Abstract Nanostructured crystalline composite (activated carbon) was synthesized from residual ashes of the burning process of the sludge generated in the flotation step of a poultry slaughterhouse and was used for Allura red dye adsorption. The ashes were chemically activated using two types of reagents, H2O2 and H3PO4, and the structure, morphology, and surface of the adsorbents were characterized by different techniques such as scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), N2 adsorption/desorption isotherms with Brunauer-Emmett-Teller (BET) method and Barret-Joyner-Hallenda (BJH) method, Fourier transform infrared spectroscopy (MID/FTIR), X-ray diffraction (XRD), and the point of zero charge (PZC). The adsorbent synthesized with H3PO4 at 400 ºC displayed the best performance in removing dye molecules in 10 mg.L-1 solution, with a removal rate of approximately 100% when using a concentration of 2 g.L-1 in particle size of 0.42 mm. Besides that, the adsorbent synthesized with H3PO4 had a particle diameter of approximately 15 Å, a size corresponding to the nanometer range, presented a crystallinity structure with well-defined phases such as quartz and the major elements in the composition were carbon and silicon. The surface area of the ashes enlarged from 14.71 to 448.1 m2.g-1 when H3PO4 was used as an activator, producing a high-quality adsorbent, with an excellent cost-benefit, being it possible to be produced for a price of 9.35 USD.kg-1, a price lower than the commercial activated carbon, making it a promising candidate for application in an industrial environment.

Resumo Durante a germinação, sementes ortodoxas tornam-se gradualmente intolerantes à dessecação, e por isso podem ser utilizadas como modelo para o estudo da recalcitrância. No presente trabalho realizou-se uma caracterização dos aspectos fisiológicos, bioquímicos e ultraestruturais da perda da tolerância à dessecação de sementes de Anadenanthera colubrina em processo germinativo. Para isso as sementes foram embebidas durante 0 (controle), 2,8,12 e aproximadamente 18 horas (sementes germinadas com 1 mm de radícula), secas por 72 horas, reidratadas e a sobrevivência avaliada. Ao longo da embebição foram realizadas análises citométricas, ultraestruturais e extração de proteínas resistentes ao calor e após embebição e secagem foram avaliados danos ultraestruturais. A tolerância à dessecação foi totalmente perdida após a protrusão radicular. Não houve aumento do conteúdo de DNA 4C quando a tolerância à dessecação foi perdida. Características ultraestruturais de células de radículas de 1 mm assemelharam-se às encontradas em sementes recalcitrantes tanto no estado hidratado quanto desidratado. A perda da tolerância à dessecação coincidiu com a redução do conteúdo de proteínas resistentes ao calor.

Abstract During germination, orthodox seeds become gradually intolerant to desiccation, and for this reason, they are a good model for recalcitrance studies. In the present work, physiological, biochemical, and ultrastructural aspects of the desiccation tolerance were characterized during the germination process of Anadenanthera colubrina seeds. The seeds were imbibed during zero (control), 2, 8, 12 (no germinated seeds), and 18 hours (germinated seeds with 1 mm protruded radicle); then they were dried for 72 hours, rehydrated and evaluated for survivorship. Along the imbibition, cytometric and ultrastructural analysis were performed, besides the extraction of the heat-stable proteins. Posteriorly to imbibition and drying, the evaluation of ultrastructural damages was performed. Desiccation tolerance was fully lost after root protrusion. There was no increase in 4C DNA content after the loss of desiccation tolerance. Ultrastructural characteristics of cells from 1mm roots resembled those found in the recalcitrant seeds, in both hydrated and dehydrated states. The loss of desiccation tolerance coincided with the reduction of heat-stable proteins.