Influence of operating conditions on ceramic ultrafiltration membrane performance when treating textile effluents

This work studies the performance of three commercial ceramic ultrafiltration membranes (ZrO2–TiO2) treating raw effluent from a textile industry. The effect of crossflow velocity at 3, 4 and 5 m s−1 as well as membrane characteristics, such as molecular weight cut-off (30, 50 and 150 kDa), on process performance were studied. Experiments were carried out in concentration mode in order to observe the effect of volume reduction factor simultaneously. Results showed a combined influence of both crossflow velocity and molecular weight cut-off on flux performance. TOC and COD removals up to 70% and 84% respectively were reached. On the other hand, almost complete color (>97%) and turbidity (>99%) removals were achieved for all the membranes and operating conditions

Fabrication and performance of low-fouling UF membranes for 2 the treatment of Isolated Soy Protein solutions

[EN] Consumers are becoming more conscious about the need to include functional and nutritional foods in their diet. This has increased the demand for food extracts rich in proteins and peptides with physiological effects that are used within the food and pharmaceutical industries. Among these protein extracts, soy protein and its derivatives are highlighted. Isolated soy protein (ISP) presents a protein content of at least 90%. Wastewaters generated during the production process contain small proteins (8-50 kDa), and it would be desirable to find a recovery treatment for these compounds. Ultrafiltration membranes (UF) are used for the fractionation and concentration of protein solutions. By the appropriate selection of the membrane pore size, larger soy proteins are retained and concentrated while carbohydrates and minerals are mostly recovered in the permeate. The accumulation and concentration of macromolecules in the proximity of the membrane surface generates one of the most important limitations inherent to the membrane technologies. In this work, three UF membranes based on polyethersulfone (PES) were fabricated. In two of them, polyethylene glycol (PEG) was added in their formulation to be used as a fouling prevention. The membrane fouling was evaluated by the study of flux decline models based on Hermia's mechanisms.The Universitat Politecnica de Valencia (Spain), through the project 2623 (PAID-05-10), funded this research.Garcia-Castello, EM.; Rodríguez López, AD.; Barredo Damas, S.; Iborra Clar, A.; Pascual-Garrido, J.; Iborra-Clar, MI. (2021). Fabrication and performance of low-fouling UF membranes for 2 the treatment of Isolated Soy Protein solutions. Sustainability. 13(24):1-16. https://doi.org/10.3390/su132413682S116132

Evolution of Membrane Performance During the Ultrafiltration of Reactive Black 5 Solutions: Effect of Feed Characteristics and Operating Pressure

[EN] In the present work, the feasibility of the ultrafiltration (UF) technology for the removal of a hazardous azo reactive dye, Reactive Black 5 (RB5), was studied. A tubular UF ceramic membrane was used to filter RB5 aqueous solutions. Solutions at different feed concentrations (50, 100, 500 mg/L) and temperatures (25, 30, 35, 40 °C) were tested in order to observe the influence of these two parameters on the evolution of permeate flux and dye rejection with operating time. Moreover, the effect of transmembrane pressure (TMP) was also studied by performing essays at different operating pressures (1, 2, 3, 4 bar). Additionally, membrane performance was also evaluated by means of the average permeate flux and the cumulative flux decline. The results showed that both the productivity and the permeate quality improved by increasing feed temperature and decreasing feed concentration. On the other hand, an increase in TMP led to an increase in permeate flux. However, in this case the flux decline was more pronounced and the retention of dye decreased. Finally, the relatively high dye rejections obtained are an indicator of the suitability of UF technology for the removal of RB5 from aqueous solutions as a pretreatment of other membrane processes to textile water reuse. Copyright © 2012, AIDIC Servizi S.r.l.This work was supported by the “Ministerio de Ciencia e Innovación” through the project ref. CTM2009-13048 and the “Ministerio de Educación” through the FPU grant ref. AP2009-3509.Alventosa De Lara, E.; Barredo Damas, S.; Alcaina Miranda, MI.; Iborra Clar, MI. (2012). Evolution of Membrane Performance During the Ultrafiltration of Reactive Black 5 Solutions: Effect of Feed Characteristics and Operating Pressure. Chemical Engineering Transactions. 29:1285-1290. https://doi.org/10.3303/CET1229215S128512902

Enhancement in hydrophilicity of different polymer phase-inversion ultrafiltration membranes by introducing PEG/Al2O3 nanoparticles

The influence of the modification by additives in the characteristics of several ultrafiltration polymeric membranes was studied. Three asymmetric membranes with similar pore size (molecular weight cutoff (MWCO) of around 30 kDa) but different materials and pore microstructures – polysulfone, polyethersulfone and polyetherimide – were used. Effects of two different hydrophilic additives on membrane structure and the resulting performance were compared to determine the material with the best antifouling properties. Polyethyleneglycol (PEG) and alumina (Al2O3) were employed as additives in the phaseinversion method, N,N-Dimethylacetamide and deionized water were used as solvent and coagulant, respectively. Membranes were characterized in terms of hydraulic permeability, membrane resistance, MWCO profile and hydrophilicity (by membrane porosity and contact angle). The cross-sectional and membrane surface were also examined by microscopic techniques. Membrane antifouling properties were analysed by the experimental study of fouling/rinsing cycles using feed solutions of PEG of 35 kDa. Permeation and morphological studies showed that the addition of PEG/Al2O3 results in formation of a hydrophilic finger-like structure with macrovoids, whereas the addition of Al2O3 results in the formation of a hydrophilic structure with a dense top layer with Al2O3 nanoparticles and a porous sponge-like sublayer. Furthermore, polyethersulfone/PEG/Al2O3 membranes displayed superior antifouling properties and desirable ultrafiltration performance.The authors of this work thank the financial support of CDTI (Centre for Industrial Technological Development) depending on the Spanish Ministry of Science and Innovation. The authors also thank the Center for Biomaterials and Tissue Engineering (Universitat Politecnica de Valencia) for contact angle measurements and BASF (Germany) and General Electric (United States) for supplying the polymers used.García Ivars, J.; Alcaina Miranda, MI.; Iborra Clar, MI.; Mendoza Roca, JA.; Pastor Alcañiz, L. (2014). Enhancement in hydrophilicity of different polymer phase-inversion ultrafiltration membranes by introducing PEG/Al2O3 nanoparticles. Separation and Purification Technology. 128:45-57. doi:10.1016/j.seppur.2014.03.012S455712

Transparent self-ordered niobium-oxide nanochannel layers formed on conducting glass by total anodization of thin metal films in glycerol/phosphate electrolyte

[EN] In the present work, we show the feasibility to grow highly ordered anodic Nb2O5 nanochannel structures from a thin Nb-layer on conducting glass (fluorine doped tin oxide, FTO). This is achieved using a glycerol-phosphate electrolyte at 180 degrees C and a suitable anodization voltage that allows a rapid and complete conversion of the entire metallic layer into a transparent oxide layer of an extremely well defined directional nature with 20-30 nm wide open vertical channels. These layers can be used, either in the amorphous state or after thermal crystallization, for efficient reversible electrochromic switching devices. (c) 2012 The Electrochemical Society. All rights reserved.The authors acknowledge DFG and the Erlangen DFG cluster of excellence (EAM) for financial support.Barredo Damas, S.; Lee, K.; Kirchgeorg, R.; Sánchez Tovar, R.; Schmuki, P. (2013). Transparent self-ordered niobium-oxide nanochannel layers formed on conducting glass by total anodization of thin metal films in glycerol/phosphate electrolyte. ECS Electrochemistry Letters. 2(1):4-6. doi:10.1149/2.008301eelS462

Algebraic identification of the physical parameters of a simplified two-degrees-of-freedom rotor-bearing system

En este trabajo se propone el desarrollo de identificadores de los parámetros de masa, rigidez y amortiguamiento de un sistema rotor-cojinete simplificado de dos grados de libertad. La técnica utilizada para el desarrollo de los identificadores se conoce en la literatura como: técnica de identificación algebraica. Para el desarrollo de los identificadores paramétricos, se utilizó el modelo matemático de un sistema rotor-cojinete que considera los efectos de inercia traslacional y rotacional, así como, los efectos giroscópicos. Los identificadores algebraicos desarrollados determinan los valores de los parámetros físicos del sistema, para dos condiciones diferentes de velocidad de operación del rotor: velocidad constante y velocidad variable. La evaluación numérica de los identificadores muestra que, es posible determinar los valores de los parámetros de masa, amortiguamiento y rigidez del sistema rotor-cojinete en un pequeño intervalo de tiempo que va de los 0.1 a 0.28 segundos

Application of tubular ceramic ultrafiltration membranes for the treatment of integrated textile wastewaters

Membrane technologies have emerged as one of the best suitable alternatives for the management of highly polluted effluents generated in the textile industry processes. These technologies are capable either of being used as a pre-treatment or to achieve complete water reclamation, depending on the process involved. This study evaluates the performance of tubular ceramic ultrafiltration membranes treating integrated raw effluents from a textile mill, at different operating conditions (transmembrane pressure, pH, and molecular weight cut-off). A joint effect from the studied operating conditions was observed. Consequently, the process efficiency varied considerably depending on the combination of operating conditions. The permeate flux increased with pressure up to pseudo-stable values for higher pressures. However, for the lowest tested pH, permeate flux rates were enhanced with pressure up to a maximum beyond which flux might decrease. The increase in the applied pressure lead to a compression of the particles rejected onto the membrane surface, which was enhanced by the lower electrostatic repulsive forces. In general, higher membrane fouling rates were observed for the highest cut-off as well as for the highest applied pressures. Significant pollutant load removals were achieved with noteworthy values for the chemical oxygen demand (>70%), color (96%) and turbidity (>93%). The results prove the suitability of the treatment in terms of permeate quality for either disposal or later final treatment aiming at the reclamation of these waste streams.This work was supported by the Ministerio de Ciencia e Innovacion through the project CTM2009-13048.Barredo Damas, S.; Alcaina Miranda, MI.; Iborra Clar, MI.; Mendoza Roca, JA. (2012). Application of tubular ceramic ultrafiltration membranes for the treatment of integrated textile wastewaters. Chemical Engineering Journal. 192:211-218. doi:10.1016/j.cej.2012.03.079S21121819

Factors influencing the Ultrasound-enhaced cleaning process of an ultrafiltration ceramic membrane fouled by Reactive Dye Particles

This work was supported by the "Ministerio de Ciencia e Innovación" through the project ref. CTM2009-13048 and the "Ministerio de Educación" through the FPU grant ref. AP2009-3509.Alventosa De Lara, E.; Barredo Damas, S.; Alcaina Miranda, MI.; Iborra Clar, MI. (2012). Factors influencing the Ultrasound-enhaced cleaning process of an ultrafiltration ceramic membrane fouled by Reactive Dye Particles. Procedia Engineering. 44:1665-1667. doi:10.1016/j.proeng.2012.08.901S166516674