Coal-based granular activated carbon helps optimize RO process: an ideal choice for the water treatment industry

In modern water treatment processes, reverse osmosis (RO) technology is widely used in drinking water, industrial water and wastewater reuse due to its efficient desalination and impurity removal capabilities. However, in order to ensure the stable operation and extend the service life of the RO membrane, the pretreatment link is crucial.

 

In modern water treatment processes, reverse osmosis (RO) technology is widely used in drinking water, industrial water and wastewater reuse due to its efficient desalination and impurity removal capabilities. However, in order to ensure the stable operation and extend the service life of the RO membrane, the pretreatment link is crucial. Among the many pretreatment materials, coal-based granular activated carbon has become an irreplaceable key material in the RO process with its excellent adsorption performance and economy.

Characteristics and advantages of coal-based granular activated carbon

Coal-based granular activated carbon is an adsorption material made from high-quality coal through multiple processes such as carbonization and activation. It has a developed pore structure, high specific surface area and excellent mechanical strength. These characteristics give it unique advantages in the RO process:

Excellent adsorption capacity

Coal-based granular activated carbon can efficiently adsorb organic matter, free chlorine and odorous substances in water, providing pure water inlet conditions for RO membranes.

Strong mechanical strength

The granular form makes it suitable for long-term use, can withstand high flow rates and backwashing operations, and reduce pulverization losses.

Strong chemical stability Under acidic, alkaline and high temperature conditions, coal-based granular activated carbon can remain stable and will not cause secondary pollution to water quality.

Economical and practical Coal is the main raw material, with low production cost, and can provide a more cost-effective solution for water treatment projects.

The role of coal-based granular activated carbon in RO process

In the RO process, coal-based granular activated carbon is mainly used as a pretreatment material to protect the RO membrane from pollutants. The following are its main functions:

1. Removal of free chlorine

Free chlorine is a common disinfectant that is widely present in tap water. However, free chlorine can cause irreversible oxidative damage to the polyamide layer in the RO membrane. Coal-based granular activated carbon has a strong dechlorination ability, and converts free chlorine into harmless chloride ions through catalytic reduction reaction. Reaction principle: Cl₂ + C → 2Cl⁻ + CO₂

Effect: The removal rate can reach more than 99%, ensuring the long-term operation of the RO membrane.

2. Adsorption of organic matter and odor

Residual organic matter (such as humic acid, pesticide residues) and odor substances (such as algae metabolites) in water will clog the pores of the RO membrane and affect its filtration efficiency. Coal-based granular activated carbon can efficiently adsorb these molecules through its developed microporous structure and reduce the TOC (total organic carbon) content in water.

3. Removal of particulate matter and colloids

Although a multi-media filter is usually equipped before the RO process, some fine particles may still pass through and cause RO membrane pollution. The adsorption characteristics and filtration function of coal-based granular activated carbon can further intercept these impurities and improve the quality of the incoming water.

4. Improve the stability of water quality

By adjusting the pH value, redox potential and mineral content in the water, coal-based granular activated carbon helps to optimize the operating environment of the RO membrane and prevent scaling and biological fouling.

Typical application process of coal-based granular activated carbon

In the RO process, coal-based granular activated carbon is usually installed after the multi-media filter and before the RO membrane to ensure that the water quality meets the requirements of membrane treatment. The following is a typical treatment process:

Raw water pretreatment

Remove large suspended solids through steps such as coagulation and sedimentation. Multi-media filters further filter out particulate impurities.

Activated carbon adsorption

Coal-based granular activated carbon acts as an independent adsorption unit to remove free chlorine, organic matter and odor in water. The inlet flow rate is usually controlled at 10-15 m³/h to ensure the adsorption effect.

RO membrane treatment

The water quality after activated carbon treatment enters the RO membrane system stably to achieve efficient desalination and purification.

Subsequent treatment

According to needs, ion exchange, ultraviolet disinfection and other processes can be used to further purify the water quality.

Case analysis: Application of coal-based granular activated carbon in an industrial RO system

An electronic manufacturing company needs to use an RO system to prepare high-purity water, and its raw water is urban tap water. Due to the high free chlorine content and excessive organic matter in the water, the service life of the RO membrane has been seriously affected. After the company introduced coal-based granular activated carbon for pretreatment, it achieved remarkable results:

Significant dechlorination effect: the free chlorine content in the influent water was reduced from 0.5mg/L to <0.01mg/L.

High TOC removal rate: the organic matter content was reduced by 85%, which greatly reduced membrane pollution.

Reduced operating costs: the RO membrane cleaning cycle was extended by more than 1 times, and the overall operating costs were significantly reduced.

Future development of coal-based granular activated carbon in RO process

With the diversification and high standardization of water treatment needs, the application prospects of coal-based granular activated carbon in RO process are broad. Future R&D and technology optimization directions include:

Developing activated carbon with higher specific surface area

Through innovative activation processes, the porosity and adsorption capacity of activated carbon are improved to cope with complex water quality problems.

Functional modification

Introducing specific functional groups to the surface of activated carbon, so that it can selectively adsorb specific pollutants, such as heavy metal ions or specific organic matter.

Automated management system

Integrate intelligent water treatment monitoring system to achieve optimal operating parameter adjustment and efficient regeneration of activated carbon.

Circular economy model

Promote the recycling technology of coal-based granular activated carbon and reduce the environmental impact of waste activated carbon.

Conclusion

With its excellent performance, coal-based granular activated carbon has become an indispensable part of the RO process. From the efficient removal of free chlorine to the deep adsorption of organic matter, its performance provides a stable operating environment for the RO membrane and effectively extends the service life of the membrane. With the continuous advancement of technology, coal-based granular activated carbon will continue to play an important role in the future water treatment industry and contribute to the realization of more efficient and environmentally friendly water treatment solutions.