Acid washed activated carbon is a specialized material known for its purity and exceptional adsorption capabilities. Despite its higher cost compared to standard activated carbon, it continues to be favored by some clients across various industries. The acid washing process enhances its surface area and pore structure, significantly improving its ability to effectively adsorb contaminants in some applications.
This article focuses on acid washed activated carbon introduction, application, advantages and the difference with non acid wash activated carbon.
What is acid washed activated carbon?
Acid-washed activated carbon is made from high-quality coal activated carbon or coconut shell activated carbon, which is acid-washed. The product is mainly made from granular carbon, which is acid washed during the manufacturing process to remove unwanted impurities, resulting in a product with very low acid soluble iron content.
Ideal for many liquid phase applications, acid-washed granular activated carbon is specifically designed to purify water and organic liquids that require low ash and leachate content. Its superior hardness levels and low levels of impurities make it cleaner than most other carbons and give it a longer service life.
Parameters of acid washing activated carbon
We specialize in providing customized solutions for our clients’ projects, providing the right metrics according to their needs.
| Item | Acid washed acativated carbon |
| Iodine | ≥ 900mg/g |
| Residual chlorine adsorption rate | ≥ 92% |
| Carbon tetrachloride adsorption rate | ≥ 45% |
| Moisture | ≤ 5% |
| Ash（after acid wash） | ≤1.5% |
| Hardness | 98% |
| PH value（after acid wash） | 6.5-8 |
| Iron content | ≤ 0.02% |
Why some clients choose acid washed carbon?
Acid washed activated carbon plays a crucial role in enhancing water purification processes. Through its unique properties, it achieves the following benefits:
Reduced Heavy Metal Content
During the acid washing process, hydrochloric acid effectively dissolves inorganic salts and heavy metal compounds from activated carbon. Subsequent water washing further reduces the heavy metal content, enhancing water safety.
Lower Ash Content
Acid washing dissolves inorganic salt impurities, such as calcium carbonate, reducing the ash content significantly. For instance, un-acid-washed coconut shell activated carbon typically contains around 5% ash. Post-acid washing, this can drop to less than 3%, and with deep acid washing, it can reach less than 1%, clarifying water quality.
PH Adjustment and Taste Improvement
Ordinary activated carbon typically has a pH between 9-11. Deep acid washing can lower this to a controlled pH range of 7-8.5, aligning well with the pH of drinking water (7.1-7.6), thereby improving taste and usability.
Reduction of Surface Dust and Black Water
Deep acid washing removes surface dust and ash from activated carbon pores, reducing black water formation. This process involves extensive flushing with softened water, crucial for maintaining membrane integrity in water purification systems.
What is the applications of acid washed carbon?
Acid washed activated carbon has extensive internal structure, neutral surface, maximum hardness, extended operational life, high volume activity, and rapid pH stabilization. This activated charcoal is produced for use in ultra-pure water treatment systems requiring low conductivity and exceptionally high purity. This activated carbon is also specifically designed for the removal of heavy hydrocarbons from recovered condensate. The acid washing process removes soluble silica from the matrix of the activated carbon to prevent leaching into the condensate.
Some of the benefits of Acid Washed activated carbon include Dechlorination of water, better taste, removal of bad odors, removal of color from water, removal of organic substances, etc.
Acid washed activated carbon is used in various applications such as is ideal for use in the treatment of water in the Electronics and Semi-Conductor Industries, Hospitals, Soft Drinks Bottling Plants, Breweries, and large RO Desalination Units, protection of reverse osmosis membranes from chlorine and organic fouling.
Acid Washed vs Non-Acid Washed Carbon
Acid Washed Activated Carbon
Acid Washed Carbon undergoes a specialized treatment process involving the use of hydrochloric acid to cleanse its surface and pores thoroughly. This procedure effectively dissolves and removes inorganic salts and heavy metal compounds, significantly reducing their presence in the activated carbon. As a result, acid washed carbon boasts lower levels of heavy metals and a reduced ash content compared to its non-acid washed counterpart. The controlled acid washing process also adjusts the carbon’s pH to a range typically between 7 to 8.5, which aligns well with the pH of drinking water, enhancing its suitability for various purification applications. Additionally, this thorough cleaning minimizes surface dust and ash accumulation, thereby reducing the likelihood of black water formation and prolonging the lifespan of filtration systems.
Non-Acid Washed Carbon
Non-Acid Washed Carbon, in contrast, lacks the rigorous acid treatment that characterizes its acid washed counterpart. As a result, non-acid washed carbon retains higher levels of heavy metals and inorganic salts on its surface and within its pores. The ash content in non-acid washed carbon tends to be higher, often exceeding 5% in materials like coconut shell activated carbon. This higher ash content can compromise filtration efficiency and may contribute to more frequent maintenance needs in water purification systems. Furthermore, non-acid washed carbon typically exhibits a higher pH range, typically between 9 to 11, which may not be suitable for all water treatment applications and can affect the taste and quality of treated water. Without the acid washing process, non-acid washed carbon is also more prone to accumulating surface dust and ash, which can lead to issues such as black water formation during filtration processes.
FAQ about acid wash activated carbon
In general, what is the amount of phosphate precipitation for coconut shell activated carbon? Can acid wash reduce the phosphate precipitation of coconut shell activated carbon? If it can work, how much can it be reduced?
Coconut shell activated carbon typically does not contain phosphate. If the objective is to reduce phosphate content through acid wash, phosphoric acid should not be used. Instead, hydrochloric acid or nitric acid can be considered. Even if there is a minimal amount of phosphate present, it can still be significantly reduced to achieve the lowest possible level.
Conclusion
Acid-washed activated carbon stands out as a superior filtration medium due to its enhanced purity and exceptional adsorption capabilities. By removing impurities and improving the surface area, acid washing ensures more effective and efficient performance across various applications, including water and air purification, industrial processes, and food and beverage production. Its ability to deliver consistent, high-quality results makes it a valuable asset for industries seeking optimal filtration solutions.
At Zhulin Carbon, we use selected quality coconut shells & Wood Based Activated Carbon to produce acid wash activated carbon of top-notch quality. Our experts will be able to advise and help you find the best solution for your needs.
If you have any need for acid wash activated carbon, please contact us.