A new, fluorinated monolithic stationary phase for CEC was first synthesized by a single-stage, thermally initiated copolymerization of a fluorinated monomer, 2,2,2-trifluoroethyl methacrylate (TFEM) and ethylene dimethacrylate (EDMA) in the presence of a porogen mixture. In this preparation, 2-acrylamido-2-methyl-1-propanesulfonic acid was used as the charge-bearing monomer. The porogen mixture was prepared by mixing isoamylalcohol and 1,4-butanediol. A clear increase in the electroosmotic mobility was observed with increasing pH. The electroosmotic mobility decreased with increasing ACN concentration. Poly(TFEM-co-EDMA) monolith prepared under optimized polymerization conditions was successfully used in the separation of alkylbenzenes and phenols by CEC. The best chromatographic separation for alkylbenzenes was performed with lower ACN concentrations (i.e. 60% v/v) with respect to the common acrylic-based CEC monoliths. The theoretical plate numbers up to 220 000 plates/m were achieved in the reversed phase separation of phenols. Poly(TFEM-co-EDMA) monolith also allowed the simultaneous separation of aniline and benzoic acid derivatives by a single run and by using a lower ACN concentration in the mobile phase with respect to the similar electrochromatographic separations. A stable retention behaviour in reversed phase separation of alkylbenzenes was obtained with the poly(TFEM-co-EDMA) monolith.

The development of a better understanding of the low temperature nanophase evolution of high surface area titania (TiO 2 ) based powders is essential for their use in photocatalytic applications. A series of rare earth (RE) element doped TiO 2 powders were prepared by sol-gel processing. The effects of RE doping level, ionic size and heat treatment temperature on the nanophase structure evolution and the dopant ion location in TiO 2 main matrix were investigated. Anatase was determined to be the main phase up to 900 C at all doping levels for all REs. Anatase to rutile phase transformation was inhibited by RE doping. The inhibitory effect of REs increased with increasing ionic radius. Oxide phases of La, Nd, Pr, Sm were not present up to 5% and Nd 4 Ti 9 O 24 phase was formed at 10% doping level at 800 C. The formation of RE 2 Ti 2 O 7 phases were determined for the REs with relatively lower ionic radii at 800 C.

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Erbium (Er) doped titania (TiO 2) powders were prepared by sol-gel technique. The effect of Er doping level on the nanophase structure, optical properties and photocatalytic hydrogen production activity was investigated throughout this study. X-ray diffraction (XRD), UV-VIS diffuse reflectance spectroscopy (UV-VIS DRS), photoluminescence (PL) and N 2 adsorption-desorption analyses were conducted for the determination of the nanostructure and optical properties of the prepared powders. It was found that Er doping inhibited the phase transformation of anatase to rutile, enhanced the visible light absorption and increased the surface area of TiO 2. Photocatalytic activity experiments indicated that the highest hydrogen yield was obtained with 0.5% Er doped TiO 2 which was 40 and 1.5 times higher than undoped TiO 2 on the basis of weight and surface area of the photocatalyst, respectively. The increased photocatalytic activity was attributed to a possible optimization of the nanophase structure which increased anatase weight fraction, enhanced light absorption and decreased the recombination rate of electron-hole pairs by forming oxygen deficiencies in the nanostructure.

Zeolitic imidazolate framework (ZIF) based metal organic framework (MOF) photocatalytsts were prepared and the effect of silver (Ag

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Increasing energy demand and global warming due to extensive use of fossil fuels will soon force mankind to use clean and sustainable fuels and artificial photosynthesis is being considered as a promising solution to both problems. Photocatalysis is a light induced process involved in artificial photosynthesis and it will make a great contribution to the solution of environmental problems and generation of renewable energy sources. Titania based photocatalytic materials are one of the widely used materials in artificial photosynthesis research due to their unique chemical and optical properties. Recent research has shown that the activity of titania phases can be improved in the visible light region by several modification techniques. This article aims to present a brief review based on the last 2 decades of global research on the preparation and modification of titania based photocatalysts, their application and importance in artificial photosynthesis and its effect on reducing global warming by the development of a sustainable energy source. This review is mostly based on the PhD thesis of the corresponding author (Yurtsever, 2015).

ÖZBu çalışmada farklı sentez koşullarında ve iki farklı çinko tuzu ile ZIF-L bazlı kristaller ve membranlar sentezlenmiştir. Sentezlenen membranların He, N2 ve CO2 gazı geçirgenliği ve ideal seçicilik ölçümleri gerçekleştirilmiştir. 0,3-2x10 -6 mol/m 2 .s.P aralığında elde edilen gaz geçirgenliği değerleri artan sentez sıcaklığı ve çinko nitrat yerine çinko klorür kullanımı ile artmıştır. Difüzyon hücresi ile sentezlenen membran ise vakum filtrasyon-ikincil büyüme ile sentezlenen membrana göre daha düşük gaz geçirgenliği değerleri göstermiştir. Çalışma kapsamında kullanılan sentez koşullarında difüzyon hücre sisteminde çinko klorürür ile sentezlenen membranın gaz geçirgenliği ve seçiciliğinde optimum performansa sahip olduğu tespit edilmiştir.Anahtar Kelimeler: Zeolitik imidazolat iskelet, ZIF-L, membran, difüzyon hücresi. ABSTRACT In this study, ZIF-L based crystals and membranes were synthesized with different zinc precursors at different synthesis conditions. The determination of the permeation and ideal selectivities for He, N2 and CO2 gases was performed with the stynthesized membranes. Gas permeation values obtained in the 0.3-2x10-6 mol/m 2 .s.P range increased with increasing synthesis temperature and by using zinc chloride instead of zinc nitrate. The membrane synthesized in the diffusion cell possessed lower gas permeance values compared to the one sytnesized with vacuum filtration-secondary growth method. The membrane synthsized with zinc chloride in the diffusion cell showed optimum performance in gas permation and ideal selectivity considering the synthesis conditions used in the context of this study.