Study on Dispersion of TiO₂ Nanopowder in Aqueous Solution via Near Supercritical Fluids

Abstract

In this study, we investigated the effects of near supercritical carbon dioxide (SCCO2) parameters, including pressure, temperature, and saturation time on titanium dioxide (TiO2) nanopowder dispersion in water-containing sodium hexametaphosphate (SHMP). The stability and morphology of TiO2 particles dispersed in an aqueous solution were examined using a zeta potential instrument, dynamic light scattering, and transmission electron microscopy. As shown in the results, of particular interest, it was found that near SCCO2’s pressure and saturation time had the strongest impact on TiO2 dispersion in water-containing SHMP. This finding indicated that TiO2’s secondary average particle size was significantly reduced with an increase in near SCCO2’s pressure and saturation time. Additionally, in the presence of SHMP, the zeta potential of the as-prepared dispersion solution reached −53.7 mV because of production of the larger negative static charge repulsion force (resulting from SHMP dissociation) on the TiO2 particle surface. The secondary average size was 127 ± 68 nm, indicating good stability of TiO2 dispersed in water containing an inorganic dispersant.

Development of Fine Particle Mechanical Separation Processes with Representative Catalyst Materials for Recycling PEM Water Electrolyzers Exploiting their Wetting Characteristics

“…From approximately 0.01 g/l of SHMP onwards, particles start to be dispersed in water more stably. The results are consistent with the findings of Kao et al., who analyzed zeta potentials of TiO 2 with addition of the SHMP dispersant and exhibited the largest negative absolute value in the presence of SHMP at a concentration of 0.1 g/l [37] . Examining the results presented by the blue line, interestingly, 78 % of TiO 2 particles transferred to the emulsion phase/water‐oil‐interphase without the dispersant.…”

“…The results are consistent with the findings of Kao et al, who analyzed zeta potentials of TiO 2 with addition of the SHMP dispersant and exhibited the largest negative absolute value in the presence of SHMP at a concentration of 0.1 g/l. [37] Examining the results presented by the blue line, interestingly, 78 % of TiO 2 particles transferred to the emulsion phase/water-oil-interphase without the dispersant. Visually, some of the particles had moved into the interphase rather than the organic phase.…”

Water-based 2-dimensional anatase TiO2 inks for printed diodes and transistors

“…13 Furthermore, 0.2%v of Triton X-100 was added to act as a dispersion agent to improve the colloidal suspension stability of the nanosheets – TiO 2 is known for being difficult to disperse in water. 40,41 Furthermore, this non-ionic surfactant also reduces the surface tension of the ink from 51 to 32 mN m −1 , allowing for adequate ink wettability and droplet spreading. A white and stable (for at least 1 month, based on visual inspection) dispersion of TiO 2 -NS has been successfully obtained (Fig.…”

Strontium ranelate incorporated 3D porous sulfonated PEEK simulating MC3T3-E1 cell differentiation

“…Zeta potential is an index that detects the stability of dispersion systems, that is the higher the absolute value of the zeta potential, the more stable the surface charge [ 36 ]. The zeta potential of each group of materials within physiological pH ranged from −50 to −80, indicating that the surface charge of each group of materials was relatively stable [ 37 ].…”