In this study, the effects of starting material types on graphene oxide (GO) are reported with the aim of developing graphene (GR) synthesis. The GOs were prepared from natural graphite (NG) powder and graphite nanoplate (GNp) based on the Hummers method. Two kinds of GR were successfully synthesized using GOs, which were prepared from NG and GNp in the presence of hydrazine and ammonia for 24 h at a 100 • C reaction temperature. The synthesized GOs and GRs were characterized by X-ray diffraction (XRD) techniques, Fourier transform infrared, highcontrast transmission electron microscopy (HCTEM), dispersive Raman spectroscopic analyses, and elemental analyses.HCTEM analyses of GOs and GRs exhibited largely folded, convoluted, and entwined GO and GR structures. The XRD and Raman analyses showed that the number of layers of GO1, GO2, GR1, and GR2 were 9. 27, 13.53, 4.11, and 5.26, respectively. On the other hand, GR1, prepared from NG powder, showed much higher quality (peak intensities (I D /I G) = 1.53, C/O = 3.64) than GR2, which was prepared from GNp (I D /I G = 1.64, C/O = 3.17). Thus, this study provides a way to produce higher quality GOs and GRs.

Graphene is an important material that has attracted attention in recent years due to its large surface area, mechanical strength, thermal, electrical and magnetic properties. In this work, reduced graphene oxide (RGO) was obtained by reducing the graphene oxide (GO) with green synthesis. For this purpose, white cabbage aqueous extract was selected to reduce GO. The total phenolic acids, which are the reducing agent in the extract, were determined according to the Folin-Cioceltau method. It was determined that there is 0.064 grams of polyphenols in 1 mL of white cabbage extract. In order to determine the reduction experimental conditions, a reduction temperature of 25, 50 and 100 ⁰C and 1, 2, 4 and 6 hours of reduction time were studied. Structural characterization of synthesized RGOs was performed with XRD, FTIR and SEM techniques. The results showed that GO was reduced at a reduction reaction temperature of 100 °C and a reduction reaction time of 6 hours. The peak seen at 22.08⁰ in the XRD data is evidence of reduction of GO.

Good quality Polycarboxylate superplasticizers (PCEs) production is increasingly important due to development of the construction industry in the world. In this study, modified PCEs were synthesized via free-radical polymerization of Translated Polyethylene Glycol (TPEG), Thioglycolic Acid (TGA) and Acrylic Acid (AA), in the presence of initiator and chain transfer agent according to molecular structure design principle in different initiatory temperatures (40 and 60 o C). The effects of PCEs synthesized at different temperatures on the concrete such as water cutting, workability and compressive strength of 7 and 28 days' have been examined. Fourier transform infrared spectroscopy (FTIR) was used for structural characterization.

In this study, a simple and efficient method of reduction for the preparation of reduced graphene oxide (RGO) from graphene oxide (GO) using Kombucha Tea (KT) is reported. The graphene oxides (GOs) were produced from natural graphite (Gr) powders based on Hummers' method. KT was used as natural reductants to reduction of GO. Polyphenol content of KT was determined by using Folin-Cioceltau method. KT and GO were mixed in certain ratios to reduce graphene oxide (RGO) at room temperature. RGO was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourer Transform Infrared (FTIR). It was clearly observed that the functional groups containing oxygen were reduced as a result of the analyzes.

Grafen pek çok eşsiz sayılabilecek özelliğe sahip, fotokatalitik bozunum ve adsorpsiyon uygulamalarında potansiyeli olan önemli bir malzemedir. Grafen elde etmek için grafen oksitin (GO) indirgenmesi tekniği son yıllarda sıkça kullanılan ilgi çekici bir yöntemdir. Bu çalışmanın amacı kolay ve etkili bir yöntem olan yeşil sentez ile mor lahana sulu özütü kullanarak GO indirgenmesi ve fotokatalitik giderim uygulamalarında kullanımının incelenmesidir. Sentezleme koşullarını optimize etmek için reaksiyon sıcaklığı 25, 50 ve 100 ⁰C’de ve reaksyon süresinin etkisi ise 1, 2, 4 ve 6 saat için incelendi. XRD, FTIR, UV/vis ve SEM sonuçlarına göre 100 ⁰C reaksiyon sıcaklığı ve 6 saat reaksiyon süresi GO’nun indirgenmesi için uygun deneysel şartlar olarak bulundu. Elde edilen indirgenmiş grafen oksit (IGO) organik ve katyonik bir boya olan metilen mavisinin (MM) sulu çözeltisinde UV lamba altında fotokatalitik bozunum deneylerinde kullanıldı. Çalışmanın bu kısmında hidrojen peroksitin (H2O2) fotokatalitik bozunum süreci üzerindeki etkisi araştırıldı. Sonuçlar 120 dakika sonunda IGO’nun sulu çözeltiden MM’yi %85 oranında giderdiğini gösterdi.