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    Ardısık Modifiye Pirit-Fenton ve Biyolojik Arıtım Sistemleri ile Klorlu Fenol Bilesiklerinin Arıtımı
    (2018) Kantar, Çetin
    Özellikle 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.
  • Küçük Resim
    Öğe
    Chlorophenolic Compounds and Their Transformation Products by the Heterogeneous Fenton Process: A Review
    (John Wiley & Sons Ltd., 2021) Kantar, Çetin; Oral, Özlem
    Chlorophenolic 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.
  • Küçük Resim
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    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, Çetin
    Aerobic 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.
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    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, İlker
    Batch 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.
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    Öğe
    Krom (Vi) ile kirlenmiş atıksu ve yeraltı sularının pirit ile arıtılmasına yönelik yeni bir yöntem
    (2014) Kantar, Çetin; Alten, Akın
    [Abstract Not Available]
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  • Küçük Resim
    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, Nurettin
    Particles 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.