Glossary Water - R.O. - Ion - Nano

ACIDITY: An expression of the concentration of hydrogen ions present in a solution.

ADSORBENT: A synthetic resin possessing the ability to attract and to hold charged particles.

ADSORPTION: The attachment of charged particles to the chemically active groups on the surface and in the pores of an ion ex changer.

ALKALINITY: An expression of the total basic anions (hydroxyl groups) present in a solution. It also represents, particularly in water analysis, the bicarbonate, carbonate, and occasionally, the borate, silicate, and phosphate salts which will react with water to produce the hydroxyl groups.

ANION: A negatively charged ion.

ANION INTERCHANGE: The displacement of one negatively charged particle by another on an anion exchange material.

ASH: The residual mineral content of resin after incineration at 800° C.

ATTRITION: The rubbing of one particle against another in a resin bed; frictional wear that will affect the size of resin particles.

BACKWASH: The upward flow of water through a resin bed (i.e., in at the bottom of the exchange unit, out at the top) to clean and reclassify the bed after exhaustion.

BASE: The hydroxyl form of a cation or a compound that can neutralize an acid.

BASE-EXCHANGE: The property of the trading of cations shown by certain insoluble naturally occurring materials (zeolites) and developed to a high degree of specificity and efficiency in synthetic resin adsorbents.

BATCH OPERATION: The utilization of ion exchange resins to treat a solution in a container where in the removal of ions is accomplished by agitation of the solution and subsequent decanting of the treated liquid.

BED: The ion exchange resin contained in a column.

BED DEPTH: The height of the resinous material in the column after the exchanger has been properly conditioned for effective operation.

BED EXPANSION: The effect produced during backwashing: The resin particles become separated and rise in the column. The expansion of the bed due to the increase in the space between resin particles may be controlled by regulating backwash flow.

BICARBONATE ALKALINITY: The presence in a solution of hydroxyl (OH ) ions resulting from the hydrolysis of carbonates or bicarbonates. When these salts react with water a strong base and a weak acid are produced, and the solution is alkaline.

BRACKISH WATER RO: You have Brackish water starting at 1000 ppm TDS to 5000 ppm TDS. All R.O. membrane systems will have to considerthe exact TDS to configure these plants correctly. We can have 80% recovery plus. Brackish water is close to shore and/or on-shore (wells) hence are suspected to contain pollutants other than salt, therefore a water analysis is required.

BREAKTHROUGH: The first appearance in the solution flowing from an ion exchange unit of unabsorbed ions similar to those which are depleting the activity of the resin bed. Breakthrough is an indication that regeneration of the resin is necessary.

BRINE: A salt solution, generally sodium chloride in a saturated solution.

BS&D: A procedure for resin volume measurement where in an ion exchange resin bed is first back washed, then allowed to settle and then drained of water. The resultant bed- height is measured for volume calculations.

CAPACITY: The ability of an ion exchange material to absorb ions. Usually expressed in kilograins per cubic foot or milliequivalents per milliliter.

CAPACITY, OPERATING: the portion of the total capacity utilized in practical ion ex change operation.

CAPACITY, SALT-SPLITTING: The portion of total capacity to split neutral salt.

CAPACITY, TOTAL: The ultimate exchange capacity of the resin.

CARBONACEOUS EXCHANGERS: Ion exchange materials of limited capacity prepared by the sulfonation of coal, lignite, peat, etc.

CARBOXYLIC: A term describing a specific acidic group (COOH) that contributes cation exchange ability to some resins.

CATION: A positively charged ion.

CHANNELING: Cleavage and furrowing of the bed due to faulty operational procedures, in which the solution being treated follows the path of least resistance, runs through these furrows, and fails to contact active groups in other parts of the bed.

CHEMICAL STABILITY: Resistance to chemical change which ion exchange resins must possess despite contact with aggressive solutions.

COLLOIDAL: Composed of extremely small size particles which are not removed by normal filtration. COLOR-THROW: Discoloration of the liquid passing through an ion exchange material; the flushing from the resin interstices of traces of colored organic reaction intermediates.

COLUMN OPERATION: Conventional utilization of ion exchange resins in columns through which pass, either upflow or downflow, the solution to be treated.

CONDENSATE POLISHERS: Ion exchange resins being used to remove or exchange ions as well as to filter condensate for reuse in the steam cycle.

CROSSLINKAGE: The degree of binding of a monomer or set of monomers to form an insoluble tri-dimensional resin matrix.

CYCLE: A complete course of ion exchange operation. For instance, a complete cycle of cation exchange would involve: exhaustion of regenerated bed, backwash, regeneration and rinse to remove excess regenerant.

DEASHING: The removal from solution of inorganic salts by means of adsorption by ion exchange resins of both the cations and the anions that comprise the salts. See deionization.

DEIONIZATION: Deionization, a more general term than deashing, embraces the removal of all chargedconstituents or ionizable salts (both inorganic and organic) from solution. See deashing.

DENSITY: The weight of a given volume of exchange material, backwashed and in place in the column.

DIFFUSION: Usually referred to ion exchange resins as the diffusion of ions through the ion exchange resin beads.

DISSOCIATE: The process of ionization of an electrolyte or a salt upon being dissolved in water, forming ions of cation and anion.

DOWNFLOW: Conventional direction of solutions to be processed in ion exchange column operation, i.e., in at the top, out at the bottom of the column .

DRY SOLIDS: The matter, usually expressed in weight percent, remaining after liquid removal.

EFFICIENCY: The effectiveness of the operational performance of an ion exchanger. Efficiency in the adsorption of ions is expressed as the quantity of regenerant required to effect the removal of a specified unit weight of adsorbed material, e.g., pounds of acid per kilograin of salt removed.

EFFLUENT: The processed solution which emerges from an R.O. system or ion exchange column.

ELECTROLYTE: A chemical compound which dissociates or ionizes in water to produce a solution which will conduct an electric current; an acid, base or salt.

ELUTION: The stripping of adsorbed ions from an ion exchange material by the use of solutions containing other ions in relatively high concentrations.

EQUILIBRIUM REACTIONS: The interaction of ionizable compounds in which the products obtained tend to revert to the substances from which they were formed until a balance is reached in which both reactants and products are present in definite ratios.

EQUIVALENT WEIGHT: The molecular weight of any element or radical expressed as grams, pounds, etc., divided by the valence.

EXCHANGE SITES: The reactive groups on an ion exchange resin.

EXCHANGE VELOCITY: The rate with which one ion is displaced from an exchanger in favor of another.

EXHAUSTION: The state in which the resin is no longer capable of useful ion exchange; the depletion of the exchanger's supply of available ions. The exhaustion point is determined arbitrarily in terms of: (a) a value in parts per million of ions in the effluent solution; (b) the reduction in quality of the effluent water determined by a conductivity bridge which measures the electrical resistance of the water.

FMA: The free mineral acidity, or sum of the mineral acids.

FINES: Extremely small particles of ion exchange materials.

FLOW RATE: The volume of solution passing through a given quantity of resin within a given time. Usually expressed in terms of gallons per minute per cubic foot of resin, as milliliters per minute per milliliter of resin, or as gallons per square foot of resin per minute.

FREEBOARD: The space provided above the resin bed in an ion exchange column to allow for expansion of the bed during backwashing.

FRESH WATER UF / UV: In this case we may be able to use Ultra Filtration. With UF you have 100% recovery of water. Water analysis will tell us how to configure the plant, as well water can have some nasty pollutions.

GRAIN: A unit of weight; 0.0648 grams.

GRAINS PER GALLON: An expression of concen- tration of material in solution, generally in terms of calcium carbonate. One grain (as calcium carbonate) per gallon is equivalent to 17.1 parts per million.

GRAM-MILLIEQUIVALENTS: The equivalent weight in grams, divided by 1000.

GEL: Ion exchange resins that are made up of firm gel structure in a solid bead form allowing for the diffusion of ions through the gel.

HARDNESS: The scale-forming and lather- inhibiting qualities which water, high in calcium and magnesium ions, possesses. Temporary hardness, caused by the presence of magnesium or calcium bicarbonate, is so called because it may be removed by boil- ing the water to convert the bicarbonates to the insoluble carbonates. Calcium sulfate, magnesium sulfate, and the chlorides of these two metals cause permanent hardness.

HARDNESS AS CALCIUM CARBONATE: The expression ascribed to the value obtained when the hardness forming salts are calculated in terms of equivalent quantities of calcium ] carbonate; a convenient method of reducing all salts to a common basis for comparison.

HEADLOSS: The reduction in liquid pressure associated with the passage of a solution through a bed of exchange material; a measure of the resistance of a resin bed to the flow of the liquid passing through it.

HYDRAULIC CLASSIFICATION: The rearrange- ment of resin particles in an ion exchange unit. As the backwash water flows up through the resin bed, the particles are placed in a mobile condition wherein the larger particles settle and the smaller particles rise to the top of the bed.

HYDROGEN CYCLE: A complete course of cation exchange operation in which the adsorbent is employed in the hydrogen or free acid form.

HYDROXYL: The term used to describe the anionic radical (OH-) which is responsible for the alkalinity of a solution.

HYDROXYMETHYL FURFURAL, HMF: 5 (Hydroxymethyl) -2-furaldehyde, a precursor of the coloring matter from the decomposition of glucose and also thereby assisting in the color development in sugars. HMF is produced during contact with strong acid cation resins in H+ form at elevated temperatures.

INFLUENT: The solution which enters an ion exchange unit.

ION: Any particle of less than colloidal size possessing either a positive or a negative electric charge.

IONI2ATION: The dissociation of molecules into charged particles.

IONIZATION CONSTANT: An expression in absolute units of the extent of dissociation into ions of a chemical compound in solution

KILOGRAIN: A unit of weight; one thousand grains.

LEAKAGE: The phenomenon in which some of the influent ions are not adsorbed or exchanged and appear in the effluent when a solution is passed through an under regenerated exchange resin bed.

MACROPOROUS: Resins that have a rigid polymer porous network in which there exists a true pore structure even after drying. The pores are larger than atomic distances and are not part of the gel structure.

MONOMER: A single reactive molecule capable of combining with another different monomer to form a polymer. Where two different monomers combine the resulting polymer is called a polymer.

NANOFILTRATION: A relatively recent membrane process used most often with low total dissolved solids water such as surface water. processed water and fresh groundwater, with the purpose of softening (polyvalent cation removal) and removal of disinfection by-product precursors such as natural organic matter and synthetic organic matter

NEGATIVE CHARGE: The electrical potential which an atom acquires when it gains one or more electrons; a characteristic of an anion. pH: An expression of the acidity of a solution; the negative logarithm of the hydrogen ion concentration (pH I very acidic; pH 14, very basic; pH 7, neutral) .

pH: The measurement of the acidity of a solution where 1 is very acidic, 7 is neutral and 14 is very basic.

PHYSICAL STABILITY: The quality which an ion exchange resin must possess to resist changes that might be caused by attrition, high temperatures, and other physical conditions.

POROSITY: An expression of the degree of permeability in ion exchange resins to liquids and large organic molecules. Gel resins, even when referred to as highly porous, have a negligible porosity in comparison to the macropores inherent in the macroporous resins .

POSITIVE CHARGE: The electrical potential acquired by an atom which has lost one or more electrons; a characteristic of a cation.

QUATERNARY AMMONIUM: A specific basic group [-N(CH3)3+] on which depends the exchange activity of certain anion exchange resins. RAW WATER: Untreated water from wells or from surface sources.

REGENERANT: The solution used to restore the activity of an ion exchanger. Acids are employed to restore a cation exchanger to its hydrogen form; brine solutions may be used to convert the cation exchanger to the sodium form. The anion exchanger may be rejuvenated by treatment with an alkaline solution.

REGENERATION: Restoration of the activity of an ion exchanger by replacing the ions adsorbed from the treated solution by ions that were adsorbed initially on the resin.

REVERSE OSMOSIS: A filtration process that is often used for water. It works by using pressure to force a solution through a membrane, retaining the solute on one side and allowing the pure solvent to pass to the other side.

RINSE: The operation which follows regener- ation; a flushing out of excess regenerant solution.

SALT SPLITTING: The conversion of salts to their corresponding acids or bases by passage through ion exchange resins containing strongly acidic or strongly basic functional groups.

SEA WATER – RO: Sea water contains 35000 to 45000 ppm TDS depending on location. We can achieve up to 45% R.O. recovery. It is not important to have water analysis here other than TDS, so we know what pressure and membrane selection.

SELECTIVITY: The difference in attraction of one ion over another by an ion exchange resin.

SILICEOUS GEL ZEOLITE: A synthetic, inorganic exchanger produced by the aqueous reaction of alkali with aluminum salts.

SPHERICITY: Relating to the spherical nature and whole bead content of a resin.

STRONG ELECTROLYTE RESIN: The equivalent of strongly acidic or strongly basic resins and capable of splitting neutral salts.

SULFONIC: A specific acidic group (S03H) on which depends the exchange activity of certain cation exchange resins

SWELLING: The expansion of an ion exchange bed which occurs when the reactive groups on the resin are converted into certain forms.

THROUGHPUT: The amount of solution treated prior to the exhaustion of the ion exchange resin.

THROUGHPUT VOLUME: The amount of solution passed through an exchange bed before exhaustion of the resin.

TURBIDITY: Turbidity is a measure of the cloudiness of water- the cloudier the water, the greater the turbidity. Turbidity in water is caused by suspended matter such as clay, silt, and organic matter and by plankton and other microscopic organisms that interfere with the passage of light through the water (American Public Health Association, 1998). Turbidity is closely related to total suspended solids (TSS), but also includes plankton and other organisms.

Turbidity itself is not a major health concern, but high turbidity can interfere with disinfection and provide a medium for microbial growth. It also may indicate the presence of microbes. (U.S. EPA Office of Water, Current Drinking Water Standards).

UPFLOW: The operation of an ion exchange unit in which solutions are passed in at the bottom and out at the top of the container.

UV: UV radiation can be an effective viricide and bactericide. Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in drinking water treatment.

VALANCE: A measurement of the number of atoms or ions of hydrogen it takes to com- bine with or be replaced by an element or radical. In short, the number of positive or negative charges of an ion.

VOID VOLUME: The space between particles of ion exchange resins in a settled bed, also called interstitial volume.

WEAK ELECTROLYTE: The equivalent of weakly acidic or weakly basic resins not capable of splitting neutral salts.

ZEOLITE: A mineral composed of hydrated silicates of aluminum and sodium or calcium. The term has been used, sometimes improperly, to describe softening done by synthetic ion exchange resins.

Engineering Data

Kgrs/ft³ (as CaCO3) x 0.0458 = eq/l
Eq/l x 21.8 = Kgrs/ft³ (as CaCO3)
1 cubic meter = 35.31 cubic feet
1 cubic foot = 28.32 liters
1 gallon = .1337 cubic foot
1 gallon = 3.785 liters
1 grain per U.S. gallon = 17.1 parts per million
1 ppm = 1 meq/l
2.204 pounds = 1 kilogram

Return to Top of Page

Return to R.O. Page

Return to R.O. UF Page

Handout R.O.


Return to Main Page

Contact us for more info