Browsing by Author "Benavides, Miren Etxeberria"
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Item Catalytic nickel and nickel-copper alloy hollow-fiber membranes for the remediation of organic pollutants by electrocatalysis(2018) Allioux, Francois Marie; David, Oana; Merenda, Andrea; Maina, James W.; Benavides, Miren Etxeberria; Tanaka, Alfredo Pacheco; Dumée, Ludovic F.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSElectrocatalytic membrane reactors are becoming a viable solution for the treatment of wastewater contaminated with persistent organic pollutants and compounds. The development of suitable membrane elements made of abundant and stable electrocatalytic materials remains a challenge to enable durable and large-scale operation. In this study, novel nickel (Ni) and nickel-copper (NiCu) alloy hollow-fiber (HF) membranes were synthesized for the first time and used for the electrocatalytic degradation of small organic molecule pollutants from model wastewater effluents. The novel porous metal HFs were characterized and tested for their capacity to degrade salicylic acid (SA) molecules by electrochemical oxidation. The degradation of SA was monitored in situ and over time using an ultraviolet-visible (UV/vis) quartz cell. The HF membranes were found to be highly stable and reusable while the kinetics of SA electro-oxidation were 9 to 20 times greater than with pure platinum wire electrodes. The high performance of the HF materials was attributed to the interconnected pore structure combined with the natural surface reactivity and excellent electron transport properties of the Ni metal and bare NiCu alloy.Item Preparation of porous stainless steel hollow-fibers through multi-modal particle size sintering towards pore engineering(2017-09) Allioux, Francois Marie; David, Oana; Benavides, Miren Etxeberria; Kong, Lingxue; Tanaka, David Alfredo Pacheco; Dumée, Ludovic F.; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe sintering of metal powders is an efficient and versatile technique to fabricate porous metal elements such as filters, diffusers, and membranes. Neck formation between particles is, however, critical to tune the porosity and optimize mass transfer in order to minimize the densification process. In this work, macro-porous stainless steel (SS) hollow-fibers (HFs) were fabricated by the extrusion and sintering of a dope comprised, for the first time, of a bimodal mixture of SS powders. The SS particles of different sizes and shapes were mixed to increase the neck formation between the particles and control the densification process of the structure during sintering. The sintered HFs from particles of two different sizes were shown to be more mechanically stable at lower sintering temperature due to the increased neck area of the small particles sintered to the large ones. In addition, the sintered HFs made from particles of 10 and 44 µm showed a smaller average pore size (<1 µm) as compared to the micron-size pores of sintered HFs made from particles of 10 µm only and those of 10 and 20 µm. The novel HFs could be used in a range of applications, from filtration modules to electrochemical membrane reactors.