Published on: Mar 3, 2016
Transcripts - Nanofiltration&electrophoresis
NANOFILTERATION• process intermediate between reverse osmosis and ultra filtration that rejects molecules which have a size in the order of one nanometer‘• separates a range of inorganic and organic substances from solution in a liquidMAIN FEATURES OF NANOFILTRATION:•Custom Build and Modular Units•High rejection of Multi Valent ionic load such as Calciumand Magnesium•Stable production of purified water•Low operating pressure compared to reverse osmosis(RO)•Complex Process Development Capability•Quality Assurance and Control Management
PRINCIPLENanofiltration is the use ofpressure to separate solublecontaminants from waterusing a semi-permeablemembrane. This is done bydiffusion through amembrane, under pressuredifferentials that areconsiderable less than thosefor reverse osmosis, but stillsignificantly greater thanthose for ultrafiltration
PROPERTIES OF NF• The membranes are produced in plate and frame form, spiral wound, tubular, capillary and hollow fibre formats, from cellulose derivatives and synthetic polymers, from inorganic materials, ceramics especially etc• NF withstand in very high or low pH environments,• NF membranes tend to have a slightly charged surface, with a negative charge at neutral pH
APPLICATIONS OF NANOFILTERATION:• Industrial applications in food and dairy sector, in chemical processing, in the pulp and paper industry, and in textiles,• effective means of water softening, as the main hardness chemicals are divalent.• removal of natural organic matter from water, especially tastes, odours and colours, in the removal of trace herbicides from large water flows. used for the removal of residual quantities of disinfectants in drinking water• NF is used to concentrate whey,• dextrose syrup and thin sugar juice are concentrated by NF, while ion exchange brines are demineralised• degumming of solutions in the edible oil processing sector, for continuous cheese production, and in the production of alternative sweeteners• the largest NF plants was installed at a petroleum refinery for the dewaxing of oils.
DRAWBACK OF NANOFILTERATION:• susceptible to fouling• proper pretreatment, with the right membrane material, with adequate cross-flow velocities to scour the membrane surface clear of accumulated slime, and by use of rotating or vibrating membrane holders.
ELECTROPHORESIS:• Electrophoresis is a separation technique based on the migration of ions in an electric field. The positively charged ions migrate towards a negative electrode and the negatively charged ions migrate towards the positive electrode. Ions have different rates of migration depending on their total charge, size, and shape and can, therefore, be separated by this technique• Swedish chemist Arne Tiselius and he was awarded Nobel prize in the year 1948 for his valuable contributions.
: ELECTROPHORESIS• BASIC PRINCIPLE AND OPERATION:• Separation method based on differential rate of migration of charged species in a buffer solution across which a dc electric field is applied. An electrophoresis separation is achieved by injection of a small volume of sample into an aqueous buffer solution which is contained on a porous support medium like paper or semi-solid gel or a narrow tube.• DIFFERENT FORMS OF ELECTROPHORESIS• Electrophoresis can be• one-dimensional (1D) meaning one plane of separation or• two-dimensional (2D) meaning two planes of separation Slab electrophoresis Capillary electrophoresis
SLAB ELECTROPHORESIS:• In slab electrophoresis, separations are carried out on a thin flat layer (slab) of porous semi-solid gel containing an aqueous buffer. In general, slab has dimensions of a few centimeter on a side and is capable of separating more than one samples imultaneously.
EXAMPLES OF SLAB ELECTROPHORESIS:• DNA Gel Electrophoresis:• In this technique, DNA samples are run through agarose gel with the help of a potential and differential mobility of different DNA samples is responsible for their separation• INSTRUMENTS• Gel casting trays: composed of U-shaped UV-transparent plastic. The open ends of the trays are closed with tape while the gel is being cast in between the A and B walls.• Combs: These are plastics combs around which molten agarose is poured to• form sample wells in the gel.• Electrophoresis buffer: The buffer which is used for the DNA gel• electrophoresis usually is Tris-acetate-EDTA (TAE) or Tris-borate-EDTA (TBE).• Loading buffer: components are glycerol and dye.Glycerol helps to allow the sample to go into the sample wells and dyes help• visual monitoring of the• Ethidium bromide: This is used for the detection of the DNA inside the gel.• Transilluminator: Transilluminator is an ultraviolet light source which is used to visualize ethidium bromide-stained DNA .
ELECTROPHORESIS• Pulse-Field Gel Electrophoresis(PFGE): This technique allows investigators to separate much larger pieces of DNA than conventional agarose gel electrophoresis. In conventional gels, the current is applied in a single direction (from top to bottom). However, in PFGE, the direction of the current is altered at regular intervals• SDS-PAGE Gel Electrophoresis: In this technique, protein samples are run through page-gel with the help of a potentialand differential mobility of different protein samples is responsible for their separation according to the mass of the protein
SDS GEL ELECTROPHORESIS• When the detergent SDS (sodium dodecyl sulphate) is added to the proteins during the sample preparation, proteins become negatively charged by their attachment to the SDS anions. When separated on a polyacrylamide gel, the procedure is abbreviated as• SDS-PAGE (for Sodium Dodecyl Sulphate PolyAcrylamide Gel Electrophoresis).Two-dimensional SDS-PAGE Gel Electrophoresis Each amino acid has its own isoelectric point i.e., pI. pI is the pH atwhich the mobility of the amino acid is zero. Hence, proteins whichcomprise amino acids, do have a characteristic pI value. In two-dimensional gel electrophoresis, proteins are separated according totheir pI and then they are allowed to mix with SDS.
2) CAPILLARY ELECTROPHORESIS:• Capillary electrophoresis is a more sensitive technique and with the similar principle,• it could detect samples as small as few nL.• high-speed and high resolution.• The capillary can also be filled with a gel, which eliminates the electroosmotic the capillary allows higher resolution, greater sensitivity and on-line detection.
Types of CGE• Capillary Gel Electrophoresis(CGE):• Capillary gel electrophoresis is generally performed in a porous gel polymer matrix,the pores of which contain a buffer mixture in which the separation is carried out.• used in electrophoresis is a polyacrylamide polymer formed by polymerizing acrylamide in the presence of a cross linking agent)Capillary Zone Electrophoresis:Capillary Zone Electrophoresis also known asFree-Solution CapillaryElectrophoresis (FSCE),simplest ,used to separate ionic species by their charge andfrictional forces. Separation based on differencesin the charge-to-mass ratio of the analytes
• Capillary Isoelectric Focusing (CIEF): This technique allows amphoteric molecules, such as proteins, to be separated byelectrophoresis in a pH gradient generated between the cathode and anode. A solute will migrate to a point where its net charge is zero. At the solutes isoelectric point (pI),migration stops and the sample is focused into a tight zone• APPLICATIONS OF ELECTROPHORESIS:• In DNA Sequencing• In Medical Research• In Protein research/purification• In Agricultural testing• Measurement of hybrid purity• Identify genetic markers used by plant breeders• Quality control in processing and other industries,etc