3 resultados para biologic removal
em Repositório Científico do Instituto Politécnico de Lisboa - Portugal
Resumo:
The assessment of surface water nanofiltration (NF) for the removal of endocrine disruptors (EDs) Nonylphenol Ethoxylate (IGEPAL), 4-Nonylphenol (NP) and 4-Octylphenol (OP) was carried out with three commercial NF membranes - NF90, NF200, NF270. The permeation experiments were conducted in laboratory flat-cell units of 13.2 x 10(-4) m(2) of surface area and in a DSS Lab-unit M20 with a membrane surface area of 0.036 m2. The membranes hydraulic permeabilities ranged from 3.7 to 15.6 kg/h/m(2)/bar and the rejection coefficients to NaCl, Na2SO4 and Glucose are for NF90: 97%, 99% and 97%, respectively; for NF200: 66%, 98% and 90%, respectively and for NF270: 48%, 94% and 84%, respectively. Three sets of nanofiltration experiments were carried out: i) NF of aqueous model solutions of NP, IGEPAL and OP running in total recirculation mode; ii) NF of surface water from Rio Sado (Settibal, Portugal) running in concentration mode; iii) NF of surface water from Rio Sado inoculated with NP, IGEPAL and OP running in concentration mode. The results of model solutions experiments showed that the EDs rejection coefficients are approximately 100% for all the membranes. The results obtained for the surface water showed that the rejection coefficients to natural organic Matter (NOM) are 94%, 82% and 78% for NF90, NF200 and NF 270 membranes respectively, with and without inoculation of EDs. The rejection coefficients to EDs in surface water with and without inoculation of EDs are 100%, showing that there is a fraction of NOM of high molecular weight that retains the EDs in the concentrate and that there is a fraction of NOM of low molecular weight that permeates through the NF membranes free of EDs.
Resumo:
Objectives - Evaluate the nutritional status of patients with inactive or mildly active Crohn's disease (CD), and identify possible causes for potential deficiencies. Methods - A total of 78 CD patients and 80 healthy controls were evaluated in respect of nutritional status, dietary intake, and life styles factors. Results - These 73/78 CD patients were on immunomodulating therapies. Mean body mass index (BMI) was lower in patients as compared to controls (P= 0.006) but 32% of CD patients and 33.8% of controls had a BMI > 25, whereas 8% and 23.8% in each group, respectively, were obese (BMI > 30Kg/m(2)). Fat free mass was significantly decreased in both genders (P < 0.05) whereas fat mass was decreased only in males (P= 0.01). Energy intake was significantly lower in CD patients (P < 0.0001) and we observed significantly lower adjusted mean daily intakes of carbohydrates, monounsaturated fat, fiber, calcium, and vitamins C, D, E, and K (P < 0.05). 29% of patients had excluded grains from their usual diet, 28% milk, 18% vegetables, and 11% fruits. Milk exclusion resulted in a significantly lower consumption of calcium and vitamin K (P < 0.001) and the exclusion of vegetables was associated to a lower consumption of vitamins C and E (P < 0.05). Physical activity was significantly lower in CD patients (P= 0.01) and this lack of physical activity was inversely correlated with increased fat mass percentage (r=-0.315, P= 0.001). Conclusions - Results showed that the most prevalent form of malnutrition in CD patients was an excess of body weight, which was concomitant with an inadequate dietary intake, namely micronutrients, clearly related to dietary exclusion of certain foods.
Resumo:
The synthesis of nanocomposite materials combining titanate nanofibers (TNF) with nanocrystalline ZnS and Bi2S3 semiconductors is described in this work. The TNF were produced via hydrothermal synthesis and sensitized with the semiconductor nanoparticles, through a single-source precursor decomposition method. ZnS and Bi2S3 nanoparticles were successfully grown onto the TNF's surface and Bi2S3-ZnS/TNF nanocomposite materials with different layouts. The samples' photocatalytic performance was first evaluated through the production of the hydroxyl radical using terephthalic acid as probe molecule. All the tested samples show photocatalytic ability for the production of this oxidizing species. Afterwards, the samples were investigated for the removal of methylene blue. The nanocomposite materials with best adsorption ability were the ZnS/TNF and Bi2S3ZnS/TNF. The dye removal was systematically studied, and the most promising results were obtained considering a sequential combination of an adsorption-photocatalytic degradation process using the Bi2S3ZnS/TNF powder as a highly adsorbent and photocatalyst material. (C) 2015 Elsevier Ltd. All rights reserved.