Sustainable Water Technology and Water-energy Nexus

As water scarcity continues expanding in regions around the globe, there is an ever-increasing need to augment municipal, industrial, and agricultural water supplies through the purification of unconventional water sources, such as seawater, industrial and municipal wastewater. Due to the inextricable linkage between water and energy consumption, often called the water-energy nexus, the augmentation of water supplies must not come with a high cost energy consumption. As such, the high energy efficiency and often superior efficacy of membrane-based technologies have gained widespread implementation in various water treatment processes. Membranes allow passage of water, but largely reject salt and most other solutes, play a critical role in the majority of these processes. These types of membranes lie at the heart of traditional reverse osmosis (RO) processes

Recent Development in Aquaporin (AQP) Membrane Design

Development of Aquaporin Z (AqpZ) proteopolymersome has been substantial enough that it can obtain water separation membranes that feature fluxes of 11,000 L m−2 h−1, a parameter value that is multiple orders of magnitude greater than the conventional industrial membranes available and possible only if the performance of AqpZ proteopolymersome can be properly scaled up. In fact, densely packed 2D AqpZ crystal arrays can in theory reach flux capacity of up to 16,000 L m−2 h−1. On the other hand, these flux values may likely not be reached in practice, since various upscaling issues would prevent them from occurring. Nonetheless, AqpZ offers immense potentials benefits when it comes to biomimetic membranes. The research in membrane development is continuously ongoing, for example, only a few years ago in 2011, aquaporin-based biomimetic polymeric membranes (ABPMs) were viewed as the radically advanced membrane solution and, at the same time, removed from practical applications and commercial production. After 4 years of innovative thinking, ABPM membranes are produced for commercial consumption and with area dimensions of tens of m2. Although it will take some time before this membrane technology becomes universally accessible, it has already gone beyond the confines of research theory and into practical application. The following chapter will explicitly outline the development of AQP biomimetic membrane technology

Applications of Biomimetic and Bioinspired Membranes

Application fields of the biomimetic and bioinspired membranes are very similar to those of the existing synthetic membranes. Due to the hierarchical structures, as well as controlled selective transport and stability/resistance, the biomimetic and bioinspired membranes have extended applications in sustainable resources, environment, and energy aspects. The most important applications of biomimetic and bioinspired membranes are water treatment, clean energy, carbon capture, and health care

Novel Desalination RO Membranes

Since the initial operation of the first reverse osmosis (RO) desalination plants, only polymeric membranes have been employed for industrial use. As described in the previous chapter, the various advancements in the conventional polymeric RO membranes have been rather limited since the late 1990s, especially in the membrane permeability issue. Although new membrane modules have been released, however most of them are improved through a method that relies on increasing the membrane area per module. Recently, advances in nanotechnology have led to the development of nanostructured materials which may form the basis for new RO membranes. Li and Wang have included inorganic membranes and thin film nanocomposite membranes in a recent review, whereas Mauter and Elimelech have discussed the potential of carbon nanotube membranes for use as high flux membrane filters. In this chapter, the development of membranes that have been discussed in the previous two reviews will be briefly highlighted with a particular focus on the possibility of them being engineered into commercial RO membranes. At the same time this chapter includes a discussion about structured polymeric membranes synthesized via a new course featuring carbon-derived nanoporous membranes and biomimetic membranes. The coverage of all proposed novel desalination RO membranes in this section is aimed to provide a general overview of these materials and to draw a fair comparison of them possibly being developed into commercial RO membranes

Fabrication of Biomimetic and Bioinspired Membranes

Biomimetic and bioinspired membranes are those membranes that are fabricated with natural or natural-like (inorganic, organic, or hybrid) materials via biomimetic and bioinspired approaches (bio-mineralization, bio-adhesion, self-assembly, etc.) to tailor-specific properties (sophisticated structures, hierarchical organizations, controlled selectivity, antifouling or self-cleaning properties, etc.). With the support of knowledge on mechanisms, models and functions from many scientific disciplines, research activity on biomimetic and bioinspired membrane during the last decade has increased rapidly

Interactions between Aquaporin Proteins and Block Copolymer Matrixes

This chapter continues to further expand its focus on aquaporins (AQPs) by offering a general outline on how the AQPs block copolymers, and polymer support structures can interrelate and such connections can be comprehensively classified and defined. The first section of the overview will consider the relationship between block copolymers and AQPs. It will also examine the general membrane protein integration into block copolymers, since this can cause AQP-block copolymer complexes in vesicular (proteopolymersomes) as well as in planar forms. The majority of considerations taken into account during AQP incorporation come from the research conducted in relation to the process of incorporating other types of membrane proteins. This chapter includes an overview of the various characterization methodologies needed for the study of proteopolymersomes, as well as freeze-fracture transmission electron microscopy (FF-TEM), fluorescence correlation spectroscopy (FCS), small-angle X-ray scattering (SAXS), and stopped-flow light scattering (SFLS). The research data presented in this chapter emphasizes the fact that a successful process of membrane fabrication requires the integration of reconstituted AQPs into a suitable supporting matrix formation

Aquaporin Biomimetic Membranes

Recent research looked at an array of aquaporin protein structures, their unique functions, and potential applications in the research and industrial sectors. This chapter focuses on the specific functional features of aquaporin biomimetic membranes to interrogate their permeability properties in relation to various biomimetic water-transporting membranes. This chapter discusses in detail functional characteristics of aquaporin, how to produce it, and the status of aquaporin development

Challenges and Opportunities for Biomimetic Membranes

A brief overview of the fundamental and practical challenges as well as of the current status of biomimetic membrane technologies is presented

Development of Conventional RO Membranes

Polymeric RO membranes have dominated commercial applications since the very first RO desalination plant became industrially active. Due to their technological development they offer low-cost fabrication, ease of handling, and improved performance in selectivity and permeability. One of the earliest reviews on polymeric RO membrane materials was reported by Cadotte. It focused on composite RO membranes and covered the period from the inception of composite RO membranes up to approximately 1985. In 1993 Petersen offered a comprehensive review of the same subject, specifically examining the chemistry of the membrane materials. This section will briefly highlight the early development of membrane chemistry and graphical illustrations are used to visualize the performance improvement potential in RO membranes. This chronological description provides the readers with a quick overview of RO membranes formed by different mechanisms and their respective impact on the desalination industry over the years. For a more complete study of the early RO membrane development, readers are advised to further refer to Petersen’s work. In general, the development of membrane materials can be divided into two periods according to research activity: (i) the search for a suitable materials (chemical composition) and membrane formation mechanisms (1960s to late 1980s), and (ii) the evolution of more controlled conditions for membrane formulation as a way of enhancing membrane functionality and durability (late 1980s to date)

Fouling in Forward Osmosis Membranes: Mechanisms, Control, and Challenges

Continuously escalating global water demand places a substantial burden on the available water and energy resources. Forward osmosis (FO) is an evolving membrane desalination technology that has recently raised interest as a promising low-energy process. FO is a unique method since it utilizes natural osmosis as the driving force, and hence, it ensures that the energy consumption is significantly reduced, in comparison to other pressure-driven membrane processes that are constrained by their excessive energy consumption and unsustainable cost. Therefore, the growing interest in FO from various disciplines and industrial sectors calls for a better understanding of the FO process and further advances in the FO technology management. This chapter aims to provide an in-depth assessment of the water transport phenomenon in FO membranes by focusing on the influence of internal concentration polarization, membrane structure/material, and membrane orientation on the permeate flux. This chapter offers critical insight that can lead to the potential development of new FO membranes with reduced internal concentration polarization and higher water permeability. In addition, key strategies for FO membrane development, some of its challenges, and the perspectives for future investigations of FO membrane fouling and effective FO fouling control methods are explored in this chapter