Publisher Summary The well-known transport equations for continuous media are used to construct a rational theory of simultaneous heat, mass, and momentum transfer in porous media. Several important assumptions regarding the structure of the gas–liquid system in a drying process are made that require theoretical or experimental confirmation. This chapter presents a general theory that provides a starting point for the construction of special theories so that various drying processes can be studied analytically without recourse to an enormous computational effort. It analyzes the motion of a liquid and its vapor through a rigid porous media. The development of the relevant volume averaged transport equations, which describe the drying process, is also focused. The transport of momentum in the gas phase and the laws of mechanics are applied to the drying process. The thermal energy equations are considered by forming the total thermal energy equation, and the problem of determining the mass average velocities in the gas and liquid phases are also discussed.

Simultaneous Heat, Mass, and Momentum Transfer in Porous Media: A Theory of Drying

Over the past decade, solvent resistant nanofiltration (SRNF) has gained a lot of attention, as it is a promising energy- and waste-efficient unit process to separate mixtures down to a molecular level This critical review focuses on all aspects related to this new burgeoning technology, occasionally also including literature obtained on aqueous applications or related membrane processes, if of relevance to understand SRNF better An overview of the different membrane materials and the methods to turn them into suitable SRNF-membranes will be given first The membrane transport mechanism and its modelling will receive attention in order to understand the process and the reported membrane performances better Finally, all SRNF-applications reported so far – in food chemistry, petrochemistry, catalysis, pharmaceutical manufacturing – will be reviewed exhaustively (324 references)

Solvent resistant nanofiltration: separating on a molecular level

Two of the greatest challenges facing the 21st century involve providing sustainable supplies of clean water and energy, two highly interrelated resources, at affordable costs. Membrane technology is expected to continue to dominate the water purifica- tion technologies owing to its energy efficiency. However, there is a need for improved membranes that have higher flux, are more selective, are less prone to various types of fouling, and are more resistant to the chemical environment, especially chlorine, of these processes. This article summarizes the nature of the global water problem and reviews the state of the art of membrane technology. Existing deficiencies of current membranes and the opportunities to resolve them with innovative polymer chemistry and physics are identified. Extensive background is provided to help the reader understand the fundamental issues involved. V C 2010 Wiley Periodi- cals, Inc. J Polym Sci Part B: Polym Phys 48: 1685-1718, 2010

Water Purification by Membranes: The Role of Polymer Science

https://cronfa.swan.ac.uk/Record/cronfa48864/Download/0048864-07032019141310.pdf

Reverse osmosis desalination: A state-of-the-art review

Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.

https://iopscience.iop.org/article/10.1088/0957-4484/22/29/292001/pdf

Nanostructured materials for water desalination.

After a brief introduction to membrane processes in general, and the reverse osmosis process in particular, the structure and properties of membranes and membrane transport theory are described. The mechanism of salt rejection and transport properties of membranes are discussed in detail. Solubility, diffusivity, and permeability of membranes to solutes and solvents are reviewed critically and compared with each other. Special attention is given to two particular types of membranes, cellulose acetate (CA) and aromatic polyamide (AP) membranes, which are often used for water desalination. The major portion of this article is devoted to the review and discussion of membrane transport theory with application to the reverse osmosis and ultrafiltralion processes. It is shown that the solvent flux can be represented reasonably well by linear models such as the solution-diffusion model (Lonsdale, et al., 1965). The contribution of pore flow to the solvent flux is small. The solute flux, however, is not ...

William N. Gill

Papers

Review of reverse osmosis membranes and transport models

Effect of natural convection on growth velocity and morphology of dendritic ice crystals

Foced convection heat and momentum transfer to dendritic structures (parabolic cylinders and paraboloids of revolution)

Hollow fiber reverse osmosis: experiments and analysis of radial flow systems

Optimal design of hollow fiber modules