İnşaat Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/205

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Arsenic removal by the micellar-enhanced ultrafiltration using response surface methodology
(IWA PUBLISHING, ALLIANCE HOUSE, 12 CAXTON ST, LONDON SW1H0QS, ENGLAND, 2020) Gokcek, Oznur Begum; Uzal, Nigmet; 0000-0002-0912-3459; 0000-0003-1730-2905; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü
The present research investigates the removal of arsenic (As) from aqueous solutions using micellar-enhanced ultrafiltration (MEUF) by utilizing two different surfactants: benzethonium chloride and dodecyl pyridinium chloride (BCl and DPCl). The impact of the operating variables and maximum removal efficiency were found under different conditions for BCl and DPCl surfactants. The maximum As rejection efficiency for MEUF with BCl and DPCl surfactants is 92.8% and 84.1%, respectively. In addition to this, a statistics-based experimental design with response surface methodology was used for the purpose of examining the impact of operating conditions, including initial pH, initial As concentration (ppb), and surfactant concentration (BCl, mM) in As-removal from aqueous solutions. In the analysis of the experimental data, a second-order polynomial model that was validated by statistical analysis for the BCl surfactant was used. On the basis of the response model created, the removal of As ions was acquired at optimum operating parameters, including the initial As concentration of 150 ppb, surfactant concentration of 5 mM and pH 10 for the BCl surfactant with 92.8% As-removal efficiency.
Arsenic removal from aqueous solutions by ultrafiltration assisted with polyacrylamide: an application of response surface methodology
(DESALINATION PUBL, 2015) Varol, Bekir; Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
The present work deals with removal of arsenic from aqueous solutions by ultrafiltration assisted with polyacrylamide as an environmental friendly complexing polymer. The system performance was evaluated in relation to quality of permeate in terms of operating variables as feed concentration of arsenic ions (C-o, gL(-1)), ratio of polymer to arsenic (r, w/w), and pH of feed solution. The effect of the operating variables and maximum arsenic removal efficiency was determined by adopting design of experiments and response surface methodology under different conditions for this polymer. The experimental data were analyzed with a second order polynomial model validated by statistical analysis. Based on the response model developed, the maximum removal efficiency, close to 100%, of arsenic ions has been obtained at optimum operating parameters as C-o: 150 gL(-1), r: 2, and pH 10.
Comparative life cycle assessment of retort pouch and aluminum can for ready-to-eat bean packaging
(SPRINGER, 2023) Gulcimen, Sedat; Ozcan, Ozlem; Cevik, Selin Babacan; Kahraman, Kevser; Uzal, Nigmet; 0000-0002-8967-3484; 0000-0002-2786-3944; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gulcimen, Sedat; Ozcan, Ozlem; Kahraman, Kevser; Uzal, Nigmet
Since packaging contributes to severe environmental impacts in food production, alternatives of packaging materials that satisfy customer needs while minimizing environmental impacts in a cost-effective manner should be preferred for food product sustainability. This paper compares two different packaging materials (aluminum cans and retort pouches) with a life cycle approach to assess the environmental impacts of ready-to-eat bean packaging. The life cycle assessment (LCA) was used to define and compare the environmental performance of ready-to-eat beans in aluminum cans and retort pouches. The gate-to-gate approach was used in the LCA, with a functional unit of 1 kg of packaged ready-to-eat bean product. Inventory for packaging in retort pouch was created in collaboration with Duru Bulgur Company (Karaman, Turkey) and the data for ready-to-eat beans in the aluminum can were gathered from the literature. The findings show that ready-to-eat beans in retort pouches have lower environmental impacts than ready-to-eat beans in aluminum cans. The packaging and washing processes for both ready-to-eat beans packaged in aluminum cans and retort pouches had the greatest environmental impact. In ready-to-eat beans production, retort pouch provides 87% better environmental performance than aluminum can in terms of global warming (GW). Overall, the results demonstrated that replacing aluminum cans with retort pouches in ready-to-eat bean production can significantly reduce environmental effects in all impact categories.
Determining the priority waste in aluminum manufacturing sector using the smaa-2 method: A case study of kayseri
(Computers and Industrial Engineering, 2014) Aydogan, Emel Kizilkaya; Ates, Nuray; Uzal, Nigmet; Ozmen, Mihrimah; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
Small and medium-sized enterprises (SMEs) constitute a major part of the Turkish economy, accounting for a large proportion of the country's businesses and total employment. Although the SMEs are known as important contributors to environmental pollution, the relative contribution of SMEs to the total environmental impacts of industrial is unknown. The most important environmental issues related with aluminum industries are emission of gases, wastewater and solid wastes from aluminum production. In multi-criteria decision making (MCDM) problems in some situations, decision makers (DMs) don't or can't express their preferences obviously. In these situations for decision making, stochastic multi-criteria acceptability analysis (SMAA-2) can be applied. In this study, a multi-criteria decision making model is presented to determine higher priority waste types (air and solid wastes, wastewaters) among the three firms. We used stochastic data by applying and the SMAA-2 results are given.
Efficiency of L-DOPA+TiO2 modified RO membrane on salinity gradient energy generation by pressure retarded osmosis
(Pamukkale Üniversitesi, 2024) Ateş, Nuray; Saki, Seda; Gokcek, Murat; Uzal, Niğmet; 0000-0001-8923-2323; 0000-0002-0912-3459; AGÜ, Fen Bilimleri Enstitüsü, Malzeme Bilimi ve Makine Mühendisliği Ana Bilim Dalı; SAKİ, Seda; Uzal, Niğmet
Harvesting energy from the salinity gradient of seawater and river water using pressure retarded osmosis (PRO) has been a major research topic of recent years. However, there is a need for efficient PRO membranes that can generate high power density and are pressure resistant, as the performance of current membranes on the market is poor. In this study, specific energy potential of PRO process using LDOPA+TiO2 modified BW30-LE membrane was evaluated on synthetic and real water samples. Polyamide BW30-LE RO membrane was modified by L-DOPA, L-DOPA+0.5 wt% TiO2 and L-DOPA+1 wt% TiO2. The effect of hydraulic pressure and temperature on generation of power density were evaluated for 5, 10, and 15 bar pressures, as well as 10 °C, 20 °C, and 30 °C degrees. The incorporation of TiO2 nanoparticles with L-DOPA increased the water flux by increasing the surface hydrophilicity and roughness of the membrane surface. The maximum specific power was observed as 1.6 W/m2 for L-DOPA+1 wt% TiO2 modified BW30-LE membrane at 15 bar pressure. Besides, Mediterranean and Aegean, Black Sea water samples were used as draw solution and Seyhan, Ceyhan, Buyuk Menderes, Gediz, Yesilirmak, and Kizilirmak Rivers were used as feed solution. The highest osmotic power density was obtained by using L-DOPA+1 wt% TiO2 modified BW30-LE membrane with Ceyhan River as feed and Mediterranean Sea water as draw solution, which have the highest differences in salinity. In the mixture of Mediterranean and Ceyhan River, the highest power density was obtained at 10 bar pressure at 30 ± 5°C with 0.70 W/m2 .
Effluent treatment in denim and jeans manufacture
(ELSEVIER, 2015) Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
This chapter discusses the major strategies that should be considered in the treatment of denim dyeing and jeans processing wastewater. It first gives an overview of wastewater characteristics and further elaborates on the different techniques currently available for treating wastewater. There follow the strategies to be adopted for water reuse and the recovery of dyes and chemicals. Also emphasised is the utilisation of novel technologies that provide waste minimisation, recovery and reuse opportunities and pollution prevention, instead of end of pipe approaches for treating this highly polluted wastewater.
Fabrication of Gd2O3/PSF Membranes via Aqueous Phase Inversion Method
(HİTİT ÜNİVERSİTESİ, 2022) Gül, Ayşe; Şenol Arslan, Dilek; Uzal, Nigmet; 0000-0001-9639-2843; 0000-0002-2305-6408; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gül, Ayşe; Şenol Arslan, Dilek; Uzal, Nigmet
The purpose of this study was to look into the effect of Gadolinium oxide (Gd2O3) concentration (0.5%, 1%, and 2%) on the performance of newly developed Gd2 O3 /PSF membranes A common phase inversion method was used to create the membranes. Pure water flux and bovine serum albumin (BSA) permeation tests were used to evaluate membrane performance. FTIR and contact angle measurements were used to characterize the membranes that were manufactured. The greatest percentage of BSA rejection was 53%. In this work, the optimum membrane (2% wt Gd2O3/17% wt PSF) successfully demonstrated 53% rejection with filtrate flux for about 8.7 L/m2.h at a pressure of 10 bar.
A holistic sustainability assessment of a university campus using life cycle approach
(Institute for Ionics, 2023) Gulcimen, Sedat; Qadri, Zakee; Dönmez, Rasim; Uzal, Nigmet; 0000-0002-8967-3484; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gulcimen, Sedat; Qadri, Zakee; Uzal, Nigmet; Dönmez, Rasim
The sustainability performances of campuses are of importance as it could model the efective sustainable initiatives that could be then applied to campuses by decision-makers and designers. Studies have been conducted on the environmental and economic assessment of campuses in specifcation with the identifcation of their carbon footprint and cost analysis, respectively. The studies have lacked a showcase of an ideal sustainable campus along with its urban and architectural features, facilities, and services through analyzing their social aspects as well. The objective of this study was to evaluate the sustainability of the Abdullah Gul University Sumer Campus to model a sustainable campus integrating the Environmental Life Cycle Assessment(E-LCA), the Life Cycle Costing (LCC) and the Social Life Cycle Assessment using life cycle sustainability assessment approaches for the use-phase analysis of the campus. E-LCA was applied to quantify the global warming potential and cumulative energy demand based on International Organization for Standardization 14,040 and 14,044 by considering the gate-to-gate approach. The environmental assessment results showed that the global warming potential of the campus was 2.92 tCO2 eq./person, and the cumulative energy demand was found as 15.4 GJ/person. In LCC, the total cost of the campus was calculated as 200 US Dollars/person, and the energy cost is found as a major contributor with 86% of the total cost for the year of 2019. In the social performance assessment, it is found that the university has a weak social performance for the local community, the consumer, the worker, and the society
The impact of organic cotton use and consumer habits in the sustainability of jean production using the LCA approach
(SPRINGER, 2023) Şener Fidan, Fatma; Kızılkaya Aydoğan, Emel; Uzal, Niğmet; 0000-0002-2397-3628; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, Endüstri Mühendisliği Bölümü; Şener Fidan, Fatma; Uzal, Niğmet
Due to the rise in clothing consumption per person and growing consumer awareness of environmental issues with products, the textile industry must adopt new practices for improving sustainability. The current study thoroughly investigates the benefts of using organic cotton fber instead of conventional cotton fber. Because of the extensive use of natural resources in the production of cotton, the primary raw material for textiles, which accounts for the environmental efects of a pair of jeans, a life cycle assessment methodology was used to examine these efects in four diferent scenarios. The additional scenarios were chosen based on the user preferences for washing temperatures, drying methods, and the type of cotton fber used in the product. The environmental impact categories of global warming potential, eutrophication potential terrestrial ecotoxicity potential, acidifcation potential, and freshwater ecotoxicity potential were analyzed by the CML-IA method. The life cycle assessment results revealed that the lowest environmental impacts were obtained for scenario 4 with 100% organic cotton fber with an improvement of 87% in terrestrial ecotoxicity potential and 59% in freshwater ecotoxicity potential. All of the selected environmental impacts of a pair of jeans are reduced in all scenarios when organic cotton is used. Additionally, consumer habits had a signifcant impact on all impact categories. Using a drying machine instead of a line dryer during the use phase is just as important as the washing temperature. The environmental impact hotspots for a pair of jeans were revealed to be the eutrophication potential, acidifcation potential, and global warming potential categories during the use phase, and the terrestrial ecotoxicity potential and freshwater ecotoxicity potential categories during the fabric manufacturing including cotton cultivation. The use of organic cotton as a raw material in manufacturing processes, as well as consumer preferences for washing temperature and drying methods, appears to have signifcant environmental impacts on a pair of jeans’ further sustainable life cycle.
İnce Film Kompozit Membranlar ile Basınç Geciktirmeli Ozmos (PRO) Prosesi Kullanılarak Sürdürülebilir Enerji Üretimi
(TUBİTAK, 2018) Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
Fosil yakıtlara bağımlılığın azalması için alternatif yenilenebilir ve temiz enerji kaynaklarının bulunmasına yönelik araştırmalar gün geçtikçe artmakta ve önem kazanmaktadır. Son yıllarda oldukça ilgi çeken “tuzluluk gradyanı esaslı ozmotik enerji” veya “mavi enerji” olarak da bilinen enerji kaynağı, artan enerji ihtiyacını karşılamada farklı bir yenilenebilir kaynak olarak ortaya çıkmıştır. Ülkemizdeki tuzluluk gradyanı esaslı enerji potansiyelinin değerlendirilmesine yönelik ilk çalışma niteliğine olan bu projede öncelikle Devlet Su İşlerinden (DSİ) elde edilen nehir debi ve tuzluluk değerleri esas alınarak teorik enerji potansiyeli hesaplamaları gerçekleştirilmiştir. Teorik hesaplamalar tamamlandıktan sonra, enerji potansiyelinin deneysel olarak belirlenmesi için sentetik ve gerçek su örnekleri kullanılarak basınç geciktirmeli ozmos (PRO) prosesinde deneysel çalışmalar gerçekleştirilmiştir. Bu amaçla dört farklı (BW30-LE, SW30-HR, AG, AC) ticari ince film kompozit (TFC) ters osmos membran 3-(3,4-Dihydroxyphenyl)-L-alanine (L-DOPA) ve LDOPA ile birlikte nanomalzemeler (MWCNT, TiO2, SiO2, Al2O3) kullanılarak modifiye edilmiş ve PRO sisteminde işletilerek enerji üretim performansı lab-ölçekli deneyler ile belirlenmiştir. TFC yapıdaki RO membranların modifikasyonu sonrası aktif yüzeylerinde meydana gelen yapısal değişiklerin belirlenmesinde SEM, FTIR, temas açısı, ve AFM analizleri gerçekleştirilmiştir. Deney sonuçları ışığında L-DOPA ile birlikte %1wt TiO2 nanomalzeme ile modifiye edilmiş BW30-LEmembranı 1,61 W/ m2 en yüksek PRO güç üretim potansiyelini göstermiştir. Gerçek su örnekleri ile gerçekleştirilen PRO deneylerinde Akdeniz, Karadeniz, Marmara ve Ege Denizlerinden deniz suyu ve bu denizlere dökülen Seyhan, Ceyhan, Büyük Menderes, Gediz, Susurluk, Kızılırmak ve Yeşilırmak nehirlerinin karıştığı noktalardan örnekler alınarak ülkemizde tuzluluk gradyanı esaslı bu enerjiye ilişkin potansiyel belirlenmiştir. Geçek su numunelerinde en yüksek enerji üretim performansı 56,8 mS/cm iletkenliğe sahip Akdeniz ile 586 µS/cm iletkenliğe sahip Ceyhan ve Seyhan nehrinin PRO prosesi uygulamasından 5 ve 10 barda sırasıyla 0,47 ve 0,68 W/m2 olarak bulunmuştur.
Integration of direct microfiltration and reverse osmosis process for resource recovery from municipal wastewater
(DESALINATION PUBL, 2023) Ozcan, Ozlem; Sahinkaya, Erkan; Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Ozcan, Ozlem; Uzal, Nigmet
For the sustainability of water resources, the recovery of water, organic matter (OM), energy, and nutrients from municipal wastewater become very attractive resources. As direct application of water, nutrient, and energy recovery from municipal wastewater cannot be feasible, the wastewater needed to be concentrated. In this study, the molecular weight distribution of OM content was determined in wastewater samples, up-concentration potential of direct microfiltration (DMF) of municipal wastewater and water recovery were investigated. In OM fractionation studies, around 52% of the chemical oxygen demand (COD) in wastewater was particulate or colloidal (>10 kDa) and 48% was soluble (<300 Da). In DMF tests, the COD concentration was concentrated up to 1,573 mg/L after sequential DMF experiments. Additionally, the theoretic total energy requirement of the DMF process was found around 0.3 kWh/m3 and it would be potentially energy positive. In crossflow experiments, the reverse osmosis (RO) process was performed using DMF effluent. When microfiltration and RO membranes were chemically cleaned, flux recovery rates of 100% and 99% were achieved, respectively. However, the foulants could not be completely removed during the cleaning according to scanning electron microscopy, atomic force microscopy, and attenuated total reflection-Fourier-transform infrared spectroscopy results of the virgin, fouled, and cleaned membranes. This study reveals that the DMF+RO p
Investigation of the treatability of pre-coagulated slaughterhouse wastewater using dead-end filtration
(WILEY111 RIVER ST, HOBOKEN 07030-5774, NJ, 2021) Ozdemir, Safiye; Uzal, Nigmet; Gokcek, Oznur Begum; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
BACKGROUND In the present study, the performance of the membrane process, one of the advanced treatment methods that can enable the reuse of slaughterhouse wastewater, was evaluated. The wastewater was treated using ultrafiltration (UF) (10, 50 kDa), nanofiltration (NF) (150-300 DA) and reverse osmosis (RO) (500 kDa) membranes alone, and UF + NF, UF + RO membrane combinations at different pressures. In addition to rejection and permeate flux considerations, it was attempted to select the most effective membrane by performing scanning electron microscopy, Fourier transform infrared, contact angle, and atomic force microscopy analyses of the membranes used. RESULTS As a result of the experiments, the highest flux was observed at 5 bar for the 50 kDa UF membrane. When the performances of the sequential application of 10 and 50 kDa UF membranes followed by NF and RO membranes were evaluated, the highest flux was obtained for the sequential application of the 50 kDa UF membrane with the NF membrane as 19.68 and 9.05 L m(-2) h, respectively. CONCLUSION The highest chemical oxygen demand (COD) removal was obtained for the RO membrane at 20 bar as 88.67%, and for the 50 kDa UF + RO sequential application, the COD removal was increased from 70% to 88.67%. (c) 2021 Society of Chemical Industry (SCI).
Life Cycle Assessment of the Neutralization Process in a Textile WWTP
(Erciyes Üniversitesi, 2020) Şener Fidan, Fatma; Kızılkaya Aydoğan, Emel; Uzal, Niğmet; 0000-0002-0912-3459; 0000-0003-0927-6698; 0000-0002-2397-3628; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
Although industrial wastewater treatment plants (WWTP) have become an important part of textile facilities in reducing environmental pollution problems, they also produce sludge and various emissions such as high chemical oxygen demand, color and conductivity which have serious negative impacts on the environment. One of the processes with enormous chemical consumption in industrial WWTP of textile facilities is the neutralization process, which aims to adjust the pH of the wastewater. Neutralization processes needed to be optimized in order to determine its overall environmental impacts and then identify the most environmentally appropriate options. The aim of this study is to compare the environmental impacts of carbon dioxide and sulfuric acid, which are two alternative chemicals used in the neutralization process of textile facilities, using Life Cycle Assessment (LCA) approach. The environmental impacts resulting from the use of these two chemicals proposed according to the Reference document on Best Available Techniques (BREF) Document for Textile Industry were revealed by the CML-IA method and the gate-to-gate method. According to the results, using carbon dioxide instead of sulfuric acid, the best improvement was in the abiotic depletion category with 92%, while the least improvement was in the eutrophication potential with 39%. No improvement was observed in the global warming potential and human toxicity impacts.
Life cycle sustainability assessment of a light rail transit system: Integration of environmental, economic, and social impacts
(WILEY111 RIVER ST, HOBOKEN 07030-5774, NJ, 2021) Gulcimen, Sedat; Aydogan, Emel K.; Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Gulcimen, Sedat; Uzal, Nigmet
The transition toward sustainable urban transportation has gained importance in recent decades. However, urban transportation has not been addressed for all dimensions of sustainability. This study presents a life cycle sustainability assessment of a light rail transit system in Kayseri, Turkey, by integrating environmental, economic, and social aspects. The sustainability performance of the light rail transit system is evaluated using a cradle-to-grave approach to assess three aspects of sustainability. For the environmental evaluation, a life cycle assessment was applied using SimaPro 8.4.1 PhD version based on ISO 14040 and 14044. The method, which includes nine environmental impact categories, was employed to assess the environmental performance of the light rail transit system with a functional unit of 1 passenger-km. For the economic assessment, life cycle costing was utilized with the functional unit of USD for 1 passenger-km. A social life cycle assessment was applied to assess the social performance of the light rail transit system based on guidelines published by the United Nations Environment Programme in collaboration with the Society of Environmental Toxicology and Chemistry. For the determination of social impacts, 11 subcategories and 18 social indicators were selected. The results showed that the global warming potential and abiotic depletion potential of the light rail system per passenger-km were 2.4E - 02 kg CO2 eq. and 2.7E - 01 MJ, respectively, with a service life of 50 years. The total life cycle cost of the light rail system was calculated as 0.046 USD for 1 passenger-km. The results also revealed that the main contributor to the total life cycle cost was energy cost, with 92% (2.88E + 08 USD) of the total cost. In the social performance evaluation, it is found that the industry performs well for society, the local community, and workers but has a weaker social performance for the consumer due to a weak feedback mechanism. Integr Environ Assess Manag 2021;00:1-13. (c) 2021 SETAC
Machine Learning-Aided Inverse Design and Discovery of Novel Polymeric Materials for Membrane Separation
(ACS Publications, 2024) Dangayach, Raghav; Jeong, Nohyeong; Demirel, Elif; Uzal, Nigmet; Fung, Victor; Chen, Yongsheng; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
Polymeric membranes have been widely used for liquid and gas separation in various industrial applications over the past few decades because of their exceptional versatility and high tunability. Traditional trial-and-error methods for material synthesis are inadequate to meet the growing demands for high-performance membranes. Machine learning (ML) has demonstrated huge potential to accelerate design and discovery of membrane materials. In this review, we cover strengths and weaknesses of the traditional methods, followed by a discussion on the emergence of ML for developing advanced polymeric membranes. We describe methodologies for data collection, data preparation, the commonly used ML models, and the explainable artificial intelligence (XAI) tools implemented in membrane research. Furthermore, we explain the experimental and computational validation steps to verify the results provided by these ML models. Subsequently, we showcase successful case studies of polymeric membranes and emphasize inverse design methodology within a ML-driven structured framework. Finally, we conclude by highlighting the recent progress, challenges, and future research directions to advance ML research for next generation polymeric membranes. With this review, we aim to provide a comprehensive guideline to researchers, scientists, and engineers assisting in the implementation of ML to membrane research and to accelerate the membrane design and material discovery process.
Potential ion exchange membranes and system performance in reverse electrodialysis for power generation: A review
(ELSEVIER, 2015) Hong, Jin Gi; Zhang, Bopeng; Glabman, Shira; Uzal, Nigmet; Dou, Xiaomin; Zhang, Hongguo; Wei, Xiuzhen; Chen, Yongsheng; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
Reverse electrodialysis (RED) is an emerging membrane-based energy conversion process used to extract electricity by mixing two water streams of different salinities. This technique utilizes transport of cations and anions during controlled mixing of saltwater and freshwater through selective ion exchange membranes. The development of ion exchange membranes and optimization of system performance are crucial for sustainable energy capture from salinity gradients using RED. Recently, increased attention has been given to the preparation of ion exchange membranes and to understanding the factors that determine the RED power performance. This review evaluates potential ion exchange membrane materials, currently available state-of-the-art RED membranes, and their key properties. Discussion will focus on the electrochemical and physical properties of these membranes (e.g., resistance, permselectivity, and swelling) because of their significant role in RED performance throughout the system. Although an interconnected relationship exists between membrane properties, RED requires high quality membranes that are uniquely tailored to have a low resistance and high permselectivity. Moreover, harnessing this potential technology demands not only carefully optimized components but also a novel RED stack design and system optimization. The key findings and advancements needed to assure proper stack design and optimization are also described. This review paper[U+05F3]s goal is to elucidate effective energy conversion from salinity gradients and expedite implementation of RED as the next promising renewable source of power for large-scale energy generation.
Pre-concentration of Municipal Wastewater Using Flocculation-Assisted Direct Ceramic Microfiltration Process: Optimization of Operational Conditions
(SPRINGER INT PUBL AG, 2022) Ozcan, Ozlem; Sahinkaya, Erkan; Uzal, Nigmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Niğmet; Özcan, Özlem
Direct ceramic microfiltration (DCMF) is an effective technology to pre-concentrate organic matter (OM) for the subsequent anaerobic energy-recovering processes and a fast, cost-effective, easy treatment process for municipal wastewater. The major problem in DCMF is the rapid fouling of the membrane. In this study, to maximize OM recovery rates and prevent membrane fouling, the DCMF process was alternately paired with dosing of a cationic polyacrylamide (PAM) flocculant and chemically enhanced primary sedimentation (CEPS). The DCMF process tested in three stages: (i) optimization of flocculant concentration (0.5, 1, 1.5, and 2 mg/L PAM) and dosing point, (ii) optimization of operational conditions (pH, filtration/backwash duration, flux, and recovery rate) to control membrane fouling, and (iii) long-term operation of the DCMF process. The influence of PAM dosage points on DCMF fouling behavior was explored, and system operating parameters in terms of OM recovery and TMP change were optimized. The CEPS + DCMF setup was discovered to be a potential option for overcoming fouling. The highest chemical oxygen demand (COD) was 520 +/- 20 mg/L in the concentrated wastewater using CEPS + DCMF experiments for 0.5 mg/L PAM. The highest OM pre-concentration was achieved at 90% recovery rate. After the optimization, COD concentration in the concentrate of the DCMF process reached 822 mg/L for the long-term (20 days) operation. The net potential energy production was calculated as 0.28 kWh/m(3) considering the theoretical COD of 1432 mg/L in the concentrate stream. As a novel approach, the CEPS + DCMF process can be used in place of conventional municipal wastewater treatment processes due to its acceptable OM removal performance, simple operation, small footprint, and potential energy generation.
Predicting potential of pressure retarded osmosis power for different estuaries in Turkey
(WILEY, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA, 2019) Saki, Seda; Uzal, Nigmet; Gokcek, Murat; Ates, Nuray; 0000-0002-7951-4236; 0000-0002-8923-4852; 0000-0002-0912-3459; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü
Pressure retarded osmosis (PRO) is an alternative renewable energy source recovered from the salinity gradient between the fresh water (feed solution) and salty water (draw solution). In order to implement osmotic power, the site-specific characteristics including the river and sea salinity, annual flow rates, ecological restrictions were taken into account. This study revealed a comprehensive analysis for a theoretical potential of PRO process for different estuaries in Turkey. In this study, the power potential prediction of PRO process for the Ceyhan, Sakarya, and Meric Rivers were analyzed via Gibbs free energy calculations. The net annual energy production is projected to be 167, 164, and 208 GWh/y for Ceyhan, Sakarya, and Meric Rivers, respectively. Meric River has the highest energy production of 208 GWh/yr with 186 m(3)/s mean flow rate and 245 mg/L salinity. These results clearly show that Turkey's rivers having high salinity and flow rate are feasible and applicable for making the osmotic power plant economically. Thereby, it is providing essential direction to the improvement of its design, installation, and operation. The developed methodology for the evaluation of the osmotic power potential of other rivers can be considered as a basis to assess the whole potential on a worldwide level. (c) 2018 American Institute of Chemical Engineers Environ Prog, 38:e13085, 2019
Recovery of caustic from mercerizing wastewaters of a denim textile mill
(DESALINATION PUBL, 2015) Varol, Cihangir; Uzal, Nigmet; Dilek, Filiz Bengu; Kitis, Mehmet; Yetis, Ulku; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
The objective of this study was to evaluate caustic recovery from mercerizing wastewater originating from a denim textile producing plant using membrane technology. For this purpose, ultrafiltration (UF) and nanofiltration (NF) processes were considered. In the first stage, in an attempt to control the possible membrane fouling, pretreatment alternatives of flocculation, centrifugation, and microfiltration were evaluated. These pretreatment application alternatives were unsuccessful as they did not provide considerable color and solids removal. In the second stage, UF and NF processes were tested using a tight UF membrane (GR95PP, Alfalaval) and three NF membranes (NP010 and NP030, Microdyn Nadir, and MPF34, Koch Membranes) to accomplish the caustic recovery without applying any pretreatment. The best performance was obtained with NP010 NF in terms of permeate flux along with color and COD rejections. Then, for this membrane the effects of transmembrane pressure (4.03 and 6.23 bar), cross-flow velocity (from 0.40 to 1.40 m/s), and feed temperature (20 and 40°C) were investigated. Temperature positively affected the permeate flux without significant loss in recovery and rejections. Caustic stream produced had about 98–100% of NaOH in the feed at a concentration of 30–40 g/L and therefore was recyclable after a concentration process.
Removal of pesticides from secondary treated urban wastewater by reverse osmosis
(SPRINGER, 2023) Ates, Nuray; Uzal, Nigmet; Yetis, Ulku; Dilek, Filiz B.; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, İnşaat Mühendisliği Bölümü; Uzal, Nigmet
The residues of pesticides that reach water resources from agricultural activities in several ways contaminate drinking water resources and threaten aquatic life. This study aimed to investigate the performance of three reverse osmosis (RO) membranes (BW30-LE, SW30-XLE, and GE-AD) in rejecting four diferent pesticides (tributyl phosphate, futriafol, dicofol, and irgarol) from secondary treated urban wastewater and also to elucidate the mechanisms underlying the rejection of these pesticides. RO experiments were conducted using pesticide-spiked wastewater samples under 10 and 20 bar transmembrane pressures (TMP) and membrane performances were evaluated. Overall, all the membranes tested exhibited over 95% rejection performances for all pesticides at both TMPs. The highest rejections for tributyl phosphate (99.0%) and irgarol (98.3%) were obtained with the BW30-LE membrane, while for futriafol (99.9%) and dicofol (99.1%) with the GE-AD membrane. The increase in TMP from 10 to 20 bar did not signifcantly afect the rejections of all pesticides. The rejection performances of RO membranes were found to be governed by projection area as well as molecular weight and hydrophobicity/hydrophilicity of pesticides. Among the membranes tested, the SW30-XLE membrane was the most prone to fouling due to the higher roughness.

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