Sutok Environmental Engineering is engaged in the field of optimizing the use of raw materials, recycling, recovery and assimilating the principles of the circular economy in industry in Israel. Over the years, we have come across many cases in which the use of activated carbon has created high costs for our customers, both in terms of procurement and handling at the end of use. Today Sutok imports activated carbon for its customers. The activated carbon imported by Sutok is ecological activated carbon based on renewable materials. Carbon based on renewable materials has smaller pores than activated carbon based on other materials. The tiny pores increase the variety and amount of materials that the carbon can adsorb. The professional knowledge and experience we have gained allows us to match a specific type of carbon to meet our customers needs and specifications providing a more efficient activated carbon that by going through activation (regeneration) can be used for a longer period of time. Through activation, the costs of purchase and treatment can be reduced by 30-50%.

 

What is activated carbon?

 

Activated carbon is carbon processed into a sort of network of carbon atoms, with tiny spaces between them, pores. The many pores that increase the surface area, along with the strong affinity of the coal for organic substances, give it a high capacity for the adsorption of various substances, gases or liquids. The types of materials that the activated carbon can adsorb depend on the size of the pores.

Activated carbon is often used to adsorb pollutants from chimneys, in cigarette filters, in water filters, in anti-aging masks and in the food industry.

 

How does activated carbon work?

 

The activated carbon contains thousands of pores, through which material flows in a liquid or gaseous state. The flowing material contains contaminants that drift into the pores. In order for the adsorption to be effective, it is necessary for the coal to have a large surface area.

When a polluted gas containing volatile organic compounds (aliphatic hydrocarbons, aromatic hydrocarbons, ketones, ethers, halogenated hydrocarbons, glycols, alcohols, esters, aldehydes, etc.), passes through activated carbon, the large surface area, the microscopic pores and the electrical forces that are created between the carbon and the organic molecules, causes the adsorption of the pollutant.

 

How is activated carbon produced?

 

Any organic material can become activated carbon, however, in practice, the production process is effective for a limited group of materials, which meets a number of requirements:

1. Low in inorganic matter

2. Available and cheap

3. Not vulnerable in storage

4. It is easy to activate it (make it active).

Therefore, the most common raw materials in the industry are coal from various types of minerals, wood and coconut shells.

 

The production process consists of two stages:

 

1. Carbonization - heating the raw material at a temperature of about 700ᵒC, without the presence of oxygen. In this process, all non-carbon elements evaporate, and pores begin to form.

 

2. Activation - the flow of steam or carbon dioxide (CO2) at high pressure and temperature through the coal, to create the pores.

There are types of activated carbon that are able to undergo activation (reactivation), with the help of cleaning by passing steam through the carbon. However, the activation process is not optimal, during which the activated carbon loses 5-15% of its weight.

We at Sutok adjust the specifications of the coal we import in order to minimize the depreciation in the operation process.

 

Main types of activated carbon and their uses

 

1. GAC - Granular Activated Carbon. This type is the most common. Suitable for gaseous and liquid materials. Used for water purification, chimney gas treatment, wastewater treatment and a variety of other industrial applications. can be regenerated.

2. PAC - Powdered Activated Carbon. Same as GAC in terms of its uses, but its particles are about 100 times smaller, so the adsorption time is much shorter than that of GAC. In addition, its cost is lower. Mainly used in liquids, but can also be used in chimneys. cannot be regenerated. Used to remove odors and tastes, treatment of industrial wastewater and algae blooms.

3. EAC - Extruded Activated Carbon. Small cylinders used mainly for adsorption of gaseous substances. Used for air purification, odor control and removal of organic toxins from natural gas.

4. Catalytic activated carbon - created by a structural change of the surface of normal activated carbon. More effective than traditional activated carbon and capable of undergoing activation easily. Used to remove chlorine and other chemicals.

5. Activated carbon that has undergone impregnation - activated carbon with the addition of elements to the surface, which will increase the efficiency of specific pollutant adsorption. For example, activated carbon bound to an oxidized metal effectively adsorbs inorganic substances of gaseous origin, such as hydrogen cyanide (HCN), H2S and phosphine (PH3). GAC with impregnation of silver atoms is used to inhibit the growth of bacteria.

 

Why is activated carbon used in industry?

1. Selective separation and removal of unwanted materials:
   a. Treatment of wastewater and water - including removal of chlorine from drinking water, organic substances, phenolic compounds, oils, toxic substances from wastewater, H2S, odors, flavors and colors, pesticides, and heavy metals.
   b. Gas treatment - purification of gases and biogas, removal of pollutants from chimney emissions, volatile organic substances (VOCs), carbon dioxide, nitrogen, H2S and metals.

2. Distillation. For example, extraction of solvents from air streams, including acetone, toluene, methylene chloride, hexane, heptane and more.

3. Storage of desired materials. For example, adsorption of natural gas on activated carbon to create a reservoir of natural gas, or extraction of gold.

4. In the chemical industry - cleaning of raw materials and intermediate products, purification of final products and removal of odors and colors.

5. In the food industry - eradication of bad tastes and odors, long-term color preservation and removal of chemicals.

6. In the pharmaceutical industry - removal of colors and odors, proteins and by-products.

7. In the metal industry - for cleaning grease.

8. In agriculture - land reclamation by improving the soil's water and nutrient retention and protecting plant seeds.

 

How can the processes related to activated carbon in industry be improved?

 

1. Activated carbon recycling

2. Choosing the source of the coal - the source of the coal affects its ecological impact. By matching the coal source to the specific process, and if possible choosing coal that is considered "greener" and more resistant to erosion compared to other types of activated carbon.

3. Choosing the appropriate type of coal for the raw material, the process, and the product, and if possible, choosing a type of carbon that can be recycled.

 

At Sutok, we enable our customers to turn environmental challenges that cost capital into profit, by accompanying customers in the implementation of processes and in the use of raw materials that contribute to a decrease in damage to the environment, alongside significant financial savings in costs.

Our extensive experience in the field of activated carbon in particular, helps us to adjust the specifications of the coal to our customers in order to "close the loop" and save between 30-50% in the costs of purchasing and handling the activated carbon.