Indian Institute of Technology, Delhi
CHL793
TERM PAPER
COMPOSITE MEMBRANE
BY:
Mradul Raj Jain
(2010CH70166)
COMPOSITE MEMBRANES
Contents
1. Introduction --------------------------------------------------------------------------------3
2. Tubular TiO2/Al2O3 composite membranes
a. Need of tubular composite membranes -------------------------------4
b. Tubular TiO2/Al2O3 composite membranes -------------------------------4
c. Materials ----------------------------------------------------------------------4
d. Preparation ----------------------------------------------------------------------5
e. Properties ----------------------------------------------------------------------6
3. ZrO2–Al2O3 composite membranes
a. Background ----------------------------------------------------------------------7
b. Preparation ----------------------------------------------------------------------7
c. Properties and conclusions --------------------------------------------------8
4. References ------------------------------------------------------------------------------10
INTRODUCTION
Membranes consisting of two materials of different densities are called composite membranes. Composite membranes are semipermeable membranes manufactured for the use of separation in water purification or water desalination systems. They also have various uses in chemical applications such as batteries and fuel cells.
Essentially, a composite membrane material is a molecular sieve constructed in the form of a film from two or more layered materials.
Membranes used in reverse osmosis are typically made out of polyamide, chosen primarily for its permeability to water and relative impermeability to various dissolved impurities including salt ions and other small, unfilterable molecules.
A basic diagram of composite membrane: In the
Stainless steel, especially, Austenitic stainless steel, because of their high corrosion resistance and customizable mechanical properties has become an indispensable part of the regularly evolving modern day technology. Stainless steels of various grades find applications in numerous fields starting from the household to the nuclear reactors; from food and beverage cans to construction of different automobile parts. The formation of impervious oxide layer on the surface makes it suitable for use in adverse environments such as sea water.
Recently, water shortage problem becomes more and more serious in the world [1]. The desire to make a drinking water by treating a ground water, a surface water, a sea water and so on has been increasing. An electrodialysis (ED) is one of the useful methods and has applied to make the drinking water as well as RO and NF membranes [2~5].
Dental materials are used for a variety of reasons. The basic reason for using dental materials is to restore the tooth back to its original anatomy. Some materials are used more than others but it depends on their characteristics. Composite resin is a type of dental material. Some dental materials do not have the esthetic characteristic that composite resin has. That is why sometimes, it is more favorable than other dental materials. It is one of the most common dental materials that are used to restore a tooth back to its natural appearance.
The epidermis is the first layer of the cutaneous membrane. The purpose of the epidermis is to create a protective layer from the outside environment. The deepest part of the epidermis is the Stratum Basale, where epidermal cells divide and are pushed towards the surface where the cells die off from lack of nutrients.
Tool wear is a problem in machining titanium alloy, so it is of great importance to find out the wear mechanism of cutting tools in order to improve the cutting tool life time. The mechanism controlling the wear of cemented carbide and influence of cutting parameters on different wear modes in machining Ti6Al4V has been investigated in this paper. Diffusion and chemical wear at high cutting speed and feed rate and attrition in low speed and feed rate is suggested to be the dominant wear mechanism in this case.
The discovery and widespread usage of composite materials has opened new doors in the manufacturing industry. Composites are materials composed of two or more different materials. The new material has distinct and superior structural properties than the individual component materials. The most ancient composite is adobe, which consists of straw reinforced clay and was commonly used as a building material [1]. Modern composites consist of a woven fiber, which reinforces a plastic polymer shell. Two major examples of modern composites are fiberglass and carbon fiber. Carbon fiber is a very new composite material and has a more recent history than materials such as steel and aluminum. Its origins can be traced to 1879, when Thomas Edison patented the usage of carbon filaments in electric lamps [2].
Composite materials have become extremely useful and since been adapted for aviation. They have been in development ever since the use of aluminum in the early 1920’s. Composites are components that are mixtures of two or more inorganic or organic compounds. One material acts as a matrix, which is the compound that keeps everything together, while the other material provides a reinforcement, in the form of fibers embedded in the matrix.
It is synthesised in plants, algae and even in some animals, and it can also be synthesised by some bacteria. Cellulose, the major chemical component of fiber wall. Cellulose has a strong tendency to form intra- and inter-molecular hydrogen bonds by the hydroxyl groups on these linear cellulose chains, which stiffen the straight chain and promote aggregation into a crystalline structure and give cellulose a multitude of partially crystalline fiber structures and morphologies. Hemicelluloses are a group of heterogeneous polymers that play a supporting role in the
Membrane filtration is a filtration technique can well performance in remove color, AOX and COD from paper mill wastewater. Researchers find out that if membrane filtration combine with dissolved air flotation can result a much higher percentage removal of TOC, color and suspended solid. Also, membrane filtration is good for heavy metal removal.
Stainless steel is a type of alloy that has a very strong lattice structure (an arrangement/ shape of the crystals or other objects) which in some case can be more beneficial than others depending on the type of application it may be used for. In many cases this structure will make the material more suited to being used in engineering applications such as tools for instance a hammer (stainless steel alloys) , also they can be used for gears, engines, electrical motors and hydraulic systems because the structure makes the material so strong. So when the arrangement of the structure is as above it makes the overall material even stronger which makes it a good for all the applications stated above. I believe its strength and durability are its main properties as these are commonly needed in the engineering industry, although it is also very well known to be used for its corrosion resistance as it is resistant to many types of corrosion. It is used for these properties because the components such as gears need to be strong in order to keep transferring and altering the rotary motion and torque exhibited in the machine that it may be used in, durable to withstand any loads or pressure put onto it and also corrosion resistance to give the components a bigger life span and increase its rate of work throughout its required use.
The electrodialysis operation was carried out on a laboratory stack “PCCell ED 64 002” supplied by PCA-Polymerchemie Altmeier GmbH and PCCell GmbH, Heusweiler, Germany. As shown in Fig 3, ED cell is packed with ion exchange membranes (cation and anion), spacers and a pair of electrodes (anode and cathode). Both electrodes are made of Pt/Ir - coated Titanium. The membranes and spacers are stacked between the two electrode-end blocks. Plastic separators are placed between the membranes to form the flow paths of the dilute and concentrate streams. These spacers are designed to minimize boundary layer effects and are arranged in the stack so that all the dilute and concentrate streams are manifolded separately. In this way a repeating section called a cell pair is formed; it consists of a cation exchange membrane, a dilute flow spacer, an anion-exchange membrane, and a concentrate flow spacer. In this work, experiments were carried out by this stack equipped with three cation exchange membranes (CEM) and two anion exchange membranes (AEM).
Osmosis is also another type of diffusion where water is transferred from a higher concentration to a lower concentration. Osmosis will then come into play when a membrane that differs in solute concentration breaks in two; the water will move from the hypotonic solution to a hypertonic solution. Initially, the hypotonic solution has a lower concentration, and the hypertonic solution has a higher concentration. The water will then continue its journey down its concentration gradient until it reaches equilibrium; that means the water will have the same solute concentration on both sides. When the solute reaches equilibrium on both sides of the semipermeable membrane, the solution then becomes isotonic. Isotonic solutions are when the solute concentration is the same on the inside and outside of the cells, and that is the reason most cells live in the isotonic state. Additionally, a semi-permeable membrane only permits specific substances to enter, usually opening for a solvent but not most solutes. The substances dissolved in a solution are referred to as a solute; and the solvent is the substance that dissolves a solute in a solution. Therefore, the mixture of a solvent and a solute
Metals possess many unique fundamental properties that make them an ideal material for use in a diverse range of applications. Many common place things know today are made from metals; bridges, utensils, vehicles of all modes of transport, contain some form of metal or metallic compound. Properties such as high tensile strength, high fracture toughness, malleability and availability are just some of the many advantages associated with metals. Metals, accompanied by their many compounds and alloys, similar properties, high and low corrosion levels, and affects, whether negative or positive, are a grand force to be reckoned with.
There are many functions lipids have. One of the main functions lipids are structural components in the cell. Lipids make up approximately 50% of the mass of most cell membranes. The lipids that are found in the cell membrane are called phospholipid. Phospholipid are the predominant lipids of cell membrane. Phospholipids aggregate or self-assemble when mixed with water, but in a different manner than the soaps and detergents. Because of the two pendant alkyl chains in phospholipids and the unusual mixed charges in their head groups, micelle formation is unfavorable relative to a bilayer structure.
Metallurgy is the field of materials science and material engineering that studies the physical and chemical behaviour of metallic elements, their microstructure compounds and their mixtures, which are mostly known as alloy. Metallurgy can be refers as the technology of metals where science is applied to the production of metals, and the engineering of metal components for the uses of products for consumers and manufacturers.