9 research outputs found
Fast Crystallization of SUZ-4 Zeolite with Hydrothermal Synthesis: Part I Temperature and Time Effect
AbstractSUZ-4 zeolites were synthesized by hydrothermal technique under autogenous pressure with SiO2:Al2O3 ratio of 21.22 using silica-sol and tetraethlyammonium hydroxide as a silica source and a template, respectively. Effect of temperature with 150, 165, and 180°C and crystallization time with 24, 18, and 12h were studied to obtain the suitable conditions at crystallization. SUZ-4 zeolite synthesis using short time compared to the conventional method was successful synthesized. The synthesized SUZ-4 zeolites were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), BET-N2 adsorption, and X-ray fluorescence (XRF). The results show that SUZ-4 zeolite was obtained from rapid crystallization having a narrow pore size distribution and needle-shaped crystals. Highly crystallined SUZ-4 depended on enhanced temperature and time of crystallization conditions
Role of Surface Area, Primary Particle Size, and Crystal Phase on Titanium Dioxide Nanoparticle Dispersion Properties
Characterizing nanoparticle dispersions and understanding the effect of parameters that alter dispersion properties are important for both environmental applications and toxicity investigations. The role of particle surface area, primary particle size, and crystal phase on TiO2 nanoparticle dispersion properties is reported. Hydrodynamic size, zeta potential, and isoelectric point (IEP) of ten laboratory synthesized TiO2 samples, and one commercial Degussa TiO2 sample (P25) dispersed in different solutions were characterized. Solution ionic strength and pH affect titania dispersion properties. The effect of monovalent (NaCl) and divalent (MgCl2) inert electrolytes on dispersion properties was quantified through their contribution to ionic strength. Increasing titania particle surface area resulted in a decrease in solution pH. At fixed pH, increasing the particle surface area enhanced the collision frequency between particles and led to a higher degree of agglomeration. In addition to the synthesis method, TiO2 isoelectric point was found to be dependent on particle size. As anatase TiO2 primary particle size increased from 6 nm to 104 nm, its IEP decreased from 6.0 to 3.8 that also results in changes in dispersion zeta potential and hydrodynamic size. In contrast to particle size, TiO2 nanoparticle IEP was found to be insensitive to particle crystal structure
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Fast Crystallization of SUZ-4 Zeolite with Hydrothermal Synthesis: Part I Temperature and Time Effect
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