“…Alternative ζ-potential change was observed with the further deposition of each opposite charged polyelectrolyte, indicating that stepwise multilayer growth successfully occurred on the organic pigment particles. However, any quantitative conclusion could not be drawn from the ζ-potential value because the value of the ζ-potential was not proportional to the charge density, since the surface was composed of charges arranged in a layer of a finite thickness, and the ζ-potential depended on the polyelectrolyte conformation at the surface. − 1 ζ-potential as a function of polyelectrolyte layer numbers for PSS/PDADMAC-coated organic pigment particles. The odd layer numbers for PSS deposition and even layer numbers for PDADMAC deposition.…”
This paper presented a novel method for the organic pigment coated with titania to improve the weatherability and dispersion ability in waterborne system. The organic pigment was first orderly adsorbed by two kinds of electrolyte: poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC), then coated by titania via sol-gel process from titanium n-butoxide (TBOT). The effects of the numbers of polyelectrolyte layer, water content, and TBOT content on the morphology, particle size, surface element composition, porosity and pore size, thermal stability, and UV shielding property of the organic pigment were systematically investigated. It was found that only two layers of electrolyte adsorption and one-step coating of titania could obviously enhance the UV shielding property even thermal stability of the organic pigment. The thickness of the titania layer could be easily tailored by TBOT content.
“…Alternative ζ-potential change was observed with the further deposition of each opposite charged polyelectrolyte, indicating that stepwise multilayer growth successfully occurred on the organic pigment particles. However, any quantitative conclusion could not be drawn from the ζ-potential value because the value of the ζ-potential was not proportional to the charge density, since the surface was composed of charges arranged in a layer of a finite thickness, and the ζ-potential depended on the polyelectrolyte conformation at the surface. − 1 ζ-potential as a function of polyelectrolyte layer numbers for PSS/PDADMAC-coated organic pigment particles. The odd layer numbers for PSS deposition and even layer numbers for PDADMAC deposition.…”
This paper presented a novel method for the organic pigment coated with titania to improve the weatherability and dispersion ability in waterborne system. The organic pigment was first orderly adsorbed by two kinds of electrolyte: poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC), then coated by titania via sol-gel process from titanium n-butoxide (TBOT). The effects of the numbers of polyelectrolyte layer, water content, and TBOT content on the morphology, particle size, surface element composition, porosity and pore size, thermal stability, and UV shielding property of the organic pigment were systematically investigated. It was found that only two layers of electrolyte adsorption and one-step coating of titania could obviously enhance the UV shielding property even thermal stability of the organic pigment. The thickness of the titania layer could be easily tailored by TBOT content.
“…The SiO 2 core particles had a narrow 5 Journal of Nanomaterials synthesized samples. As shown in Figure 5(a), the adsorption isotherm of TiO 2 nanoparticles can be categorized as type IV with hysteresis loop of type H2, which indicated the characteristic type of TiO 2 nanoparticles with mesoporous materials [33]. The isotherms of the core-shell SiO 2 @TiO 2 nanoparticles (CSTNs) with the molar ratios of Ti/Si (1 : 1, 2 : 1, 5 : 1, and 8 : 1) exhibited the similar shape of type IV with H2 hysteresis loops (Figure 5(a)) and showed the characteristic type of mesoporous materials as the TiO 2 nanoparticles.…”
After the core-shell SiO2@TiO2 nanoparticles (CSTNs) were synthesized by hydrothermal method, we investigated the influence of different molar ratios of Ti/Si on morphology, structure, and photocatalytic activity of the CSTNs. It was found that the CSTNs showed different size and surface morphology as the Ti/Si molar ratio changed. Besides, the TiO2 and the CSTN had the anatase phase after hydrothermal process and calcination at 450°C for 2 h. The N2 adsorption-desorption isotherms demonstrated the CSTNs with the molar ratio of Ti/Si increased from 1 : 1 to 8 : 1 can be categorized as type IV with hysteresis loop of type H2 and showed to be mesoporous materials. In addition, the CSTNs with the Ti/Si molar ratio of 5 : 1 had the highest surface area of 176.79 m2/g. Surface charges showed the isoelectric point (IEP) of the CSTNs ranged between silica (IEP at pH 3.10) and titania (IEP at pH 5.29). Since the molar ratio of Ti/Si increased from 1 : 1 to 8 : 1 by degradating both colorless organic pollutant of phenol and colored substances of methylene blue (MB) under UV irradiation, the photocatalytic activity of CSTNs exhibited higher photodegradation efficiency compared with TiO2. What is more, the experimental results also showed the CSTNs with Ti/Si molar ratio of 5 : 1 had the highest photocatalytic activity and showed higher photocatalytic efficiency compared with other TiO2-SiO2 composites reported for photodegradation of phenol and MB.
“…It can be observed from Figure 7 that the highest phenol removal efficiency can be obtained at about 5.7 mg ZnO nanorod catalyst quantity. At range of ZnO nanorod catalyst quantity from 0 mg 5.7 mg, an increase in ZnO nanorod catalyst quantity gives rise to a increase in catalytic activity and adsorption sites [18] , which enhance the photocatalytic efficiency of ZnO nanorod accordingly. However, the excessive ZnO nanorod catalyst makes the light transmittance of suspension become bad, it is not advantageous for use of ultraviolet light, which result in a decrease of the photocatalytic efficiency [19] .…”
Section: Effects Of Zno Nanorod Catalyst Quantity On Phenol Removal Efficiencymentioning
ZnO nanorod arrays were prepared by the hydrothermal synthesis. SEM images were used to observe the morphologies of ZnO nanorod arrays. The phase structures of ZnO nanorod arrays were characterized by means of XRD. The phenol wastewater was degraded with ZnO nanorod as catalyst. The effects of UV light application time and ZnO nanorod catalyst quantity on phenol removal efficiency were investigated. The results show that the phenol removal efficiency is as high as 70.12% when 5.7 mg ZnO nanorod catalyst is added, pH is 7.3, and UV light application time is 2 h. The ZnO nanorod arrays prepared under the action of pulsed electromagnetic field (PEMF) have greater order than that prepared by conversional hydrothermal synthesis. The catalytic performance of ZnO nanorod arrays prepared with PEMF is better accordingly.
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