Packaging
Each Purolite resin is packaged to ensure the contents are protected from contamination and loss or uptake of moisture. If packaging is damaged or left open and resins are exposed to the atmosphere, the resin can deteriorate through a combination of physical, chemical or biological contamination. For example, hydroxide form anion resins can become carbonated from contact with carbon dioxide present in the air. No matter what type of resin, once the package is opened, the contents should be used as soon as possible, and unused resin should be resealed in a suitable, clean container. In the event of damage to bags, drums, kegs etc., every effort should be made to repair the damage to ensure the resin is not exposed in the atmosphere.
Over time, and especially at elevated temperatures, resins may dry out. Unless re-hydration is carried out carefully, beads will crack or break. To minimize damage, the following procedure is recommended for rewetting resins.
A concentrated brine solution is slowly introduced and left for at least 1 hour to equilibrate. Brine displacement is carried out, by reducing brine concentration by 5% on consecutive treatments. A contact time of 39 minutes is used for each successive displacement. The final 5% brine solution is then displaced and rinsed out with water. In cases where resin is very dry, it is recommended that the process is optimized in the laboratory by adjusting the starting concentration of brine, temperature, rates of addition and contact time.
Note that cation resins in the hydrogen form will generate hydrochloric acid by passage of brine through the bed. Anion resin in the hydroxide form will likewise produce sodium hydroxide (caustic soda). In each case, cation resin will be converted to the sodium form and anion resin to the chloride form and will require multiple regenerations to return to the regenerated form.
Storage
Purolite recommends storing resin indoors, maintaining a temperature below 40°C, (104°F), and ensuring UV light (which promotes oxidation, and growth of algae bacteria) does not contact the sealed package. Additionally, do not store resin near a radiator, a heating appliance, or in a warm boiler house.
Although Purolite resins can withstand temperatures as low as -40°C, (-40°F), it is recommended that resins are stored above 0°C, (32°F) as successive thawing and freezing may damage the product, and/or the packaging. If resin becomes frozen for any reason, it should be left to thaw out naturally. No attempt should ever be made to free frozen resin mechanically as this will damage the product. If resin will be handled at sub-zero temperatures, the resin may be conditioned with saturated brine to prevent freezing.
Additionally, avoid double stacking full pallets in the warehouse. If this is unavoidable due to space limitations, use pallet boards between each pallet to prevent damage to the product.
Requirements for Resin Storage During Equipment Shut-down
To prevent problems associated with dehydration, freezing, growth of bacteria, algae & molds, chemical stability, precipitation and corrosion, simple precautions should be taken when ion-exchange equipment is shut down for an extended period.
Dehydration
For short-term storage in the service vessles, the unit should be filled with water to prevent dehydration. If draining is necessary, the vessel should be filled with dilute brine or ethylene glycol mixtures.
Freezing
To reduce the chance of freezing, the vessel should be filled with dilute brine or ethylene glycol mixtures.
Growth of Bacteria, Algae, and Mold
With long-term storage in the service vessels, microorganisms such as algae and bacteria can proliferate in ion exchange plants where conditions are favorable. If such growth is allowed to continue unhindered, irreversible fouling of the resin and blockage of the resin bed can occur.
To ensure the plant remains in good working order, take the following precautions prior to shut-down:
Subject resin beds to an extended backwash to remove suspended material collected during service. Regenerate the bed to ensure the resin is in a "clean state" before conditioning for long-term storage.
Exhaust cation beds with 10% NaCI solution until neutral pH is achieved. Close all valves and leave resin beds immersed in the sodium chloride solution for the period of shut-down.
Treat anion resins with 2 to 3 bed volumes (BV) of alkaline brine (10% NaCI + 2% NaOH), allowing the last bed volume to stand for several hours before displacing with a further 2 BV of neutral brine (10% NaCI). Leave the bed immersed in the sodium chloride solution for the period of shut-down.
At the end of the shut-down, rinse NaCI from resin and, if necessary, sanitize with peracetic acid.
Note: where softeners are subject to regular shut-downs or infrequent use, Purolite C100EAg should be considered to control biological fouling due to its biostatic properties.
Chemical Stability
Strong and weak acid cation resins are stable in terms of ion exchange capacity. However, after a short time, strong acid resins can produce color throw when trace leachables diffuse from the resin matrix. Diffusion is more pronounced in the hydrogen form strong acid cation resins. Therefore, in addition to classification backwash (where appropriate), the resin should be regenerated and rinsed prior to use. This process should also be used for the sodium form resin.
When treated water is intended for human consumption, for use within the food industry, or when the resins are intended for direct food processing, preconditioning should be used as specified by local, national or other regulatory authorities.
Strong base anion resins are stable in the chloride and sulfate forms. The hydroxide form, and to a lesser extent carbonate and bicarbonate forms, slowly degrade (even at room temperature) to produce some weak base functionality at the expense of the strong base groups – plus a small (almost insignificant) loss of total capacity. The degradation processes accelerate at higher temperatures and the loss of total capacity becomes significant close to or above the maximum recommended operating temperature. It is important to convert the resin to a salt form, generally chloride form, prior to shut-down or storage. This will also prevent the generation of an amine odor which develops when hydroxide form anion resins are stored.
Weak base anion resins are more stable and can be stored in either freebase or chloride form. To avoid possible bacteriological growth, the chloride form resins should be immersed in brine, as outlined above. This may be preferred for storage of used resin.
If cation or anion resins are left standing in the presence of strong oxidizing agents such as nitric acid, there is a risk of explosion. This risk is greater at elevated temperatures. Seek expert advice before storage of resins in nitrate form. For full details on safe handling of ion exchange resins or copolymers, consult the relevant Purolite material safety data sheet.
Precipitation and Corrosion
Take care to choose an ionic form resin and water source for making up storage solutions to avoid precipitation within the bed. For example, high hardness in the presence of high bicarbonate or hydroxide can cause precipitation. This can block collector systems, foul the resin, and cause deposits that can set up corrosion. Such problems may result from changes in temperature that occur during shutdown when contaminant ions are oxidized or become insoluble.
Care should also be taken to ensure that storage solutions are compatible with materials of construction, not only the vessel / lining, but also materials of construction for vessel components. For example, certain grades of stainless steel cannot accommodate high chloride levels.
Transportation
Most Purolite resins are non-hazardous, temperature-stable materials and do not have specific temperature storage requirements. Precautions should be taken to avoid extreme temperatures during the transport of resins. If product becomes frozen during transportation, thawing should take place gradually, without any physical interference. Moving resin in their primary packaging should be avoided if possible when in a frozen state. Some products do have special storage, handling and temperature requirements. Please reference the respective Safety Data Sheet and Product Data Sheet documents.
Most of our resins are defined by the US Department of Transportation as non-hazardous. All Purolite products are Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) certified and product labels are Classification, Labeling and Packaging (CLP) compliant for international transportation. Check product Safety Data Sheets and Product Data Sheets for details on special transportation requirements.
