Application of Activated Carbon in the Paper Industry

Activated carbon is used to remove organic and inorganic impurities, as well as taste and odor issues, from domestic and industrial wastewater. It is also utilized to purify chemicals.

Activated carbon is a carbonaceous material with high surface area and pore structure. Thanks to these features, it is used in many industrial applications. Activated carbon is an ideal material to remove and purify pollutants thanks to its adsorption properties. For this reason, it is also used at different stages in paper mills.

Activated carbon is effective in removing certain chemicals utilized during the paper manufacturing process. Wastewater can suffer from severe environmental issues due to the use of chlorinated chemicals, particularly in the bleaching process. By adsorbing these chemicals, activated carbon enhances the effectiveness of water purification.

The primary concept behind paper manufacturing is to create a sheet-like material by intertwining and binding plant fibers, typically from wood.

There are several different processes in paper mills. In general, the main processes for paper production are:

1. Preparation of Raw Materials: The preparation of raw materials to be used for paper production is the first stage in paper factories. This process includes stages such as the felling of trees, sawing of wood, processing of timber, production of pulp, and storage of pulp.
2. Pulp Production: Pulp production is one of the most important stages of paper production. This process is the preparation of dough formed by passing raw materials through various processes. Methods used for pulp production include mechanical methods (e.g., wood pulp pulp), chemical methods (e.g., sulphuric acid pulp), and semichemical methods (e.g., neutral sulphur dioxide pulp).
3. Paper Production: Pulp is processed on machines used for paper production. This process includes stages such as thinning the dough, drying, pressing, polishing, and cutting.
4. Dyeing and Coating: After paper production, papers can be subjected to dyeing and coating processes. This process helps improve the quality and properties of the paper.
5. Wastewater Treatment: Purifying large amounts of water used in paper production is an important stage in paper mills. Wastewater treatment is carried out using various methods.

These processes cover the basic stages of paper production, and each can be divided into various sub-stages. Paper mills can apply these processes in different ways depending on the type and quality of paper they produce.

Activated carbon is an important part of many processes in paper mills.

Areas of use of activated carbon in different processes in paper mills are as follows:

1- Water softening: The hardness of the water used in paper production may be high, and this hardness may reduce the effectiveness of the chemicals used in paper production. The water softening process is a treatment process used to reduce hardness. During this process, activated carbon can be used to remove organic matter present in the water and to remove calcium, magnesium, and iron ions.

Application Method: The water softening process is a process used to remove hardness-causing minerals from water. The minerals that create hardness are generally calcium and magnesium salts. These minerals dissolve in water to form hard water. The hardness of the water used in paper mills can negatively affect paper quality.

• Therefore, the water softening process has an important place in paper production. The water softening process reduces the hardness of water by removing calcium and magnesium salts from hard water. This process can be carried out by different methods, such as precipitation, ion exchange, or reverse osmosis.
• Activated carbon adsorbs and removes sediments and coloured substances formed due to hardness in the water softening process. In this way, the quality of water increases, and better results are achieved in paper production.

2- Reverse Osmosis: It is a process used to convert the water used in paper production into high-quality water. During this process, the salt and mineral content of the water are reduced. Activated carbon can be used to remove organic and inorganic substances from water in a reverse osmosis unit.

Application method: The reverse osmosis process is a water purification method used to remove salt, minerals, pollutants, and other undesirable substances from the water. Activated carbon can be used in the pre-treatment step for the reverse osmosis process.

If there are undesirable substances, such as organic substances and odor- and taste-forming compounds, in the water before reverse osmosis, these substances are removed by using activated carbon filters.

Activated carbon adsorbs organic substances and removes them from the water as it passes through the water in these filters. Since activated carbon is used to remove organic substances in water, it is preferred in the pre-treatment stage of the reverse osmosis process. In this way, the reverse osmosis membrane prevents organic substances from damaging the membrane and lasts longer.

Activated carbon filters are designed for use as part of the reverse osmosis pretreatment process. These filters are made of activated carbon granules or blocks and adsorb organic matter in the water.

3- Bleaching: One of the important stages in the paper mill is the paper bleaching process. Cellulose and semi-cellulose are the fibrous structures that make up paper. The lignin it contains keeps them stuck together, creating the woody structure. However, the structure that gives the wood its dark colour is lingin. Therefore, the basic principle in paper manufacturing is to separate these fibres from each other and eliminate the dark color. In papermaking, bleaching is a procedure used to whiten raw fiber. In this process, activated carbon is used to remove traces of bleach and can be used to remove coloured substances present in the raw cellulose.

Application Method: Activated carbon is generally not used together with other bleaching agents in the bleaching process. However, activated carbon is used during the treatment of wastewater after bleaching.

The wastewater obtained after the bleaching process may contain residues of bleach and other chemicals. This wastewater needs to be treated to prevent it from harming the environment. For this purpose, activated carbon can be used in wastewater treatment plants.

In wastewater treatment plants, wastewater is first taken into pre-treatment pools. It is then passed through activated carbon filters to remove residues of bleach and other chemicals. Activated carbon adsorbs organic substances and coloured substances in wastewater, making the water cleaner.

4- Filtration: In paper mills, filtering is done to purify waste water. During this process, activated carbon can be used to remove organic matter from the wastewater. Activated carbon is used to clean and purify raw material water. Activated carbon removes pollution from water by absorbing and filtering it.

5- Flotation: Flotation is a process used to purify wastewater. During this process, activated carbon can be used to remove organic matter from the wastewater.

Application method: Paper mills use different methods to purify wastewater, and one of these methods is flotation. Flotation is the removal of solid particles in wastewater by covering them with air bubbles on the water surface and then accumulating them there. However, the flotation process may not be sufficient, and different methods can be used to improve the quality of purified water. Therefore, the use of activated carbon can also be included in the flotation process.

During the flotation process, activated carbon can be used by adding it to wastewater. Activated carbon can improve the quality of water by adsorbing organic and coloured substances in wastewater. In this way, the flotation process becomes more effective, and the quality of the purified water improves.

Activated carbon is generally used in powder or granular form. Activated carbon added to the wastewater is mixed to homogenise the wastewater, and then air bubbles are created with the help of the aeration system. These bubbles cover the solid particles in the wastewater and allow them to rise to the surface.

Enough time should be given for activated carbon to adsorb organic substances and coloured substances in the wastewater. Therefore, the mixture of wastewater and activated carbon should be mixed for a sufficient time with the help of the ventilation system. At the end of the period, the wastewater will accumulate on the surface, and the particles accumulated on the surface of the wastewater can be removed mechanically.

As a result, the use of activated carbon in the flotation process is an effective method to improve the quality of wastewater. Activated carbon improves the quality of water by adsorbing organic and coloured substances in wastewater and making the flotation process more effective.

6- Wastewater treatment process: Paper mills produce large amounts of wastewater during the production process. Activated carbon is used to purify this wastewater. Activated carbon filters and removes organic matter and chemicals from wastewater.

Application method: Activated carbon is generally used by adsorption for wastewater treatment in paper mills. Wastewater is first subjected to pre-treatment, and then biological treatment is carried out. After the biological treatment process, wastewater is directed to the activated carbon bed.

The activated carbon bed can be thought of as a filter system in which wastewater carries out the adsorption process. When wastewater is directed to the activated carbon bed, the activated carbon particles in the bed adsorb organic compounds and filter the cleaned water. Since the activated carbon bed adsorbs the organic substances contained in the wastewater, the purified water becomes cleaner and less polluted.

The activated carbon bed reaches saturation after a certain time and no longer adsorbs organic substances. Therefore, the bed must be periodically renewed or subjected to regeneration. The regeneration process involves renewing the activated carbon particles of the bed and making it ready for the adsorption process again.

The use of activated carbon in wastewater treatment helps effectively remove organic matter and other pollutants and improves the quality of the treated water.

7- Purification of odour, gas, and air: In paper mills, odourous gases formed during production are purified using activated carbon. Activated carbon helps absorb bad odours in gases. It cleans the air by absorbing pollutants, odours, and harmful gases in the air.

Application method: In the treatment of odours, gases, or air, activated carbon is usually placed in a filter system. This filter is usually associated with a fan or ventilator that sucks or consumes air. The ventilation system is protected by a pre-filter before the activated carbon filter, through which air is allowed to pass. An activated carbon filter can be a closed box or cylinder through which air flow passes across the carbon surface. Carbon filters the airflow, adsorbing pollutants from gases or odours in the air. This process is an effective method for cleaning the air and removing pollutants.

Chemicals, organic compounds, and waste used in paper production can create bad odours in the air. For this reason, the use of activated carbon is widely preferred in order to purify the air and make the business environmentally friendly.

Pollutants in the air are absorbed through the pores on the surface of the activated carbon. Activated carbon can be used in many different technologies to purify the air from pollutants. One of these is the use of carbon filters. Carbon filters are a type of passive filtration system used to purify the air from pollutants. The use of these filters continues until they become full and clogged by absorbing airborne pollutants, and then the filters need to be replaced.

Activated carbon can also be used to purify gases. In this case, the gas stream is passed through and filtered through activated carbon filters. Contaminants are absorbed into the pores of the activated carbon and are then retained in the filters until the filters are replaced.

As a result, the use of activated carbon to purify odour, gas, and air in paper mills is very important and plays a critical role for an environmentally friendly business.

8- Pre-treatment: The pre-treatment process is used to improve the quality of water used in paper production. During this process, activated carbon can be used to remove organic matter from water.

Application Method: Pretreatment is one of the basic treatment processes for wastewater and can be done using several different methods. These methods include physical, chemical, and biological pretreatments.

Activated carbon is a common material used in the pretreatment process. In physical pretreatment, activated carbon is often used to remove pollution from sedimentable or ventilable particles. Wastewater is passed through a bed of activated carbon on a filter, and the activated carbon adsorbs organic compounds and some chemical pollutants. The adsorption process occurs thanks to the porous structure and high surface area properties of the activated carbon.

In chemical pretreatment, activated carbon is used to reduce the presence of organic compounds that may result from the presence of oxidizing agents such as chlorine. This process is accomplished by loading activated carbon with chlorine and then passing wastewater through this bed. Activated carbon aids in chemical purification by adsorbing oxidising substances.

In biological pretreatment, the use of activated carbon occurs as part of the pretreatment process ahead of the biological treatment process. Since activated carbon adsorbs organic compounds, it causes less damage to the cells of microorganisms in the biological treatment process. Therefore, the use of activated carbon can improve biological treatment efficiency.

In summary, activated carbon can be used in the pre-treatment process in wastewater treatment plants. It is used in physical, chemical, and biological pre-treatment processes and helps reduce pollution by purifying wastewater through adsorption.

9- Biological Treatment: In paper mills, biological treatment processes are used to purify wastewater. During this process, activated carbon can be used to remove organic matter from the wastewater.

Method of application: The biologically activated carbon process generally consists of two steps: biological treatment and activated carbon adsorption. Each step requires different equipment, processes, and control strategies.

Biological treatment is the biological decomposition of organic substances by bacteria. This process is carried out in a biological reactor. A biological reactor is a tank in which water is decomposed by bacteria under oxygenated or anoxic conditions. In this process, bacteria convert organic substances into carbon dioxide and water. Biological treatment is the main process for removing organic substances.

Activated carbon adsorption is carried out after biological treatment. In this stage, activated carbon is added to the purified water and adsorbs the pollutants in the water. The application of activated carbon improves the quality of purified water. Activated carbon adsorbs pollutants such as organic substances, colours, odours, and some inorganic substances in water.

Application of activated carbon may vary depending on adsorption capacity, tank size, and application requirements. Activated carbon can be applied in a series of steps, which may include:

• First, activated carbon is added in a filter towards the outlet of the biological treatment tank.
• Activated carbon can also be applied by adding it directly to water collected in a container.
• Activated carbon can also be applied in a column designed to come into contact with purified water in a separate reactor.

Another factor to consider when applying activated carbon is the type of contaminants adsorbed. Some pollutants may reduce the adsorption capacity of activated carbon or may not be adsorbed. Therefore, the success of the application may vary depending on the type of contaminants, their concentration, and other factors.

10- Chemical Treatment: Activated carbon is used to remove organic pollutants in chemical treatment. Such treatment processes are generally applied in the treatment of industrial wastewater or drinking water.

In the chemical refining process, activated carbon is used as a chemical precipitation agent. In particular, some organic compounds (e.g., aromatic compounds, phenols, compounds with high chemical oxygen demand, etc.) cannot be adsorbed or biodegraded by activated carbon. To remove these organic pollutants, a chemical precipitation agent (e.g., ferric chloride or alum) is used along with activated carbon. In this method, the chemical precipitation agent is added to activated carbon and mixed with water. The sediment formed during the chemical treatment process is removed from the upper part of the water and directed to the activated carbon filter to obtain purified water by filtration. In this way, organic pollutants are both adsorbed and removed by chemical precipitation. The use of activated carbon can improve the efficiency of the chemical treatment process and play an important role in the removal of organic pollutants. However, the correct selection, dosage, and application method of activated carbon are important for the effectiveness of the purification process.

The application of activated carbon is important for the efficiency of the chemical treatment process. Determining and applying the correct dosage will be effective in removing organic pollutants. Moreover, filtering activated carbon can further improve the quality of water and play an important role in removing organic pollutants.

11- Physical Treatment: Wastewater is subjected to physical treatment to reduce the final pollution level. In this process, various physical methods can be used, for example, flotation, membrane filtration, and activated carbon adsorption.

Method of application: First of all, the water may need to be filtered. The solution is passed through a filtration system to eliminate large particulate impurities. Activated carbon is usually placed in a column. The size of the column depends on the application requirements.

Activated carbon is loaded into the column and compressed. Water is then introduced into the column from the top of the column.

Activated carbon helps remove contaminants by adsorbing impurities from solutions while releasing clean water. Activated carbon can work until saturation as contaminants are adsorbed. In this case, activated carbon is replaced or renewed.

Activated carbon is a material that has the ability to adsorb pollutants in water during the physical purification process. Therefore, activated carbon is widely used in water treatment plants. The application method of activated carbon may vary depending on the nature of the physical treatment process and the quality of the water.

The physical treatment process is designed to remove solid particles, suspended solids, colours, odours, and tastes from the water. This process primarily consists of different stages, such as sedimentation, flotation, filtration, and adsorption.

Activated carbon is used in the adsorption stage of physical purification. Adsorption occurs when contaminants in water accumulate on the surface of activated carbon and penetrate into the porous structure of the material. This process improves the quality of water by removing organic matter, chemicals, colours, and odours from the water.

The way activated carbon is applied depends on the type and concentration of pollutants in the water. Granular activated carbon is generally used by mixing it with water in a chamber to remove pollutants from water. This allows the activated carbon to adsorb contaminants in the water and then filter them out.

Activated carbon can also be used in different filtration systems, such as pressure filters and bed filters. In pressure filters, activated carbon is often used in conjunction with other filter materials to remove contaminants from water. Bed filters, on the other hand, are filled with granules of activated carbon and adsorb pollutants in the water. As a result, the application method of activated carbon depends on the nature of the physical purification process, the quality of the water, and the type of pollutants. Therefore, a different method may be preferred for each application.

Activated carbon is an important purification agent to protect the environment and reduce operating costs in paper mills. Activated carbon removes organic substances from water thanks to its adsorption feature. Activated carbon adsorbs organic compounds in wastewater, reducing the colour and odour of the water and helping the wastewater become cleaner.

The use of activated carbon in paper mills may vary depending on the design of wastewater treatment systems, the type of raw materials used in the paper production process, and other factors. In order to avoid using highly reactive chemicals with old bleaching technologies and causing highly polluting and toxic wastes such as TOCI and AOX, the use of activated carbon products, which is a natural method and provides maximum absorption by retaining all undesirable parameters in paper manufacturing, has become widespread.

The use of activated carbon in paper mills has many advantages:

1. Purification efficiency: When activated carbon is used in water purification processes, it provides high purification efficiency by removing various organic and inorganic substances.
2. Bad odour removal: activated carbon is effective in removing bad odours, especially in wastewater.
3. Colour removal: activated carbon removes coloured substances in water and improves the colour quality of the water.
4. Easy applicability: Activated carbon is easy to apply and can be used with many different purification methods.
5. Economical: Activated carbon can be an economical option compared to other purification methods.
6. Recycling: Activated carbon can be reprocessed and recycled after use.
7. Long-lasting: Activated carbon is ideal for long-term use under the correct storage conditions. can be used over and over again.
8. Environmental benefits: activated carbon is an environmentally friendly purification method and is effective in removing water-insoluble substances.

Carbontech produces highly active powdered, granular and pelletised activated carbon, which is manufactured using specially developed carbonisation and various activation methods and ensures maximum speed, high surface reactivity, advanced pore structure, mechanical resistance, large surface area and maximum hardness with its solid carbon skeleton. It enables paper mills to obtain the clean water and air they need by absorbing and removing unwanted organic and inorganic contaminants and chemicals in the liquid and gas phase.

As Carbontech, our products are completely dust-free and have high wear resistance. Provides resistance for dust-free operation. While the high surface reactivity, advanced pore structure, mechanical resistance, large surface area and robust carbon skeleton guarantee maximum hardness, it aims to maximise efficiency and profitability by providing maximum absorption in the shortest possible time, improving the life of your capital investment.

SOME PROPERTIES OF OUR ACTIVATED CARBONS

• High absorption capacity
• Advanced pore structure
• Mechanical resistance
• Large surface area
• Minimum ash content Maximum speed
• Maximum speed
• High surface reactivity
• Maximum hardness
• Correct pore distribution
• Maximum absorption capacity

Carbontech offers a wide range of customised activated carbons to improve customer requirements.

At Carbontech, we offer first-class products, excellent service, highly competitive prices and fast, on-time delivery.

Whatever the need for activated carbon, Carbontech offers the best solution

Our products can be customised to the customer's needs and all parameters can be adjusted accordingly.

We do our best to ensure that our customers get the best out of our products and we look forward to working with our customers.

Please feel free to contact us for further details and product ranges. We will help you find the optimum activated carbon solution for your application.