Muzaffer Yasar

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.

Asphaltene and resid pyrolysis: Effect of reaction environment

ABSTRACT Hondo and Maya vacuum resids and their isolated asphaltenes were pyrolyzed at 400, 425, and 450°C (752, 797, 842°F) for batch holding limes ranging from 20 to 180 minutes. Maltene, asphaltene, and coke product fractions were isolated by a solvent extraction sequence; gas yield was determined gravimetrically. Results were summarized in terms of a lumped reaction network. The variation of product yields, kinetics, and apparent activation energies with feedstock and asphaltene environment provided insight into asphaltene structure and thermal reaction pathways.

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.