Se Jin In

Improved photodegradation properties and kinetic models of a solar-light-responsive photocatalyst when incorporated into electrospun hydrogel fibers.

The capacity of a photocatalyst system to degrade water pollutants was optimized using solar-light-sensitive TiO(2) and the swelling behavior of a hydrogel. TiO(2) synthesized via a sol-gel process was modified by multielement doping to change its solar-light-responsive properties. A hydrogel was used for the rapid absorption of both anionic and cationic water pollutants. TiO(2) particles were immobilized in/on hydrogel fibers by an electrospinning method for the easy recovery of TiO(2), and the ability of the hydrogel/TiO(2) composite to degrade dye molecules was studied. The TiO(2) particles were observed to have maintained their original anatase-type crystallinity in/on the electrospun hydrogel fibers. The dye degradation capacity of the hydrogel/TiO(2) composite was investigated using both anionic and cationic dyes under sunlight. Two mechanisms were suggested by which the hydrogel/TiO(2) composite can remove dye particles from the water: (1) the absorption of dyes by the hydrogel and (2) the degradation of the dye by the TiO(2) in the hydrogel. Both of these mechanisms were investigated in this study. We found that the dye was effectively absorbed by the hydrogel fibers as demonstrated by the swelling behavior of the hydrogel and the nano-size effects. The dye was then introduced to the TiO(2) particles for degradation.

Na 3 PO 4 Flame Retardant Treatment on Lyocell Fiber for Thermal Stability and Anti-oxidation Properties

The improved thermal stability and anti-oxidation properties of lyocell fiber were studied based on flame retardant treatment by using Na PO solution. The optimized conditions of flame retardant treatment were studied on various concentrations of Na PO and the mechanism was proposed through experimental results of thermal stability and anti-oxidation. The integral procedural decomposition temperature (IPDT), limiting oxygen index (LOI) and activation energy (E ) increased 30, 160% respectively via flame retardant treatment. It is noted that thermal stability and anti-oxidation improved based on char and carbon layer formation by dehydrogenation and dissociation of C-C bond resulting the hindrance of oxygen and heat energy into polymer resin. The optimized conditions for efficient flame retardant property of lyocell fiber were provided using Na PO solution and the mechanism was also studied based on experimental results such as initial decomposition temperature (IDT), IPDT, LOI and E .

Water vapor adsorption capacity of thermally fluorinated carbon molecular sieves for CO 2 capture

The surfaces of carbon molecular sieves (CMSs) were thermally fluorinated to adsorb water vapor. The fluorination of the CMSs was performed at various temperatures (100, 200, 300, and 400°C) to investigate the effects of the fluorine gas (F2) content on the surface properties. Fluorine-related functional groups formed were effectively generated on the surface of the CMSs via thermal fluorination process, and the total pore volume and specific surface area of the pores in the CMSs increased during the thermal fluorination process, especially those with diameters ≤ 8 A. The water vapor adsorption capacity of the thermally fluorinated CMSs increased compared with the as-received CMSs, which is attributable to the increased specific surface area and to the semicovalent bonds of the C-F groups.