Yazarlar
- Duran, Celal(38)
- Ozdes, Duygu(33)
- Kankal, Murat(13)
- Şan, Murat(12)
- Gundogdu, Ali(11)
- Nacar, Sinan(10)
- Ozeken, Sengul Tugba(7)
- Soylak, Mustafa(7)
- Alemdag, Selcuk(6)
- Bulut, Volkan Numan(6)
- Kıranşan, Murat(6)
- Serencam, Huseyin(6)
- Akar, Bülent(5)
- Baltaci, Cemalettin(5)
- Gücer, Mehmet Ali(5)
- Tufekci, Mehmet(5)
- Akaryali, Enver(4)
- Bozbeyoglu, Pinar(4)
- Camoglu, Aslihan Yilmaz(4)
- Elvan, Hamide(4)
- Imamoglu, Mustafa(4)
- Seker, Serdal(4)
- Akpinar, A.(3)
- Akçay, Fatma(3)
- Alemdağ, Selçuk(3)
- Başoğlu, Aysel(3)
- Günen, Mehmet Akif(3)
- Kaygusuz, K.(3)
- Okkan, Umut(3)
- Senturk, Hasan Basri(3)
- Turfan, Fatma Asya(3)
- Vural, Alaaddin(3)
- Yagmur, Nur(3)
- Yıldız, Mehmet Berkant(3)
- Şibil, Rahim(3)
- Aras, Egemen(2)
- Ayas, Mustafa Sinasi(2)
- Ayas, Selen(2)
- Bahadir, Zekeriyya(2)
- Barinova, Sophia(2)
Yayınlar
- MakaleYalnız künye2024Remote sensing and monitoring of water resources: A comparative study of different indices and thresholding methods
Günen, Mehmet Akif; Atasever, Umit Haluk
Water resources are essential for the ecological system and the development of civilization. Water is imperative factor for health preservation and sustaining various human activities, including industrial production, agriculture, and daily life. Remote sensing provides a cost-effective and practical means to detect and monitor water bodies, offers valuable insights into the impact of climatic events on water structures, especially in coastal lake regions. The research primarily utilizes Landsat-9 OLI-2 satellite images to evaluate the effectiveness of various water indices (WRI, NWI, MNDWI, NDWI) in combination with global automatic thresholding methods (K-Means, Zhenzhou's, Adaptive, Intermodes, Prewitt and Mendelsohn's Minimum, Maximum Entropy, Median, Concavity, Percentile, Intermeans, Kittler and Illingworth's Minimum Error, Tsai's Moments, Otsu's, Huang's fuzzy, Triangle, Mean, IsoData, Li's). The study was carried out on Lake Nazik, Lake Iznik, and Lake Beyşehir, which have unique geographical characteristics, and examined the adaptability and robustness of the selected indices and thresholding methods. MNDWI consistently stands out as a robust index for water extraction, delivering accurate results across different thresholding methods in regions all three lakes. As a result of quite extensive analysis, it is obtained that MNDWI and NDWI are reliable choices for water feature extraction in various lake environments, but the specific index should consider the thresholding method and unique lake characteristics. The Minimum thresholding method stands out as the most effective thresholding technique, demonstrating impressive results across different lakes. Specifically, it achieved an average Peak Signal-to-Noise Ratio (PSNR) of 78.97 and Structural Similarity Index (SSIM) of 99.37 for Lake Nazik, 74.08 PSNR and 98.34 SSIM for Lake Iznik, and 63.96 PSNR and 93.61 SSIM for Lake Beyşehir.
- MakaleAçık Erişim2024Trends and amount changes of temperature and precipitation under future projections in high–low groups and intra-period for the Eastern Black Sea, the Wettest Basin in Türkiye
Nacar, Sinan; Şan, Murat; Kankal, Murat; Okkan, Umut
This study investigates the possible effects of climate change on temperature and precipitation variables in the Eastern Black Sea Basin, Türkiye’s wettest and flood-prone region. The outputs of three GCMs under historical, RCP4.5, and RCP8.5 scenarios were downscaled to regional scale using the multivariate adaptive regression splines method. The future monthly temperature and precipitation for 12 stations in the basin were projected for three periods: the 2030s (2021–2050), 2060s (2051–2080), and 2090s (2081–2100). In addition to relative changes, high and low groups and intra-period trends were analyzed for the first time using innovative methods. For the pessimistic scenario, an increase of 3.5 °C in the interior and 3.0 °C in the coastal areas of the basin is projected. For the optimistic scenario, these values are expected to be 2.5 and 2.0 °C, respectively. A decrease in precipitation is projected for the interior region, and a significant increase is expected for the eastern and coastal areas of the basin, especially in spring. This result indicates that floods will occur frequently coastal areas of the basin in the coming periods. Also, although the monotonic trends of temperatures during periods are higher than precipitation in interior regions, these regions may have more uncertainty as their trends are in different directions of low and high groups of different scenarios and GCMs and contribute to all trends, especially precipitation.
- MakaleAçık Erişim2024Extraction of Water Bodies from High-Resolution Aerial and Satellite Images Using Visual Foundation Models
Ozdemir, Samed; Akbulut, Zeynep; Karsli, Fevzi; Kavzoglu, Taskin
Water, indispensable for life and central to ecosystems, human activities, and climate dynamics, requires rapid and accurate monitoring. This is vital for sustaining ecosystems, enhancing human welfare, and effectively managing land, water, and biodiversity on both the local and global level. In the rapidly evolving domain of remote sensing and deep learning, this study focuses on water body extraction and classification through the use of recent deep learning models of visual foundation models (VFMs). Specifically, the Segment Anything Model (SAM) and Contrastive Language-Image Pre-training (CLIP) models have shown promise in semantic segmentation, dataset creation, change detection, and instance segmentation tasks. A novel two-step approach involving segmenting images via the Automatic Mask Generator method of the SAM and the zero-shot classification of segments using CLIP is proposed, and its effectiveness is tested on water body extraction problems. The proposed methodology was applied to both remote sensing imagery acquired from LANDSAT 8 OLI and very high-resolution aerial imagery. Results revealed that the proposed methodology accurately delineated water bodies across complex environmental conditions, achieving a mean intersection over union (IoU) of 94.41% and an F1 score of 96.97% for satellite imagery. Similarly, for the aerial imagery dataset, the proposed methodology achieved a mean IoU of 90.83% and an F1 score exceeding 94.56%. The high accuracy achieved in selecting segments predominantly classified as water highlights the effectiveness of the proposed model in intricate environmental image analysis.
- MakaleYalnız künye2024Spatiotemporal analysis of transition probabilities of wet and dry days under SSPs scenarios in the semi-arid Susurluk Basin, Türkiye
Şan, Murat; Nacar, Sinan; Kankal, Murat; Bayram, Adem
Precipitation, especially in regions dominated by the Mediterranean climate, is one of the most critical parameters of the hydrological cycle and the environment affected by climate change. One the one hand, the transition probabilities of wet and dry days in precipitation occurrence are a relatively new topic, on the other hand these are essential in defining the regional climate. For the first time, spatiotemporal variations of transition probabilities of wet and dry days in the Susurluk Basin, northwestern Türkiye, dominated by a semi-arid Mediterranean climate and also having a mountain climate, were analyzed based on the observation (1979–2014) and future terms (2030–2059 as short and 2070–2099 as long), under four Shared Socioeconomic Pathways (SSPs) scenarios. To do this, statistical downscaling was performed for 14 general circulation models (GCMs) from the CMIP6. By applying an ensemble of four high-performing GCMs, four indices for transition probabilities of wet and dry, i.e., a dry day following a dry day (FDD), a wet day following a dry day (FDW), a dry day following a wet day (FWD), and a wet day following a wet day (FWW), were calculated, and their changes were determined statistically. Monotonic and partial trends of the indices were also analyzed. According to the results, the FDD will increase in water year and wet period and autumn in the future, especially for the long term, in the basin dominated by the FDD (75 % in water year). The risks are higher in the western part of the basin, where human activities are intense, as the FDD is higher in this part than other parts especially in summer (90–100 %) in SSP3-7.0 and SSP5-8.5 scenarios for the long term. So, the length of consecutive dry days in the wet period and water year will increase in the basin, thus increasing the likelihood of droughts. As for the intra-term trends, the FDD increases and the FWW decreases in the water year and seasons in SSP3-7.0 and SSP5-8.5, contrary to the observation term.
- MakaleAçık Erişim2023Geri dönüşüm işletmelerinin inşaat ve yıkım atıkları açısından performanslarının bütünleştirilmiş SWARA-EDAS yöntemiyle değerlendirilmesi: Türkiye örneği
Gergin, Ramazan Eyüp
Günümüzde, inşaat ve yıkım atıklarının artan miktarı nedeniyle ülke ekonomileri birçok zorlukla karşı karşıya gelmektedir. Döngüsel ekonomilerde inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerinin daha önemli rol oynaması beklenmektedir. Buna paralel olarak inşaat ve yıkım atıklarının geri dönüşümü ülkelerin rekabet gücünü doğrudan etkilemektedir. Bu çalışma inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmelerin performanslarını değerlendirmeyi amaçlamaktadır. İşletmelerin performanslarını değerlendirmek için kullanılan kriterler detaylı bir literatür taraması yapılarak belirlenmiştir. Çalışmanın alternatiflerini ise inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmeler oluşturmaktadır. Belirlenen kriterlerin ağırlıklandırılmasında Step-Wise Weight Assesment Ratio Analysis (SWARA) kullanılmıştır. Kriter ağırlıklarının belirlenmesinin ardından inşaat ve yıkım atıklarının geri dönüşüm faaliyetlerini gerçekleştiren işletmelerin performansı Evaluation Based on Distance from Average Solution (EDAS) ile değerlendirilmiştir. Çalışmanın sonuçlarına dayalı olarak, inşaat ve yıkım atıklarının geri dönüşümünde en önemli kriter Sürdürülebilirlik olarak belirlenmiştir. Ayrıca çalışma çevresel etkiler ile inşaat ve yıkım atıklarının taşınması kriterlerinin sırasıyla diğer önemli kriterler olduğunu göstermektedir. EDAS yönteminin sonucu ise Alternatif 5 işletmesinin inşaat ve yıkım atıklarının geri dönüştürülmesi açısından en iyi performansa sahip olduğunu göstermektedir.
- MakaleAçık Erişim2023Natural and H2SO4 modified plane sawdust as a low-cost adsorbent: Removal of anionic and cationic dyes from aqueous solutions
Duran, Celal; Kalkışım, Özgün; Ozdes, Duygu; Ozeken, Sengul Tugba; Top, Yener
Natural and H2SO4-modified plane (Platanus orientalis L.) sawdust were used for the adsorptive removal of cationic methylene blue (MB) and anionic indigo carmine (IC) dyes from aqueous media to suggest a new and cost-effective method for wastewater treatment applications. The influences of initial pH values, concentrations of MB and IC, period of contact, dosages of the natural and modified plane sawdust, and the presence of foreign ions on the adsorption of dyes were investigated in the experimental studies to describe the best conditions of the most efficient adsorption processes. Initial pH values were optimized to be between 6.0-8.0 for MB and 2.0 for IC. Experimentations of Boehm titration, FTIR analysis, pHpzc value, and moisture content determinations were utilized to characterize the natural and modified sawdust materials. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were used to evaluate the sorption mechanism. Maximum adsorption capacities of natural plane sawdust (NPS) and H2SO4-modified plane sawdust (MPS) calculated from the Langmuir isotherm model were 55.56 and 38.46 mg g-1 in MB adsorption, and 55.82 and 55.55 mg g-1 in IC adsorption, respectively. Results showed that the natural and H2SO4-modified plane sawdust serve as low-cost and efficient materials in the adsorptive removal of MB and IC dyes for industrial wastewater treatment applications.
- MakaleAçık Erişim2023Adsorption of hexavalent chromium from aqueous solution onto corn cobs – activated carbon
Gundogdu, Ali; Bozbeyoglu, Pinar
This study evaluated the performance of a new activated carbon (CCs-AC) produced from corn cobs by boric acid activation for the effective removal of hexavalent chromium, a heavy metal with high potential to pollute the environment, from wastewater. For this purpose, with the help of parameters such as solution pH, contact time, initial Cr(VI) concentration, CCs-AC dose, desorption and temperature, the removal of Cr(VI) ions from aqueous solution by adsorption on CCs-AC was investigated from equilibrium, kinetic and thermodynamic point of view. As a result of the experiments, it was determined that the optimum solution pH was 2.0, the contact time was 4 hours, and the desorption solution was 3.0 M NaOH. From the kinetic data, it was determined that the adsorption was compatible with the pseudo-second order kinetic model and the maximum Cr(VI) adsorption capacity (123.7 mg/g) obtained from the Langmuir isotherm model showed that CCs-AC was of competitive quality with the literature. From the thermodynamic data, the positive ΔH value indicates that the adsorption is endothermic and the value of 12.00 kj/mol indicates that the adsorption is rather chemically driven. The negative ΔG value indicates that the process proceeds spontaneously with an increase in temperature, while the ΔS value indicates an increase in the amount of unused energy.
- MakaleAçık Erişim2023Yerel yönetimlerde katı atık yönetimi ve gelişimi: genel çerçeve ile türkiye’ye bakış
Sarıhan, Nazlı Özcan; Çakır, Erkan
Son yıllarda kentleşme, hızlı nüfus artışı ve sanayileşmeyle birlikte doğal kaynaklar üzerindeki baskının hızla artmasıyla ekolojik dengenin bozulduğu görülmektedir. İnsanoğlunun doğal kaynakları hoyratça ve savurganca kullanması, toplumsal refahın yalnızca tüketimle sağlanacağı görüşü, kentleşme ve gelir seviyesindeki artışlar, tüketim alışkanlıklarında meydana gelen değişiklikler kentsel atıkların ortaya çıkmasına neden olmuştur. Tüketim alışkanlığındaki artışların temelde iki önemli problemi ortaya çıkardığı görülmektedir. Bunlardan ilki tüketimde meydana gelen artışın doğal kaynaklar üzerinde yapmış olduğu baskı, bir diğeri ise tüketim sonrasında ortaya çıkan atığın bertarafına ilişkin sorundur. Kentsel katı atıkların ortaya çıkmasını önlemek ve ortaya çıkan bu atıkların atılıp kurtulunması gereken madde olmaktan çıkarıp ekonomik bir değere dönüştürecek ve en önemlisi de sağlıklı bir şekilde bertaraf edilecek Entegre Katı Atık Yönetimine ihtiyaç duyulmaktadır. Bu çalışmada, katı atık yönetimi ve bu kapsamda atık yönetimi hiyerarşisi açıklanarak, Türkiye’de katı atık yönetiminin veriler ışığında ne düzeyde olduğu ve bu süreçte yerel yönetimlerin görev ve sorumluluklarının yasalar çerçevesinde neler olduğuna ilişkin bilgi verilmeye çalışılmıştır. Türkiye’de bu sürecin gün geçtikçe daha sağlıklı bir şekilde yönetilmesine rağmen bazı atık yönetim stratejilerinin verimli bir şekilde kullanılmadığı sonucuna ulaşılmıştır.
- MakaleAçık Erişim2023Analysis of Basin Characteristics for Stream Management Using GIS: A Case Study of Gümühane Micro-Watershed
Çakir, Gunay
Aim of study: Topography and climatic conditions have effected in determining the processes of the streams of the micro-watershed. Nowadays, the management plans were made for water and soil protection measures in the basins. Area of study: This study was carried outto characterize and prioritize the streams of the Gumushane upper Harsit micro-watershed using a GIS-based spatial approach. Material and methods: Fundamental watershed characteristics including drainage density, slope, land use types, and stream class were evaluated and interpreted for the Gumushane micro-watershed. Calculatea comprehensive value for each parameter, drainage density (Dd), flow frequency (Fs), slope (S), length of land flow (Lg), and land use (Lu) was used. Main results: The drainage density, stream flow frequency, and form factor of the microwatershed are from-4 to 26. Finally, the weighted rankings were summarized, and all micro-watersheds were categorized to five classes based on the risk index as very low risk, low risk, medium risk, high risk, and very high risk. This risk map overlaid to land use type maps in GIS where risk areas were evaluated in the finalrisk results. The 739 ha productive forest area within very high-risk areas was changed to non-risk parameters. Highlights: The carrying capacity of streams was calculated using the stream density of streams in the Gumushane micro-watershed. The risk values produced by streams that pass through neighborhoods where land use values for preventing erosion are present.
- BildiriYalnız künye2023Anomaly Detection in Predicted Water Treatment Data using Hybrid CNN-LSTM Network Model
Özgenç, Busra; Ayas, Selen; Dogan, Ramazan Ozgur; Çavdar, Bora; Sahin, Ali Klvanc; Ayas, Mustafa Sinasi
Water treatment systems are among the industrial control systems where it is essential to detect anomalies accurately and efficiently due to the potential threat to public health. With advances in computer science, machine learning models have been successfully used in the anomaly detection process in recent years. In this paper, a hybrid CNN-LSTM network model is proposed to detect anomalies in water systems. Using a statistical window-based anomaly detection approach, the performance of the proposed model in detecting different types of attacks is analyzed on the open SWaT dataset. Experimental results show that the precision, recall and F1-score values of the proposed model are 0.994, 0.973 and 0.983, respectively, and can be successfully used to detect anomalies in water treatment systems.
- MakaleYalnız künye2023An Overview of Applications of the Electro-Fenton (e–/H2O2/Fe2+) Oxidation Processes: Degradation of Acid and Basic Dyes in the Industrial Wastewaters
Kıranşan, Murat
Abstract: As a result of the rapid development of industry and technology, a great increase has been observed in the use of chemicals and toxic substances harmful to the environment, especially in the last 20 yr. The harmful effects of industrial wastewater, which are formed as a result of the use of chemical and toxic substances as raw substances and by products in many technology branches, adversely affect the environment. Traditional treatment methods are quite inadequate in the treatment of industrial wastewater. Water pollution is one of the most important environmental problems of today. Since water is the most basic need of living things and the source of great economic activities, it is an indispensable resource for the continuation of living and non-living life. Acid dyes, one or more in the molecule contain a sulfonic acid group or a carboxylic acid group. Acid dyes are chemically classified as anionic dyes. Direct metal-complex and reactive dyestuffs containing sulfonic acid groups are also anionic. Basic dyes are in the form of hydrochlorides of organic bases and are found in the colored part of the cationic group dye. Basic dyes, contain N or S atoms as positive charge carriers. Different chemical, physical and biological processes such as chlorination, ozonation, adsorption and microfiltration are widely used in cleaning the environments where industrial wastes are present. However, in all of these methods organic substance can be removal by transferring it from one phase to another. However, due to increasing environmental pollution, the treatment process has changed to develop new methods that can decompose organic substances into CO2 and H2O instead of transferring them from one phase to another. Hybrid systems in which different oxidation processes are applied simultaneously in the same electrochemical cell, are widely used today in order to increase the efficiency of the electrochemical methods.
- MakaleAçık Erişim2023Sustainable water consumption and water-saving behaviours: A review of consumers' environmental and economic concerns in Turkey
Avci, İbrahim
Water, which plays an important role in human life, has been depleted as a result of changing consumption patterns, climate change and increasing population, and water scarcity has emerged as one of the most pressing issues facing the world in the coming years. One solution to this problem is to make more efficient and sustainable use of existing water resources. In this context, the study aims to investigate the effects of consumers' environmental and economic concerns on sustainable water consumption behaviour, as well as the mediating role of water-saving behaviour in these effects. For this purpose, it was discovered that environmental and economic concerns have positive effects on sustainable water consumption behaviour as a result of an analysis of data collected from 591 consumers in Turkey via the online survey method; it was determined that environmental concerns have no effect on water-saving behaviour, whereas economic concerns have a positive effect on water-saving behaviour. According to the findings of the mediation analysis, water-saving behaviour only serves to mediate the effect of economic concerns on sustainable water consumption behaviour.
- MakaleYalnız künye2023Hydrodynamic performance evaluation of screening on the physical unit operations in wastewater treatment based on experimentally validated CFD computations
Şahin, Nagehan; Şibil, Rahim
This paper introduces an evaluation of the hydrodynamic performance of the flow in the screens used on the physical unit operations in a selected full-scale wastewater treatment plant (WWTP) based on Computational Fluid Dynamics (CFD) simulations. The numerical study was carried out with the ANSYS Fluent, CFD software by using the three-dimensional (3 D), steady, incompressible flow based on the Reynolds-Average Navier-Stokes equations with three different turbulence modeling. The hydrodynamic behavior of the screening facility, combined with head pond-upstream channel-bar screens was evaluated under different conditions of the mass flow rate and velocity fields. Also, the numerical study was validated against the experimental study, which implemented in-situ measurements by Acoustic Doppler Velocimeter (ADV), and consistent results were obtained between the numerical and experimental study. Interestingly, while the Realizable (real) k-ε turbulence model with the relative error of 9.31% gave the best predicting results in the head pond, the renormalization group (RNG) k-ɛ turbulence model with the relative error of 9.05% gave the best predicting results in the upstream channel and through bar screens. As a result of the experimental measurements and CFD analyses carried out in the full-scale WWTP, the function of the screening facility was found to be incomplete. Moreover, a hydraulically improved new geometry was presented to operate the existing WWTP efficiently.
- BildiriYalnız künye2023A Hybrid CNN-LSTM Framework for Unsupervised Anomaly Detection in Water Distribution Plant
Sahin, Ali Kivanc; Cavdar, Bora; Dogan, Ramazan Ozgur; Ayas, Selen; Ozgenc, Busra; Ayas, Mustafa Sinasi
To reduce potential threats to public health and economic losses, water distribution systems, which are critical parts of industrial control systems, require accurate and effective anomaly detection. The successful incorporation of machine learning models into anomaly detection procedures has been made possible by recent developments in computer science. In this research, a hybrid CNN-LSTM framework for anomaly detection in water distribution systems is presented using Python programming language in the JupyterLab environment. The performance of the proposed CNN-LSTM network model is carefully evaluated on the publicly available WADI dataset, which contains several types of attacks for a water distribution testbed, using a statistical window-based anomaly detection approach. The experimental results show acceptable precision, recall and F1 scores of 0.8619, 0.7041, and 0.775, respectively, demonstrating the efficiency of the framework in detecting anomalies in the water distribution system.
- MakaleYalnız künye2023Trend analysis of precipitation using innovative approaches in northwestern Turkey
Körük, Ali Emre; Kankal, Murat; Yıldız, Mehmet Berkant; Akçay, Fatma; Şan, Murat; Nacar, Sinan
Precipitation is highly sensitive to climate change, and monitoring its trends over time is essential for understanding the effects of global warming on the Earth's water cycle. This study investigates the effects of climate change on monthly precipitation in the Susurluk Basin located in northwestern Turkey, using innovative trend analysis methods. Innovative Polygon Trend Analysis (IPTA) using star graphics and Improved Visualization for Innovative Trend Analysis (IV-ITA) techniques were used to analyze precipitation data from nine stations in the basin over 50 years (1970–2019), and the findings were compared to classical Mann-Kendall (MK) results. According to the trend analysis results, the MK method detected significant trends in only two months in the decreasing direction. In these decreasing trends observed at Simav and Keles stations in November, z values were calculated as −2.38 and −2.05, respectively. IPTA method detected increasing trends in 54 months and decreasing trends in 40 months; this means there is a change of more than 5% between two half series. The IV-ITA method indicated an increase of more than 40% in the low values for January, March, August, and September. In addition, there was an increasing trend of more than 40% in the high values observed in September at all stations. It was observed that mean precipitation heights increased from September to December and then decreased throughout the basin. It is predicted that decreases in precipitation during dry seasons may put intense pressure on agricultural water use and affect water quality. In addition, the increase in precipitation in spring months may increase flood events. It was determined that graphical innovative trend analysis methods are more effective in trend identification than MK, and these methods' results have much higher visual inspection and linguistic interpretation possibilities. Innovative methods allow for more flexible and in-depth analysis using different statistical parameters.
- MakaleAçık Erişim2023Comparison of the removal efficiencies of Basic red 46 from aqueous solutiousing Aşkale lignite with and without ultrasound assisted processes
Karaca, Canan; Karaca, Melike; Kıranşan, Murat; Karaca, Semra; Açışlı, Özkan; Gürses, Ahmet
This study compared the removal efficiencies of Basic red 46 from aqueous solutions with and without ultrasound-assisted processes using lignite as a low-cost adsorbent. The effects of various experimental parameters such as contact time, adsorbent dosage, initial solution, pH, initial dye concentration and temperature on the dye removal efficiency were investigated. The experimental results were modelled by the kinetic and isotherm models. Both of processes fitted well to pseudo-second-order kinetics and the Langmuir model with highest correlation coefficients for all of three temperatures. The results showed that the influence parameters have a different effect on the removal efficiency in the presence and absence of ultrasonic irradiation. When the results obtained for both processes are compared, it is seen that the removal efficiency obtained with the ultrasound assisted process is much higher than that obtained with non-ultrasound assisted process at high dye concentrations. The removal efficiency of ultrasound-assisted and unassisted processes was found to be 81.5% and 54.6%, respectively, at 80 mg/L dye concentration and 60 min. Thermodynamic parameters showed that the adsorption process was spontaneous and exothermic. The enthalpy and entropy changes for the ultrasound-assisted process were –9.35 kJ/mol and –0.03 kJ/K·mol, respectively.
- MakaleAçık Erişim2023Adsorption Behaviour of EDTA Modified Magnetic Fe3O4 Coated Brewed Tea Waste on Cr(VI) Removal
Yilmaz Camoglu, Aslihan; Ozdes, Duygu; Duran, Celal
The study focused on fabricating a novel magnetic Fe3O4 loaded and EDTA modified brewed tea waste (TW-Fe3O4-EDTA) as a cheap, environmentally friendly, and efficient adsorbent for the removal of Cr(VI) ions from aqueous medium in a batch system. Characterization of the prepared adsorbent was performed with different techniques. Adsorption experiments were implemented at different conditions including initial solution pH (1.0–7.0), equilibrium time (1–480 min), adsorbent dosage (1.0–20.0 g L–1), and initial Cr(VI) concentration (50–1000 mg L–1). The optimum adsorption performance was observed at pH 2.0 with 120 min of contact time. Maximum adsorption capacity of 114.9 mg g–1 was acquired for TW-Fe3O4-EDTA which is much higher than the recently developed adsorbents for Cr(VI) removal. Adsorption process was well explicated by Freundlich isotherm model and the adsorption rate is described in accordance with pseudo-second order kinetic model. It was observed that common salts did not have a notable influence on Cr(VI) adsorption. The results of the study indicated that TW-Fe3O4-EDTA can be applied as an effective adsorbent in heavy metal removal as an alternative to many expensive adsorbents available in the literature.
- MakaleAçık Erişim2023A green and simplified approach for the quantitative and sensitive analysis of heavy metal ions in sea and stream waters
Duran, Celal; Camoglu, Aslihan Yilmaz; Ozdes, Duygu; Bekircan, Olcay
Elimination of the matrix effect is a major challenge in developing a method for the quantification of heavy metals (HMs) in water samples. In this regard, the current research describes the simultaneous analyses of Cu(II), Cd(II), and Ni(II) ions in water matrices through flame atomic absorption spectrophotometry (FAAS) after preconcentration with carrier element-free co-precipitation (CEFC) technique by the help of an organic co-precipitant, 3-{[5-(4-Chlorobenzyl)-3-(4-chlorophenyl)-1H-1,2,4-triazol-1-yl]-methyl}-4-[2,4-(dichlorobenzylidene)amino]-1H-1,2,4- triazole-5(4H)-thione (CCMBATT). Based on our literature research, CCMBATT was employed for the first time in this study as an organic co-precipitant for the preconcentration of HMs. Factors such as solution pH, concentration of co-precipitant, sample volume, standing time, centrifugation rate, and time were thoroughly examined and optimized to achieve the highest efficiency in terms of HM recovery. The limits of detection (LODs) (with 10 number of tests) of 0.54, 0.34, and 1.95 μg L-1 and the relative standard deviations (RSD %) of 2.1, 3.3, and 3.0 were determined for Cu(II), Cd(II) and Ni(II) ions, respectively. Recovery results of HMs for the spiked samples were in the range of 92.8-101.0%, demonstrating the trueness of the method and its applicability to the water samples matrix.
- MakaleAçık Erişim2023Enhancement of adsorptive removal efficiency of an anionic dye from aqueous solutions using carboxylic acid-modified mulberry leaves: Artificial neural network modeling, isotherm, and kinetics evaluation
Duran, Celal; Ozeken, Sengul Tugba; Camoglu, Aslihan Yilmaz; Ozdes, Duygu
Natural mulberry leaves and carboxylic acid-modified mulberry (Morus alba L.) leaves were used for the first time to scrutinize the effects of modification on the retention efficiency of an anionic dye (Remazol Brilliant Blue R (RBBR)) from aqueous solutions to suggest an economical and promising adsorbent for the treatment of dye-contaminated water. The characterization of the adsorbents was accomplished through common techniques including SEM, FTIR, and pHpzc determination. Several parameters studied in batch experiments pointed out that the initial pH of 2.0 and the contact time of 240 min were optimum conditions for all the developed RBBR uptake processes. An artificial neural network (ANN) model was applied to formulate a forecast model for the uptake efficiency of RBBR. The experimental data were assessed by different kinetic and isotherm models to explain the mechanism of the developed processes in more detail. Maximum monolayer adsorption capacities of natural mulberry leaves and acetic acid-, citric acid-, and oxalic acid-modified mulberry leaves were determined as 64.5, 95.2, 84.8, and 91.7 mg g1, respectively, by the Langmuir isotherm model. These results demonstrated that the modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves.
- MakaleYalnız künye2023Excessive groundwater withdrawal and resultant land subsidence in the Küçük Menderes River Basin, Turkey as estimated from InSAR-SBAS and GNSS measurements
Yalvaç, Sefa; Alemdağ, Selçuk; Zeybek, Halil İbrahim; Yalvaç, Murat
Küçük Menderes River Basin (KMRB) is located in the western part of Turkey in the city of İzmir. The basin hosts about half a million people and 90% of the population makes their living from farming and animal husbandry. Most of the water needs for agricultural irrigation, animal husbandry, and drinking are met from groundwater resources in the basin. Since the water pumped from the aquifers cannot be naturally recharged by surface waters and precipitation, the groundwater level is rapidly receding and a decrease of up to 150 meters has been observed in the historical groundwater level time series since the 1990s. For this reason, land subsidence occurred in the basin and as a result of this, crustal surface cracks have formed and infrastructure and superstructure facilities have been endangered. To prevent loss of life and property that may occur in the future, it has become necessary to estimate the magnitude and the expansion zone of the land subsidence by carrying out geodetic monitoring studies in the region. In this study, the analyzes performed by Interferometric Synthetic Aperture Radar-Small Baseline Subset (InSAR-SBAS) and Global Navigation Satellite System (GNSS) methods to monitor land subsidence in the KMRB are presented. For this purpose, monthly 74 SAR images from 2017 to the end of 2022 were evaluated according to the SBAS procedure in the GMTSAR academic analysis software. In order to, both validate the InSAR-SBAS results and convert the deformation rate in the Line of Sight (LOS) to the ellipsoid normal direction, 3 periods of GNSS campaign were performed between 2021 and 2023 in 5 different GNSS stations and evaluated with the GAMIT/GLOBK software. According to the analyses, the land subsidence rate of up to −165 mm/year has been estimated in the KMRB, especially in the district centers of Bayındır and Ödemiş. In addition, unlike many studies, different rates and propagation of subsidence were determined in different parts of the basin depending on the aquifer type and precipitation. Monthly time series of the deformations were created and the behavior of the deformations and its relationship with the groundwater withdrawal and the lithological structure in the region was scrutinized. Thus, the spatio-temporal behaviour of the land subsidence and the associated geological factors were revealed.
