ABSTRACT
Organically modified vermiculites were synthesized by previous silylation of three leached vermiculites, V0.3Cl, V0.5Cl and V0.8Cl, under anhydrous conditions following reaction with imidazole (Im), which acted as chelating agent for copper retention. Elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, (29)Si and (13)C NMR and nitrogen adsorption/desorption measurements were used to characterize pristine, leached and organofunctionalized solids. X-ray photoelectron spectroscopy (XPS) was used to evaluate the surface after copper sorption. Parameters such as contact time, pH and initial cation concentration for the adsorption of Cu(II) ions were investigated. The adsorption equilibrium data were fitted using the Langmuir isotherm model and the monolayer adsorption capacities were 2.38, 2.52 and 2.69mmolg(-1) for V0.5Cl-Im, V0.3Cl-Im and V0.8Cl-Im, respectively, at pH 6.0 and 298K for a time reaction of 80min. The sorption rates were described by pseudo-second-order kinetics. The chloropropyl imidazole vermiculites are promising adsorbents for the rapid removal of Cu(II) ions from aqueous solution.
ABSTRACT
Co-products from the juice processing of guava (CG), mango (CM) and barbados cherry (CB) were investigated with a view to their exploitation as a potential source of natural antioxidants. The ethanolic extracts were analyzed for total extractable phenolic content (TEP), DPPH radical scavenging activity (RSA-DPPH), ferric reducing antioxidant power (FRAP) and antioxidant activity in relation to the ß-carotene/ linoleic acid system. The TEP levels in the CG, CM and CB extracts were (24.15 ± 1.59), (44.18 ± 1.73) and (49.21 ± 3.70) mg GAE/g extract, respectively. The CM extract showed higher DPPH, FRAP and antioxidant activity in the ß-carotene/linoleic acid system. The data revealed a positive linear correlation between TEP, RSA-DPPH and FRAP (r² = 0.85-0.98); however, the ß-carotene/linoleic acid system (r² = 0.01-0.26) shows low correlation with the TEP levels and other assessment systems. The results suggest that co-products generated from the juice processing of the studied fruit have promising use as a natural source of antioxidants.
Subject(s)
Antioxidants/chemistry , Mangifera/chemistry , Plant Extracts/chemistry , Prunus/chemistry , Psidium/chemistry , Free Radical Scavengers/chemistry , Phenols/chemistry , beta Carotene/chemistryABSTRACT
Chitosan-montmorillonite (KSF-CTS) beads were prepared by crosslinking with pentasodium tripolyphosphate (TPP). Montmorillonite (KSF-Na), CTS and KSF-CTS biocomposite were used to remove Cu(II) from aqueous solutions. These materials were characterized before and after copper adsorption by XRD, FTIR and thermogravimetry (TG). The data indicated that the adsorption process proceeds kinetically according to a pseudo-second-order model. The adsorption processes were adjusted to the Langmuir model for KSF-Na and CTS and to the Temkin model for KSF-CTS. The maximum adsorption capacity followed the order CTS>KSF-CTS>KSF-Na. Percentages desorption of copper ions from the KSF-CTS composite after three desorption cycles were 86%, 85% and 84%, respectively, using EDTA as regeneration agents.
Subject(s)
Bentonite/chemistry , Cations/chemistry , Chitosan/chemistry , Copper/chemistry , Adsorption , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Water Purification , X-Ray DiffractionABSTRACT
A cúrcuma é o rizoma limpo, em boas condições, seco e moído da Curcuma longa L., uma planta herbácea da família Zingiberaceae. Visando novas alternativas para o controle da esquistossomose, os extratos de Curcuma longa L. foram testados para a avaliação da atividade moluscicida contra caramujos adultos da espécie Biomphalaria glabrata, e toxicidade (ensaio de letalidade com Artemia salina). A oleoresina e o óleo essencial de cúrcuma foram ativos contra Artemia salina (CL50 = 80,43 e CL50 = 319,82 μg/mL, respectivamente) e também ativos contra os indivíduos adultos de Biomphalaria glabrata (CL50 = 58,3 e CL50 = 46,73 μg/mL, respectivamente). A partir dos resultados obtidos pôde ser concluído que ambos os extratos podem constituir uma alternativa no controle da população desses caramujos e na redução da esquistossomose.
The turmeric is the clean rhizome at good conditions, dried and powdered of Curcuma longa L., an herbaceous plant of Zingiberaceae family. Aiming new alternatives for Schistosomiasis control, the Curcuma longa L. extracts were tested for molluscicidal activity evaluation against adult snails of Biomphalaria glabrata specie, and the toxicity (Brine Shrimp Lethality-BSL-bioassay). The oleoresin and the essential oil of turmeric were active against Artemia salina (CL50 = 80.43 and CL50 = 319.82 μg.mL-1, respectively) and also active against the adult snails of Biomphalaria glabrata (CL50 = 58.3 and CL50 = 46.73 μg.mL-1, respectively). From the obtained results it was concluded that both extracts can constitute an alternative to population control of these snails and in the reduction of Schistosomiasis.
