DCN 2032 HAZARDOUS& TOXIC WASTE

MANAGEMENTION EXCHANGE

BY: NUR SHUHADA BT ARBAAN

Ion exchange analogy

Ion exchange mechanism

Ion exchange mechanisme

Definition Ion Exchange

• Ion exchange is a reversible chemical reaction wherein an ion from solution is exchanged for a similarly charged ion attached to an immobile solid particle.

ION ~ an atom or molecule that has lost or gained an electron and thus acquired an electrical charge

Ion Exchange ApplicabilityIon exchange was a standard method of purification water and

usually removes the pollutant from the water.Since the offending pollutant is often present in low concentration,

ion exchange is frequently more efficient in treating large flows of dilute hazardous waste stream.

Operating cost depend mainly on the amount of the pollutant to be removed.

Ion Exchange Applicability

• Ion exchange have a ability to separate, or purify as well as to concentrate pollutants.

• Some exchanger are selective for certain metals and can remove low concentrations of toxic metal from a waste water containing a high background level of nontoxic-metal such as sodium or calcium.

• Ion exchange can also be utilized in some application to purify a spent chemical concentrate by removal of low-level contamination.

Ion Exchange Applicability

• The greatest utility of ion exchange has been in the treatment of inorganic waste.

• There are a number of possible applications of ion exchange to treatment of organic waste ~ phenol removal and decolorization of kraft pulp-mill effluents.

Ion Exchange Applicability

• The greatest utility of ion exchange has been in the treatment of inorganic waste.

• There are a number of possible applications of ion exchange to treatment of organic waste ~ phenol removal and decolorization of kraft pulp-mill effluents.

Ion Exchange Applicability

The ion exchange limitation and advantages,

1. Chemical wastes are produced if excess, regenerant is required.

2. There are limitations on the concentration of what can be treated and produced.

3. Down time is required for regeneration.4. Resins cannot yet be made which are specific to a

particular substance.5. Ion exchange resins are prone to fouling by some

organic substances and are subject to chemical oxidation by oxidants (chlorine, hydrogen peroxide)

Ion Exchange Reaction

• These solid ion exchange particles are either naturally occurring inorganic zeolites or synthetically produced organic resins.

• The synthetic organic resins are the predominant type used today because their characteristics can be tailored to specific applications.

Ion Exchange Reaction

• An organic ion exchange resin is composed of high-molecular-weight polyelectrolyte's that can exchange their mobile ions for ions of similar charge from the surrounding medium. Each resin has a distinct number of mobile ion sites that set the maximum quantity of exchanges per unit of resin.

Ion Exchange Reaction• Ion exchange reactions are stoichiometric and reversible,

and in that way they are similar to other solution phase reactions.For example:

NiSO4 +Ca(OH)2 = Ni(OH)2 + CaSO4

Ion Exchange Reaction

• This reaction, the nickel ions of the nickel sulfate (NiSO4) are exchanged for the calcium ions of the calcium hydroxide [Ca(OH)2 molecule. Similarly, a resin with hydrogen ions available for exchange will exchange those ions for nickel ions from solution. The reaction can be written as follows:

2(R-SO3H)+ NiSO4 = (R-SO3)2Ni+ H2SO4 (2)

Ion Exchange Resin• Ion exchangers are either cation exchangers that exchange positively charged ions (cations) or anion exchangers that exchange negatively charged ions (anions). There are also amphoteric exchangers that are able to exchange both cations and anions simultaneously.

Ion Exchange Resin• However, the simultaneous exchange of cations

and anions can be more efficiently performed in mixed beds that contain a mixture of anion and cation exchange resins, or passing the treated solution through several different ion exchange materials.

Ion Exchange ResinResin types,• Strong Acid Cation Resins. Strong acid resins are so

named because their chemical behavior is similar to that of a strong acid.

• Weak Acid Cation Resins. In a weak acid resin. the ionizable group is a carboxylic acid (COOH) as opposed to the sulfonic acid group (SO3H) used in strong acid resins.

• Strong Base Anion Resins. Like strong acid resins. strong base resins are highly ionized and can be used over the entire pH range.

• Weak Base Anion Resins. Weak base resins are like weak acid resins. in that the degree of ionization is strongly influenced by pH.

Ion Exchange Application

• Groundwater remediation, heavy metal recovery.• Heavy metal removal from waste water• Water recycling (Water purification, Water softening, Production of high

purity water).• Decationization system for the pharmaceutical and chemical industries.Decationization ~ removes cations, usually sodium in exchange for H+ on

resin

Ion Exchange Application

• Ion exchange is widely used in the food & beverage, hydrometallurgical, metals finishing, chemical & petrochemical, pharmaceutical, sugar & sweeteners, ground & portable water, nuclear, softening & industrial water, semiconductor, power, and a host of other industries.

• Ion exchange is a method widely used in household (laundry detergents and water filters) to produce soft water. This is accomplished by exchanging calcium Ca2+ and magnesium Mg2+ cations against Na+ or H+ cations (water softening)

Ion Exchange Application

• Ion exchange resins in the form of thin membranes are used in chloralkali process, fuel cells and vanadium redox batteries. Ion exchange can also be used to remove hardness from water by exchanging calcium and magnesium ions for hydrogen and chlorine ions in an ion exchange column.

• Ion exchangers are used in nuclear reprocessing and the treatment of radioactive waste.

Ion Exchange Application

• Ion-exchange processes are used to separate and purify metals, including separating uranium from plutonium and other actinides, including thorium, and lanthanum, neodymium, ytterbium, samarium, lutetium, from each other and the other lanthanides.

• The ion-exchange process is also used to separate other sets of very similar chemical elements, such as zirconium and hafnium, which incidentally is also very important for the nuclear industry.

ACTIVITIES