Application of Activated Carbon in Water Treatment And Activated Carbon Modification Method

1. Analysis of modification methods of activated carbon.

   
   

  1. Surface oxidation modification. This modification method mainly uses oxidants to treat activated carbon, which can cause        oxidation reactions on the surface of activated carbon, thereby increasing the number of oxygen-containing functional groups, such as phenolic hydroxyl groups, ester groups, etc., and further enhancing the hydrophilic properties of activated carbon. Surface oxidation can effectively improve the adsorption capacity of polar substances. Common oxidants mainly include nitric acid, hydrogen peroxide, perchloric acid, ozone, etc. Among these oxidants, nitric acid has the strongest oxidizing performance.

A large number of acidic groups can appear in the activated carbon reaction, and the remaining oxidants are relatively mild and can be used to increase the surface acidity of activated carbon. The surface structure of activated carbon modified by oxidation is more uniform, and different quantities and polarities of activated carbon materials can be obtained by using different oxidants, which greatly increases the application scope of activated carbon.

2. Surface reduction modification. Surface reduction modification mainly uses different activated carbon surface functional groups for reduction modification, which can increase the content of activated carbon to avoid oxygen-containing basic groups and hydroxyl functional groups, thereby enhancing the polarity on the surface of activated carbon and strengthening the resistance of activated carbon to non-polar properties. 

Adsorption capacity. Normally, activated carbon reducing agents can use nitrogen, hydrogen, potassium hydroxide, sodiumhydroxide, ammonia, etc. For example, treating the surface of activated carbon with hydrogen can

It was found that the pore properties of the modified activated carbon did not change significantly, but the number of oxygen-containing functional groups on the surface gradually decreased, which can improve the adsorption capacity of the activated carbon material for organic pollutants.

3. Load metal modification. By using the loading metal modification method, the metal ions in the dissolved salt are loaded into the activated carbon, and the carbon atoms are redoxed under high temperature conditions. This can cause carbon deficiency, expand the pores of the activated carbon, and improve its adsorption function. .

Furthermore, metal ions themselves also have the ability to adsorb certain special substances. Relevant scientists use substances such as iron sulfate and iron nitrate to modify activated carbon. The use of high-temperature heating can decompose metal salts into nitrogen oxides, sulfur oxides and other substances, and chemically react with activated carbon pores, successfully expanding the pore size of activated carbon.

4. Acid-base modification method. The acid-base modification method is to use acidic substances and alkaline substances to treat the surface of activated carbon, thereby changing the functional groups on the surface of activated carbon. It can also adjust the number of functional groups of activated carbon, and ultimately obtain higher quality activated carbon, which greatly improves the adsorption of activated carbon.Function. The main acid-base modifiers are: citric acid, hydrogen chloride, etc.

2. Application of activated carbon in water treatment

1. Remove organic matter from water. According to relevant research, activated carbon with platinum elements in the redox process can greatly improve the adsorption performance of organic matter. By modifying activated carbon with a variety of impregnation liquids, the impregnation liquid can effectively change the desorption activation energy in the activated carbon, thus affecting the adsorption effect.

   
   

Bring huge impact. Through a series of experimental work, it was found that the surface chemical properties of activated carbon have a stronger performance improvement in the oxidation method and the metal loading method, which greatly improves the adsorption capacity of activated carbon. Therefore, when activated carbon is used in water treatment, activated carbon can be modified by loading metals and oxidation methods, thereby improving the treatment capacity of organic matter in water.

2. Remove heavy metal ions from water. Since the adsorption capacity of activated carbon will be greatly increased after modification, it can not only remove organic matter in water, but also adsorb inorganic pollutants, that is, heavy metal ions. From a theoretical analysis, adding amino groups, hydroxyl groups, and carboxyl groups to the surface of activated carbon.

Substances such as base functional groups can further improve the adsorption capacity of activated carbon, thereby better processing heavy metal ions in water (adsorption). Relevant scholars have conducted modification tests on activated carbon. By adding HNO3 solution with a concentration of 13.2 mol.L-1 into the activated carbon, the application ratio is 4:1. Under the action of a reflux temperature of 100°C and a reflux time of 1 hour, That is, activated carbon can be modified. This method can greatly improve the adsorption capacity of activated carbon for Pb2 ions.

The adsorption capacity of activated carbon is 105 times stronger, and the adsorption effect is extremely obvious. In experiments, some scholars mixed HNO3 solution and activated carbon at a mixing ratio of 1:1, allowing the activated carbon to undergo oxidative modification, and then heated it at a temperature of 350°C to finally obtain modified activated carbon. This kind of active peptide has very strong ion exchange performance and higher cation exchange capacity. Especially for Cr(Ⅲ) substances, the adsorption performance will be significantly improved. 

Sodium thiocarbamate and tetrabutylammonium modify activated carbon, which can remove chromium, zinc, copper, etc. from the water. In short, different modification methods need to be used for different metal elements to ensure the pertinence of water treatment work.

3. Remove other substances. Because activated carbon is heated at a certain temperature, it can obtain stronger anion adsorption and exchange functions. For example, activated carbon modified with sodium hydroxide can effectively remove pesticides and other substances.

Photocatalytic function, thereby reducing the methyl orange content in industrial wastewater. It can be seen that for different water treatment goals, different substances need to be used to modify activated carbon when applying it, so as to improve the water treatment effect.The modified activity can effectively adsorb organic pollutants such as phenolic compounds, petroleum products, and benzene compounds,dyes and inorganic compounds such as heavy metal ions. At the same time, modified activated carbon can also remove synthetic dyes, compounds, pesticides, methylene blue active substances, etc.