştikleri belirlenmiştir. İnorganik gazlardan ozon için, bulgular iç hava ozon derişimlerinin, dış hava ozonu ile ilintili olduğunu ve hassas insanlarda sağlık etkisi yaratma sınırının altında kaldığı yönündedir. Karbon monoksit ise neredeyse tüm ölçümlerde ya tespit sınırı olan 1 ppm’in altında ya da oldukça düşük derişimlerde bulunmuştur. Partikül madde için elde edilen dane sayısı – boyut dağılımları, kütle – boyut dağılımları, bina‐içi hava ve dış hava derişimi bulguları, partikül madde kaynağının dış hava olduğu ancak çocukların hareketliliği sebebiyle bina‐içi mikroçevrelerde derişimlerin dış hava derişimlerinin üzerine çıkabildiğini göstermiştir. Hesaplanan Hava Kalitesi Göstergesi ‐ PM Alt Gösterge değerleri, PM2,5 derişimlerinin “sağlıksız” sınıfında yer aldığını göstermiştir. Boyut ayırımlı kütlesel PM derişimleri göstermektedir ki, ince partiküllerin (PM2,5) çoğunluğu ultra ince partiküllerdir (PM1) ve ultra ince partiküller ince partiküllere göre sayıca 2‐5 kat daha yüksek derişimlerde bulunmaktadırlar. Partikül maddede Al, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Zn elementleri tespit edilmiş olup kütle‐boyut dağılımlarının ultra ince boyutlarında görülen zirveler, hem ağırlıklı yerküre kaynaklı hem de ağırlıklı insan aktiviteleri kaynaklı elementler için ultra ince fraksiyonun önemli olduğunu göstermiştir.Research Project Mermer anıt yüzeylerinin polimer nanokompozit flimler ile korunması(2010) Tıhmınlıoğlu, Funda; Böke, Hasan; Sofuoğlu, Aysun; Ocak, Yılmaz; Oğuzlu, Hale; Akın, OkanMermer gibi kalsit içeren doğal taşlarla inşa edilmiş tarihi binalar ve anıtlarda artan hava kirliliğinin yarattığı problemler sonucu ortaya çıkan yüzey bozulmaları geçtiğimiz yüzyılda ivme kazanmıştır. Kükürt dioksit gazı mermerin yapısını oluşturan kalsit kristalleri ile reaksiyona girerek alçı taşını (CaSO4.2H2O) oluşturarak yüzeyi erozyona uğratmaktadır. Bu çalışmada hem geri dönüşebilen hem de koruyuculuk özelliği olan biyobozunur polimer nano kompozit kaplama geliştirilerek, koruyuculuk özelliklerinin belirlenmesi amaçlanmıştır. Bu amaçla silika ve kil nano partikülleri içeren biyobozunur polimerle hazırlanmış yüzey koruyucu kaplamalarının koruma potansiyelleri belirlenmiştir. Polilaktid bazlı nanokompozitlerin filmlerin kil dağılımı ve yapı XRD analizlenmiş, polilaktid-10A nanokompozitlerinde %7, polilaktid-93A nanokompozitlerinde ise %5 kil derişimine kadar eksfoliye ve interkale yapılar elde edilmiştir. Bununla birlikte nanoparçacıkların polimer matriksindeki dağılımına paralel olarak biyo-nanokompozitlerin geçirgenlik değerlerinde düşüş gözlenmiştir. Biyo-nanokompozitlerin bariyer özelliklerindeki değişim göz önüne alınarak mermer yüzey kaplamalarındaki nanoparçacık derişim aralıklarına karar verilmiştir.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 - Scopus: 22Multi‑purpose Reverse Logistics Network Design for Medical Waste Management in a Megacity: Istanbul, Turkey(Springer, 2022) Balcı, Esin; Balcı, Sezin; Sofuoğlu, AysunIn the study, a multi-purpose reverse logistics network has been designed to create effectual management of medical waste (MW) generated in 39 districts of Istanbul, a heavily populated city, during the COVID-19 pandemic as well as that to be generated in the next decade. With the model, the medical waste management system in Istanbul is analyzed during the pandemic and for the next 10 years. The model attempts to integrate economic, environmental, and social objectives within the sustainable development goals. It aims to maximize the number of personnel and government earnings for the estimated MW of a megacity while minimizing the total fixed cost and the cost of carbon emissions and transportation. The results indicated that the existing facilities are sufficient for the treatment and disposal of MW generated even under pandemic conditions. However, the capacity of the sterilization facility could be insufficient to treat the estimated amount of MW in the next decade. Opening a sterilization facility near the sanitary landfill in Komurcuoda with a total management cost of 62,450,332 €/year would be an optimum solution for Istanbul MW. In comparison to the single-purpose model results, the multi-purpose model resulted in approximately 42,000 € more in total cost. Sensitivity analyses show that the amount of MW has the most significant effect on the total cost. This simple model created an effective MW management proposal for Istanbul, which can be a model for megacities.Article Citation - WoS: 21Citation - Scopus: 24Phytoremediation of Olive Mill Wastewater With Vetiveria Zizanioides (l.) Nash and Cyperus Alternifolius L.(Elsevier, 2021) Gören, Ayşegül Yağmur; Yücel, Arzu; Sofuoğlu, Sait Cemil; Sofuoğlu, AysunOlive Mill Wastewater (OMW) contains high concentrations of contaminants, including organic, nitrogen, and phenolic compounds that are extremely harmful to the environment and human health. The key purpose of this study was to remove total organic carbon (TOC), total nitrogen (TN), and phenolic compounds (TP) from OMW using floating wetland planted with Vetiveria zizanioides (L.) Nash (vetiver) and Cyperus alternifolius L. (umbrella palm) species. A total of eighteen floating wetlands were constructed. Twelve tanks were planted with vetiver and umbrella palm while another six tanks were maintained as unplanted controls. Experiments were conducted with wastewater volume of 56 L for 67 days using 5% (OMW-5) and 15% (OMW-15) treatments of OMW in a greenhouse. The highest TOC, TN, and TP removal efficiencies were found to be 95.3 ± 0.01, 82.7 ± 2.55, and 98.8 ± 0.07% in umbrella palm planted OMW-5, while the removal efficiencies were 84.9 ± 0.38, 92.7 ± 0.37, and 38.9 ± 1.97% in vetiver planted OMW-5. Similarly, the TOC, TN, and TP removal efficiencies in OMW-15 were 89.3 ± 0.28, 40.86 ± 1.73, and 96.8 ± 0.18% with umbrella palm and 89.1 ± 0.70, 23.7 ± 1.27, and 92.1 ± 0.41% with vetiver. The plants accumulated trace elements, especially in the roots, with the order of Fe > Mn > Cu > Zn > B > Pb > Cr > Ni > Co > Cd for umbrella palm. The umbrella palm shoot phenol content was found to be 2358 ± 201 and 1421 ± 198 mg/kg in OMW-5 and OMW-15, respectively. Overall, this study revealed that floating wetlands planted with vetiver and umbrella palm species have the potential to be used as a green treatment method to treat diluted high strength OMW.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.