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Öğe Ardısık Modifiye Pirit-Fenton ve Biyolojik Arıtım Sistemleri ile Klorlu Fenol Bilesiklerinin Arıtımı(2018) Kantar, ÇetinÖzellikle ilaç sanayi gibi çesitli endüstrilerde arıtımı önemli bir sorun olan klorofenol ve diklofenak içeren atıksuların yönetilmesinde alternatif teknolojilerin arastırılması büyük önem tasımaktadır. Klorlu fenol bilesikleri son derece toksik organik bilesikler olup dogrudan biyolojik arıtımları zordur. Bu tip toksik organik bilesiklerin biyolojik olarak arıtılabilmesi için deklorizasyon gibi toksisiteyi azaltıcı bazı ön arıtıma tabi tutulmaları sarttır. Projenin amacı; organik asitler (sitrat, tartarat) ve farklı kimyasal kosullar (pH, katı/sıvı oranı, ligand konsantrasyonu vs.) altında klorofenol ihtiva eden sentetik atıksular ile gerçek bir ilaç fabrikasından temin edilen atıksuyun birlesik pirit Fenton-biyolojik arıtım sistemlerinde arıtılabilirligini test etmektir. Bu amaçla proje kapsamında kesikli ve sürekli akımlı reaktör kosullarında pirit-Fenton arıtım deneyleri ile ön arıtımsız ve pirit-Fenton ön arıtımlı atıksular kullanılarak hem aerobik hem de anaerobik kosullar altında kesikli/ardısık kesikli reaktörlerde biyolojik arıtım deneyleri yapılmıstır. Kesikli arıtım deneyleri klorofenol/diklofenak içeren atıksuların pirit-Fenton prosesi ile arıtımının bazı ortam kosullarına baglı olarak farklılık gösterdigine isaret etmektedir. Özellikle azalan çözelti pH degeri ve artan katı/sıvı oranına baglı olarak Fenton proses verimi artarken çözeltiye ilave edilen organik asitler arıtım verimini olumsuz yönde etkilemektedir. Bunun nedeni proseste sınırlı miktarda açıga çıkan OH* radikallerinin organik ligandlar tarafından amaç dısı harcanmasıdır. Kesikli deneylerin aksine kolon deneyleri organik ligand ilavesinin sürekli akımlı reaktör kosulları altında klorofenol/diklofenak arıtımını olumlu yönde etkiledigini göstermistir. Iki sistem arasında görülen bu farklılık kolon deneylerinde katı/sıvı oranının daha yüksek ve bunun sonucu olarak OH* radikali olusumunun daha fazla olusu ile izah edilebilir. Biyolojik reaktör deneyleri klorofenol türüne baglı olarak pirit-Fenton ön arıtımının CP içeren atıksuyun toksisitesini azalttıgını ve dolayısyla genel arıtım verimini olumlu yönde etkiledigini göstermistir. Ayrıca çamur aklimizasyonu da özellikle aerobik biyoreaktörlerde genel proses arıtım verimine pozitif katkı sunmustur. Sonuç olarak projeden elde edilen veriler pirit-Fenton ön arıtımının toksik organik atıksuları arıtan aerobik ve anaerobik biyolojik sistemlere etkili bir biçimde entegre edilebilecegini göstermektedir.Öğe Chlorophenolic Compounds and Their Transformation Products by the Heterogeneous Fenton Process: A Review(John Wiley & Sons Ltd., 2021) Kantar, Çetin; Oral, ÖzlemChlorophenolic compounds are persistent contaminants commonly observed in contaminated soil and groundwater due to their high toxicity and low biodegradability. While the classical homogenous Fenton process suffers from high operating costs and excessive sludge formation, heterogeneous Fenton processes show a viable, cost-effective solution to the oxidative dehalogenation of chlorophenolic compounds due to the use of solid-based catalyst materials with much lower chemical costs and less sludge production. The catalyst materials used in the heterogeneous Fenton degradation of chlorophenols include monometallic iron materials (e.g. Fe oxides/sulfides, zero-valent iron), multimetallic iron composites, and iron catalysts with support material. This chapter covers an extensive review of papers regarding the applicability of heterogeneous Fenton processes to the treatment of chlorophenolic compounds under different operating conditions, including catalyst type, size, and dose, chlorophenol type, pH, H2O2 requirements, and reactor configurations. In addition, reaction intermediate species and their biodegradability are discussed.Öğe Comparison of treatability of four different chlorophenol-containing wastewater by pyrite-Fenton process combined with aerobic biodegradation: Role of sludge acclimation(Academic Press, 2021) Kayan, İremsu; Ayman Öz, Nilgün; Kantar, ÇetinAerobic biodegradation combined with pyrite-Fenton process was used for the treatment of wastewater containing different chlorophenols (4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP). Fenton degradation using pyrite as the low cost iron catalyst was used as a pre-treatment step to lower the toxicity of CPs prior to aerobic biodegradation. Synthetic wastewater spiked directly with either 100 mg/L CPs or pyrite-Fenton pre-treated CPs was fed to the batch bioreactors inoculated with unacclimated or acclimated activated sludge using glucose as the C-source. The results show that the CP biodegradation under aerobic conditions was highly dependent on the type of CP treated. Except for 2,4-DCP, all other CPs investigated caused severe sludge toxicity, and thus significantly hindered glucose degradation by unacclimated sludge. The CP toxicity decreased in the order of: 2,4,6-TCP > 2,3-DCP > 4-CP > 2,4-DCP. The toxic effect was explained through an interaction of CPs with the lipid fraction of cell membrane. While the pyrite-Fenton pre-treatment improved the COD removal efficiency using unacclimated sludge, the sCOD removal efficiency was still less than the control reactor operated with no CP addition. With sludge acclimation, however, the sCOD removal efficiencies increased, and approached 74% for 2,4-DCP, 61% for 4-CP, 56% for 2,4,6-TCP and 46% for 2,3-DCP, suggesting an enhanced biomass tolerance to CP toxicity. On the other hand, the sludge acclimation combined with pyrite Fenton pre-treatment provided the best bioreactor performance for all CPs with the sCOD removal efficiencies reaching 81% for 2,4,6-TCP, 78% for 2,4-DCP, 73% for 4-CP and 62% for 2,3-DCP. This suggests that the dechlorination of CPs with Fenton process, in conjunction with sludge acclimation, not only reduced the sludge toxicity, but also enhanced the bioavailability of CP-containing wastewater for microorganisms, especially for highly chlorinated toxic CPs such as 2,4,6-TCP. Overall, the findings highlight the need for sludge acclimation for effective treatment of chlorophenol-containing wastewater by a combined pyrite-Fenton and aerobic biodegradation system.Öğe Effect of pyrite on the treatment of chlorophenolic compounds with zero-valent iron-Fenton process under uncontrolled pH conditions: reaction mechanism and biodegradability(Springer, 2024) Oral, Özlem; Kantar, Çetin; Yıldız, İlkerThis current study explored the effect of pyrite on the treatment of chlorophenolic compounds (CP) by Fenton process with micron-sized zero-valent iron (ZVI) as the catalyst. The experiments were conducted in batch reactors with 100 mg L?1 CP, 0–0.02 M H2O2, and variable pyrite and ZVI doses (0–1 g L?1). Our findings show that while the reactor with 1 g L?1 ZVI as the only catalyst achieved only 10% CP removal efficiency due to rapid ZVI surface passivation and ZVI particle aggregation, the CP removal efficiency increased with increasing pyrite dose and reached 100% within couple of minutes in reactors with 0.8 g L?1 pyrite and 0.2 g L?1 ZVI. The CP removal was mainly driven by the oxidative treatment of CPs with some strong radicals such as hydroxyl radicals (•OH) while the adsorption onto the catalyst surface was only responsible for 10 to 25% of CP removals, depending on the type of CP studied. The positive impact of pyrite on CP removal by the ZVI/H2O2 system could be attributed to the ability of pyrite to (1) create an acidic environment for optimum Fenton process, (2) provide support material for ZVI to minimize ZVI particle agglomeration, and (3) stimulate iron redox cycling for improved surface site generation. Following oxidative Fenton treatment, the degradation intermediate products of CPs, including some aromatic compounds (benzoquinone, hydroquinone, etc.) and organic acids (e.g., acetic acid), became more biodegradable in comparison to their mother compounds. Overall, the treatment systems with a mixture of ZVI and pyrite as catalyst materials could offer a suitable cost-effective technology for the treatment of wastewater containing biologically non- or low-degradable toxic compounds such as chlorophenols. © The Author(s) 2024.Öğe Influence of pyrite on oxidative treatment of diclofenac with zero-valent iron/H2O2 system coupled with chemical precipitation under controlled and uncontrolled pH conditions(Elsevier Ltd, 2024) Oral, Özlem; Kantar, Çetin; Yıldız, İlkerBatch experiments, combined with surface measurements, were conducted to elucidate the impact of pyrite on diclofenac treatment by zero-valent iron (ZVI)/H2O2 system. In binary systems with ZVI/H2O2, diclofenac removal was limited under controlled-pH conditions due to the agglomeration of ZVI particles and low rate of iron leaching. However, the use of pyrite in batch systems under uncontrolled-pH conditions drastically increased diclofenac removal by the ZVI/H2O2 system due to a significant drop in pH and enhanced iron dissolution. The diclofenac removal by the ternary ZVI/pyrite/H2O2 system could be explained through a combined effect of adsorption, oxidative degradation of diclofenac with hydroxyl radicals (*OH) and chemical precipitation of diclofenac and/or its intermediate species with the iron species dissolved from the ZVI/pyrite particles. While adsorption/chemical precipitation accounted for 75% of diclofenac removal in the initial stage, oxidative degradation achieved the remaining 25% diclofenac removal in the second stage. Surface analyses show that, in systems with diclofenac, the iron species dissolved from ZVI and pyrite particles complexed with diclofenac and/or intermediate species to form some spherical particles. Overall, this study sheds light on the reaction mechanism for the practical application of the ternary ZVI/pyrite/H2O2 system to diclofenac removal.Öğe Krom (Vi) ile kirlenmiş atıksu ve yeraltı sularının pirit ile arıtılmasına yönelik yeni bir yöntem(2014) Kantar, Çetin; Alten, Akın[Abstract Not Available]Öğe Methylene blue treatment with zero-valent iron/pyrite/H2O2 system under static and continuous flow conditions: Reaction mechanism and toxicity evaluation(Elsevier Science Inc, 2024) Oral, Özlem; Arslan, Şevki; Doğan, Nazime Mercan; Yıldız, İlker; Kantar, Çetin; Abdelsalam, Amine Hafis; Kuzucu, VolkanLaboratory batch and continuous flow studies, coupled with surface and toxicity analysis, were performed to evaluate methylene blue treatment by heterogeneous Fenton process using zero-valent iron (ZVI) and pyrite as co-catalyst. The use of pyrite in batch reactors significantly enhanced methylene blue treatment by the ZVI/H2O2 system because of improved iron redox cycling. The continuous-flow experiments revealed that the reactor performance increased in the order of: ZVI/H2O2 < pyrite/H2O2 < ZVI/pyrite/H2O2 under dynamic flow conditions. The methylene blue treatment by the ternary ZVI/pyrite/H2O2 system was described by an initial degradation of methylene blue with *OH radicals, followed by the adsorption and/or co-precipitation of degradation intermediates with some spherical particles. The surface analysis showed that these spherical particles formed, even at pH less than 4. The genotoxicity and cytotoxicity tests performed on mouse embryonic fibroblast (3 T3-L1) and human embryonic kidney (HEK293) cell lines showed that the Fenton treatment of methylene blue using the ZVI/pyrite/H2O2 system resulted in the formation of degradation species with much lower toxicity levels relative to methylene blue. Moreover, the Fenton degradation species of methylene blue significantly enhanced the metabolic activity of several bacterial strains, including E. coli ATCC 8739 and P. aeruginosa PAO1.Öğe Pirit malzemeli geçirgen reaktif bariyerlerde su sertliği ve hümik maddelerin Cr(Vi) ile kirli yeraltısularının arıtımına etkisi(2015) Kantar, Çetin; Bülbül, Muhammed S.[Abstract Not Available]Öğe Preparation of Poly(Humic Acid) Particles and Their Use in Toxic Organo-Phenolic Compound Removal from Aqueous Environments(Springer International Publishing Ag, 2014) Sağbaş, Selin; Kantar, Çetin; Şahiner, NurettinParticles derived from humic acid, as p(HA), are synthesized in a single step via a water-in-oil microemulsion system employing different cross-linkers such as divinylsulfone (DVS), glutaraldehyde (GA), epichlorohydrine (ECH), and adipochloride (AC). The different phenolic groups on humic moieties are connected via these cross-linkers to form particles. The prepared p(HA) particles were successfully used in the removal of toxic organo-phenolic such as phenol (Ph), 4-nitrophenol (4-NPh), 4-chlorophenol (4-CPh), 2-chlorophenol (2-CPh), and 2,3-dichlorophenol (2,3-CPh) from aqueous environments. Various parameters such as pH, contact time, reusability of particles, and the initial concentration of adsorbate are investigated. It is found that the absorption capacity of p(HA) particles for Ph is 180 mg/g, and the maximum absorption amount is obtained at pH 6. Furthermore, the reuse experiments are shown that p(HA) particles can release the absorbed Ph by the treatment of methanol, and an absorption capacity of 85 % is attainable up to five consecutive absorption and release cycles. p(HA) particles are characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta potential, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) techniques.
