Activated carbon can remove a wide range of odorous gases, volatile organic compounds and airborne chemical pollutants from contaminated industrial air. Typical applications include the treatment of hydrogen sulphide, ammonia, mercaptans, VOCs and other odour-causing compounds generated by sewage, waste handling, anaerobic digestion and industrial processes.
The effectiveness of activated carbon depends on both the contaminant being treated and the type of carbon selected. Different carbon grades have different adsorption characteristics, which means the media should be matched to the composition and concentration of the incoming air stream.
Exeon’s hi-flo™ activated carbon system can be configured with specialist carbon media selected according to the pollutants present and the required treatment performance.
Can Activated Carbon Remove Hydrogen Sulphide?
Hydrogen sulphide (H₂S) is one of the most common contaminants treated using activated carbon.
It is frequently generated by sewage treatment, sludge handling, anaerobic digestion and organic waste processes. Because hydrogen sulphide can create strong odours and may contribute to corrosion within industrial environments, effective removal can be an important part of a site’s emission control strategy.
Specialist impregnated activated carbons can be used to enhance the removal of H₂S. Exeon uses activated carbon treatment in applications such as sewage works odour abatement, where hydrogen sulphide is a common process emission.
Can Activated Carbon Remove Ammonia and Mercaptans?
Activated carbon can also be used to remove ammonia and mercaptans, although the appropriate carbon media is particularly important.
Chemically impregnated carbons can be selected to increase their affinity for specific compounds. Rather than relying on one standard carbon for every application, the media should be chosen according to the expected contaminants, concentrations and environmental conditions.
Exeon provides further information about this process on its activated carbon air treatment page.
Where concentrations or process conditions make liquid-phase treatment more appropriate, a scrubX™ wet scrubber may also be considered for gases such as ammonia and hydrogen sulphide.
Can Activated Carbon Remove VOCs?
Activated carbon is widely used for removing volatile organic compounds (VOCs) from industrial air streams.
VOCs can be produced by manufacturing, chemical processes, waste handling, solvents and other industrial activities. As contaminated air passes through the carbon bed, suitable organic molecules become adsorbed onto the extensive internal surface area of the media.
However, not all VOCs behave in the same way. Molecular properties, concentration, humidity and temperature can all affect adsorption performance.
Activated carbon is therefore most effective when the air stream has been assessed and an appropriate carbon grade has been selected.
What Other Industrial Odours Can Activated Carbon Treat?
Activated carbon may also be suitable for a broad range of organic vapours, solvent emissions and general industrial odours.
For example, Exeon uses activated carbon for waste handling emissions, where facilities can generate mixtures of ammonia, hydrogen sulphide, VOCs and other odorous compounds during tipping, storage and processing.
The suitability of activated carbon depends on several factors, including:
- Pollutant type and chemical properties
- Normal and peak concentrations
- Airflow rate
- Temperature and humidity
- Required removal efficiency
- Contact time within the carbon bed
- Type and quantity of activated carbon
These factors determine both treatment efficiency and expected carbon life.
Where an air stream contains several pollutants, activated carbon can also form part of a wider industrial odour and emission control system, alongside biological filtration or wet scrubbing.
Correctly identifying the pollutants before selecting the media helps ensure the carbon is suited to the application, provides effective removal and avoids premature replacement caused by using an unsuitable carbon grade.