What is the difference between activated carbon nonwoven, ACF felt and carbon foam?
The main difference is the carrier structure. Activated carbon sandwich nonwoven holds granular carbon between supporting nonwoven layers; activated carbon fiber felt is a fibrous carbon adsorption medium; and activated carbon foam uses porous polyurethane foam carrying powdered activated carbon. These structures affect supply format, thickness options, conversion and installation.
This guide compares activated carbon sandwich nonwoven fabric, activated carbon fiber felt and activated carbon foam. The sandwich construction discussed here is not the same product as activated carbon nonwoven fabric, which is supplied as a thinner functional nonwoven for filtration and converted odor-control layers.
There is no universal “best” activated carbon filter media. Selection depends on the target pollutant, airflow, available installation space, required component shape and downstream manufacturing process. For a broader overview, see the activated carbon filter media guide.
Activated carbon works by adsorption: gaseous pollutants are transferred from the air stream to the solid surface of the adsorbent. The U.S. Environmental Protection Agency notes that adsorption capacity is finite, so service life and replacement planning must be considered as part of the complete filter design.
Quick selection summary
| If the project needs... | Material to evaluate first | Why |
|---|---|---|
| A flexible carbon-containing layer for slitting, lamination or die cutting | Sandwich nonwoven | Granular carbon is held between supporting nonwoven layers. |
| Flexible fibrous adsorption media for layering or cartridge conversion | ACF felt | The activated carbon is present as a fibrous felt medium. |
| A porous sheet or custom-shaped foam component | Activated carbon foam | Open-cell polyurethane foam carries powdered activated carbon. |
This is a starting point, not a performance guarantee. Final selection must be checked against the pollutant, airflow, dimensions, installation and complete filter design.
Material 01
Activated Carbon Sandwich Nonwoven Fabric
Activated carbon sandwich nonwoven fabric holds granular activated carbon between supporting nonwoven layers. This construction helps contain the carbon while keeping the material flexible for filter conversion.
- Supply form: roll, sheet or cut pad
- Structure: granular carbon between nonwoven layers
- Applications: air purifier, HVAC, fresh-air and odor-control filters
- Conversion: slitting, lamination and die cutting
This format is suitable when a filter design needs a relatively thin, flexible carbon-containing layer that can be processed together with supporting media. Buyers should specify roll width or sheet dimensions, basis weight, carbon loading, lamination structure and required cut size.
Material 02
Activated Carbon Fiber Felt
Activated carbon fiber felt is a flexible fibrous adsorption medium. It can be supplied in rolls or sheets, layered, cut or converted into cartridges and other filter components.
- Supply form: roll or sheet
- Material: viscose-based activated carbon fiber felt
- Applications: VOC adsorption, odor control and industrial filtration
- Conversion: layering, cutting and cartridge development
The confirmed thickness range is 0.8–4.5 mm. Final selection should also consider the target VOC or odor source, required width, airflow, installation structure, temperature, humidity and component conversion method.
Material 03
Activated Carbon Foam Filter Media
Honeycomb activated carbon foam filter uses open-cell polyurethane foam as the carrier for powdered activated carbon. The porous structure can be supplied as sheets or custom-cut components.
- Supply form: foam sheet or cut pad
- Structure: polyurethane foam with powdered activated carbon
- Applications: air purifier, ventilation, fume and odor-control filters
- Conversion: sheet cutting and custom component shaping
Confirmed options include 20, 30 and 35 PPI pore densities and thicknesses from 3 to 100 mm. Selection should be based on airflow, installation space, required dimensions, target odor or VOC and whether a flame-retardant option is needed.
Activated carbon filter media comparison
| Selection factor | Sandwich nonwoven | ACF felt | Activated carbon foam |
|---|---|---|---|
| Basic structure | Granular carbon between nonwoven layers | Fibrous activated carbon felt | Open-cell PU foam with powdered carbon |
| Common format | Roll, sheet or cut pad | Roll, sheet or converted component | Sheet or cut component |
| Confirmed catalog data | Final values confirmed by selected construction | 0.8–4.5 mm thickness | 20, 30 or 35 PPI; 3–100 mm thickness |
| Typical conversion | Slitting, lamination and die cutting | Layering, cutting and cartridge conversion | Cutting and component assembly |
| Typical use | HVAC, air purifier and fresh-air filters | VOC, industrial exhaust and adsorption components | Air purifier, ventilation and compact modules |
| Buyer information needed | Width, basis weight, layer structure and cut size | Thickness, width, layer or cartridge structure | PPI, thickness, dimensions and component shape |
Which material should you choose?
Choose activated carbon sandwich nonwoven when the design requires a flexible carbon layer that can be laminated, slit or die-cut.
Choose activated carbon fiber felt when the project requires a fibrous adsorption medium for layering, cartridge conversion or industrial VOC and odor-control components.
Choose activated carbon foam when the filter requires a porous sheet or custom-cut component with selectable pore density and thickness.
Activated carbon media is mainly selected for gas-phase adsorption and odor control. If the incoming air also contains dust or particles, a suitable particulate pre-filter should be considered before the carbon stage.
When should activated carbon media be paired with white pre-filter media?
Activated carbon media and white synthetic pre-filter media serve different functions. Carbon media is selected mainly for gas-phase adsorption and odor control, while white pre-filter media is selected for particulate pre-filtration.
Depending on the equipment design and incoming air, a white synthetic pre-filter may be installed before the carbon stage to handle dust and larger particles. This can help keep the carbon stage focused on its intended adsorption function. The exact arrangement must be checked against the required filtration grade, airflow, available installation space and replacement plan.
When requesting both materials, provide the equipment type, filter dimensions, airflow direction, target dust or odor source and whether rolls, sheets, cut pads or assembled filters are required. Final specifications for each layer are confirmed separately.
Frequently asked questions
What is activated carbon filter media?
Activated carbon filter media is an adsorption material used as a functional layer or component in odor-control and gas-phase filtration systems. Available structures include carbon-containing nonwoven, activated carbon fiber felt and activated carbon carried by porous foam.
What is the difference between activated carbon sandwich nonwoven and activated carbon fiber felt?
Activated carbon sandwich nonwoven holds granular activated carbon between supporting nonwoven layers. Activated carbon fiber felt is itself a fibrous activated carbon adsorption medium. The different structures affect supply format, conversion method and the type of filter component in which each material is used.
Is activated carbon felt better than activated carbon foam?
Neither structure is universally better. ACF felt is selected as flexible fibrous adsorption media for rolls, layers and converted components, while carbon foam is selected when a porous sheet or shaped foam component is required. Final selection depends on the application and filter design.
Is activated carbon foam the same as a rigid honeycomb activated carbon block?
No. The carbon foam in this guide uses open-cell polyurethane foam as the carrier for powdered activated carbon. A rigid honeycomb activated carbon block has a different structure and must be evaluated as a separate product type.
Can activated carbon filter media remove dust?
Activated carbon media is mainly selected for gas-phase adsorption and odor control. When the incoming air also contains dust or particles, the complete filter design may need a separate particulate pre-filter before the carbon stage.
Does activated carbon filter media replace a white pre-filter?
Not normally. Activated carbon media and white synthetic pre-filter media perform different functions. Depending on the equipment design and incoming air, the two stages may be used together, with the particulate pre-filter installed before the carbon stage.
What information is needed to select activated carbon filter media?
Provide the filter application, target odor or VOC, required roll, sheet or component format, dimensions, installation space, airflow conditions and any lamination, cutting, frame or sealing requirement. A drawing or reference sample is also useful when available.
Information to send before requesting a sample
- Filter application or equipment type
- Target odor, VOC or gas-phase contaminant
- Required roll, sheet or finished-component format
- Length, width, thickness and available installation space
- Operating airflow, temperature and humidity
- Required lamination, cutting, frame or sealing structure
- Product drawing or reference sample, when available
If some specifications are not yet confirmed, describe the current application and equipment structure. Junkang Filter Media can introduce the available factory product formats for evaluation.
Technical reference
General adsorption principles referenced in this guide are consistent with the U.S. Environmental Protection Agency’s overview of activated carbon adsorbers.
U.S. EPA: Activated Carbon Adsorber Monitoring and Control Technique