Öz Bu çalışmada akrilamid-krotonik asit hidrojelleri metilen mavisi boyasının gideriminde adsorban olarak kullanılmıştır. Boyanın adsorpsiyonuna pH'nın, krotonik asit yüzdesinin, başlangıç boya derişiminin ve tekrar kullanım sayısının etkisi araştırılmıştır. Yalnızca akrilamidle hazırlanan hidrojellerde pH'nın artması ile adsorpsiyonda bir miktar artış görülmüştür. Akrilamid-krotonik asit hidrojellerinde pH 7, 9 ve 10'da adsorpsiyon hemen hemen yakın bulunmuş, buna karşılık pH 8'de belirgin bir azalma gözlenmiştir. Hidrojellerde bulunan krotonik asit yüzdesinin artması ile adsorpsiyon belirgin bir şekilde artmıştır. Ayrıca adsorbsiyon-desorpsiyon çalışmaları sonucu göstermektedir ki, 20 kere tekrar kullanımdan sonra bile hidrojellerin adsorpsiyon kapasitesi hemen hemen hiç azalmamıştır. Sonuçlar akrilamid-krotonik asit hidrojellerin endüstriyel ölçekte tekstil atık sularından boyaların gideriminde adsorban olarak kullanılabileceğini göstermektedir. Anahtar Kelimeler "akrilamid, krotonik asit, hidrojel, metilen mavisi, adsorpsiyon, tekstil" Abstract In this study acrylamide-crotonic acid hydrogels are used as adsorbent for removal of methylene blue. The effects of pH, crotonic acid percentage, initial dye concentration and reusage number on the adsorption of the dye are investigated. When the pH increased adsorption also slightly increased with the hydrogels made up of only acrylamide. With the acrylamide crotonic acid hydrogels adsorption rates are similar in pH 7,9 and 10 but there is a significant decrease in pH 8. Adsorption increases with the increasing crotonic acid percentage in hydrogels. In addition, the adsorption-desorption results showed that the adsorption capacity of the hydrogel was not changed even after 20 times repeated use. Results show that acrylamide-crotonic acid hydrogels can be used as adsorbent for dye removal in industrial textile waste water.

The effects of boron carbide (B4C) additions on characteristic of diamond impregnated Fe-Co-Cu matrix composites have been investigated using powder metallurgy (PM) method. For this purpose, samples of Fe-(30-60)wt. % Cu–20 wt. %Co alloys and1wt. % B4C additions of its matrix were processed by cold pressing at 350 MPa, followed by sintering at 1100°C. Microstructural examination, hardness and wear tests were performed.The microstructure of Fe–Cu–Co alloys was very sensitive to the Cu content and pore closure took place with increasing the Cu content.In addition, the addition of B4C particles increased Fe–Cu-Co hardness about 44% compared to samples without B4C particles. The experimental results showed that alloy Fe–60 wt. % Cu–20 wt. %Co-1 wt. % B4C presented the best results for use in diamond cutting tools.

In this study, 20 fish taken from Sapanca Lake, Sakarya River and Western Black Sea (Karasu) in total and heavy metal accumulation (Cu, Fe abd Zn) in the muscles of 15 species was determined with ICP-OES (Inductively Coupled Plasma-Optical Emission Spectometer) device. When the results were examined, Cu, Fe and Zn concentration was determined to be 2.60-5.31 μg/g, 0.25-54.36 μg/g and 13.66-47.11 μg/g respectively in fish samples. In addition, the same procedures were applied with the standard reference material DORM-3 reference material (Fish Protein Certified Reference Material for Trace Metals) to determine the accuracy of the method. As a result, it has been determined that the amount of heavy metals contained in the analyzed fish samples is below the limit values provided by the Turkish Food Codex, Food and Agriculture Organization and World Health Organization and therefore consumption of these does not constitute a threat to health.

To selectively remove mercury(II), 2-hydroxyethyl methacrylate (HM) and 2-hydroxyethyl methacrylate/acrylamide (HM/ACR) hydrogels were synthesized using radiation. These hydrogels were used in swelling, diffusion, and binding studies. Swelling parameters for HM/ACR−Hg2+ system are higher than those of HM−Hg2+ systems. Binding of Hg2+ has been observed to be C-type for HM and L-type for HM/ACR hydrogels. Binding parameters were calculated using Freundlich, Langmuir and Henry models. Effects of Hg2+ concentration, radiation dose, ACR ratio, temperature, counter ions were investigated. Binding and swelling of HM increased with the incorporation of acrylamide. HM/ACR hydrogels absorbed only Hg2+, and did not absorb heavy metal ions.