Sapanca Havzası yan dereleri ve Sapanca Gölün’ndeki fosfor yüklerinin belirlenmesi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada, Sapanca Gölü havzasında 2012-2014 yılları arasında su kalitesini belirlemek üzere yan derelerde ve göl üzerinde belirlenen istasyonlarda, gölün geleceği için önemli görülen bazı su kalite parametrelerine ait ölçümler yapılmıştır. Ölçüm yapılan derelerdeki su kalitesi, genel şartlar ve oksijenlendirme parametrelerine göre genel olarak I. ve II. sınıf olarak belirlenirken, nutrient parametrelerine göre III. ve IV. sınıf olarak belirlenmiştir. Gölde yapılan ölçümlerde, genel şartlar bakımından su kalitesi her noktada I. sınıf olarak tayin edilmiştir. Oksijenlendirme parametreleri bakımından B, C, D noktalarındaki su kalitesi I. sınıf olup A, E ve F noktalarında ise II. sınıf olarak belirlenmiştir. Göl içindeki tüm ölçüm noktalarda nutrient parametreleri bakımından su kalitesi II. sınıf olarak tespit edilmiştir. Gölden ve yan derelerden elde edilen ölçüm sonuçları kullanılarak Yüzeysel Su Kalitesi Yönetimi Yönetmeliği'ne ve Carlson Trofik Durum İndeksi'ne göre trofik durum tespit edilmiştir. Sapanca Gölü'ndeki trofik durumun her iki indekste de genel olarak toplam fosfor parametresine göre ötrofik, görünürlük parametresine göre oligotrofik, klorofil-a parametresine göre mezotrofik, YSKYY'de yer alan toplam azot parametresine göre de mezotrofik olduğu gözlenmiştir. Gölü besleyen derelerdeki besi maddesi yükü hesabı yapılarak, Vollenweider yaklaşımıyla besi yüklemesi incelenmiş ve göldeki trofik durumun toplam fosfor ve toplam azot parametrelerine göre ötrofik olduğu belirlenmiştir. Ayrıca, Sapanca Gölü'nü besleyen yan derelerdeki kirletici konsantrasyonları belirlenmiş, yan derler ve Sapanca Gölü su kalitesinin iyileştirilmesi için çözüm önerileri sunulmuştur.  In this study, important water quality parameters for the future of the lake were analyzed on measurement stations selected on tributaries and Lake Sapanca Basin between 2012 and 2014. The water quality of all streams were determined as class I and class II for general conditions and oxygenating parameters, however, the water quality for nutrient parameters were class III and class IV. The water quality of the lake was determined as class I for general conditions on whole measurement stations, class I on B, C, D stations and class II on A, E, F stations for oxygenating parameters. The water quality for the nutrient parameters were determined as calss II on every measurement points. According to obtained results, trophic level for lake has been identified based on Surface Water Quality Management Directive and Carlson's Trophic Status Index. Trophic level for Lake Sapanca was determined as eutrophic for total phosphorus, oligotrophic for secchi disc and mesotrophic for chlorophyll-a based on both of indexes; and as mesotrophic for total nitrogen based on SWQM. The nutrient loads have been calculated and the trophic status of the lake has been examined by Vollenweider approach and determined as eutrophic for total phosphorus and total nitrogen parameters. Furthermore, the pollutant concentrations on tributaries of Lake Sapanca were determined and the proposed solutions were presented to improve the water quality in Lake Sapanca Basin

Investigation of the ozonation kinetics of bentazone in multiple substrate oxidation systems

Zor ayrışabilir organik maddelerin sularda ve atık sularda gerek miktar gerek çeşit olarak giderek yükselen düzeylerde bulunması ve buna bağlı olarak artan ileri arıtma ihtiyacı, kimyasal oksidasyon proseslerinin kullanımını gerekli kılmaktadır. Ozon, oksidasyon proseslerinde kullanımına en sık rastlanan oksidanlardan biridir. Uygulamada ozon reaksiyonları, organik madde içeren sulu çözeltilerden, ozon gazının geçirilmesi ile gerçekleştirilmektedir. Organik maddelerin ortamda beraber bulunması durumunda oksidasyon kinetiğinin belirlenmesi ve ozon proseslerinin değerlendirilmesinde karmaşık olması nedeni ile güçlükler yaşanmaktadır. Bu bağlamda, pratikteki uygulamaların daha doğru değerlendirilebilmesi için “çoklu substrat oksidasyonu”nun karakterizasyonu büyük önem taşımaktadır. Bentazon, büyük yapraklı bitkilerde yaygın olarak kullanılan bir herbisittir. Bu maddenin distile su içinde, karanlık koşullarda, bozunumu 120 gün sonunda dahi görülmemektedir. Fenol ve fenolik maddeler toksisiteleri, ayrışmaya dirençli yapıları ve sudaki yüksek stabiliteleri nedeni ile büyük önem taşımaktadır. Bu neden ile fenol ve fenolik maddeler oksidasyon proseslerinin incelenmesinde, genellikle örnek madde olarak kullanılmaktadırlar. Bu çalışmanın amacı, kabarcıklı kolon reaktörlerinde, asidik koşullarda, bentazonun tek başına veya fenol ile birlikte bulunması durumunda, moleküler ozon ile oksidasyon reaksiyon mekanizmasının ve kinetiğinin incelenmesidir. Bu amaç doğrultusunda sentetik olarak hazırlanmış numunelerde bentazon ve fenol giderimi, ara ürün oluşumu ve giderimi, TOK giderim mekanizması ve çözelti içindeki çözünmüş ozon konsantrasyonları izlenmiştir. 3.0 mg/dak ozon dozunda gerçekleştirilen tekil bentazon ozonlama deneysel çalışmalarından elde edilen görünür 1. derece kinetik katsayıları 0.044-0.0953 1/dak olarak hesaplamış, bentazonun fenol ile beraber bulunması durumunda ise bu katsayılar 0.0450-0.0253 1/dak olarak bulunmuştur. Anahtar Kelimeler: Ara ürün oluşumu, bentazon, çoklu substrat oksidasyon sistemleri, fenol, giderim kinetiği.Increasing amount and number of resistant organics present in water and wastewaters and the increasing demand for advanced treatment have resulted in increasing use of chemical treatment processes. Chemical oxidation is the most effective process for the removal of organic pollutants present in water. Ozone is a very powerful oxidizing agent, which is able to participate in numerous reactions with organic and inorganic compounds. The role of ozonation and its related oxidation processes in the removal of organic compounds have been studied by different researchers. However, most of these studies have been conducted on systems that include single compound and also paid little attention to the influence of intermediates formed during the oxidation reactions on mechanism and chemical kinetics. In natural waters and wastewaters organic compounds cannot be found alone in the medium. Therefore for a better understanding the ozone oxidation process the removal pattern and kinetic evaluations of organics compounds should be analyzed as they exist alone and together within the aqueous medium. For this purpose phenol and bentazone was selected as model compounds to carry out the analysis mentioned above. Bentazone formulations are used as post-emergence herbicides for the control of broad-leaved weeds and Cyperaceae in a range of crops. Bentazone is not degraded after 120 days in either distilled water or WHO Standard Hard Water (FAO, 1991). Thus, bentazone was chosen as a model compound because it is commonly used as herbicide all over the world. Phenol and phenolic substances are abundantly present in wastewaters from agro-industries. Phenol is also considered to be an intermediate product in the oxidation pathway of higher molecular weight aromatic hydrocarbons. Thus it is usually taken as a model compound for treatment systems. In this respect, this study was devoted to analyze the ozone oxidation process for multiple substrate removal systems. The main objective of this study was to investigate the mechanism and kinetics of oxidation reactions of bentazone with molecular ozone when it exists individually or together with phenol in the aqueous medium under acidic conditions and in bubble column reactors. The parameters monitored were, organic compound removal, intermediate formation and removal, dissolved ozone concentration in the solution for an accurate evaluation of the kinetic behavior and the process of multiple substrate oxidation systems. Cis, cis-muconic acid and phenol were the intermediates monitored during the ozone oxidation of bentazone. For single bentazone oxidation experiments with initial concentrations of 25-100 mg/l, the peak concentration of phenol was ranged between 1.21-5.70 mg/l while the peak values of cis, cis-muconic acid formed for all experiments were less than 1 mg/l. The peak dissolved ozone concentrations were ranged between 7.64 and 9.75 mg/l for experiments with initial bentazone concentrations of 50-100 mg/l. In single substrate oxidation systems of organic compounds, overall removal has found to fit first-order model with respect to the organic compound concentration. Kinetic constants of single ozonation of bentazone have been found to range between 0.044-0.095 1/min at 3.0 mg/min ozone dosage. The kinetics and reaction pattern of bentazone in the multiple substrate oxidation systems were determined to be different from those of bentazone presents alone in the aqueous medium. This variation was considered to be due to the modification of reaction patterns by the interaction between the bentazone and phenol during their oxidation reactions, formation and oxidation of intermediates, as well as ozone transport limitations. In the mixture experiments a steady removal pattern was observed for both bentazone and phenol for all concentrations. Cis, cis-muconic acid was found to be the most important formed intermediate during the mixture oxidation experiments. The peak concentrations of cis, cis-muconic acid formed during the multiple substrate oxidation experiments increased with increasing initial phenol and bentazone concentrations. The peak concentration of cis, cis-muconic acid was ranged between 2.9-9.21 mg/l. The effect of dissolved ozone concentration in the mixture experiments was considered insignificant since it followed a close variation with those of single oxidation systems. The evaluation of the results showed that first-order model was also applicable for the oxidation of mixtures. However, the rate constant of bentazone was found always lower than those obtained for single oxidation kinetics. These changes in the rate constants were related to the accumulation of intermediates, particularly cis, cis-muconic acid. Keywords: Bentazone, intermediate formation, multiple substrate oxidation systems, phenol, removal kinetics

Effect of chelating agents on reactive dyebaths color removal with high pH ozone oxidation

Bu çalışmada, tekstil endüstrisinde yaygın olarak kullanılan reaktif boyar maddelerden Procion Navy HEXL ile boyama proseslerinde iyon tutucu olarak kullanılan EDTA ve EDTMPA’nın yüksek pH'da ozon ile renk ve organik madde giderimi üzerine etkileri deneysel olarak incelenmiş ve anılan iyon tutucuların ortamda ayrı ayrı ve Procion Navy HEXL ile birlikte bulunmaları durumunda oksidasyon karakterindeki değişimleri karşılaştırmalı olarak değerlendirilmiştir. 15 dakikalık reaksiyon süresi sonunda %72 KOİ giderim verimi elde edilmiş ve rengin tamamına yakını giderilmiştir. EDTMPA ve EDTA'nın ortamda tekil olarak bulunmaları durumunda 90 dakikalık ozonlama sonunda, EDTMPA ve EDTA için sırasıyla 2.81 ve 3.32 mg O3/mg giderilen KOİ ozon tüketim oranında, % 80 ve % 43 KOİ giderim verimleri elde edilmiştir. Boyar madde ve iyon tutucuların ortamda tekil ve birlikte bulunmaları durumunda organik maddenin ozon ile oksidasyonun görünür birinci derece reaksiyon kinetiğine uyum sağladığı belirlenmiştir. Elde edilen KOİ giderim hızları EDTMPA'nın (0.0291 1/dak) EDTA ya (0.0258 1/dak) nazaran daha hızlı okside olduğunu göstermiştir. Yüksek pH’da boyar maddenin ortamda EDTA ile birlikte bulunması durumunda 90 dakikalık reaksiyon süresi sonunda % 78 lik KOİ giderimi 2.88 mg O3/mg giderilen KOİ ozon tüketim oranında gerçekleşmiştir. Ortamda boyar madde ve EDTMPA’nın beraber bulunması durumunda ise bu değerler sırası ile % 90 ve 2.40 mg O3/mg giderilen KOİ olarak bulunmuştur. İyon tutucunun boyar maddenin kromofor grubunun oksidasyonu engellenmediği ancak bu grubun aynı seviyede oksidasyonu için gerekli süreyi uzattığı tespit edilmiştir. Aminopolikarboksilat yapısına sahip ve iyon tutucu olarak kullanılan yardımcı kimyasal maddelerin renk giderim hızını, fosfonik asit yapısına sahip iyon tutuculara nazaran daha fazla yavaşlattığı saptanmıştır. Anahtar Kelimeler: Boya banyoları yardımcı kimyasalları, EDTA, EDTMPA, reaktif boya banyoları, renk ve organik madde giderimi, tekstil endüstrisi, yüksek pH'da ozon ile oksidasyon.Color is one of the characteristic parameters of textile industry wastewaters. Although there are several physical-chemical methods applied for color removal such as adsorption, membrane processes and chemical oxidation, chemical oxidation has become the method of choice due to its high efficiency and ease of operation. Ozone is one of the most effective oxidant used for this purpose. Ozone oxidation of textile industry wastewaters, spent and simulated dye baths has been a focus of investigations (Davis et al., 1982; Grau, 1991; Carriére et al., 1993; Namboodri et al., 1994a,b). Mechanism and kinetics of ozonation of synthetic dye solutions were also extensively studied (Snider and Porter,1974; Perkins et al., 1980; Teramoto et al., 1981; Perkins et al., 1995). Actual dye baths involve the use of several assisting chemicals in addition to dyes. Basic chemicals used in reactive dyeing are NaCl, Na2CO3 and sequestering agents. NaCl is used to facilitate diffusion of the dye to the fiber. Na2CO3 mostly has a dual purpose: it helps the fixing of the dye and increasing and buffering the pH. Sequestering agents are chelate forming ligands that bind the metal ions such as Cu2+, Fe2+, and prevent their interference with dye. Kabdaşlı et al. (2002) studied the effect of assisting chemicals in the dye bath on ozonation of dyestuffs. They found out that sequestering agents exerted a significant effect on the ozone oxidation of the dye by reducing the reaction rate and increasing the amount of ozone being used, while NaCl and Na2CO3 had negligible effect on color removal. Commonly used conventional sequestering agents such as NTA (nitrilo triacetic acid) and EDTA (ethylenediamine tetraacetic acid) contain aminopolycarboxylate groups. Recently a new generation sequestering agents that are based on phosphonic acid derivatives has been introduced. The advantage of these compounds in addition to their capability of strongly binding the metal ions, is their stability at high temperatures employed in reactive dyeing. The study aimed to asses several aspects of oxidation dye bath assisting chemical, by ozonation emphasizing their effect on decolorization at high pH. In the first stage of experiments dyestuff and chelating agents were separately oxidized by ozone at high pH. In the second stage, oxidation of the combination of dyestuff and chelating agent was carried out. The dyestuff used in the experiments was Procion brand Navy HEXL that involved the bifunctional group bis(amino chlorotriazine) and have been frequently used for dyeing cellulosic fibers. The chelating agents selected were, EDTA which has been used commonly as a conventional sequestering agent and a new generation sequestering agents EDTMPA (ethylenediamine tetramethylene phosphonic acid) which has been actually used in textile dyeing and had a similar structure to EDTA. EDTA and EDTMPA concentrations were selected considering the actual concentrations used in the reactive dye baths. Oxidation experiments were conducted at pH 10.5 which was also reflected the actual pH of the spent dye bath. Oxidation of the Procion Navy HEXL was relatively fast providing over 50 % color removal in 3 minutes and reaching almost complete removal in 10 minutes. COD removal efficiency was 72% at the end of the 15 minute reaction time. At the end of the experiment a specific ozone consumption of 0.8 mg O3 /mg COD removed was determined. The evaluation of the single dye ozonation results showed that pseudo-first order kinetic expression was applicable with respect to the COD. 80 % and 43 % COD removal efficiencies were obtained in 90 minutes by the ozonation of 2.293 mM EDTMPA and EDTA solutions respectively. The ozone utilization ratios were of 2.8132 mg O3/mg COD removed for EDTMPA and 3.32 mg O3/mg COD removed for EDTA at the end of the oxidation period. The evaluation of the results showed that pseudo-first order kinetic was also applicable for the oxidation of selected chelating agents with respect to COD. The rate constants were 0.0291 and 0.0258 1/min for EDTMPA and EDTA respectively. As can be seen from the results it can be concluded that EDTMPA could oxidize more rapidly than EDTA. Results of ozone oxidation of combination of the dye and chelating agents at pH 10.5 showed that when they were existed together oxidation rate of both reduced. The same degree of color removal (below 100 Pt-Co) was obtained in 30 minutes for EDTMPA and 60 minutes for EDTA versus 10 minutes when dye existed singly. COD removal characteristics of the systems were also modified when the dye and chelating agents existed in combination as well as pseudo-first order reaction rates. Keywords: Color and organic matter removal, dye bath additive, EDTA, EDTMPA, high pH ozonation, reactive dye baths, textile industry

A coronary cameral fistula displaying exaggerated neovascularity on angiogram with atypical drainage site in left atrium

GİRİŞ: Bir koroner arterle bir kalp boşluğu arasında miyokardiyal kapiller yatağı köprüleyerek oluşmuş belirgin bağlantı koroner-kameral fistül olarak tanımlanır. Mitral darlık hastalarında, sirkumfleks koroner arterden köken alan fistül ve koroner revaskülarizasyon varlığı, sol atriyal trombüsün bir belirtisidir. OLGU: 51 yaşında eski bir maden işçisi olan erkek hasta hastanemize nefes darlığı ve atipik göğüs ağrısı yakınmaları ile başvurdu. Transtorasik ekokardiyografide mitral darlık ve sol atriyumda trombüs tespit edildi. Transözefajeal ekokardiyografide trombüsün sol atriyum apendiksinden köken alarak interatriyal septum ve atriyum tabanına doğru uzanım gösterdiği gözlemlendi. Koroner anjiyografide sirkumfleks koroner arterden çıkan ve sol atriyum içindeki kitle lezyonuna drene olan yaygın damar ağı görüldü. Hastaya mitral kapak ve koroner-kameral fistülün kapatılmasına yönelik cerrahi planlandı. Operasyonda, atriyum tabanından başlayarak sağ pulmoner ven ağzı seviyesinden interatriyal septum ve mitral kapak anülüsü seviyesine kadar olan mesafeyi kaplayan dev trombüs saptandı. Trombüs dikkatli bir şekilde atriyum duvarından diseke edilerek ayrıldı. Trombüsün altında posterior mitral anülüsten yaklaşık 2-2,5 cm mesafede –süperior pulmoner venler ve atriyal apendiks arasındaki hattın orta noktasında– yerleşimli olan koroner-kameral fistül ostiumu bulundu. Ostium primer olarak sütüre edildi ve mitral kapak replase edildi. SONUÇ: Mitral darlık olgularında sol atriyal trombüse eşlik eden koroner-kameral fistüller değişik şekillerde ortaya çıkabilmektedir. Bu tip koroner-kameral fistüller en sık atriyal apendikse drene olmakla birlikte, fistülün açıldığı yerin kesin olarak saptanabilmesi için sol atriyumun diğer bölgeleri de dikkatli bir şekilde incelenmelidir.OBJECTIVE: The term coronary cameral fistula describes a sizeable communication between a coronary artery and a chamber of the heart that bypasses the myocardial capillary bed. In patients with mitral stenosis, coronary revascularization and fistula originating from the circumflex coronary branch is an indicator of left atrial thrombus. CASE: A 51-year-old male who was a former coal miner admitted to our hospital with complaints of shortness of breath and atypical chest pain. Transthoracic echocardiography revealed mitral stenosis and left atrial thrombus. Transesophageal echocardiography showed that the thrombus was spreading out from the left atrial appendix towards the interatrial septum and the base of atrium. Coronary angiogram revealed extensive network of vessels arising from the circumflex coronary artery draining into a solid lesion originating from left atrium. He was scheduled to undergo mitral valve surgery and surgical closure of the coronary cameral fistula. In the operation, giant thrombus extending from the base of atrium to the origin of the right pulmonary vein and down to the interatrial septum and mitral valve annulus was detected. Thrombus was carefully dissected and peeled off from the left atrial wall. Underneath the thrombus –situated at the center of the line between the superior pulmonary veins and atrial appendage– approximately 2-2,5 cm. distant from the posterior mitral annulus, ostium of the coronary cameral fistula was found. The ostium was closed by simple sutures and the mitral valve was replaced. CONCLUSION: Coronary cameral fistulas accompanying left atrial thrombus in cases of mitral stenosis may emerge in variable forms. Although the most common drainage site for these fistulas is atrial appendage, the other regions of left atrium should be carefully inspected for exactly localizing the ostium of the fistula

Feasibility of the use of electrocoagulation process sludges as adsorbents for the removal of dyestuffs

Bu çalışmada, elektrokoagülasyon (EK) prosesinden kaynaklanan arıtma çamurlarının tekstil son işlemleri boya banyolarında yaygın olarak kullanılan reaktif boyarmaddelerin adsorpsiyon yöntemi ile gideriminde adsorban olarak kullanılabilirliği araştırılmıştır. Elektrolit olarak 1500 mg/L NaCl kullanılarak, 22.5 mA/cm2 akım yoğunluğunda EK uygulamaları yürütülmüş ve 10 ile 90 dakika arasında değişen sürelerde elektrokoagülatörden alınan çamurların adsorban olarak kullanılabilirliği çelik ve alüminyum elektrodların kullanılması durumları için ayrı ayrı incelenmiştir. Çalışma kapsamında adsorpsiyon özellikleri incelenen Reactive Black 5, Crimson HEXL ve Yellow HE4R reaktif boyar maddeleri, çelik elektrodların kullanıldığı elektrokoagülasyon uygulamalarında üretilen arıtma çamurları ile %90’ın üzerinde verimlerle giderilmişlerdir. EK prosesi ile üretilen Fe(OH)3 çamurunun proseste gerçekleşen oksidasyon redüksiyon reaksiyonları çerçevesinde yüzeyinin modifiye olup olmadığının araştırılması ve karşılaştırma yapmak amacı ile FeCl3 kullanılarak gerçekleştirilen koagülasyon ve bu prosesle oluşturulan taze Fe(OH)3 floklarının kullanımıyla yürütülen adsorpsiyon deneylerinde elde edilen giderim verimleri ise Reactive Black 5 için %2-14, Crimson HEXL için %10-12, Yellow HE4R için ise %13-18 olarak bulunmuştur. Elde edilen bu sonuçlar ışığında EK uygulaması esnasında taze oluşturulan Fe(OH)3 floklarının yüzeylerinin modifiye olduğu söylenebilmektedir. Alüminyum elektrodların kullanılması durumunda ise Reactive Black 5 boyar maddesi için ancak 5 g/L gibi çok yüksek absorban dozajında %63 gibi bir giderme verimi elde edilebilmiştir. Crimson HEXL ve Yellow HE4R için ise 1 g/L adsorban dozajında %95’in üzerinde boyar madde gideriminin olduğu tespit edilmiştir. Alüminyum elektrodlar kullanıldığı EK prosesi ile oluşturulan Al(OH)3 çamurunun adsorbsiyon kapasitesinin çelik elektrotlar ile oluşturulan Fe(OH)3 çamuruna göre çok daha düşük olduğu elde edilen sonuçlar ışığında söylenebilmektedir. Anahtar Kelimeler: Adsorpsiyon, alüminyum elektrodlar, çelik elektrodlar, elektrokoagülasyon, reaktif boyar madde, tekstil endüstrisi.The textile industry plays a significant role in the economy of several countries around the world. Dyeing is a fundamental operation during textile fiber processing. This operation causes the production of more or less colored wastewater, depending on the degree of fixation of the dyestuffs on the substrates, which varies with the nature of the substances, the desired intensity of coloration, and the application method. Little attention has been paid to color since it was considered a problem only of aesthetics. Recently the color in textile wastewaters has been investigated for its effects on wastewater treatment systems and on the environment. Color, depending on its origin, is not only a problem of aesthetics but also of toxicity and reduced biodegradability because of the complex nature of used dyestuff. Disposal of this colored water into receiving water may cause toxicity to aquatic life. The dyes can upset the biological activity in water bodies. They also pose a hazard because they may be mutagenic and carcinogenic and can cause severe damage to human beings. Various treatment methods including, physical, physico-chemical and chemical processes have been investigated for treating dye bearing effluents. All these methods have different color removal capabilities, capital and operating costs. Among these processes, adsorption has been found to be superior to other techniques for wastewater treatment in terms of initial cost, simplicity of design, ease of operation and insensitivity to toxic substances. For instance activated carbon which has a high adsorption capacity for organic molecules is commonly used as an adsorbent for color and organic material removal from wastewater. But the activated carbon is an expensive adsorbent and its recycling processes are extra costly for operation. Several wastes and residues have been investigated for the adsorption of dye bearing effluents with varying success. However, new economical and highly effective adsorbents are still needed. Electrochemical technologies contribute in many ways to a cleaner environment and cover a very broad range of techniques. There has been a growing interest in the use of environmental electrochemistry. Environmental electrochemistry involves electrochemical techniques in order to remove impurities and to prevent environmental pollution. Among these techniques, electrocoagulation (EC) is an electrolytic process that generates metallic hydroxide flocks in situ via electro-dissolution of the soluble sacrificial anode immersed in the wastewater. The electrochemically generated metallic ions can be hydrolyzed next to the anode and generate a series of metal hydroxides. The generated metal hydroxides are believed to be responsible for the adsorption of the dissolved pollutants. Therefore the use of electrochemically generated metal hydroxide sludge can be a potential adsorbant for adsorptive removal of dyestuffs from aqueous solution. In this study, use of sludges generated through the electrocoagulation process which is of a common interest, for the removal of reactive dyestuffs that are frequently used in the textile industry, by adsorption was investigated. Scope of the study included the adsorption of Reactive Black 5, Crimson HEXL and Yellow HE4R reactive dyes onto the sludges generated through electrocoagulation using stainless steel and aluminum electrodes. Study results indicated that all dyestuffs were removed with efficiencies over 90% using the sludges produced by the use of stainless steel electrodes. 66 and 100% removals were observed for Crimson HEXL with 200 and ³1000 mg/L of electrochemically generated Fe(OH)3 sludge. The same trend was also seen for Reactive Black 5 and Yellow HE4R. This increase in color removal efficiencies was attributed to the increase in available adsorption area with the increase in adsorbent dose. The sludges produced by coagulation using FeCl3 were used to compare the adsorption capacities of freshly coagulated Fe(OH)3 and electrochemically generated Fe(OH)3 sludges. Fresh coagulation sludges provided removals 2-14%, 10-12% and 13-18% for Reactive Black 5, Crimson HEXL and Yellow HE4R, respectively. From the results of experimental studies it can be concluded that the surface modification of Fe(OH)3 sludges occured during electrocoagulation thus increasing the adsorption capacity. However, the sludges generated by the use of aluminum electrodes yielded over 95% removal of Crimson HEXL and Yellow HE4R dyes at 1 g/L solid doses, while Reactive Black 5 could be removed 63% at a high solid dose of 5 g/L. The results of the study indicated that electrochemically generated Fe(OH)3 sludge is an effective adsorbent for reactive dye stuff. All studied reactive dyestuffs have been effectively removed by adsorption on electrochemically generated Fe(OH)3 sludge. Keywords: adsorption, aluminium electrodes, electrokoagulation, reactive dyestuff, stainless stell electrodes, textile industry

Endokrin bozucu dimetil fitalatın elektrokoagülasyon ve elektrokoagülasyon/Fenton prosesleri ile arıtımı

Phthalic acid esters (phthalates) are frequently used as plasticizers for cellulosic and vinyl ester resins, but also in ceramic, paper, cosmetic, ink and paint industries. Phthalates are readily adsorbed through the skin and have negative impacts on human health and fertility. They have been detected in surface and groundwater in the ng/L-mg/L concentration range and associated with birth defects, organ damage, infertility, as well as testicular cancer, and are also known to be among the major endocrine disrupting compounds. The short-chained esters such as dimethyl phthalate (DMP), which mainly originate from industrial wastewater discharge and leaching and volatilization from plastic products during their usage and after disposal, are among the most frequently, identified phthalates in diverse environmental samples. Studies of DMP's biodegradation in fresh water, marine water, sediment, wastewater and sludge, have revealed a low degradation rate in the range of several days to a few months. Thus the destruction of these bio-recalcitrant organic pollutants requires the application of advanced treatment technologies such as electrocoagulation (EC) and electrocoagulation/ Fenton (EC/Fenton) processes. EC offers high removal efficiencies in compact reactors with simple equipments for control and operation of the process. In an EC reactor, the coagulant is generated in the reaction solution from a sacrificial electrode (e.g. iron, aluminum) leading to the in-situ formation of the respective metal hydroxides. A complex and yet not deeply understood reaction mechanism is thought to be involved in the EC process featuring a complex scheme of coagulation, particle entrapment, adsorption, absorption, flotation and redox reactions. In EC/Fenton process, strong oxidizing hydroxyl radicals (HO·) are generated in the solution by the well-known Fenton's reaction between H2O2 and electrochemically generated Fe2+ ions from sacrificial iron anodes. HO· is one of the most reactive free radical (oxidation potential: + 2.8 eV) and can indiscriminately degrade organic compounds. The number of parameter involved in the design and operation of the EC and EC/Fenton processes is relatively high and thus an efficient design and operation of the processes call for a detailed and careful evaluation and optimization. The main targets of the present study were: to assess the performance of EC and EC/Fenton processes in the treatment of aqueous solution of DMP selected as a model phthalate and to determine the most appropriate operating conditions for maximizing the processes performances. In this study, classical optimization method (a single-factor-at-a-time approach) and Central Composite Design (CCD) Response Surface Methodology (RSM) were used to optimize the treatment of aqueous DMP by EC and EC/Fenton with stainless steel electrodes, respectively. The effects of the key process variables such as initial DMP concentration (DMPo), current density (Jc), electrolyte concentration (NaCl) and treatment time (tr) and H2O2 dosage on DMP and total organic carbon (TOC) removals were evaluated. According to the second-order polynomial regression models, established for EC process by CCD-RSM, DMP and TOC removal efficiencies were affected by the process variables in the following decreasing order; Jc>tr>DMPo>NaCl (negative impact), tr>DMPo (negative impact)>Jc>NaCl (negative impact). Analysis of variance indicated that the experimental design models obtained for the EC treatment of aqueous DMP solutions in terms of the model pollutant and mineralization were statistically significant. For aqueous DMF concentration of 100 mg/L, current density of 13.5 mA/cm2, electrolyte concentration of 1250 mg/L NaCl and treatment time of 120 min were found to be as optimum conditions. At these conditions at the end of 120 minutes, 95% DMP and 7% TOC removals were obtained. The results of the present study also clearly indicated that the EC/Fenton process run with stainless steel electrodes is an effective treatment application for DMP destruction as well as mineralization. The optimum operational conditions for the EC/Fenton process were determined as follows: initial pH of 2.0, current density of 22 mA/cm2, an electrolyte concentration of 1500 mg/L NaCl, and H2O2 dosage of 40 mM for the treatment of aqueous DMP (100 mg/L). Under these conditions at the treatment time of 120 minutes 94% DMP and 71% TOC removal were obtained. Keywords: Dimethyl phthalate, endocrine disruptive substances, electrocoagulation process, electrocoagulation/Fenton process, response surface methodology.Fitalik asit esterleri (fitalatlar) endüstriyel uygulamalarda yaygın olarak kullanılan ve Dünya genelinde yıllık üretim miktarları 2.7 milyon ton gibi yüksek değerlere ulaşan, toksik özellik gösteren, kanserojen, endokrin bozucu ve birikim potansiyeline sahip maddelerdir. Bu çalışmada konvansiyonel yöntemlerle istenilen düzeyde arıtılamayan fitalat benzeri kirleticilerin gideriminde elektrokoagülasyon (EK) ve elektrokoagülasyon/Fenton (EK/Fenton) proseslerinin kullanımı araştırılmış ve bu iki prosesin verimleri ana madde ve toplam organik madde (TOK) giderimleri dikkate alınarak karşılaştırılmıştır. Her iki proses için en uygun işletme koşullarının belirlenmesi amacıyla optimizasyon çalışmaları yürütülmüştür. Her iki proses için en uygun işletme koşullarının belirlenmesi amacıyla optimizasyon çalışmaları yürütülmüştür. EK prosesinin optimizasyonu “Cevap Yüzey Yöntemi” metodolojisi kullanılarak, EK/Fenton prosesinin optimizasyonu ise geleneksel optimizasyon çalışmaları ile gerçekleştirilmiştir. EK/Fenton prosesi ile yürütülen çalışmalarda, 100 mg/L DMF sulu çözeltisi için optimum koşullar 22.5 mA/cm2 akım yoğunluğu, 1500 mg/L NaCl elektrolit konsantrasyonu, başlangıç pH’sı 2 ve H2O2 dozajı 40 mM olarak belirlenmiştir. Bu koşullarda 60 dakikalık reaksiyon süresi sonunda %100 DMF ve %90 TOK giderimi elde edilmiştir. EK prosesi için ise farklı giriş DMF konsantrasyonları (20-100 mg/L) için optimum işletme koşulları cevap yüzey yöntemi ile belirlenmiştir. 100 mg/L DMF sulu çözeltisi için optimum koşullar 13.5 mA/cm2 akım yoğunluğu, 1250 mg/L NaCl elektrolit konsantrasyonu ve başlangıç pH’sı 6 olarak belirlenmiş ve bu koşullarda 120 dakika sonunda %95 DMF ve %7 TOK giderimleri elde edilmiştir. Anahtar Kelimeler: Dimetil fitalat, endokrin bozucu maddeler, elektrokoagülasyon prosesi, elektrokoagülasyon/Fenton prosesi, cevap yüzey yöntemi

Treatability of wastewaters containing complex metal by electrocoagulation process

Toxic metals have been categorized in priority pollutant lists and their proper management is the main subject of recent environmental studies. Conventionally, hydroxide precipitation of metals is being employed for the treatment of metal finishing industry wastewaters. However, effluents bearing complexed heavy metals cannot be efficiently removed by employing precipitation methods. Recent research has demonstrated that electrocoagulation (EC) offers an attractive alternative to conventional treatment methods applied to metal finishing wastewaters. EC is known as an easy-to-operate and efficient electrochemical treatment method preferentially applied to treat "hard" industrial wastewater. EC using stainless steel and aluminum electrodes appears to be an ideal candidate for treatment of wastewaters containing complexed metals. Considering the above indicated facts, the present study focused on the treatability of metal finishing effluent originating from the nickel and zinc plating process by EC using stainless steel electrodes. In order to observe the system's performance as a function of varying process variables such as electrolyte (chloride) concentration, current density (mA/cm2), initial pH of the reaction solution and operation time, the feasibility of the proposed alternative treatment system was evaluated under different working conditions in terms of heavy metal (nickel and zinc) and organic matter (TOC) removal. Generally speaking, the treatment performance of EC  highly dependent upon the pH of the wastewater to be treated and the pH increases from its original pH to alkaline pH values during the course of reaction due to cathodic hydroxide formation. For the evaluation of the effect of initial pH on process performance, a series of experiments were carried out with the effluent at a fixed electrolyte concentration (1615 mg/L chloride) and current density (22.5 mA/cm2) at initial pH values of 3-10. The obtained findings indicated that the overall TOC removals were independent from pH at the studied pH range. On the other hand, heavy metal removal via EC was governed by the effluent pH. This is mainly because the pH value reached at the end of the selected EC operation time (120 min) was in the proper range for zinc and nickel hydroxide precipitation. On the other hand, nickel removal was influenced by the residual TOC and significant nickel removal began after TOC fell below 100 mg/L. The electrolyte concentration increases the conductivity of the reaction solution which in turn reduces the voltage needed to achieve a certain current. The effect of electrolyte concentration on the process performance was also examined. The experiments were conducted with effluent having initial pH of 6.0 at a fixed current density (22.5 mA/cm2) at electrolyte (chloride) concentrations in the range of 1500-3000 mg/L. Increasing the chloride concentration from 1500 to 3000 mg/L accelerated the TOC removals for an operation time of 75 min. However, the actual chloride concentration of the wastewater (1350-1480 mg/L) was adequate for TOC, nickel and zinc removal employing EC. In terms of both treatment efficiencies and electrical energy requirements, the applied current density is the most critical factor and hence key design parameter affecting the treatment systems's response time as well as dominant separation/pollutant mode. For any specific application, the optimal current density has to be determined and will invariably involve a trade-off between operational costs and most efficient use of the produced coagulant. Therefore, a series of EC experiments was carried out with the same effluent at densities varying between 2.25 - 56.25 mA/cm2. For the evaluation of the affect of current density on system performance the original pH (6.0) and chloride concentration (1480 mg/L) of the wastewater were selected. From the experimental results it could be concluded that increasing the current density from 2.25 to 9.0 mA/cm2 dramatically increased TOC removal efficiencies from 20% to 60%. For the higher current densities investigated (22.5-56.25 mA/cm2), the same TOC removal efficiencies could be achieved but at relatively shorter reaction times. Keywords: Electrocoagulation; metal finishing industry, nickel and zinc removal; organic carbon abatement, stainless steel electrodes.Günümüzde ağır metal içeren atıksuların arıtılması gerek bu tip akımların çok çeşitli kaynaklarının olması gerekse kirlenmede taşıdıkları önem nedeniyle dikkatle değerlendirilmesi gereken bir nokta olarak gündeme gelmektedir. Kompleks olarak bağlı metal içeren atıksular, bünyelerinde organik kompleks yapıcıların (organik ligandların) bulunduğu atıksulardır. Henüz bu atıksularının arıtımı için uygun bir arıtma teknolojisi tanımlanmamıştır. Bu çalışmada elektrokoagülasyon prosesinin, metal son işlemleri endüstrisi kompleks olarak bağlı metal içeren atıksularına uygulanabilirliği, bir asidik nikel çinko kaplama banyosundan kaynak bazında alınan atıksu numunesi ile bu işlemi takip eden yıkamaları karakterize etmek üzere hazırlanan kompozit numune (TOK=173-207 mg/L; Ni=275-291 mg/L, Zn=226-236 mg/L) kullanılarak araştırılmıştır. Elektrolit konsantrasyonunun, başlangıç pH sının ve akım yoğunluğunun çinko ve nikel ile birlikte organik madde (TOK) giderimi üzerine etkileri incelenmiş ve değerlendirilmiştir. Deneysel çalışmadan elde edilen sonuçlar; paslanmaz çelik elektrodların kullanıldığı elektrokoagülasyon uygulaması ile söz konusu atıksulardan nikel ve çinkonun % 100 verimle tamamen giderilebildiğini göstermiştir. Başlangıç pH sının ve elektrolit konsantrasyonunun TOK giderimi üzerine önemli bir etkisinin olmadığı ve atıksuyun kendi bünyesindeki klorür konsantrasyonunun elektrokoagülasyon prosesinin işletimi için yeterli olduğu sonucuna varılmıştır. Akım yoğunluğunun etkisinin belirlendiği deneysel çalışmalarda ise 2.25-9.0 mA/cm2 akım yoğunlukları arasında artan akım yoğunluğu ile TOK giderme veriminin arttığı, daha yüksek akım yoğunluklarında (22.5-56.25 mA/cm2 aralığı) ise aynı TOK giderim verimlerine daha kısa sürelerde ulaşıldığı belirlenmiştir. Bu proses ile optimum işletme koşullarında (akım yoğunluğu= 22.5 mA/cm2; başlangıç pH= 6); numunenin kendi bünyesindeki çözünmüş madde konsantrasyonundan elektrolit olarak  faydalanılarak çinko ve nikel tamamen, TOK ise %50 oranında giderilmiştir. Anahtar Kelimeler: Çelik elektrodlar, elektrokoagülasyon, kompleks olarak bağlı metal içeren atıksular, metal son işlemleri endüstrisi,  nikel ve çinko giderimi, organik madde giderimi

Dimethyl phthalate degradation by Peroxymonosulfate (oxone)/UV-C photochemical process

Ftalik asit esterleri (ftalatlar) kağıt, karton, kozmetik, deterjan, şampuan, sabun, tıbbi malzeme, plastik kap ve boya üretiminde hammadde veya yardımcı kimyasal madde olarak kullanılmaktadır. Endüstrilerde, malzemelerin esneklik özelliğini arttırmak için kullanılan ftalatlar, toksik özellik gösteren, kanserojen, endokrin bozucu ve birikme potansiyeline sahip maddelerdir. Ftalatların arıtımında konvansiyonel arıtma prosesleri ile yüksek giderme verimleri elde edilememekte ve bu nedenle arıtımlarında adsorpsiyon ve ileri oksidasyon proseslerinden yararlanılmaktadır. Bu çalışma kapsamında endokrin bozucu ve toksik etkileri nedeniyle kullanımlarında yasal düzenlemeler yapılmış ftalatlara örnek teşkil etmek üzere seçilen dimetil ftalat (DMF) model kirleticisinin sulu çözeltisinin fotokimyasal ileri oksidasyon proseslerinden olan peroksimonosülfat (PMS-okson)/UV-C ile arıtımı incelenmiştir. Giriş PMS konsantrasyonunun ve başlanıç pH değerinin proses giderim verimi üzerine etkisi araştırılmış ve prosesin arıtma performansı DMF ve TOK ölçümleri yapılarak değerlendirilmiştir. Gerçekleştirilen deneysel çalışmalarda PMS/UV-C prosesi ile DMF’nin gideriminin birinci dereceden hız kinetiğine uyum sağladığı belirlenmiştir. Belirli bir değere kadar (50mM) artan PMS konsantrasyonu ile DMF giderimi için birinci dereceden hız sabitinin arttığı tespit edilmiştir. En yüksek hız sabiti k40mM= 0.276 L/dk olarak bulunmuştur ve PMS konsantrasyonu 50 mM’a arttırıldığında hız sabiti k50mM= 0.246 L/dk değerine düşmüştür. TOK giderimi incelendiğinde ise artan PMS konsantrasyonu ile tam mineralizasyonun sağlandığı arıtma süreleri azalmaktadır. Optimum PMS konsantrasyonunda (40mM) 40. dakikanın sonunda tam mineralizas-yon sağlanmıştır. Elde edilen sonuçlar ışığında DMF gideriminde PMS/UV-C prosesinin uygulanabilir etkin bir arıtma prosesi olduğu sonucuna varılmıştır.  Anahtar Kelimeler: Dimetil ftalat; elektrik enerjisi tüketimi; endokrin bozucu maddeler; fotokimyasal arıtma; kimyasal oksidasyon; peroksimonosülfat (okson).Phthalate esters (PAEs) are used as plasticizers to impart flexibility and resilience to plastic products. Other uses of phthalates are in ceramic, paper, cosmetic, ink, and paint industries. In recent years, PAEs have become a controversial issue because many phthalates are suspected to be mutagens, hepatotoxic agents and endocrine disruptors, and can lead to adverse effects on organisms even in a low concentration. The short-chained esters such as dimethyl phthalate (DMP), which mainly originate from industrial wastewater discharge and leaching and volatilization from plastic products during their usage and after disposal, are among the most frequently, identified PAEs in diverse environmental samples including marine water, surface waters and sediments. Studies of DMP?s biodegradation in fresh water, marine water, sediment, wastewater and sludge, have revealed a low degradation rate in the range of several days to a few months. Thus the destruction of these bio-recalcitrant organic pollutants requires the application of vigorous oxidizing agents, such as those used in advanced oxidation processes (AOPs). Recently, sulfate radical based-AOPs have attracted great scientific and technological interest in the area of wastewater treatment and other environmental applications. OxoneÒ, the commercial name of potassium peroxymonosulfate, is a triple salt with the composition of 2KHSO5·KHSO4·K2SO4 is a convenient source of generating sulfate radical (SO4·-). Peroxymonosulfate (PMS), is a mono-SO3- substituted hydrogen peroxide (H2O2) and has been used in a restricted way as an oxidant in light induced processes. Radiolysis, photolysis, or thermal activation of PMS leads to the formation of both SO4·- and hydroxyl radical (HO·). The use of UV light leads to the generation of SO4·- and HO· through the photolysis of the PMS. SO4·- is a very strong oxidant (Eo = 3.1 eV) and engages in at least three reaction modes with organic compounds similar to HO·: by abstracting a hydrogen atom from saturated carbon, by addition to unsaturated or aromatic carbon, and by removing one electron from carboxylate anions and from certain neutral molecules which may eventually lead to the mineralization of the organic substance. The main targets of the present study were: to assess the performance of PMS/UV-C process in the treatment of aqueous solution of DMP (100 mg/L) selected as a model PAE and to explore the effect of some important operating parameters, such as reaction pH (3-9), initial PMS concentration (0-60 mM) and reaction time (0-120 min) on DMP and organic carbon abatement rates. The  results of this study is expected provide fundamental and practical information as a guide for the treatment of bio-recalcitrant organic pollutants by the PMS/UV-C process. For the initial pH values tested, it was found that lowering the initial pH of the aqueous DMP solution slightly improved the degradation rate of DMP. For instance, higher than 95% DMP abatement was achieved after 60 min at pH 3 while the extended reaction times, i.e. 90 and 120 min, required in order to achieve the same level of DMP reduction at initial pH values of 6 and 9 for 5 mM initial PMS concentration, respectively. However, TOC abatements were slightly enhanced with increasing the initial pH. Based on these results pH 3 was selected as the most effective pH for the degradation of DMP. DMP abatement increased with elevating initial PMS concentrations from 5 to 40 mM. Further increase in initial PMS concentration to 50 and 60 mM, however, slightly reduced the extent of DMP removal. With an initial DMP concentration about 100 mg/L, more than 95% of DMP could be removed at time of 20 min under an initial PMS concentration of 40 mM. DMP degradation by PMS/UV-C process successfully represented by a pseudo first-order kinetic model and the highest reaction rate constant was calculated as 0.276 L/min for 40 mM initial PMS concentration. As aforementioned further increase of the PMS concentration slightly reduces the DMP removal rates to 0.246 L/min for 50 mM and 0.243 L/min for 60 mM initial PMS concentrations. The photodegradation of aqueous organic pollutant is an electrical-energy-intensive process, and electrical energy typically represents a major fraction of the operating costs. The lowest electrical energy per order (EE/O) value for DMP oxidation by PMS/UV-C process was calculated as  2.9 kWh m-3 order-1 at the case of 40 mM PMS concentration. Keywords: Dimethyl phthalate; operating cost analysis; endocrine distrupting compounds; photochemical treatment; peroxymonosulfate (oxone), chemical oxidation

Influence of ıschemic preconditioning and n-acetylcysteine on ınflammatory process in rat skeletal muscle ıschemia-reperfusion

OBJECTIVE: Skeletal muscle ischemia-reperfusion (I/R) injury is a complex process in which the inflammatory mechanisms play important role. Ischemic preconditioning (IPC) and reactive oxygen radical scavenger N-acetylcsyteine (NAC) have been shown to attenuate I/R injury. We aimed to investigate the effects of IPC and NAC on I/R induced inflammation and the influence of synchronous application. MATERIALS and METHODS: Thirty-five Sprague-Dawley rats were randomly assigned to five groups. In sham group, infrarenal aorta was isolated without induction of ischemia. In control group, ischemia was induced for 120 min, followed by reperfusion for 50 minutes. In IPC group, three cycles of 10 min ischemia, followed by 10 min reperfusion was formed preceding I/R. NAC group rats received an intravenous NAC (20 mg/kg) at the end of ischemic period and a maintenance dose of 20mg/kg/hr throughout the reperfusion. In IPC+NAC group, an equal amount of NAC was administered in an identical time period during IPC. Blood samples were obtained at the end of reperfusion for analysis of IL-1β, IL-6 and TNF-α level then rats were sacrificed. RESULTS: All serum cytokine levels which were analyzed in this study were found to be significantly increased in control group in comparison with sham group. Although cytokine levels in the study groups were moderately increased as compared with sham group, all of three groups had significantly reduced levels than control group. There were no significant differences between the study groups regarding the serum cytokine levels. CONCLUSION: These findings indicate that inflammation plays an essential role in skeletal muscle I/R injury. Our results suggested IPC and NAC exert beneficial effects on I/R induced inflammatory process in skeletal muscle. It was observed that there was no superiority of either of the measures over each other regarding the serum cytokine levels and concomitant use of them did not generate an additional benefit