What is activated carbon for water treatment？
What is the core definition of activated carbon used in water treatment?
Water treatment activated carbon is a porous carbon adsorbent specifically tailored for water purification scenarios. With adsorption principle as its core, it can efficiently capture organic pollutants, odor substances, some heavy metals, and other impurities in water. It is widely used in various fields such as municipal drinking water purification, process water treatment, industrial wastewater treatment, food and beverage water purification, and water quality purification in the pharmaceutical industry. It is an indispensable key purification material in the water treatment process. With a long history of application, modern technology has further optimized its adsorption performance and adaptability to meet different water treatment needs.
II. What is the correlation between the structure and performance indicators of activated carbon for water treatment?
The core advantage of activated carbon for water treatment stems from its well-developed porous structure, which determines its adsorption capacity and purification efficiency. The performance indicators are a direct reflection of this structural advantage:
Iodine value (mg/g): Reflects the adsorption capacity for small molecular organic pollutants. The common range is 500-1100 mg/g. The higher the value, the stronger the adsorption performance for small molecules.
Methylene blue adsorption value (mg/g): Reflects the adsorption effect on medium molecular weight organics, with a typical range of 50-200 mg/g, suitable for colored pollutant removal scenarios.
Molasses value: It measures the adsorption capacity for macromolecular organics, typically requiring a value greater than 210-230, and is suitable for the treatment of highly polluted water.
Strength (%): It is related to service life. High-quality products typically have a strength of over 90%, with some reaching over 95%, capable of withstanding wear from repeated backwashing and hydraulic transmission.
Ash content (%): An important indicator of impurity content. Products with low ash content (<10%) exhibit more stable adsorption efficiency and are suitable for applications requiring high-purity water quality.
Moisture content (%): It is generally controlled to be less than 5%-10% to avoid the impact of moisture on adsorption activity and storage stability.
Bulk density (g/l): The common range is 330-700 g/l, which affects the packing density of the filter bed and the water flow rate.
III. What are the types of raw materials for water treatment activated carbon? What are their respective characteristics?
The selection of raw materials for water treatment activated carbon directly affects product performance. The mainstream raw materials are divided into the following categories:
Coal raw materials: including high-quality selected coal, etc., can be used to produce activated carbon with high strength and bulk density, excellent iodine value and carbon tetrachloride adsorption value, suitable for high-intensity usage scenarios such as industrial wastewater treatment and municipal water treatment.
Biomass raw materials: including wood, bamboo, etc., with low ash content, well-developed microporous structure, and fast adsorption speed, suitable for water treatment in food and beverage, pharmaceutical industries that require high purity.
Other specialized raw materials: Some products incorporate ingredients such as magnesium oxide to enhance their adsorption capacity for specific pollutants, making them suitable for targeted water purification needs.
IV. What are the mainstream forms of activated carbon for water treatment? What are the applicable scenarios?
Based on different application scenarios, activated carbon for water treatment mainly comes in the following forms, each with its specific application direction:
1. Granular activated carbon for water treatment (GAC)
Particle size specifications: Common specifications include 8×16 mesh, 8×30 mesh, 10×30 mesh, 10×40 mesh, 12×40 mesh, 20×50 mesh, and more. These specifications can be selected according to your needs.
Core characteristics: Made through steam activation or briquet crushing process, it boasts high strength and large adsorption capacity, and can be repeatedly regenerated and reused.
Application scenarios: municipal drinking water purification filter bed, industrial process water pretreatment, large-scale wastewater treatment system, achieving deep purification through water flow gravity infiltration.
2. Powdered activated carbon for water treatment (PAC)
Particle size specification: Predominantly fine particle size, commonly including 200 mesh, 325 mesh, etc., with strong dispersibility.
Core characteristics: large specific surface area, fast adsorption rate, flexible dosage adjustment, suitable for batch processing scenarios.
Application scenarios: emergency response to sudden water pollution, decolorization and purification of food and beverages, precise purification of small-scale water treatment equipment, which completes purification through the process of dosing - stirring - filtering.
3. Columnar water treatment activated carbon
Size specifications: Cylindrical design, with common diameters of 0.9mm, 1.5mm, 2mm, 3mm, 4mm, etc.
Core features: high mechanical strength, low dust generation, low pressure drop, uniform structure, and stable adsorption efficiency.
Application scenarios: industrial circulating water treatment, high-flow water purification systems, gas-liquid combined treatment equipment, especially suitable for scenarios with strict requirements on water flow resistance.
4. Special-form activated carbon
Including briquet crushing activated carbon, raw coal crushing activated carbon, acid washing activated carbon, etc., with optimized performance through special processes.
Core Features: The acid-washed product features low iron content (100-500) and strict ash control, meeting the demand for high-purity water quality. The raw coal crushing type retains the natural pore structure of the raw material, offering high cost performance.
Application scenarios: ultrapure water preparation in the pharmaceutical industry, water treatment in the electronics industry, and advanced purification of highly challenging industrial wastewater.
What are the manufacturing processes of activated carbon for water treatment?
Water treatment activated carbons with different morphologies and properties correspond to various manufacturing processes, with the core processes including:
Direct activation method: The raw material is processed through carbonization, high-temperature activation, and screening, resulting in a simple process that preserves the natural pore structure of the raw material. It is suitable for raw coal crushing and biomass-based activated carbon production, and the product exhibits fast adsorption speed.
Briquetting (re-agglomeration) activation method: After crushing the raw materials, a binder is added to form briquettes, which are then crushed, carbonized, activated, and sieved. The resulting product has high strength and uniform particle size, making it suitable for the mass production of granular activated carbon and capable of withstanding repeated regeneration.
Acid washing activation method: After activation, an acid washing process is added to remove impurities such as iron and ash, optimizing the adsorption selectivity. This method is specifically used for activated carbon products for high-purity water treatment.
Molding and activation method: The raw materials are processed through grinding, mixing, extrusion molding, carbonization, and steam activation to produce cylindrical products. These products exhibit outstanding mechanical strength and structural stability, making them suitable for high-flow water treatment scenarios.
VI. How to choose the right activated carbon for water treatment based on water quality requirements?
When selecting activated carbon for water treatment, it is necessary to consider the characteristics of the water quality and the treatment objectives. The key reference factors include:
Pollutant type: For small molecular organic compounds, products with high iodine value (>900 mg/g) are preferred; for macromolecular pollutants or colored substances, focus on molasses value (>230) and methylene blue adsorption value; for pollutants containing heavy metals or special impurities, modified or impregnated products can be selected.
Processing scenario: For large-scale continuous processing systems, granular or columnar products are preferred for ease of loading and regeneration; for emergency processing or small-batch processing, powdered products are preferred for flexible dosing.
Operating conditions: For scenarios with high water flow rates and frequent backwashing, high-strength products (>95%) are preferred. For those with requirements on filter bed pressure drop, products with low bulk density and uniform particle size should be selected.
Purity requirements: For water used in the food, pharmaceutical, and electronics industries, choose acid-washed or biomass-based products with low ash content (<10%) and low iron content.
7. How can activated carbon used in water treatment be disposed of after use?
Activated carbon for water treatment exhibits excellent recyclability and environmental friendliness:
Regeneration and reuse: After the adsorption of particulate, columnar, and other shaped products reaches saturation, the surface adsorbed pollutants can be removed through thermal regeneration process to restore the adsorption performance, allowing for multiple reuse and reducing the cost of use.
Customization and Adjustment: The particle size and performance indicators (such as iodine value, strength, ash content) of the product can be flexibly adjusted according to actual processing needs, adapting to the personalized requirements of different water qualities and equipment.
Environmental disposal: Non-renewable products can be recycled as industrial fuel to recover energy, or disposed of safely according to environmental standards to avoid