Environmental Engineering / Çevre Mühendisliği

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Citation - WoS: 6
Citation - Scopus: 8
3d Electrode Use in Mdc for Enhanced Removal of Boron From Geothermal Water
(Elsevier, 2022-05) Gören, Ayşegül Yağmur; Ökten, Hatice Eser; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Microbial desalination cell (MDC) is a significantly promising technology due to its simultaneous features of electricity production, wastewater treatment and desalination. In this paper, the three-dimensional (3D) sponge with activated carbon-chitosan (AC-CS) was synthesized to enhance the efficiency of the MDC system. Effects of operating parameters (boron concentration, electrode surface area, catholyte solution, and activated sludge volume) on MDC performance were also investigated. The MDC with 3D AC-CS anode provided a higher power density of 970 mW/m2, boron removal efficiency of 75.9%, and COD removal efficiency of >90% under optimized conditions. The maximum boron and COD removal efficiencies were 65.6 and 81.4% with the power density of 866.9 mW/m2 for geothermal brine. Moreover, BET analysis showed that the 3D AC-CS anode presented high surface area (230 m2/g) and pore volume (0.202 cm3/g). As an overall result, not only the production of 3D sponge anode electrodes with AC-CS composite was achieved but also desalination and power generation results that were comparable with the literature were presented.
3d Modeling of a Historical Mine Waste Site Using Uav Images: Estimation of Stockpile Volumes
(Springer, 2023) Önal, Okan; Gündüz, Orhan; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In recent decades, the use of Unmanned Aerial Vehicles (UAV) for land surveying became very popular because of their simplicity and low cost. Aerial images of the site can be used for the reconstruction of the site’s 3D digital model. Once proper calibrations are made, these digital models can be used for several purposes including stockpile volume estimation, stability analyses, forensic engineering and archiving, etc. In this study, the 3D model of an abandoned historical mine waste disposal site located in Balıkesir-Turkey was reconstructed for the estimation of the waste stockpile volumes. The historical mine site is a facility that was abandoned more than 80 years ago. Mine wastes of different quality were disposed of in and around the site along the hydrologically intermittent creek that passes through the site. No engineered precautions were taken at the site to reduce the environmental impacts and all waste piles were exposed to the natural eroding effect of precipitation and wind. The total amount of the waste volume is not known accurately, which prevents researchers to quantify the potential impacts associated with different waste stockpiles. Thus, a 3D digital model of the site was created by using UAV data obtained from a quadcopter and later processed to obtain a digital topography of the site with an improved accuracy value of ± 2 cm. The stockpiles were later analyzed with geographic information systems to characterize the magnitude of mine wastes and to propose alternative engineering solutions for environmental mitigation. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2023.
Afet sonrası atıkların yönetimi hakkında değerlendirme
(01. Izmir Institute of Technology, 2023) Küçüker, Mehmet Ali; Kaplangı, Berat Batuhan; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Ülkemizde 6 Şubat 2023 tarihinde Kahramanmaraş’ın Pazarcık ve Elbistan ilçelerinde sırasıyla 7,7 ve 7,6 büyüklüklerinde depremler meydana gelmiştir. Bu depremleri peşi sıra binlerce artçı deprem gerçekleşmiştir [1]. Gerçekleşen afetin ülkemizde ve milletimizde derin yaralar açtığı acı bir gerçektir. Tüm bunların yanında, bu tip afetlerin maalesef çevre üzerinde de çok ciddi boyutlarda etkileri olmaktadır. Çevresel açıdan değerlendirilmesi gereken en önemli konularında birisi de deprem sonrasında oluşan atıkların yönetimidir. Bu çalışmada, afet sonrasında oluşan atıkların yönetiminin önemine dikkat çekilecektir.
Citation - WoS: 2
Anaerobic Co-Digestion of Tannery Solid Waste: Optimum Leather Fleshing Waste Loading
(2020) Bayrakdar, Alper; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, loading of optimum leather fleshings was investigated with four identical batch reactors with different fleshings and treatment sludge ratios (0:1, 0.25:1, 0.35:1, 0.50:1) to contribute to the state of art of the biogas production from tannery solid wastes. Results showed that lipids-containing leather fleshings boosted the methane production potential. However, H2S inhibition and volatile fatty acids accumulation were the main concern in the anaerobic digestion of these wastes. The modified Gompertz model was applied to the batch tests data to determine the kinetic constants of anaerobic digestion of tannery solid wastes. It was calculated with the model outputs that the ultimate methane production potential and maximum methane production rate in reactors having mixing ratio of 0.35:1 and 0.5:1 (dry basis) were highly similar. 0.35 was found to be an optimum leather fleshing and treatment sludge ratio with a 54% more methane production potential than that of control reactor in this study.
Citation - WoS: 11
Citation - Scopus: 11
An Appraisal of the Local-Scale Spatio-Temporal Variations of Drought Based on the Integrated Grace/Grace-fo Observations and Fine-Resolution Fldas Model
(Wiley, 2023) Khorrami, Behnam; Ali, Shoaib; Gündüz, Orhan; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The gravity recovery and climate experiment (GRACE) observations have so far been utilized to detect and trace the variations of hydrological extremes worldwide. However, applying the coarse resolution GRACE estimates for local-scale analysis remains a big challenge. In this study, a new version of the fine resolution (1 km) Famine early warning systems network Land Data Assimilation System (FLDAS) model data was integrated into a machine learning model along with the GRACE data to evaluate the subbasin-scale variations of water storage, and drought. With a correlation of 0.99 and a root mean square error (RMSE) of 3.93mm of its results, the downscaling model turned out to be very successful in modelling the finer resolution variations of TWSA. The water storage deficit (WSD) and Water Storage Deficit Index (WSDI) were used to determine the episodes and severity of drought events. Accordingly, two severe droughts (January 2008 to March 2009 and September 2019 to December 2020) were discerned in the Kizilirmak Basin (KB) located in Central Turkiye. The characterization of droughts was evaluated based on WSDI, scPDSI, and model-based drought indices of the soil moisture storage percentile (SMSP) and groundwater storage percentile (GWSP). The results indicated discrepancies in the drought classes based on different indices. However, the WSDI turned out to be more correlated with GWSP, suggesting its high ability to monitor groundwater droughts as well.
Citation - WoS: 1
Arsenate Removal From Groundwater by Air-Injected Ec With Al Ball Anodes: Effects of Operational Parameters
(Pamukkale Üniversitesi, 2020) Gören, Ayşegül Yağmur; Öncel, Mehmet Salim; Kobya, Mehmet; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Treatment of arsenate from groundwater by electrocoagulation (EC) reactor with air supply unit using Al ball electrodes were studied in this paper. Influence of some operating variables, for instance, applied current (0.075-0.3 A), initial pH (5.5-8.5), air flow rate (0-6 L/min), size of Al ball electrodes (5-10 mm), and height of electrode in EC reactor (2-8 cm) on the As(V) removal efficiency were evaluated. The As (V) removal efficiency increased with the increment of applied current, air flow, electrode altitude in EC reactor, and EC time while its removal efficiency decreased with the increment of size of Al ball electrodes. The maximum As(V) removal percentage, minimum operating cost and energy consumption were found as 98.68 %, 0.609 $/$m^3$ and 3.7694 kWh/$m^3$ at pH of 7.5, current density of 0.30 A, size of Al balls of 7.5 mm, height of electrode in EC of 5 c†m, and air flow rate of 6 L/min, respectively
Arsenic Removal by Electrocoagulation
(Wiley, 2022) Gören, Ayşegül Yağmur; Kobya, Mehmet; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Because of the toxic impacts on human health, the arsenic (As) limit value in drinking water was decreased from 50 to 10 ?g l-1 by the relevant authorities (WHO 1993; US EPA 2001). In this case, the problem of As pollution in natural water resources used for drinking water has grown even more and turned into a global crisis. According to reports in many parts of the world, over about 230 million people appear to be affected by high arsenic concentrations in groundwater. In this case, it turned out that there was a great need for cost-effective and environmentally friendly technologies from drinking water sources. One of the emerging water treatment technologies in recent years is electrocoagulation (EC) and it has been seen that it is effective in treating As (>99%) from water and eliminates some of the disadvantages of other conventional treatment processes. EC method includes electro-oxidation of anode electrode materials (iron and aluminum) and in situ production of coagulant agents. From groundwater resources with As content of 5-1000 ?g l-1, As removal efficiencies and operating costs (OCS) of EC technology using iron (Fe) and aluminum (Al) anodes were 85.0-99.9% and 0.0020-1.04 US$ m-3, respectively. Different types (plate, scrap, rod, and ball) of electrodes were used for As removal with the EC process, and it was observed that Fe electrodes or Fe-Al hybrid electrodes performed better in As removal. In addition, it has been determined that arsenate (As(V)) removal is more effective than arsenite (As(III)). A significant quantity of As(III) is oxidized in the EC process, resulting in precipitation, adsorption, and metal-oxy hydroxylic complex reactions. EC process has a lower OC to achieve As removal below the permissible WHO value compared to conventional treatment processes, accomplishing it as a further applicable option for As removal. © 2023 John Wiley & Sons, Inc.
Citation - WoS: 43
Citation - Scopus: 54
Arsenic Removal From Groundwater Using an Aerated Electrocoagulation Reactor With 3d Al Electrodes in the Presence of Anions
(Elsevier, 2021) Gören, Ayşegül Yağmur; Kobya, Mehmet; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Co-occurrence of arsenic and anions in groundwater causes a severe health problems and combine effects of these pollutants significantly affect performance of treatment process. Thus, this study has been conducted to examine the combine effects of anions on arsenic removal using aerated electrocoagulation (EC) reactor with 3D Al electrodes in groundwater. A 3-level, six factors Box-Behnken experimental design (BBD) was applied to investigate the individual and combine effect of anions and operating time: phosphate (x1: 1–10 mg L?1), silica (x2: 20–80 mg L?1), bicarbonate (x3: 130–670 mg L?1), fluoride (x4: 2–10 mg L?1), boron (x5: 5–10 mg L?1), and operating time (x6: 8–22 min) on desired responses. The specified responses were effluent arsenic concentration (Cf,As), removal efficiency of arsenic (Re), consumptions of energy and electrode (ENC and ELC), operational cost (OC), and adsorption capacity (qe). The optimum operating parameters predicted using BBD were found to be x1: 1.0 mg L?1, x2: 26.0 mg L?1, x3: 651.5 mg L?1, x4: 2.0 mg L?1, x5: 9.9 mg L?1, and x6: 10.5 min considering highest removal efficiency of arsenic and lowest operational cost. Under these operating conditions, the experimental values of Cf,As, Re, ENC, ELC, OC, and qe were found to be 2.82 ?g L?1, 98.6%, 0.411 kWh m?3, 0.0124 kg m?3, 0.098 $ m?3, and 17.65 ?g As (mg Al)?1, respectively. Furthermore, mathematical modelling was conducted using quadratic regression model and response surface analysis was performed to understand the relationship between independent parameters and responses. © 2020 Elsevier Ltd
Citation - WoS: 27
Citation - Scopus: 28
Arsenite and Arsenate Removals From Groundwater by Electrocoagulation Using Iron Ball Anodes: Influence of Operating Parameters
(Elsevier Ltd., 2017-08) Şık, E.; Demirbaş, Erhan; Gören, Ayşegül Yağmur; Öncel, Mehmet Salim; Kobya, Mehmet; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Removals of arsenite (As(III)) and arsenate (As(V)) from groundwater by a cylindrical packed-bed electrocoagulation (EC) reactor using Fe ball anodes were investigated in this study. Effects of some operating parameters such as initial pH (pHi of 6.5–8.5), applied current (i of 0.075–0.30 A), initial concentration (Co of 30–200 μg/L), diameter of iron ball (dp of 5.0–10.0 mm), height of anode balls in the reactor (h of 2–8 cm) and airflow rate (Qair of 0.0–6.0 L/min) on the removal efficiency of arsenic were evaluated. The removal efficiency of arsenic decreased with increase in concentrations of arsenic from 30 to 200 μg/L while its removal efficiency increased with increase in operating time, applied current, height of anode in the reactor, and airflow rate. The optimum operating conditions for effective As(III) and As(V) removals to meet the permissible level of arsenic effluent concentration of <10 μg/L were determined as 0.3 A, 14 min of EC time for As(III) and 12 min for As(V), a pHi of 7.5, Co of 200 μg/L, dp of 7.5 mm, h of 7.5 cm and Qair of 6 L/min, respectively. Arsenic removal efficiency, energy and electrode consumptions, operating cost, charge loading and arsenic removed capacity per amount of electrochemically generated Fe at the optimum conditions were also calculated as 96.0%, 1.442 kWh/m3, 0.0752 kg/m3, 0.612 $/m3, 252 C and 2.55 μg/mg Fe (0.762 μg/C) for As(III) removal and 95.8%, 1.386 kWh/m3, 0.0628 kg/m3, 0.546 $/m3, 216 C and 3.05 μg/mg Fe (0.887 μg/C) for As(V) removal, respectively.
Citation - WoS: 34
Citation - Scopus: 38
Arsenite Removal From Groundwater by Aerated Electrocoagulation Reactor With Al Ball Electrodes: Human Health Risk Assessment
(Elsevier, 2020) Gören, Ayşegül Yağmur; Kobya, Mehmet; Öncel, Mehmet Salim; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The application of conventional electrocoagulation (EC) process for removal of As(III) from groundwater suffers from the need of external oxidation agent for oxidation of As(III) to As(V). To tackle this limitation, an aerated EC reactor for the removal of As(III) from groundwater was evaluated in this study. The effect of initial pH(i), air flow rate, applied current, and electrode height in the EC reactor was examined. The experimental results showed that removal of arsenic mostly dependent on the applied current, electrode height in EC reactor, and air flow rate. The As(III) removal efficiency (99.2%) was maximum at pH(i) of 7.5, air flow rate of 6 L min(-1), applied current of 0.30 A, and electrode height in EC reactor of 5 cm, with an total operating cost of 0.583 $ m(-3). Furthermore, the carcinogenic risk (CR) and non-carcinogenic risk of arsenic (As) was in the range of tolerable limits at all operating conditions except applied current of 0.075 A at the end of the aerated EC process to remove As from groundwater. The present EC reactor process is able to remove As(III) from groundwater to below 10 mu g L-1, which is maximum contaminant level of arsenic in drinking water according to the World Health Organization (WHO). (C) 2020 Elsevier Ltd. All rights reserved.
Citation - WoS: 25
Citation - Scopus: 32
Arsenite Removal From Groundwater in a Batch Electrocoagulation Process: Optimization Through Response Surface Methodology
(Taylor & Francis, 2019) Şık, Emrah; Gören, Ayşegül Yağmur; Demirbaş, Erhan; Kobya, Mehmet; Öncel, Mehmet Salim; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this study, influences of seven process variables such as initial pH (pH(i)), applied current (i), operating time (t(EC)), initial As(III) concentration (C-o), diameter of Fe ball anode (d(p)), column height in the electrocoagulation (EC) reactor (h) and airflow rate (Q(air)) for removal of As(III) from groundwater by a new air-fed fixed-bed EC reactor were evaluated with a response surface methodology (RSM). The proposed quadratic model fitted very well with the experimental data for the responses. The removal efficiencies and operating costs were determined to be 99% and 0.01 $/m(3) at the optimum operating conditions (a pH(i) of 8.5, 0.05 A, 4.94 min, d(p) of 9.24 mm, h of 7.49 cm, Q(air) of 9.98 L/min for 50 mu g/L). This study clearly showed that the RSM in the EC process was a very suitable method to optimize the operating conditions at the target value of effluent As(III) concentration (10 mu g/L) while keeping the operating cost to minimal and maximize the removal efficiency.
Citation - WoS: 12
Citation - Scopus: 14
Assessment and Improvement of Indoor Environmental Quality in a Primary School
(Taylor and Francis Ltd., 2017-02) Ekren, Orhan; Karadeniz, Ziya Haktan; Atmaca, İbrahim; Ugranlı Çiçek, Tuğba; Sofuoğlu, Sait Cemil; Toksoy, Macit; 03.07. Department of Environmental Engineering; 03.06. Department of Energy Systems Engineering; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
This study reports levels of indoor environmental quality variables before and after installation of heat recovery ventilation in a primary school located in an urban area in Izmir, Turkey. A CO2-based modeling was performed to determine the required flow rates that would comply with an international ventilation standard, followed by computational fluid dynamics modeling for best airflow distribution in a classroom. Temperature, CO2, PM2.5, and total volatile organic compounds were found at undesired levels, among which relative humidity, CO2, and PM2.5 were improved after the intervention. Reductions in the mean and maximum concentrations were 29% and 68% for CO2 and 29% and 46% for PM2.5. This intervention study was a part of the city-wide main project that aimed to increase awareness of the students and their families, teachers, and staff regarding importance of indoor environmental quality in both at school and home due to its possible effects on children's health and academic performance, one of the major challenges of today's societies all around the globe.
Citation - WoS: 52
Citation - Scopus: 54
Assessment of Different Nanofiltration and Reverse Osmosis Membranes for Simultaneous Removal of Arsenic and Boron From Spent Geothermal Water
(Elsevier, 2021) Jarma, Yakubu A.; Karaoğlu, Aslı; Tekin, Özge; Baba, Alper; Ökten, H.Eser; Tomaszewska, Barbara; Kabay, Nalan; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
One of the factors that determine agricultural crops’ yield is the quality of water used during irrigation. In this study, we assessed the usability of spent geothermal water for agricultural irrigation after membrane treatment. Preliminary membrane tests were conducted on a laboratory-scale set up followed by mini-pilot scale tests in a geothermal heating center. In part I, three commercially available membranes (XLE BWRO, NF90, and Osmonics CK- NF) were tested using a cross-flow flat-sheet membrane testing unit (Sepa CF II, GE-Osmonics) under constant applied pressure of 20 bar. In part II, different spiral wound membranes (TR-NE90-NF, TR-BE-BW, and BW30) other than the ones used in laboratory tests were employed for the mini-pilot scale studies in a continuous mode. Water recovery and applied pressure were maintained constant at 60% and 12 bar, respectively. Performances of the membranes were assessed in terms of the permeate flux, boron and arsenic removals. In laboratory tests, the permeate fluxes were measured as 94.3, 87.9, and 64.3 L m?2 h?1 for XLE BWRO, CK-NF and NF90 membranes, respectively. The arsenic removals were found as 99.0%, 87.5% and 83.6% while the boron removals were 56.8%, 54.2%, and 26.1% for XLE BWRO, NF90 and CK-NF membranes, respectively. In field tests, permeate fluxes were 49.9, 26.8 and 24.0 L m?2 h?1 for TR-NE90-NF, BW30-RO and TR-BE-BW membranes, respectively. Boron removals were calculated as 49.9%, 44.1% and 40.7% for TR-BE-BW, TR-NE90-NF and BW30-RO membranes, respectively. Removal efficiencies of arsenic in mini-pilot scale membrane tests were all over 90%. Quality of the permeate water produced was suitable for irrigation in terms of the electrical conductivity (EC) and the total dissolved solids (TDS) for all tested membranes with respect to guidelines set by the Turkish Ministry of Environment and Urbanisation (TMEU). However, XLE BWRO, CK-NF and NF90 membranes failed to meet the required limits for irrigation in terms of boron and arsenic concentrations in the product water. The permeate streams of TR-BE-BW, TR-NE90-NF and BW30-RO membranes complied with the irrigation water standards in terms of EC, TDS and arsenic concentration while boron concentration remained above the allowable limit. © 2020 Elsevier B.V.
Citation - Scopus: 2
Biogas Production From Aquatic Biomass
(Elsevier, 2022-01) Wieczorek, Nils; Kosheleva, Arina; Kuchta, Kerstin; Önen Çınar, Senem; Küçüker, Mehmet Ali; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The use of aquatic biomass such as algae, macrophytes, or submerged macrophytes as raw material for biogas production has numerous technical and biological advantages. In addition, synergy effects can be exploited taking into account the implementation of biogas systems in urban areas, and coupling between the production of aquatic biomass, biogas production, and urban material flows can be established. Aquatic biomass, which can be the residue of downstream processes or collected from water bodies in cities, represents an excellent opportunity for both material and energy needs. Anaerobic digestion is a widely implemented technology that is already proven for the treatment of various biomasses. Several studies showed that aquatic biomass is a valuable substrate with its high methane yield, especially codigestion processes. This chapter represents the main idea of the anaerobic digestion process while focusing on the features of the aquatic biomass applications in this process.
Citation - WoS: 23
Citation - Scopus: 29
Biosorption of Methylene Blue From Water by Live Lemna Minor
(Elsevier, 2021) Can Terzi, Begüm; Gören, Ayşegül Yağmur; Ökten, Hatice Eser; Sofuoğlu, Sait Cemil; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
A number of green treatment technologies have been used for textile wastewater treatment, among which phytoremediation is a low cost, effective, and promising alternative - to conventional treatment techniques. The aim of this study was to investigate performance of Lemna minor (L. minor) for phytoremediation of Methylene Blue (MB). A Box-Behnken experimental design (BBD) was applied to study individual and combined effect of operating parameters on MB dye removal efficiency: MB dye concentration (x(1): 5 - 25 mgL(-1)), amount of L. minor (x(2): 1 - 5 g), and pH of the solution (x(3): 4.5 - 9.0). Response surface analysis and response model were utilized to reveal the relationship between operating parameters and MB removal efficiency. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analyses of L. minor samples were used to infer on the removal mechanism. The predicted optimum values were x(1) = 15 mgL(-1), x(2) = 4.9 g, and x(3) = 6.8, for the highest removal efficiency (98%) within 24 h. FTIR and SEM analyses indicated that the dye removal mechanism was mainly biosorption. Desorption experiments revealed that L. minor released only a small fraction of the sorbed dye. Consequently, in addition to being environmental friendly and cost effective, results of this study show that L. minor can be effectively used for MB dye removal from wastewaters while adding to the pertinent but limited literature by presenting its applicability in wider operating parameter ranges, maximization of removal efficiency through experimental design, and evidence that biosorption is a plausible mechanism. (C) 2021 Elsevier B.V. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 6
Bleach-Containing Automatic Toilet-Bowl Cleaners as Sources of Vocs, Associated Indoor Air Concentrations and Carcinogenic Risk
(Turkish National Committee for Air Pollution Research (TUNCAP), 2020) Ayrı, İlknur; Genişoğlu, Mesut; Gaygısız, Handan; Sofuoğlu, Aysun; Sofuoğlu, Sait Cemil; 03.02. Department of Chemical Engineering; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Household cleaning products are sources of volatile organic compounds (VOCs). Bleach containing products are a special case because reactions occur between chloride and their organic content such as surfactants, perfumes, etc., generating VOCs. This study aimed to determine concentration of 13 VOCs in bleach-containing automatic toilet cleaners, to estimate their indoor air concentrations and associated exposure and health risk levels. Experiments with products purchased from supermarkets were conducted in 20-mL headspace vials by placing 1 g of sample with and without water. Solid-phase micro extraction with a DVB/CAR/PDMS fiber assembly was used for adsorption of VOCs from the headspace, and analyzed using a GC-MS. The median carbon tetrachloride and chloroform concentrations of the studied products ranged from 5.03 × 10?3 to 2.37 × 10?2 ?g/g and 2.53 × 10?2 to 2.37 ?g/g, respectively. The modeled 95th percentile indoor air concentrations in a 1.6 m3 bathroom with no ventilation were estimated to be 1 and 20 ?g/m3 for carbon tetrachloride and chloroform, respectively. The 95th percentile carcinogenic risk associated even with the use of the highest content product, 3.72 × 10?7 and 8.62 × 10?7 for carbon tetrachloride and chloroform respectively, were below the acceptable risk. In conclusion, automatic toilet-bowl cleaners were found to be sources of VOCs, but their emission potentials are not high to cause considerable indoor air concentrations over their suggested product lifetime. In turn, carcinogenic risks associated with inhalation exposure are below the de Minimis risk level of 10?6. © 2020
Citation - WoS: 34
Citation - Scopus: 39
Boron Carbon Nitride Nanosheets in Water and Wastewater Treatment: a Critical Review
(Elsevier, 2022-07) Recepoğlu, Yaşar Kemal; Gören, Ayşegül Yağmur; Vatanpour, Vahid; Yoon, Yeojoon; Khataee, Alireza; 03.07. Department of Environmental Engineering; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
The availability and accessibility of clean and secure water supplies are pressing technological and scientific issues worldwide. As a result of global water constraints, wastewater treatment and reuse are being evaluated as feasible alternatives to fresh water for agricultural irrigation and domestic and industrial purposes. Boron carbon nitride (BCN) nanosheets have been studied intensively in the last decade in batteries, biosensors, and capacitors, and for use as catalysts, and they have recently been used in wastewater treatment. BCN materials, along with their synthesis processes, characteristics, and application areas in water and wastewater treatment, are discussed thoroughly in this paper. Additionally, synthesis processes for ternary BCN compounds, including chemical vapor deposition, ion beam-aided deposition, magnetron sputtering, and pulsed laser deposition, are described. BCN materials have also been explored because of their flexible electrical features, excellent mechanical strength, outstanding unreactivity, and significant stability, which make them appropriate for a range of severe environment applications. Thus, the use of BCN materials as photocatalysts and adsorbents and in electrochemical reduction and capacitive deionization are also discussed thoroughly. The highest ammonia production of 172,226.5 μg/h.mg.cat and faradic efficiency of 95.3% have been obtained using the BCN@Cu/CNT catalyst, whereas the ammonia production and FE values for metal-free BCN are 7.75 μg/h.mg.cat and 13.8%. Moreover, the maximum attained adsorption capacities of BCN nanosheets for Pb2+ and Hg2+ are 210 and 625 mg/g, respectively. Overall, this review indicates that essential work on BCN nanosheets is still needed. Future research should focus on the development of BCN nanostructures to encourage multidisciplinary research.
Citation - WoS: 32
Citation - Scopus: 43
Boron in Geothermal Energy: Sources, Environmental Impacts, and Management in Geothermal Fluid
(Elsevier, 2022-10) Mott, A.; Baba, Alper; Hadi Mosleh, Mojgan; Ökten, Hatice Eser; Babaei, Masoud; Gören, Ayşegül Yağmur; Feng, C.; Recepoğlu, Yaşar Kemal; Uzelli, Taygun; Uytun, Hüseyin; Morata, Diego; Yüksel Özşen, Aslı; 03.07. Department of Environmental Engineering; 03.02. Department of Chemical Engineering; 03.03. Department of Civil Engineering; 01.01. Units Affiliated to the Rectorate; 01. Izmir Institute of Technology; 03. Faculty of Engineering
The problem of hazardous chemicals in geothermal fluid is a critical environmental concern in geothermal energy developments. Boron is among the hazardous contaminants reported to be present at high concentrations in geothermal fluids in various countries. Poor management and inadequate treatment of geothermal fluids can release excessive boron to the environment that has toxic effects on plants, humans, and animals. Despite the importance of boron management in geothermal fluid, limited and fragmented resources exist that provide a comprehensive understanding of its sources, transport and fate, and the treatment strategies in geothermal energy context. This paper presents the first critical review from a systematic and comprehensive review on different aspects of boron in geothermal fluid including its generation, sources, toxicity, ranges and the management approaches and treatment technologies. Our research highlights the origin of boron in geothermal water to be mainly from historical water-rock interactions and magmatic intrusion. Excessive concentrations of boron in geothermal fluids have been reported (over 500 mg/L in some case studies). Our review indicated that possible boron contamination in geothermal sites are mostly due to flawed construction of production/re-injection wells and uncontrolled discharge of geothermal water to surface water. The dominancy of non-ionic H3BO3 species makes the selection of the suitable treatment method for geothermal waters limited. Combining boron selective resins and membrane technologies, hybrid systems have provided effluents suitable for irrigation. However, their high energy consumption and course structure of boron selective resins encourage further research to develop cost-effective and environmentally friendly alternatives.
Citation - WoS: 10
Citation - Scopus: 11
Boron Removal From Geothermal Brine Using Hybrid Reverse Osmosis/Microbial Desalination Cell System
(Elsevier, 2023-03) Jarma, Yakubu A.; Kabay, Nalan; Baba, Alper; Ökten, Hatice Eser; Gören, Ayşegül Yağmur; 03.07. Department of Environmental Engineering; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
Agriculture sector leads worldwide as the most water consuming sector with water demand. Since natural water resources cannot keep up with the demand, a shift from conventional water resources to unconventional ones is needed. While geothermal water was gaining importance for its energy content, small-scale (<10 L/s) energy plants were not required to reinject their spent geothermal brine. As geothermal resources align with agricultural areas in Western Anatolia, discharge of untreated brine might have severe adverse effects on crop yields and soil quality. In this study, we investigated use of spent geothermal brine for irrigation after treatment with Reverse Osmosis/Microbial Desalination Cell (RO/MDC) hybrid process. Treatment efficiencies for B, COD, As, Li, Fe, Cr concentrations and energy production values were determined. Treated water was initially evaluated for irrigation considering three quality categories (I, II, and III) comprised of parameters such as electrical conductivity (EC), total dissolved solids (TDS), and sodium adsorption ratio (SAR), along with sodium, chloride and boron concentrations. Additionally, magnesium adsorption ratio (MAR) and permeability index (PI) were used to evaluate for irrigation suitability. Although B concentrations in MDC-treated permeate (3.29 mg/L) and concentrate (2.99 mg/L) streams were not low enough to meet Quality I criterion (<0.7 mg/L), they can be still utilized in irrigation of moderate-to-high tolerant plants. Furthermore, PI and MAR parameters pointed to suitability for irrigational use. © 2022
Citation - WoS: 7
Citation - Scopus: 11
A Box–behnken Design (bbd) Optimization of the Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D) Using Tio2/H2o2
(Desalination Publications, 2018-08) Doğdu Okçu, Gamze; Baldan Pakdil, Nazlı; Ökten, Hatice Eser; Yalçuk, Arda; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
2,4-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.

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