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Decolorization of Corn Fiber Arabinoxylan Extract with (MN102) Resin
Publication . Weng, Verónica; Gago, Diana; Brazinha, Carla; Alves, Vítor D.; Coelhoso, Isabel M.; DQ - Departamento de Química; LAQV@REQUIMTE; MDPI - Multidisciplinary Digital Publishing Institute
Arabinoxylan is a polysaccharide with film-forming properties, present in corn fiber, and a low-value by-product. The extract has a deep brown color, producing films of the same shade, which may not be appealing. This study addresses, for the first time, the adsorption of colored compounds present in an arabinoxylan extract using resin MN102. The resin successfully adsorbed the colored compounds from the arabinoxylan extract. After four consecutive adsorption/desorption cycles, the efficiency of the resin was similar, only decreasing from 63.3% to 52.9%. Langmuir and Freundlich models were fitted to the results of adsorption isotherm experiments, with the Freundlich model demonstrating the best fit to the experimental results. A fixed-bed column loaded with the resin was used for the removal of the colored compounds from the arabinoxylan extract, and the effect of the volumetric flow rate was investigated. The Yan and log-Gompertz models showed the best fit to the experimental breakthrough curves. This study systematically evaluated the adsorption conditions, providing a comprehensive analysis of the performance of the resin in the removal of the colored compounds. Additionally, the ability of the extract to maintain its film-forming properties after decolorization was evaluated, and some of the film’s key characteristics were evaluated, namely its color, solubility in water and mechanical properties.
Adsorption-assisted membrane filtration with a cellulose derivative for separation of cationic compounds
Publication . Gago, Diana; Viegas, Ândria; Chagas, Ricardo; Ferreira, Luísa M.; Coelhoso, Isabel; DQ - Departamento de Química; LAQV@REQUIMTE; Elsevier
This study explores the first-time use of dicarboxymethyl cellulose (DCMC) in an adsorption-assisted membrane filtration (AMF) process for the removal of cationic compounds from aqueous solutions. DCMC and microfiltration commercial membranes were used in an integrated dead-end filtration system, with Cytochrome C (Cyt C) as a model protein. The experiments were performed in a stirred cell with powdered DCMC on the retentate side. The work evaluated the effect of stirring, contact time and membrane material on the removal efficiency. Regenerated cellulose, polyamide and polyethersulfone membranes were tested, showing no significant differences in performance. High retention was achieved without compromising permeability, with fluxes up to 700 L m-2 h−1. The filtration performance remained consistent after three consecutive regeneration cycles. The adsorption capacity of DCMC was assessed by discontinuous filtration with a PES membrane and 200 mg of DCMC. Following 38 min of filtration, saturation occurred with approximately 1.8 L of a 100 mg L-1 Cyt C solution. The results showed that the AMF system was successfully employed, with the adsorbent (DCMC) playing a crucial role in the removal of Cyt C.
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Fundação para a Ciência e a Tecnologia
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2020.05529.BD