Effect of preparation and processing conditions on UV absorbing properties of hydroxyapatite-Fe2O3 sunscreen

Teixeira, M.A. C.; Piccirillo, Clara; Tobaldi, David Maria; Pullar, Robert C.; Labrincha, J.A.; Ferreira, Mara; Castro, Paula M. L.; Pintado, Manuela

doi:10.1016/j.msec.2016.09.065

Cited by 34 publications

(28 citation statements)

References 30 publications

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“…Figure shows the SEM images of the samples treated with either IR or green laser, with the cycle repeated two or six times. It can be seen that within the untreated powder (Figure A) the particles are quite large and have an irregular shape, with an average dimension of about 250 nm; this is in agreement with what observed in previous studies of these materials …”

Section: Resultssupporting

confidence: 91%

“…Considering the specific features of the spectra, it can be seen that FeHAp shows a profile similar to what previously reported, that is, absorption for the whole UV range, partially also in the visible region and in the NIR. Several broadly shaped peaks are characteristic of α‐Fe 2 O 3 ; the UV peak at about 285‐290 nm (a) is due to the 6 A 1 → 4 T 1 ( 4 P) of Fe (III) ligand field transitions, while the absorption in the visible (peaks at 410 and 500 nm; (b) are associated with the 6 A 1 → 4 E 1 4 A 1 ( 4 G) ligand field transition of Fe 3+ .…”

Section: Resultssupporting

confidence: 84%

“…The FeHAp powder was prepared as previously reported; the protocol is briefly described again for clarity. The cod fish bones were placed into a solution containing FeCl 2 in excess (about five times the HAp content in the bones) at a basic pH; the solution was stirred at 75‐80°C for 5 hours.…”

Section: Methodsmentioning

confidence: 99%

“…Further studies showed that treatments performed on the powder after the calcination (prolonged high‐energy ball milling and ultrasonication) to reduce and homogenize the size of the particles led to an increase in the UV absorption and, hence, an improved sunscreen potential. Such better performance was linked to the smaller particle size, as well as the higher surface area . With both mechanical and ultrasound treatments, however, the dimensions of the particles were still about 50‐100 nm; these data showed that these methods have limited effectiveness to reduce the particles’ size and to achieve powders of nanoscale dimension.…”

Section: Introductionmentioning

confidence: 99%

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Increased UV absorption properties of natural hydroxyapatite‐based sunscreen through laser ablation modification in liquid

et al. 2018

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Sunfilters based on hydroxyapatite (HAp) and iron‐containing compounds (Fe2O3 and calcium iron phosphates) are of increasing interest, as they show UV absorption without generating health endanger free radicals (usually observed when other inorganic sunscreens are used). In this paper, laser ablation of solids in liquids has been applied to improve the UV absorption properties of a HAp based Fe‐containing sunscreen powder derived from cod fish bones. Two different laser wavelengths were explored (532 and 1064 nm, green and infrared, respectively); an improved experimental device was used, to allow a fine control of the volume of the irradiated particles. Results show an increased UV absorbance for the laser‐treated powders in comparison with the untreated ones; this can be explained considering the smaller particle size and increased surface area; the higher iron concentration in the powders may also be determinant. Enhanced absorption was also observed in the near‐infrared range, making the powders even more suitable for sunscreen applications. The green laser was more effective than the infrared one. Overall, laser ablation showed to be a powerful technique to control the size of the sunscreen particles and tailor their optical properties.

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Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Increased UV absorption properties of natural hydroxyapatite‐based sunscreen through laser ablation modification in liquid

et al. 2018

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“…The band at 595 cm −1 belongs to the phosphate group. These peaks confirm that the phosphate group occupies two sites in the crystal lattice [11,31].…”

Section: Characterization Of the Calcium Precursor Materials (Eggshellsupporting

confidence: 52%

Eggshell-Derived Nanohydroxyapatite Adsorbent for Defluoridation of Drinking Water from Bofo of Ethiopia

Workeneh

Zereffa

Segne

et al. 2019

Journal of Nanomaterials

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Fluoride has become a notable toxicological environmental hazard worldwide because it is often found in groundwater. In the present study, hydroxyapatite adsorbent was synthesized from eggshell waste to remove fluoride from aqueous solution. XRD, FT-IR, and TGA techniques were used to characterize the prepared adsorbent. Batch adsorption studies were performed to examine the adsorption capacity of hydroxyapatite such as the effect of the initial pH of the solution, contact time, adsorbent dose, and initial fluoride concentration. The fluoride ion-selective electrode was used to determine the fluoride removal efficiency. 98.8% of fluoride was removed at pH 3.0, but at pH ~7.0, 85% of fluoride was removed; it shows that the fluoride adsorption is pH dependent. The adsorption isotherm studies (Langmuir and Freundlich models) and the experimental results for the removal of fluoride showed that the Langmuir model was more favorable and the reaction followed pseudo-second-order kinetics. In real water samples, the prepared hydroxyapatite derived from eggshell exhibited 81% removal efficiency. Our results indicate that eggshell waste-derived hydroxyapatite may be an alternative source for defluoridation in developing countries.

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Synthesis of carbon quantum dots to fabricate ultraviolet‐shielding poly(vinylidene fluoride) films

Dong

Xiong

Liu

et al. 2019

J of Applied Polymer Sci

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The paper presents a simple and effective approach to fabricating a poly(vinylidene fluoride) (PVDF) film with excellent ultraviolet (UV) shielding performance. Carbon quantum dots (CQDs) with a highly UV absorbing property were made via a hydrothermal reaction and were then added to a poly(vinyl alcohol) (PVA) solution. The PVDF membrane pretreated with an alkaline solution was immersed in the prepared CQD/PVA solution to coat a UV‐shielding layer on the film surface. Fourier transform infrared spectroscopy, X‐ray photoelectron spectrometry, X‐ray diffraction, transmission electron microscopy, and UV–visible spectrophotometry were applied to study the structure, morphology, and optical performance of the CQD particles. The stability and UV‐shielding performance of the obtained PVDF‐OH@CQDs/PVA composite film were further investigated. The results showed that the CQD particles with diameter of 18 nm could be well dispersed in solution. Additionally, the CQDs had fairly high UV absorbance, and the PVDF‐OH@CQDs/PVA composite film could shield the UV light completely. The method described in this paper is a promising one for fabricating UV‐shielding composite films. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47555.

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Effect of preparation and processing conditions on UV absorbing properties of hydroxyapatite-Fe2O3 sunscreen

Cited by 34 publications

References 30 publications

Increased UV absorption properties of natural hydroxyapatite‐based sunscreen through laser ablation modification in liquid

Increased UV absorption properties of natural hydroxyapatite‐based sunscreen through laser ablation modification in liquid

Eggshell-Derived Nanohydroxyapatite Adsorbent for Defluoridation of Drinking Water from Bofo of Ethiopia

Synthesis of carbon quantum dots to fabricate ultraviolet‐shielding poly(vinylidene fluoride) films

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