The use of SPEEK/KİTOSAN/IL composite structures as 1)proton exchange membrane in PEM fuel cells 2)murexide adsorbent

The increasing need for energy with industrial and technological developments causes an increase in the demand for fossil fuels from traditional energy sources. In response to this increasing demand, serious problems such as air pollution and global warming arise with the widespread use of fossil fuels. Due to the limited reserves and disadvantages of fossil fuels, it is inevitable to move towards cleaner and more efficient energy sources. Polymer electrolyte membrane fuel cells (PEMFC) are the most important class of fuel cells that use hydrogen as fuel, which is becoming increasingly important among alternative energy sources. In PEMFC systems, chemical energy is directly transformed into electrical energy and only water and heat are released as waste, which highlights these systems as environmentally friendly energy technologies. The most important factor affecting energy conversion efficiency in PEMFC systems is polymer electrolyte membranes that provide proton transport. In PEMFC systems, the development of low-cost membrane structures with high ionic conductivity and thermal/mechanical strengt is one of the primary research topics. In this thesis, it is aimed to prepare sulphonated polyether ether ketone (SPEEK) and biopolymer chitosan (CH) based polymer electrolyte membranes with ionic liquid (IL) additives, which will be alternative to commercial membranes. Structural, thermal, morphological and mechanical analyzes of the prepared composite membranes were carried out and their proton conductivity and dielectric characteristics were evaluated in a wide range of temperatures and frequencies. The thermal and mechanical analysis and proton conductivity and dielectric measurements revealed that the prepared polymer electrolytes exhibit high proton conductivity values and thermal/mechanical stability in a wide temperature range. In the light of these results, it is thought that composite polymer electrolytes prepared within the scope of the thesis can be used as efficient, alternative proton exchange membranes in PEMFC systems. In addition, the effectiveness of CH-containing ternary composites in the dye adsorption process from aqueous solutions has been tested. Although polymer composite has low adsorption efficiency in murexide removal, it has been observed that CH-containing ternary composite has a high removal potential in methylene blue dye adsorption. CH-containing ternary composite is an effective electrolyte alternative in PEMFC applications as well as an efficient adsorbent potential in methylene blue dye removal.