Solmaz Akmaz

The Effect of Ag Content of the Chitosan-Silver Nanoparticle Composite Material on the Structure and Antibacterial Activity

The aim of this study is to investigate the antibacterial properties and characterization of chitosan-silver nanoparticle composite materials. Chitosan-silver nanoparticle composite material was synthesized by adding AgNO3 and NaOH solutions to chitosan solution at 95°C. Different concentrations (0,02 M, 0,04 M, and 0,06 M) of AgNO3 were used for synthesis. Chitosan-silver nanoparticle composite materials were characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet (UV) spectrophotometer, and Fourier transform infrared (FTIR) spectrometer techniques. Escherichia coli, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Streptococcus pneumoniae were used to test the bactericidal efficiency of synthesized chitosan-Ag nanoparticle composite materials. The biological activity was determined by the minimum bacterial concentration (MBC) of the materials. Antibacterial effect of chitosan-silver nanoparticle materials was increased by increasing Ag amount of the composite materials. The presence of small amount of metal nanoparticles in the composite was enough to significantly enhance antibacterial activity as compared with pure chitosan.

The Structural Characterization of Saturate, Aromatic, Resin, and Asphaltene Fractions of Batiraman Crude Oil

Abstract The structural characterization of fractions of Batiraman crude oil, which is the heavy crude oil from a field in the southeastern part of Turkey, was investigated. Batiraman crude oil and its saturate, aromatic, resin, and asphaltene (SARA) fractions were seperated. Treatment of crude oil with n-heptane provided the separation of asphaltene. Maltene was collected by evaporating the n-heptane from the filtrate. Then, maltene was separeted into saturates, aromatics, and resins by SARA technique. Maltene was separated into saturate, aromatic, and resin fractions using column chromatography. SARA fractions were quantified on a weight percent basis. Fractions of Batiraman crude oil were characterized by elemental analysis, proton nuclear magnetic resonance (1H NMR) analysis, electrospray ionization mass spectrometry (ESI-MS), and Fourier transform infrared (FTIR) spectroscopy techniques.

Investigation of the Molecular Structure of Turkish Asphaltenes

Abstract Molecular structure of asphaltenes prepared from four Turkish crude oils with different origin were characterized by elemental analysis, proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC) by X-ray diffraction (XRD) and by Fourier transform infrared spectroscopy (FTIR). The X-ray diffraction method was used to investigate the crystallite and aromaticity parameters of the asphaltenes. Average distance between the aromatic sheets, average distance between the aliphatic chains, average diameter of the cluster, and average number of aromatic sheets per stack parameters were calculated for the asphaltenes. The combined NMR, FTIR, molecular weight, elemental content, and XRD results have been used to calculate hypothetical structure of the Turkish asphaltenes.

The Effect of TiO2 Contained within a Titanium Silicalite (TS-1) Catalyst and on the Selective Oxidation of Ammonia

Abstract The selective oxidation of ammonia to hydroxylamine using titanium silicalite-1 as a catalyst with an increasing content range of 1–2.5 wt% TiO2 was systematically investigated in a batch reactor. The hydroxylamine yielded 33, 43, 52 and 62% at reaction temperatures of 50, 60, 70 and 80°C, respectively, for 8 min using a TS-1a catalyst, which contained 2.5% TiO2. The molar ratio of 15 NH3/H2O2 was kept during these reactions. Experiments were also conducted with different amounts of NH3/H2O2 in molar ratios, which were between 7 and 60 to investigate the effect of NH3/H2O2 molar ratio on the reactions. Reactions with higher ratios of NH3/H2O2 were seen to have a higher yield at the end of the reaction performance time.

An efficient heterogeneous CrOx–Y zeolite catalyst for glucose to HMF conversion in ionic liquids

ABSTRACT In this study, CrCI3, H–Y, Cr–Y and calcined CrOx–Y zeolites were studied in the liquid phase heterogeneous catalytic conversion of glucose to HMF in ionic liquids. Characterization of catalysts was done in XPS, XRD and NH3-TPD. Both glucose conversion and HMF yield decreased with the addition of chromium (III) chloride impregnated catalysts in comparison to the homogeneous CrCI3–[BMIM]CI system. High glucose and HMF yields were obtained with heterogeneous calcined CrOx–Y zeolite. Best HMF yield achieved was 52.8%.