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Abstract: In this work, xyloglucan extracted from the seeds of Hymenaea courbaril (jatobá) collected in Rancho Alegre, Paraná, Brazil (JRAXG), was oxidized at the C-6 position of galactose or glucose units, using 2,3,6,6-tetramethylpiperidine-1-oxyl, to form uronic acid-containning polysaccharides (JRAOXGs), with different degrees of oxidation (10, 23 and 34%) and high yield (~95%). The properties of the news polyelectrolyte were studied by intrinsic viscosity, Gel Permeation Chromatography (GPC), Infrared spectroscopy (FTIR), 13C-NMR (13C-Nuclear Magnetic Resonance), and by Atomic Force Microscopy (AFM). The FTIR and 13C-NMR spectra confirmed the oxidation process. In comparison to JRA XG the JRAOXGs derivatives showed by GPC a homogeneous profile, but with hydrodynamic volume and molecular weight (Mw) reduction. Furthermore, AFM images on mica, after dewetting hydrodynamic volume, show different states of aggregation accordingly to the degree of oxidation when compared to the native state. The native XG presents a rather compact and quite homogeneous topography with a few holes and absence of aggregates, while the oxidation products present spherical-like conformation whose diameters is in the range of 8–30 nm. The morphological changes observed by AFM to JRAOXG34 derivative, can be very important to guide to drug encapsulation, for example. [Copyright &y& Elsevier]

This work assesses the efficiency of polyacrylamides for natural organic matter (NOM) removal from Paraíba do Sul River (Brazil) raw water for drinking purposes. Jar tests were performed following an experimental design protocol. Three kinds of polyacrylamides (anionic, cationic, and non-ionic) at 0.2mgL-1 were tested. After coagulation, turbidity, DOC, UVA254 and SCAN (UV-absorbing material) were determined. Color and pH were also measured. It was found that polyacrylamides did not reduce the amounts of alum and lime needed in the process and that the amount of alum alone for removing UV-absorbing organic matter is significantly higher. Efficiency of the coagulation process decreased as follows: non-ionic → cationic → anionic → no polyacrylamide. Removal efficiencies for the best case were: 100%, 90%, 83%, and 68% for turbidity, DOC, UVA254, and SCAN, respectively. [ABSTRACT FROM AUTHOR]

Contaminated water consumption is one of the greatest risks to human health, especially in underdeveloped and developing countries. Water is a universal right, but millions of people worldwide consume untreated surface water. The objective in this study is to evaluate water purification with Nopalea cochenillifera var. Miúda biomass. Fragments (1, 2, and 3 g) of N. cochenillifera were added to the aqueous solution containing red-yellow Chromic and Podzolic Luvisol simulating turbid water sources in Northeastern Brazil. The total, non-structural (i.e., reducing and non-reducing sugars, alcohol insoluble solids), and structural (i.e., pectin) carbohydrates, adsorption kinetics, turbidity, electrical conductivity, pH, zeta potential, and total coliforms presence were evaluated. Findings show that the Nopalea cochenillifera biomass adsorbed the suspended particles in the aqueous solution, making it more translucent due to the complex and heterogeneous adsorbents' ion exchange matrix, but the biomass addition did not eliminate total coliforms from the aqueous solution. We concluded that the Nopalea cochenillifera biomass water treatment reduces suspended dissolved particles and turbidity, but it needs to be associated with other treatments to eliminate total coliforms and ensure water safety for human consumption. [ABSTRACT FROM AUTHOR]