Membranas nanoestructuradas, compuestas de capa fina y nanocompuestas para el tratamiento de aguas

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, leída el 06/11/2020. Tesis formato europeo (compendio de artículos)During last decades, population growth, climate change, natural disasters, uncontrolled urbanization, and pollution have left about one third of the world’s population without adequate access to drinking water. Water issue is expected to be more exacerbated in the coming decades, with water scarcity occurring globally and affecting even regions currently considered waterrich. Addressing this problem requires a great deal of adequate research to improve the efficiency of water use and wastewater treatment, as well as to mitigate the impacts of a wide variety of factors affecting water availability worldwide. Over the past twenty years, membrane filtration technology has become a significant separation methodology for drinking water production from saltwater (i.e. desalination) and wastewater (or groundwater), providing environmentally friendly and effective alternatives to conventional technologies. The main advantages of membrane filtration technology over conventional separation methods are its high removal capacity of particulates and microorganisms, very low thermal and chemical impact, flexibility of operation, modular design, moderate energy consumption and high cost effectiveness. The growth of the global membranes market is mainly the result of the impressive development of materials used for membrane fabrication and modification, improvements in membrane modules, and the progress of related systems, plants and equipment. However, the application of membranes in water treatment is limited by membrane fouling, which reduces water production rate, increases energy consumption, deteriorates membrane separation capability, and shortens membrane lifespan increasing, consequently, operation and maintenance costs. Particularly, organic and microbial fouling are the initial steps for biofilm formation, resulting in severe fouling problems in many environmental and engineered applications including membrane water filtration. Therefore, it is crucial the preparation of membranes with optimized surface properties, which induce a high fouling resistant capacity. This PhD thesis is focused on the preparation, characterization, modification and optimization of novel and advanced membranes with enhanced organic and microbial antifouling performance for the treatment, clearance and disinfection of different types of water as a sustainable way to increase drinking water availability and reduce water scarcity. First, an overview of the progress made during last few years on the preparation of novel membranes and their modification for water treatment by hydrostatic pressure and vapor pressure gradient membrane processes (i.e., microfiltration, MF; ultrafiltration, UF; nanofiltration, NF; reverse osmosis, RO; membrane distillation, MD and pervaporation, PV) is outlined in order to better understand the challenges and drawbacks that still need to be overcome for these membrane filtration technologies...Durante las últimas décadas, el crecimiento demográfico, el cambio climático, los desastres naturales, la urbanización descontrolada y la contaminación han dejado a aproximadamente un tercio de la población mundial sin acceso adecuado al agua potable. Se espera que el problema del agua se agrave aún más en las próximas décadas, habiendo escasez de agua en todo el mundo y afectando incluso a las regiones actualmente consideradas ricas en agua. Abordar este problema requiere una gran cantidad de investigación adecuada para mejorar la eficiencia del uso del agua y el tratamiento de aguas residuales, así como para mitigar los impactos de una amplia variedad de factores que afectan la disponibilidad del agua en todo el mundo. En los últimos veinte años, la tecnología de filtración por membrana se ha convertido en una metodología de separación significativa para la producción de agua potable a partir de agua salada (es decir desalinización) y aguas residuales (o aguas subterráneas), proporcionando alternativas ecológicas y efectivas respecto a las tecnologías convencionales. Las principales ventajas de la tecnología de filtración por membrana sobre los métodos de separación convencionales son su alta capacidad de eliminación de partículas y microorganismos, muy bajo impacto térmico y químico, flexibilidad de operación, diseño modular, consumo moderado de energía y alta rentabilidad. El crecimiento del mercado mundial de membranas es principalmente el resultado del impresionante progreso en los materiales utilizados para la fabricación y modificación de membranas, las mejoras en los módulos de membranas y la evolución de los sistemas, plantas y equipos relacionados. Sin embargo, la aplicación de membranas para el tratamiento de agua está limitada por el ensuciamiento de la membrana, lo que reduce la tasa de producción de agua, aumenta el consumo de energía, deteriora la capacidad de separación de la membrana y acorta la vida útil de la misma aumentando, en consecuencia, los gastos de operación y mantenimiento. Particularmente, el ensuciamiento orgánico y microbiano conforman las etapas iniciales para la formación de biopelículas, lo que da lugar a graves problemas de ensuciamiento en muchas aplicaciones ambientales y de ingeniería, incluida la filtración de agua por membrana. Por consiguiente, resulta crucial preparar membranas con propiedades superficiales optimizadas que induzcan una alta capacidad de resistencia al ensuciamiento. Esta tesis doctoral se centra en la preparación, caracterización, modificación y optimización de membranas novedosas y avanzadas con una eficiencia de anti-ensuciamiento “antifouling” orgánico y microbiano mejorada para el tratamiento, depuración y desinfección de diferentes tipos de agua como una forma sostenible de aumentar la disponibilidad de agua potable y reducir la escasez de agua. Primero, se ofrece una visión general del progreso realizado durante los últimos años en la preparación de nuevas membranas y su modificación para el tratamiento de agua mediante procesos de membrana con gradiente de presión hidrostática y presión de vapor (incluyendo microfiltración, MF; ultrafiltración, UF; nanofiltración, NF; ósmosis inversa, OI; destilación en membrana, DM y pervaporación, PV) con el objetivo de comprender mejor los desafíos y los inconvenientes que aún deben ser superados por estas tecnologías de filtración de membrana...Fac. de Ciencias FísicasTRUEunpu

Thin film composite membrane based forward osmosis with complex inorganic draw solution for copper removal

In order to efficiently remove heavy metal ions from wastewater using forward osmosis (FO), selection of preferable membrane and draw solution (DS) is essential. Thus, the purpose of this study is to investigate the synergistic effect of thin-film composite membranes (TFCs) with complex MgCl2 draw solution for the removal of copper (II) from its aqueous solution using FO. A total of five TFCs with different concentration ratio of polyethyleneimine (PEI) over piperazine (PIP) annotated as 1.0- PIP, 0.3-PEI, 0.5-PEI, 0.7-PEI and 1.0-PEI were fabricated and the physicochemical properties of these membranes were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, zeta potential and contact angle analysis. Preliminary performance study was done using nanofiltration system on their water fluxes and Cu (II) rejection. The used TFCs were then autopsied under energy dispersive X-ray (EDX) to examine copper attachments on it. Meanwhile, MgCl2 undergoes complexation with complexing agent poly(sodium 4-styrenesulfonate) (PSS). The affinity of MgCl2 with PSS with fixed loading was first studied at different pH (3.0, 5.0, 7.0 and 9.0) using dead-end filtration system. Study of PSS loadings (0.0, 0.1, 0.5, 1.0, 2.5 and 5.0 w/w%) was done later using FO system at 1.0 M MgCl2 DS and reverse solute flux (RSF) was determined. From all of the aforementioned experiments, removal of Cu (II) using FO was carried out at different feed concentrations (1000, 2000 and 5000 ppm) and the performances in term of water flux and rejection were discussed. Physicochemical analysis confirmed the formation of polyamide layer for all TFC membranes. Zeta potential revealed that the positivity of the TFCs’ surface charge increased in an order of 1.0-PIP < 0.3-PEI < 0.5-PEI < 0.7-PEI < 1.0-PEI. Consequently, 1.0-PEI exhibited higher flux compared to 1.0-PIP owing to its higher hydrophilicity. Interestingly, excellent selectivity of 1.0-PEI resulted in Cu (II) ion rejection of more than 95% and 99% in NF and FO operation respectively outperforming the other produced TFCs. EDX result further explained that the copper rejection was also facilitated by the electrostatic interaction with the surface charge of the TFCs. Based on the performance evaluation, 1.0-PIP was selected for complexation study since it portrayed good capability of Cu (II) retention and better FO water flux. Complexation of MgCl2 with PSS was able to lower the effect of RSF up to 60% reduction while maintaining satisfactory water fluxes compared to the control MgCl2 DS. Final Cu (II) rejection by FO using 1.0-PIP and the 1.0 w/w% PSS-MgCl2 complex DS revealed that the water flux slightly decreased with average Cu (II) retention of 95% with increasing Cu (II) feed concentration. This study promotes FO as a promising option for heavy metals removal application using innovative DS with lowered RSF

Morphological, chemical and electrical characterization of a family of commercial nanofiltration polyvinyl alcohol coated polypiperazineamide membranes

Three AFC membranes from PCI, of the thin film composite (TFC) nanofiltration type, have been characterized by using XPS, AFM, Contact angles, Zeta potential and permeation experiments. This plethora of complimentary methods portrays a deep and exhaustive description of these membranes that could be used to tune fabrication and modification of nanofiltration membranes to get better properties. Morphological properties, including porosity, water permeability, fractal dimension, Wenzel parameter and roughness, correlate well with pore sizes. While functional characteristics as, for example wettability correlate well with the O/N ratio. Increasing O/N ratios should be interpreted as caused by increasing PVA coverages. The charge on the membrane's surface is ordered in a different way for different pH but are quite similar anyway. The effect of charges on retention of 1:1, 1:2 and 2:1 salts (as tested with NaCl, Na2SO4 and CaCl2) increases with increasing O/N and wettability. Consequently, the trend of salt retentions can be explained in terms of the PVA coverage and the details of the amphoteric behavior of the three AFC membranes studied.This work was supported by the Spanish Ministry of through project MAT2016-76413-C2-1-R and the Regional Government of Castilla y León and the EU-FEDER (CLU2017-09, UIC082 and VA088G19)

DESIGN AND ENGINEERING OF GRAPHENE OXIDE (GO) BASED FRAMEWORK MEMBRANES FOR WATER TREATMENT VIA NANOFILTRATION

Ph.DDOCTOR OF PHILOSOPH

Recent advances in surface tailoring of thin film forward osmosis membranes: A review

The recent advancements in fabricating forward osmosis (FO) membranes have shown promising results in desalination and water treatment. Different methods have been applied to improve FO performance, such as using mixed or new draw solutions, enhancing the recovery of draw solutions, membrane modification, and developing FO-hybrid systems. However, reliable methods to address the current issues, including reverse salt flux, fouling, and antibacterial activities, are still in progress. In recent decades, surface modification has been applied to different membrane processes, including FO membranes. Introducing nanochannels, bioparticles, new monomers, and hydrophilic-based materials to the surface layer of FO membranes has significantly impacted their performance and efficiency and resulted in better control over fouling and concentration polarization (CP) in these membranes. This review critically investigates the recent developments in FO membrane processes and fabrication techniques for FO surface-layer modification. In addition, this study focuses on the latest materials and structures used for the surface modification of FO membranes. Finally, the current challenges, gaps, and suggestions for future studies in this field have been discussed in detail

Cellulose Acetate Membrane Preparation for Wastewater Treatment

For a long time, humans have used cellulose, as a natural, renewable, and transformative polymer, for scientific development to create new technologies. Cellulose is the most abundant biopolymer on Earth, accounting for more than 50% of terrestrial biomass. For this reason, the treated cellulose (cellulose acetate (CA)) was used in the membrane preparation for water desalination. However, membrane preparation has recently attracted big attention of several research groups. In this case, cellulose acetate (CA), as an inexpensive hydrophilic biopolymer, was chosen as a polymer for preparing the membranes via the inversion phase, since it offers an efficient purification benefit with low energy consumption and less cost. The purpose of this chapter is to describe the various types of membrane preparation based on cellulose acetate, with pathogens, bacteria, and heavy metal (cadmium), and the applications of these membranes in the treatment of contaminated water, to ensure a clean water supply for both human and industrial uses

Recent advancements in the application of new monomers and membrane modification techniques for the fabrication of thin film composite membranes: A review

Thin film composite (TFC) membranes have been experiencing significant modifications recently aiming to improve their structure, properties and separation efficiency. One of the promising modifications to tailor the membranes more efficient is changing the materials used. m-phenylene diamine (MPD), piperazine (PIP), and trimesoyl chloride (TMC) are the most common monomers used to fabricate TFC membranes. Recent studies have introduced several alternatives to these traditional monomers showing significant contribution of these monomers to the physicochemical properties of the membranes (e.g., surface roughness, hydrophilicity, cross-linking density, chemical structure) as well as membranes\u27 separation efficiency. Emergence of more favorable functional groups such as carboxylic and amine groups due to the new materials integration facilitates the polymerization process and is beneficial to the membrane properties. Here, a critical review on the new interfacial polymerization monomers applied for reverse osmosis (RO) and nanofiltration (NF) membranes fabrication is presented. The membrane molecular structure and fabrication mechanism are investigated in details. This is followed by a review of the recent surface modification methods including grafting, coating and additive incorporating into the thin layer of membranes. The application of alternative monomers to MPD, PIP and TMC are investigated and the benefits of using these monomers or co-monomers are discussed