Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Pomza ve Nsdd-pomza ile Sabit Yataklı Kolon Reaktörde Metilen Mavisi Giderimi: Deneysel ve Modelleme Çalışması(2019) Balcı, Esin; Ökten, Hatice Eser; Genişoğlu, Mesut; Recepoğlu, Yaşar Kemal; Gören, Ayşegül YağmurNano sıfır değerlikli demir (nSDD) yüksek renk konsantrasyonlarına sahip tekstil atıksularının arıtımında ekonomik ve çevre dostu bir adsorban olarak ortaya çıkmaktadır. Ancak nSDD partikülleri sulu çözeltilerde elektrostatik etkileşimler sebebiyle kolayca topaklaşmakta ve bu da arıtma veriminin düşmesine neden olmaktadır. Dolayısıyla düşük maliyetli, doğal poröz yapıda ve ortalama 2m2/gr spesifik yüzey alanına sahip pomza, nSDD topaklaşmasını önleyici bir malzeme olarak kullanılabilir. Bu çalışmada sadece pomza ve pomzanSDD (ağırlıkça 9:1) karışımının kullanıldığı kolon reaktörde 25, 50, 75 ve 100 mg/L metilen mavisi konsantrasyonları için arıtma verimleri incelenmiştir. Pomzanın ve pomza-nSDD karışımının 100 mg/L metilen mavisi deneyindeki toplam kapasiteleri sırasıyla 2,8 ve 4,2 mg/g-adsorban olarak bulunmuştur. Özellikle düşük konsantrasyonlarda, pomza-nSDD karışımının arıtma performansını önemli ölçüde arttırdığı görülmüştür. Thomas modeli deneysel verilere uygulanmış ve modelin öngörü gücünün düşük konsantrasyonda yüksekken, yüksek konsantrasyonlarda ortalama olduğu kanısına varılmıştır.Article Fotobiyokataliz Yöntemi Kullanılarak Pestisit Giderimi-derleme Çalışması(Niğde Ömer Halisdemir Üniversitesi, 2019) Okçu, Gamze; Ökten, Hatice Eser; Yalçuk, ArdaAromatik yapılı, çevresel koşullarda zorlukla parçalanabilen, kararlı organik kirleticilerin başında gelen pestisitler, atmosfere, su sistemlerine, besin zincirine taşınmakta, asıl kaynaklarından çok uzak noktalarda birikebilmektedir. Konvansiyonel arıtma proseslerinin pestisitlerin gideriminde yetersiz kalmasından dolayı kirletilmiş sulardan uzaklaştırılmaları için yeni arıtım teknolojilerine ihtiyaç duyulmaktadır. Son yıllarda, su sistemlerinden konvansiyonel tekniklerle arıtılamayan kirleticilerin giderilmesinde birleşik fotokatalitik-biyolojik arıtma umut verici bir alternatiftir: Fotokataliz toksik organikleri biyolojik olarak parçalanabilir ürünlere dönüştürürken, biyolojik parçalama ürünlerini verimli şekilde mineralize eder. Ön arıtma sırasında gereksiz kimyasal ve %60 oranında enerji sarfiyatından kaçınmak amacıyla ön arıtma basamağında mineralizasyon yüzdesi minimalize edilerek çalışma maliyeti düşürülür. Literatüre göre yalnız kimyasal prosesle yaklaşık %80 pestisit parçalanması ve %50’den az mineralizasyon gözlemlenebilirken hibrit reaktör sistemiyle tamamen parçalanma ve yaklaşık %90 pestisit mineralizasyonu elde edilebilmektedir. Bu derlemenin amacı, fotobiyokataliz işleminin, bireysel fotokataliz ve/veya biyolojik arıtma yöntemlerine göre pestisit giderim koşulları kapsamında, temellerini, mekanizmalarını ve literatürde yer alan güncel çalışmaları ele almak ve incelemektir.Editorial Special Issue on the 4th International Conference on Recycling and Reuse 24–26 October 2018, Istanbul, Turkey: Preface(Elsevier B.V., 2019) Okten, H.E.; Ökten, Hatice Eser; Balkaya, N.; Aydin, S.; Elmaslar, E.; Ongen, A.; Selcuk, H.[No abstract available]Article Citation - WoS: 8Citation - Scopus: 12A Box–behnken Design (bbd) Optimization of the Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D) Using Tio2/H2o2(Desalination Publications, 2018) Doğdu Okçu, Gamze; Baldan Pakdil, Nazlı; Ökten, Hatice Eser; Yalçuk, Arda2,4-Dichlorophenoxyacetic acid (2,4-D), a chlorinated phenoxy-alkanoic herbicide, is used extensively in agriculture. This work investigates TiO2/H2O2 mediated UV photocatalytic degradation of 2,4-D in a laboratory-scale photoreactor. Three levels of Box–Behnken design technique, combined with response surface methodology (RSM), were used to design the experiments. Two kinds of multivariate experimental design (pH, TiO2, and 2,4-D concentration) and (pH, TiO2, and H2O2 concentrations) were employed to establish two quadratic models (Model 1 and Model 2), showing the functional relationship between degradation rate of 2,4-D and three independent experimental parameters. Model 1 predicted optimum values for pH, TiO2, and 2,4-D concentrations to be 5.7, 1.20 g L−1, and 32 mg L−1, respectively. Model 2 predicted optimum values for pH, TiO2, and initial H2O2 concentrations to be 4.94, 1.34 g L−1, and 161 mg L−1. Degradation rate of 2,4-D approached 78.10% for Model 1 and 83.63% for Model 2. For both models, similar results were obtained through optimizing variables by RSM and using single factorial batch reactor operation. Regression analysis showed good agreement between experimental results and predictive values for Models 1 and 2, with R2 values of 0.9958 and 0.9976, respectively.Article Methylene Blue Removal of Fixed-Bed Column Reactor With Pumice and Nzvi-Pumice: Experimental and Modeling Study(Süleyman Demirel Üniversitesi, 2019) Genişoğlu, Mesut; Gören, Ayşegül Yağmur; Balcı, Esin; Recepoğlu, Yaşar Kemal; Ökten, Hatice EserNano zero-valent iron (nZVI) emerges as a low cost and eco-friendly adsorbent to treat textile wastewater, which is rich in dye content. However nZVI particles can easily agglomerate in aqueous environment due to electrostatic interaction, decreasing their treatment efficiency. Therefore pumice, a low-cost and naturally found porous material with lower specific surface area (2m2/gr), can be used as support material to reduce agglomeration of nZVI. Treatment efficiencies of pumice/nZVI packing (10:0 and 9:1 (w/w)) in column reactor for specified initial methylene blue concentrations (25, 50, 75 and 100 mg/L) were investigated in this study. Adsorption capacities of the adsorbents were calculated as 2.8 and 4.2 mg/g-adsorbent, respectively at 100 mg/L initial methylene blue concentration. Mixed bed column performed significantly better than its pumice-only counterpart for low initial concentrations. Thomas adsorption model was applied to experimental results with a moderate to high predictive power.Article Citation - WoS: 4Citation - Scopus: 7Heterogeneous Photocatalytic Degradation and Mineralization of 2,4-Dichlorophenoxy Acetic Acid (2,4-D): Its Performance, Kinetics, and Economic Analysis(Desalination Publications, 2019) Doğdu Okçu, Gamze; Ökten, Hatice Eser; Yalçuk, ArdaThe photocatalytic degradation and mineralization of commercial solution of 2,4-dichlorophenoxy-acetic acid (2,4-D) was carried out by UVA/P25 TiO 2 and UVA/P25 TiO 2 /H 2 O 2 oxidation processes under batch-mode conditions. In UVA + TiO 2 photocatalysis (TiO 2 1.5 gL −1 , pH 5, initial 2,4-D 25 mg L −1 ), 97.47% ± 0.27% degradation, 39.89% ± 3.42% mineralization, and 65.52% ± 4.88% oxidation were achieved in 180 min, and in UVA +TiO 2 + H 2 O 2 photocatalysis (TiO 2 1.5 g L −1 , pH 5, initial 2,4-D 25 mg L −1 , H 2 O 2 150 mg L −1 ), 99.74% ± 0.08% degradation, 55.99% ± 2.67% mineralization, and 82.49% ± 1.90% oxidation were obtained in 180 min. The pseudo-first-order kinetic model fitted the experimental data well, and the photocatalytic degradation process was explained by the modified L–H model; k c and K LH were 1.293 mg L −1 min −1 and 0.232 L mg −1 , respectively. Fourier transform infrared (FTIR) spectroscopy spectra and scanning electron microscopy (SEM) analysis indicated degradation of organic bonds of the herbicide and adsorption of 2,4-D particles onto the TiO 2 catalyst during 24-h experiments. Moreover, the dependence of k app on the half-life time was determined by calculating the electrical energy per order (E EO ). UVA/TiO 2 /H 2 O 2 photocatalysis may be applied as a pretreatment to 2,4-D herbicide wastewater at a pH of 5 for biological treatment.Article Citation - WoS: 3Citation - Scopus: 4Use of Nano Zero-Valent Iron Coated Coffee Grounds for Removal of Zn(ii) and Ni(ii) From Aqueous Solutions(Desalination Publications, 2019) Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Ökten, Hatice EserThis research investigates the adsorption capacity of a novel composite material, namely nano zero-valent iron coated coffee grounds (nZVI-CG), for removal of zinc (Zn) and nickel (Ni). nZVI particles were synthesized and immobilized to the surface of waste coffee grounds (CG) using the ultrasonic-assisted liquid phase method. Characterization of synthesized nZVI-CG composite and bare CG showed that nZVI coating has increased the surface area significantly. Batch tests were conducted to examine the effects of pH, reaction time and initial metal concentrations on Zn2+ and Ni2+ removal. At an initial metal concentration of 10 mg-Ni/L and 10 mg-Zn/L, nZVI-CG removal rates for Zn2+ and Ni2+ were observed as 98.89% and 97.29%, respectively; while removal rates of bare CG have remained at 51% (Zn2+) and 48.1% (Ni2+). Moreover, acidic conditions were observed to deteriorate Ni2+ and Zn2+ adsorption since most functional groups of the metals were protonated. Increasing initial nickel and zinc concentrations decreased removal rates. While the model fittings improved with increasing pH, in the case of nZVI-CG, Langmuir isotherm gave the best fits for Ni2+ and Zn2+ at pH 5 and 7. Also, our experimental results followed the pseudo-second-order kinetic model, regardless of the used adsorbent. Consequently, our results showed that nZVI-CG composite material is a promising alternative adsorbent for pilot scale metal removal/recovery applications.Article Citation - WoS: 41Citation - Scopus: 43Chloride or Sulfate? Consequences for Ozonation of Textile Wastewater(Academic Press Inc., 2019) Öktem, Yalçın Aşkın; Yüzer, Burak; Aydın, Muhammed Iberia; Ökten, Hatice Eser; Meriç, Süreyya; Selçuk, HüseyinOzonation of chloride-rich textile wastewater is a common pretreatment practice in order to increase biodegradability and therefore meet the discharge limits. This study is the first to investigate ozone-chloride/bromide interactions and formation of hazardous adsorbable organic halogens (AOX) in real textile wastewater. Initially effect of ozonation on chloride-rich real textile wastewater samples were investigated for adsorbable organic halogens (AOX) formation, biodegradability and toxicity. After 15 min of ozonation, maximum levels of chlorine/bromine generation (0.3 mg/l) and AOX formation (399 mg/l) were reached. OUR and SOUR levels both increased by approximately 58%. Daphnia magna toxicity peaked at 100% for 10 min ozonated sample. Considering adverse effects of ozonation on chloride-rich textile industry effluents, we proposed replacement of NaCl with Na2SO4. Comparative ozonation experiments were carried out for both chloride and sulfate containing synthetic dyeing wastewater samples. Results showed that use of sulfate in reactive dyeing increased biodegradability and decreased acute toxicity. Although sulfate is preferred over chloride for more effective dyeing performance, the switch has been hampered due to sodium sulfate's higher unit cost. However, consideration of indirect costs such as contributions to biodegradability, toxicity, water and salt recovery shall facilitate textile industry's switch from chloride to sulfate.Article Citation - WoS: 45Citation - Scopus: 45The First Countrywide Monitoring of Selected Pops: Polychlorinated Biphenyls (pcbs), Polybrominated Diphenyl Ethers (pbdes) and Selected Organochlorine Pesticides (ocps) in the Atmosphere of Turkey(Elsevier Ltd., 2018) Kurt Karakuş, Perihan Binnur; Ugranlı Çiçek, Tuğba; Sofuoğlu, Sait Cemil; Çelik, Halil; Güngörmüş, Elif; Gedik, Kadir; Sofuoğlu, Aysun; Ökten, Hatice Eser; Birgül, Aşkın; Alegria, Henry; Jones, Kevin C.Atmospheric levels of 43 PCBs, 22 OCPs, and 14 PBDEs were determined in 16 cities at urban and rural sites by passive sampling to generate the first large-scale nationwide dataset of POP residues in Turkey's atmosphere. Sampling campaign was performed from May 2014 to April 2015 with three-month sampling periods at locations on east-west and north-south transects through the country to investigate seasonal and spatial variations, including long range atmospheric transport (LRAT). Factor analysis was conducted to infer on the potential sources. Overall average Σ43PCBs concentration was 108 ± 132 pg/m3. PCB-118 (26.3 ± 44.6 pg/m3) was the top congener, and penta-CBs had the highest contribution with 54.3%. ΣDDTs had the highest annual mean concentration with 134 ± 296 pg/m3 among the OCP groups among which the highest concentration compound was p'p-DDE (97.6 ± 236 pg/m3). Overall average concentration of Σ14PBDEs was 191 ± 329 pg/m3 with the highest contribution from BDE-190 (42%). Comparison of OCPs and PCBs concentrations detected at temperatures which were above and below annual average temperature indicated higher concentrations in the warmer periods, hence significance of secondary emissions for several OCPs and Σ43PCBs, as well as inference as LRAT from secondary emissions. The first nationwide POPs database constructed in this study, point to current use, local secondary emissions, and LRAT for different individual compounds, and indicate the need for regular monitoring. The first country-wide passive sampling of selected POPs showed no unequivocal trends reflecting transitional location of Turkey.Conference Object Groundwater Pollution by Nitrate From Agricultural Fertilizers: the Case of Menemen Basin (aegean Region, Turkey)(İZSU, 2017) Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Balcı, Esin; Ökten, Hatice Eser; Baba, AlperGroundwater is an essential drinking water source in Menemen subbasin of İzmir city, Turkey. The aim of this study was to investigate the groundwater contamination by nitrates of agricultural lands. For this purpose, we evaluated variations of groundwater pH, redox potential, electrical conductivity (EC), major anions (NO3, Cl, SO4, HCO3 and CO3) and cations (Na, K, Ca and Mg). A statistical correlation procedure and piper diagram for hydrogeochemistry of groundwater were also applied. Nitrate levels were found to be higher around agricultural areas. Also EC values and Cl were measured to be higher as proximity to coastal areas increased, indicating seawater intrusion. Agricultural activities and excessive freshwater withdrawal were shown to impair groundwater quality and quantity at Menemen subbasin.