Environmental Engineering / Çevre Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4321

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Author: search.filters.author.Şahin, ÇağrıLanguage: search.filters.language.en

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  • Article
    Citation - WoS: 31
    Citation - Scopus: 35
    Electrochemical Degradation of Methylene Blue by a Flexible Graphite Electrode: Techno-Economic Evaluation
    (American Chemical Society, 2022) Ökten, Hatice Eser; Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Genişoğlu, Mesut; Ökten, Hatice Eser; 03.07. Department of Environmental Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, electrochemical removal of methylene blue (MB) from water using commercially available and low-cost flexible graphite was investigated. The operating conditions such as initial dye concentration, initial solution pH, electrolyte dose, electrical potential, and operating time were investigated. The Box-Behnken experimental design (BBD) was used to optimize the system's performance with the minimum number of tests possible, as well as to examine the independent variables' impact on the removal efficiency, energy consumption, operating cost, and effluent MB concentration. The electrical potential and electrolyte dosage both improved the MB removal efficiency, since increased electrical potential facilitated production of oxidizing agents and increase in electrolyte dosage translated into an increase in electrical current transfer. As expected, MB removal efficiency increased with longer operational periods. The combined effects of operating time-electrical potential and electrical potential-electrolyte concentration improved the MB removal efficiency. The maximum removal efficiency (99.9%) and lowest operating cost (0.012 $/m3) were obtained for initial pH 4, initial MB concentration 26.5 mg/L, electrolyte concentration 0.6 g/L, electrical potential 3 V, and operating time 30 min. The reaction kinetics was maximum for pH 5, and as the pH increased the reaction rates decreased. Consequent techno-economic assessment showed that electrochemical removal of MB using low-cost and versatile flexible graphite had a competitive advantage.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 14
    Indoor Environmental Quality in Naturally Ventilated Schools of a Dusty Region: Excess Health Risks and Effect of Heating and Desert Dust Transport
    (Wiley, 2022) Şahin, Çağrı; Rastgeldi Doğan, Tuba; Sofuoğlu, Sait Cemil; Sofuoğlu, Sait Cemil; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Indoor air quality (IAQ) is impacted by polluted outdoor air in naturally ventilated schools, especially in places where both anthropogenic and natural sources of ambient air pollution exist. CO2, PM2.5, PM10, temperature, relative humidity (RH), and noise were measured in five naturally ventilated primary schools in City of Sanliurfa, in a dusty region of Turkey, Southeast Anatolia. Excess risk levels were estimated for particulate matter. Investigation was conducted through an educational year including two seasons in terms of anthropogenic effect, that is, heating/non-heating, and natural effect, that is, desert dust transport/non-dust transport. The median CO2 concentration was measured to be >1000 ppm in all seasons/schools. Temperature and RH fell out of the comfort zone in October-December, during which pollutant concentrations were considerably increased, specifically in November, that heating and dust transport periods coincide. The overall mean indoor PM10 and PM2.5 levels were 58 and 31.8 mu g/m(3), respectively. Risk assessment indicate that both short (incidence of asthma symptoms in asthmatic children) and long-term (prevalence of bronchitis) effects are considerable with 10.9 (2.4-19.6)% and 19.5 (2.2-38.8)%, respectively. The findings suggest that mechanical ventilation retrofitting with particle filtration is needed to mitigate potential negative health consequences on children.
  • Article
    Citation - WoS: 47
    Mitigation of Organophosphate Pesticide Pollution in Agricultural Watersheds
    (Elsevier, 2020) Şahin, Çağrı; Karpuzcu, M. Ekrem; 01. Izmir Institute of Technology
    Adsorption and biodegradation processes for four organophosphate pesticides (chiorpyrifos, diazinon, fenthion, dichlorvos) in wetlands and agricultural drains in Meric-Ergene Basin, Turkey have been investigated. K-oc (organic carbon normalized partition coefficient) values for all pesticides except diazinon were higher in more aromatic Pamuklu Drain sediments, indicating the possible influence of aromaticity on the extent of adsorption. The average half-lives of pesticides in Gala Lake sediments and Pamuklu agricultural drain sediments ranged from 2.25 to 69.31 days with chlorpyrifos exhibiting the slowest biotransformation rate and dichlorvos having the fastest biotransforrnation rate. The presence of humic substances and hydroperiod of wetlands have been identified as possible factors that affected the behavior of organophosphate pesticides in this study. The results from this study provide insight into the constructed wetland design offered for the mitigation of organophosphate pesticides in the basin. (C) 2019 Elsevier B.V. All rights reserved.