This paper describes the development of ZnO semiconductors applied as photocatalysts for the degradation of water contaminants, with the shape of ceramic pellets thick enough to maintain their structures, prepared by slip casting and sintering. The samples presented porosities around 40% and densities around 3.4 g/cm 3 , which represented about 61% of the theoretical density of ZnO. After obtaining the ceramic samples, the degradation of Rhodamine B dye by photocatalysis was evaluated in six cycles of degradation. After the cycles, changes in the surface of the samples were verified, possibly due to leaching during photocatalysis since they presented mean grain sizes of 0.61 μm before and 0.36 μm after the photocatalysis. The ceramic ZnO samples were able to satisfactorily degrade Rhodamine B for several cycles, resulting in successful reuse of photocatalysts and increased facility of removing the photocatalysts from the medium after degradation compared to powders in suspensions.
With industrial and technological advances, it has been increasingly possible to raise the production capacity of essential items for various activities, in addition to promoting comfort and safety for people. However, human actions cause society to face several environmental problems, which are increasingly the target of global concern in all areas, especially in the scientific community. Among these problems is the high and constant worldwide use of dyes, mostly associated with the textile industry, since the demand for clean water is high, 1,2 mainly in the dyeing stage,
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<p>Drug nanocarriers have been continuously improved to promote satisfactory release control. In this sense, luminescent materials have become an alternative option in clinical trials due to their ability to monitor drug delivery. Among the nanocarriers, silica stands out for structural stability, dispersibility, and surface reactivity. When using ceramic nanocarriers, one of the challenges is their interaction and selectivity capability for organic molecules, such as drugs. In order to overcome such adversity, superficial modifications can be carried out to enable a higher affinity for the desired drug. Thus, the present study aimed to obtain silica nanoparticles (NPs) doped with low concentrations of europium (III) superficially modified by (3-aminopropyl)triethoxysilane (APTES) to assess their interaction with the model drug cloxacillin benzathine. This drug was chosen because it is part of the ampicillin family and is commonly used in several treatments. Near-spherical and homogeneous silica NPs were obtained via sol-gel synthesis, with particle sizes of approximately 21 nm. It was possible to verify the fluorescence capacity of the silica NPs when doped with europium (III) in a mole percent that varied from 0.5 to 3.0%. A 10% volume percent of APTES caused the silica nanoparticles to increase the degree of hydrophobicity, with a shift in the contact angle from 8° to 51°. After surface modification by APTES, the silica nanocarrier (10 g·L<sup>-1</sup>) achieved a satisfactory degree of CLOX incorporation (25 g·L<sup>-1</sup>), increasing the adsorptive capacity to values above 50%. Therefore, silica NPs doped with europium (III) in a low percent of 0.5% (mole) modified by APTES showed promising results as an alternative option for trials and clinical studies of drug incorporation.</p>
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<p>Developments in nanofibers seek to increasingly expand the field of support and release of actives, such as fertilizers. Using nanofibers as materials for mineral nutrients aims to increase the efficiency of contact release of the fertilizer to the plant root in the soil. Poly lactic acid (PLA) is a polymer with biocompatibility characteristics and spinning conditions. The starch biopolymer combined with PLA can improve the biodegradation properties and hydrophilicity of the fibers and allow the solubilization of the fertilizer source for the plant. Thus, the present paper sought to find a polymeric matrix in the form of PLA/starch nanofibers that could act in the release of the mineral micronutrient manganese as a model asset. The electrospinning method was employed to obtain the fibers varying the starch concentration from 10 to 50% (w/w) in the polymeric matrix. The nanocomposite containing manganese carbonate as a source of Mn<sup>2+</sup> ions was produced from the best membrane composition. The results showed that the analyzed PLA/starch blends with 20% (w/w) provided better fiber affinity with water, which is fundamental for fiber degradation time. Regarding fertilizer release, the starch present in the PLA fiber at a concentration of 20% (m/m) promoted better control in the release of Mn<sup>2+</sup>. The total release occurred after 5 d in contact with the 2% citric acid extractive medium. Thus, PLA/starch fiber becomes an alternative in the packaging of particulate fertilizers, providing increased contact area during root application with gradual delivery of mineral nutrients and minimizing loss by leaching.</p>
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