What are the common pollutants of mixed bed resin

Mixed bed resin is a material commonly used in water treatment systems, which can simultaneously remove cations and anions from water and improve water quality. As the usage time increases and the water quality of the influent changes, the mixed bed resin may encounter various pollution problems, affecting its normal operation.

The following are common types of contamination in mixed bed resins:

1. Suspended solids and particles: Suspended solids and particles in water can accumulate in the resin bed of the mixed bed. If not pretreated, these particles will adhere to the surface of the resin particles in the mixed bed, producing dirt. Particles can come from sediment, dust, algae, etc. in the raw water.

2. Organic pollutants: refer to organic compounds in water, including organic dissolved substances, colloids, and microbial metabolites. They may adhere to the pores and surfaces of the mixed bed resin, thereby reducing its adsorption capacity and removal efficiency.

3. Microorganisms: The presence of microorganisms can lead to the formation of biofilm on the surface of mixed bed resin, thereby affecting the working performance of the resin. The hardness of scale is due to the crystallization of calcium and magnesium ions on the surface of the mixed resin after prolonged use in water, resulting in a decrease in the resin's exchange capacity.

4. Iron and manganese: Iron and manganese ions in water are prone to form oxides or precipitates in mixed bed resins, which adhere to the surface of the resin and cause pollution.

5. Silicone: Silicone is one of the common pollutants in water, which can form colloidal precipitates in mixed bed resins, block resin pores, and reduce exchange efficiency.

6. Sulfates and sulfides: Sulfates and sulfides in water may react with cation exchange resins in mixed bed resins, producing sulfate or sulfide precipitates that adhere to the surface of the resin.

7. Colloids and coagulants: Colloids and coagulants in water may react with coagulants in mixed bed resins, producing gelatinous substances that can cause deformation and blockage of the resin bed.

The treatment methods adopted for pollution

The treatment method for mixed bed resin pollution depends on the specific type and degree of pollution. The following are some common methods for treating mixed bed resin pollution:

1. Regeneration: For adsorbed pollutants, appropriate regeneration agents can be used to restore the exchange capacity of the mixed bed resin. Commonly used regenerants include hydrochloric acid, sulfuric acid, sodium hydroxide, etc. Pollutants are desorbed from the resin during the regeneration process, restoring it to a reusable state. The regenerated resin can continue to be used for water treatment.

2. Cleaning: For sedimentary pollutants, appropriate cleaning agents can be used to clean the mixed bed resin. The selection of cleaning agents depends on the nature of the pollutants and can include acidic, alkaline, or oxidizing cleaning agents. The cleaning process removes pollutants from the surface or pores of the resin, restoring its effectiveness.

3. Replacement: If the pollution level of the mixed bed resin is severe and cannot be effectively regenerated or cleaned, it can be considered to replace the heavily polluted resin with a new one. This method is suitable for situations where the resin has a long lifespan or cannot be regenerated.