Boyar maddelerin molekül ağırlığının elektrooksidasyon ve elektrokoagülasyon proseslerinde renk giderme verimine etkisi
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Dosyalar
Tarih
2018
Yazarlar
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Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Boyar maddeler, çeşitli cisimleri (kumaş, elyaf vb.) renkli hale getirmek için kullanılan organik bileşiklerdir. Farklı kimyasal yapıya ve molekül ağırlığına sahip birçok farklı boyar madde endüstriyel uygulamalarda kullanılmaktadır. Özellikle yüksek çözünürlüğe sahip reaktif boyalar zengin parlak renk gamları ve birçok şekilde uygulanabilme kolaylıkları nedeniyle tekstil boyamada çok tercih edilmektedir. Tekstil boyama endüstrisinde, üretimin çeşitli adımlarında çok miktarda su, sentetik boya ve çeşitli kimyasallar kullanılır ve bunun sonucunda farklı molekül yapılarında kompleks kirleticileri içeren atıksu meydana gelir. Özellikle suda çözünürlüğü yüksek ve sabitlenme oranları düşük olan boyar maddeler uygulama sırasında tamamen tutunmadan hidrolize olmaları nedeniyle çok miktarda tutunmamış boya atık haline gelir. Alıcı su ortamında atık boyanın oluşturacağı renk nedeniyle ışık geçirgenliği azalarak fotosentez faaliyetleri engellenir ve oksijen tükenmesi meydana gelir. Ayrıca toksik ve mutojenik boyar maddelerin su kütlelerinde bulunmaları sucul yaşamı olumsuz etkiler. Kanalizasyon sistemine arıtılmadan bırakılmaları kentsel atıksu arıtma tesislerinin biyolojik proseslerinde sorunlara yol açabilir. Bu nedenle boyar madde içeren atıksuların su sistemlerine bırakılmadan önce arıtılmaları için yenilikçi, uygun maliyetli ve etkili atıksu artım teknolojilerine ihtiyaç vardır. Bu çalışmada boyar maddelerin elektrooksidasyon ve elektrokoagülasyon prosesleri ile giderilmelerinde molekül ağırlıklarının etkisi araştırıldı. Bu amaçla, molekül ağırlıkları sırasıyla 1304,80 g/mol, 1026, 25 g/mol ve 626 g/mol olan Reactive Blue 198 (RB198), Reactive Yellow (RY145) ve Reactive Blue 19 (RB19) boyar maddeleri seçildi. Deneylerde kullanılan sentetik boya solüsyonları her boyar maddeden 50 mg alınarak 1 L saf su içerisinde çözdürülmesi ile hazırlandı. Laboratuvar ölçekli deneyler 1000 mg/L NaCl içeren 500 mL boya çözeltileri kullanılarak kesikli sistem ile gerçekleştirildi. Elektrokoagülasyon (EC) deneyleri, 5 alüminyum elektrot içeren elektorkoagülasyon reaktörü (3 anot, 2 katot), güç kaynağı ve manyetik karıştırıcı kullanılarak yürütüldü. Elektrooksidasyon (EO) deneyleri, anot olarak bor katkılı elmas elektrot (BDD), katot olarak ise Ti/IrRuO2 elektrotlarını içeren EO reaktörü ve DC güç kaynağı kullanılarak yürütüldü. Her iki prosesin giderim performanslarına molekül ağırlıkları ile birlikte akım yoğunluğunun etkisi de araştırıldı. Boya giderim verimleri UV/vis spektrofotometre ile ölçülen absorbans değerlerinden konsantrasyonların hesaplanması ile bulundu. Çalışma sonuçlarından; Boyar madde molekül ağırlığının büyüklüğü bunların elektrokimyasal yöntemlerle (elektrokoagülasyon ve elektrooksidasyon) sulardan gideriminde avantaj sağladığı görüldü. Elektrokimyasal proseslerden elektrokoagülasyon ise boyar madde gideriminde elektrooksidasyona göre daha kısa sürede ve daha düşük işletme maliyeti ile giderim yapabilmektedir. Ancak elektrokoagülasyonda oluşan flok çamurlarının giderilmesi gerektiği unutulmamalıdır.
Dyes are organic compounds that are used to impart color to substances (fabric, fiber etc.). Various kinds of dyes with different chemical structures and molecular weights are used in industrial applications. Particularly, highly soluble reactive dyes are much preferred in textile dying due to their wide bright color gamut and ease of application in different ways. Textile dying industry uses large amount of water, synthetic dyes and various chemicals in different steps of production line and this results in wastewater which contains complex pollutants with varying molecular structure. Especially dyes that have high water solubility and low fixation rate hydrolyze during application without a complete fixation resulting in large amount of waste dye. In receiving waters, photosynthetic activities may be prevented as a consequence of the color caused by the waste dyes and the depletion of oxygen will occur. Additionally, introduction of dyes that are toxic and mutagenic into the water bodies adversely affect aquatic life. If they enter sewage system without proper treatment, they may cause problems in biological processes in urban wastewater treatment plants. Therefore, new, cost-efficient and effective treatment technologies are needed for the treatment of dye containing wastewaters before they are discharged into the water systems. In this study, the effect of molecular weights of dyes on removal efficiencies with electrocoagulation and electrooxidation processes were investigated. For this purpose, three different reactive dyes, Reactive Blue 198 (RB198), Reactive Yellow 145 (RY145) and Reactive Blue 19 (RB19) were chosen, which have molecular weights of 1304,80 g/mol, 1026,25 g/mol and 626,533 g/mol respectively. Synthetic dye solutions used in experiments was prepared dissolving 50 mg of each dye in 1 L distilled water. Laboratory scale experiments with 500 ml solutions containing 1000 mg/L NaCl were performed in batch mode. Electrocoagulation (EC) experiments performed in an electrochemical cell containing 5 aluminum electrodes (3 anodes, 2 cathode), a power source, and magnetic stirrer. Electrooxidation (EO) experiments performed in an EO reactor containing a boron doped diamond (BDD) anode and Ti/IrRuO2 cathode. Along with molecular weight, the effect of current density over the performance of two processes were investigated. Dye removal efficiencies were found out by calculating concentration from absorbance values, which were measured using UV/Vis spectrophotometer. Results of the study shows that the higher size of the molecular weights of dyes favors the removal of them from water by electrochemical methods (electrocoagulation and electrooxidation). Treatment of dyes by electrocoagulation took less time with lower cost of operation compared to the electrooxidation. However, it should be noted that the flocs formed after electrocoagulation needs further treatment.
Dyes are organic compounds that are used to impart color to substances (fabric, fiber etc.). Various kinds of dyes with different chemical structures and molecular weights are used in industrial applications. Particularly, highly soluble reactive dyes are much preferred in textile dying due to their wide bright color gamut and ease of application in different ways. Textile dying industry uses large amount of water, synthetic dyes and various chemicals in different steps of production line and this results in wastewater which contains complex pollutants with varying molecular structure. Especially dyes that have high water solubility and low fixation rate hydrolyze during application without a complete fixation resulting in large amount of waste dye. In receiving waters, photosynthetic activities may be prevented as a consequence of the color caused by the waste dyes and the depletion of oxygen will occur. Additionally, introduction of dyes that are toxic and mutagenic into the water bodies adversely affect aquatic life. If they enter sewage system without proper treatment, they may cause problems in biological processes in urban wastewater treatment plants. Therefore, new, cost-efficient and effective treatment technologies are needed for the treatment of dye containing wastewaters before they are discharged into the water systems. In this study, the effect of molecular weights of dyes on removal efficiencies with electrocoagulation and electrooxidation processes were investigated. For this purpose, three different reactive dyes, Reactive Blue 198 (RB198), Reactive Yellow 145 (RY145) and Reactive Blue 19 (RB19) were chosen, which have molecular weights of 1304,80 g/mol, 1026,25 g/mol and 626,533 g/mol respectively. Synthetic dye solutions used in experiments was prepared dissolving 50 mg of each dye in 1 L distilled water. Laboratory scale experiments with 500 ml solutions containing 1000 mg/L NaCl were performed in batch mode. Electrocoagulation (EC) experiments performed in an electrochemical cell containing 5 aluminum electrodes (3 anodes, 2 cathode), a power source, and magnetic stirrer. Electrooxidation (EO) experiments performed in an EO reactor containing a boron doped diamond (BDD) anode and Ti/IrRuO2 cathode. Along with molecular weight, the effect of current density over the performance of two processes were investigated. Dye removal efficiencies were found out by calculating concentration from absorbance values, which were measured using UV/Vis spectrophotometer. Results of the study shows that the higher size of the molecular weights of dyes favors the removal of them from water by electrochemical methods (electrocoagulation and electrooxidation). Treatment of dyes by electrocoagulation took less time with lower cost of operation compared to the electrooxidation. However, it should be noted that the flocs formed after electrocoagulation needs further treatment.
Açıklama
Anahtar Kelimeler
Çevre Mühendisliği, Environmental Engineering
