Comparative evaluation of the pH of calcium hydroxide powder in contact with carbon dioxide (CO2)

Cavalcante, Amaro de Mendonça; Lima, Jailson Costa; Santos, Lucineide de Melo; Oliveira, Paulo César Costa de; Júnior, Karlos Antônio Lisboa Ribeiro; Santana, Antônio Euzébio Goulart

doi:10.1590/s1516-14392010000100002

Cited by 9 publications

(2 citation statements)

References 5 publications

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“…Calcium oxide is a very reactive compound that interacts with water molecules causing a hydration reaction, incorporating hydroxyl ions (OH − ) into their crystalline structure to form transforming calcium hydroxide [Ca(OH) 2 ]. The dissolution of calcium hydroxide offers an early abundant supply of calcium and hydroxyl calcium [16], that can participate in the formation of pure hydroxyapatite crystals, the major component of the inorganic mineral phase of the bone matrix [17]. The chemical composition of otoliths may thus possible favor bone neoformation, since the higher the content of carbonate in a biomineral, the greater the osteoconductivity [18].…”

Section: Resultsmentioning

confidence: 99%

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Valido

Júnior

Andrade

et al. 2020

Drug Deliv. and Transl. Res.

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Evidence that otoliths, mineral-rich limestone concrescences present in the inner ear of bone fishes, can accelerate bone formation in vivo has been previously reported. The goal of this work was the development, characterization, and evaluation of the cytocompatibility of otoliths-incorporated sodium alginate and gelatin scaffolds. Cynoscion acoupa-derived otoliths were characterized by X-ray fluorescence spectrometry (FRX), particle size, free lime, and weight loss by calcination. Furthermore, otoliths were incorporated into sodium alginate (ALG/OTL-s) or gelatin (GEL/OTL-s) scaffolds, previously developed by freeze-drying. Then, the scaffolds were characterized by thermogravimetric analysis (TGA/DTG), differential scanning calorimetry (DSC), infrared spectroscopy with Fourier transform (FTIR), swelling tests, and scanning electron microscopy (SEM). Cytotoxicity assays were run against J774.G8 macrophages and MC3T3-E1 osteoblasts. Data obtained from TGA/DTG, DSC, and FTIR analyses confirmed the interaction between otoliths and the polymeric scaffolds. SEM showed the homogeneous porous 3D structure rich in otolith micro-fragments in both scaffolds. Swelling of the GEL/OTL-s (63.54 ± 3.0%) was greater than of ALG/ OTL-s (13.36 ± 9.9%) (p < 0.001). The viability of J774.G8 macrophages treated with both scaffolds was statistically similar to the group treated with DMEM only (p > 0.05) and significantly higher than that treated with Triton-X (p < 0.01) at 72 h. Both scaffolds showed approximately 100% growth of MC3T3-E1 osteoblasts by 24 h, similarly to control (p > 0.05). However, by 48 h, only ALG/OTL-s showed growth similar to control (p > 0.05), whereas GEL/OTL showed a significantly lower growth index (p < 0.05). In conclusion, the physicochemical profiles suggest proper interaction between the otoliths and the two developed polymeric 3D scaffolds. Moreover, both materials showed cytocompatibility with J774.G8 macrophages but the growth of MC3T3-E1 osteoblasts was higher when exposed to ALG/OTL-s. These data suggest that sodium alginate/otoliths scaffolds are potential biomaterials to be used in bone regeneration applications.

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Section: Resultsmentioning

confidence: 99%

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Valido

Júnior

Andrade

et al. 2020

Drug Deliv. and Transl. Res.

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“…It worthy to note that the pH rapidly increased to 12-13 in all experiments in catalysts were added. This is due to the presence of Ca(OH) 2 in their composition, as it was proved by XRD and FTIR analyses, which is a strong base [56] that caused the increase in pH. This high amount of Ca(OH) 2 is originated from the hydration of the calcium oxide, which is the main component of the waste eggshell after strong calcination [21].…”

Section: Catalytic Propertiesmentioning

confidence: 92%

Eggshell-supported Catalysts for the Advanced Oxidation Treatment of Humic Acid Polluted Wastewaters

Oulego

Laca

Calvo

et al. 2019

Water

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Metal nanoparticles have been reported as effective catalysts for the removal of refractory compounds from industrial wastewaters in advanced oxidation processes. Additionally, hundreds of thousands of tons of eggshells are discarded worldwide each year. In this work, this waste has been evaluated as support for the synthesis of nanomaterials by wet impregnation method. Four supported catalysts, with a load of iron or copper of 5% and 15%, were prepared and thoroughly characterized by means of different techniques (elemental analysis, XRF, XRD, FTIR, N2 adsorption-desorption, SEM, TEM and TGA). The catalysts performance was evaluated in wet oxidation tests to degrade humic acids, analyzing the evolution with time of COD, biodegradability index (BOD5/COD), color number and pH. The best results were achieved with 15% Cu and 5% Fe catalysts (COD reduction being 82.3% and 75.1%, respectively), whereas a COD reduction of 58% was obtained employing non-impregnated eggshell. This can be mainly attributed to the metal loading and the good metal distribution on the surface of the support. The BOD5 value of humic acids was initially null and, in all assays, the oxidation treatment enhanced the biodegradability. Therefore, eggshell has proved to be an interesting material to be employed as support in nanoparticles preparation.

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Solid‐state hydrolysis of postconsumer polyethylene terephthalate after plasma treatment

Mancini

Nogueira

Rangel

et al. 2012

J of Applied Polymer Sci

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Plasma treatments were applied on the surface of postconsumer polyethylene terephthalate (PET) bottles to increase their wettability and hasten the subsequent hydrolysis process. Sixty-four treatments were tested by varying plasma composition (oxygen and air), power (25-130 W), pressure (50-200 mTorr), and time (1 and 5 min). The best treatment was the one applied in air plasma at 130 W and 50 mTorr for 5 min, as it provided the lowest contact angle, 9.4 . Samples of PET before and after the optimized plasma condition were subjected to hydrolysis at 205 C. Although the treatment changed only a thin surface layer, its influence was evident up to relatively high conversion rates, as the treated samples presented more than 40% higher conversion rates than the untreated ones after 2 h of reaction. Infrared spectroscopy showed that the terephthalic acid obtained from 99% of depolymerization was similar to the commercial product used in PET synthesis.

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Comparative evaluation of the pH of calcium hydroxide powder in contact with carbon dioxide (CO2)

Cited by 9 publications

References 5 publications

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

Eggshell-supported Catalysts for the Advanced Oxidation Treatment of Humic Acid Polluted Wastewaters

Solid‐state hydrolysis of postconsumer polyethylene terephthalate after plasma treatment

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