Resumo em Inglês:

This work produced chemically activated sugarcane bagasse-based activated carbon (AC) for the controlled release of urea. Fourier transform infrared (FTIR) and Raman analysis confirmed the presence of graphitic structures and multiple oxygen-containing functional groups. After the solid-state reaction that formed the material, their surface area reached 1401 m2 g-1 for the sample prepared with a pyrolysis temperature of 400 °C, a concentration of sodium hydroxide equivalent to 11 mol L-1, and an activation temperature of 900 °C (AC 400-11-900). Zeta potential measures indicated negative charges at pH > 4, reaching almost (–50 mV) at pH 9. The adsorptive capacity of the AC with the highest surface area was equal to (758.7 ± 263.8) mg g-1. Nevertheless, the matrix did not release the urea molecules previously adsorbed into it, which is appealing for fertilizer-releasing purposes because the activated carbon would be able to re-adsorb the non-absorbed urea molecules, sustaining nutrient availability for longer periods.

Resumo em Inglês:

The increase in anthropogenic activity over time has led to an exponential increase in greenhouse gas emissions, especially CO2. Proftable technologies for CO2 capture and separation are conspicuous, and porous biochars derived from biomass waste can be a useful solution. Herein, we produced activated nitrogen-doped biochars for CO2 capture from corn husk waste, urea and K2CO3, named N-Bio-X (X = 600, 700, and 800 °C). N-Bio-X exhibited microporosity and different nitrogen contents and thus played an important role in the adsorption of CO2. N-Bio-700 exhibited the highest CO2 adsorption capacity, fastest adsorption kinetics and excellent stability after multiple adsorption-desorption cycles. N-Bio-600 showed excellent CO2/N2 selectivity, induced by nitrogen sites, particularly pyridinic and graphitic nitrogen. The cost-effectiveness of the raw material, coupled with its high adsorption capacity, rapid kinetics, and stable properties, provided highly promising N-doped biochars for practical implementation in CO2 capture and separations in postcombustion processes.

Resumo em Inglês:

This study presents the synthesis and characterization of five Schiff bases derived from the reaction of 4-(2-aminoethyl)-benzenesulfonamide (compound 1) with corresponding aldehydes, (benzaldehyde, 2-pyridinecarboxaldehyde, 2-quinolinecarboxaldehyde, 8-hydroxy2-quinolinecarboxaldehyde and 4-imidazolecarboxaldehyde, for compounds 2-6, respectively). Characterization was performed by various spectroscopic techniques and supported by density functional theory (DFT) calculations. The crystal structures revealed how the substituent groups influenced the present supramolecular interactions. Compounds 1-4 and 6 showed no cytotoxicity to BHK-21 and VERO E6 cells at the highest concentration of 50 µmol L-1, while compound 5 was cytotoxic at this concentration. Compound 5 was active against the Chikungunya virus at the concentration of 10 µmol L-1, highlighting the effect of the 8-hydroxyquinoline substituent for the antiviral activity. For Zika virus, compound 6 was the only one active at 50 µmol L-1. The results suggest the potential of combining sulfonamides with other chemotypes for further development of antiviral agents, especially in the treatment of arboviral diseases.

Resumo em Inglês:

Pure and cobalt-doped 3D ZnO were produced using the microwave (MW)-ultraviolet (UV)-visible (Vis) radiation-assisted hydrothermal method (MW-UV-Vis HM). Using experimental design, the effects of cobalt and UV-Vis radiation during the synthesis stage on the physicochemical properties of the materials were evaluated with different characterization techniques such as X-ray diffraction, scanning and transmission electron microscopy, diffuse reflectance, and electrochemistry. The presence of cobalt had a great influence on the reduction of charge donors in the ZnO matrix and had their photocatalytic properties improved when produced under the effect of UV-Vis radiation. The catalytic activity of the materials has been verified in important environmental remediation reactions, such as the electrochemical reduction of CO2 and the photocatalytic degradation of emerging pollutants. The results achieved in this study show competitive efficiency values for CO2 reduction (97%) and photocatalytic degradation (91%) of emerging pollutants in natural waters, illustrating the great versatility of the produced material in distinct applications.

Resumo em Inglês:

Niobium pentoxide shows an interesting reactivity that allows the control of different aspects of its morphology and chemistry. In this study, Nb2O5 nanoparticles were modified with protoporphyrin IX (PPIX) and tris(ethynylphenyl) pyrene derivative (PyPh3) by using 3-aminopropyltriethoxysilane as linkage group and used as photosensitizers against lung cancer. The antitumor photoactivity against the A549 tumor cell line as a model of in vitro study showed half maximal inhibitory concentration (IC50) ca. 15 μmol L-1 for both materials and the absence of dark activity, indicating the viability of dye-modified Nb2O5 as a photodynamic therapy (PDT) agent.