The effect of surface OH-population on the photocatalytic activity of rare earth-doped P25-TiO2 in methylene blue degradation

Haruki

2015

J Adv Ceram

Abstract:Zinc oxide, which has photocatalytic activity, is used as a white pigment for cosmetics, resulting in a certain amount of sebum on the skin to be decomposed by the ultraviolet radiation in the sunlight. In this work, zinc phosphates as novel white pigments for use in cosmetics were prepared from zinc nitrate and sodium dihydrogen phosphate, and then ball-milled under various conditions. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were studied. The zinc phosphate particle size was decreased by mechanical treatment. In particular, the sample treated with sodium lactate solution had much smaller particles. The milled zinc phosphates exhibited less photocatalytic activity than zinc oxide, and thus should not decompose sebum on the skin. The milled zinc phosphates showed sufficiently high reflectance within the range of visible light to act as novel white pigments. The sample treated with sodium lactate solution had higher water retention than the sample treated with water. Further, the slip resistance and roughness of the powder particles decreased as a result of treatment with sodium lactate solution.

Section: Methodsmentioning

confidence: 99%

Effect of mechanical treatment on the powder properties of zinc phosphate white pigments

Haruki

2015

J Adv Ceram

“…The photo catalytic activity of the samples was estimated with the decomposition of methylene blue by 365 nm radiation [18,19]. A 0.01 g portion of the sample was placed in 4 ml of methylene blue solution (1.0×10 5 mol/L); this solution was then irradiated.…”

Section: Methodsmentioning

confidence: 99%

pH-controlled hydrothermal synthesis of titanium phosphates and their powder properties

Yamaguchi

2014

J Adv Ceram

Titanium phosphates were prepared from titanium chloride and sodium pyrophosphate at various pH in hydrothermal process as a novel white pigment for cosmetics. Their chemical composition, powder properties, photo catalytic activity, colour phase and smoothness were studied. The obtained materials had a higher Ti/P ratio than that used in preparation conditions because of the formation of titanium oxide and hydroxide. The samples prepared at pH = 4 had particles smaller than 100 µm. Titanium phosphates had less photo catalytic activity to protect the sebum on the skin. The obtained materials in hydrothermal process and their thermal products at 100 ℃ showed high reflectance in the range of visible light.

“…The photo catalytic activity of samples was estimated with the decomposition of methylene blue by 365 nm radiation [13,14]. The color of phosphate pigments was estimated by ultraviolet-visible (UV-Vis) reflectance spectra with a Shimadzu UV2550.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Titanium Phosphates with Sodium Triphosphate in Hydrothermal Process and Their Powder Properties for Cosmetics

Yamaguchi²

2013

AMPC

As a white pigment, titanium oxide is used for cosmetic application. This oxide is well known to have the photo catalytic activity. Therefore, a certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium phosphates were prepared with titanium chloride and sodium triphosphate in hydrothermal process as a novel white pigment. Their chemical composition, powder properties, photo catalytic activity, color phase, and smoothness were studied. The obtained phosphates had little photo catalytic activity. The particle size of phosphate pigments consisted of a normal distribution at 2 µm by the hydrothermal treatment for 4 and 8 hours. The slipping resistance of samples became small by the hydrothermal treatment.