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Activated carbon is a specially treated carbon with numerous tiny pores and a huge surface area, with a surface area of 500-1500 square meters per gram of activated carbon. Activated carbon has strong physical adsorption and chemical adsorption functions, and also has a detoxification effect. The detoxification function is to use its huge area to adsorb the poison in the air of the activated carbon, thereby preventing the absorption of the poison. At the same time, activated carbon can bind to a variety of chemical substances, thereby preventing the absorption of these substances.

Because activated carbon has high requirements for water pretreatment and the price of activated carbon is expensive, in wastewater treatment, activated carbon is mainly used to remove trace pollutants in wastewater, which has achieved the purpose of deep purification.

(1) Activated carbon treatment of chromium-containing wastewater

Chromium is a metal raw material with a large amount in electroplating, and hexavalent chromium exists in different forms in wastewater with different pH.

Activated carbon has a very developed microporous structure and high specific surface area, and has strong physical adsorption capacity, which can effectively adsorb Cr(VI) in wastewater. There are a large number of oxygen-containing groups on the surface of activated carbon, such as hydroxyl (-OH). ), carboxyl group (-COOH), etc., they all have electrostatic adsorption function, and produce chemical adsorption for Cr(VI) after-sales service. It can be used to treat electroplating wastewater and can meet the national discharge standard.

The test shows that when the mass concentration of Cr(VI) in the solution is 50mg/L, PH=3, and the adsorption time is 1.5h, the adsorption performance of activated carbon and the detachment rate of Cr(VI) far reach the best effect. The process of chromium wastewater is the result of the combined effect of activated carbon on the physical adsorption, chemical adsorption and chemical reduction of Cr(VI) in solution. Activated carbon for treating chromium-containing wastewater has stable adsorption performance, high treatment efficiency, low operating cost, and has certain social and economic benefits.

(2) Activated carbon treatment of cyanide-containing wastewater

In industrial production, the wet extraction of gold and silver, the production of chemical fibers, coking, ammonia synthesis, electroplating, gas production and other industries all use cyanide or by-product cyanide, so a certain amount of cyanide must be discharged in the production process. waste water.

Activated carbon has a long history of being used to purify wastewater, and there are more and more literature reports on its application in the treatment of cyanide-containing wastewater. Varies by species), not cost-effective in handling.

(3) Activated carbon treatment of mercury-containing wastewater

Activated carbon has the properties of adsorbing mercury and mercury-containing compounds, but its adsorption capacity is limited, and it is only suitable for treating wastewater with low mercury content. If the concentration of mercury is high, it can be treated by chemical precipitation first, and the mercury content is 1 mg/L, and when it is high, it can reach 2-3 mg/L, and then activated carbon is used for further treatment.

(4) Activated carbon treatment of phenol-containing wastewater

Phenolic wastewater is widely sourced from petrochemical plants, resin plants, coking plants and refinery chemical plants. Experiments show that the adsorption performance of activated carbon for phenol is good, and the increase of temperature is not conducive to the adsorption, which reduces the adsorption capacity, but the time for reaching the adsorption equilibrium is shortened when the temperature is increased. There are optimal values ​​for the amount of activated carbon and the adsorption time. Under the acidic and ZTE conditions, the removal rate does not change much; under the strong alkaline condition, the phenol removal rate drops sharply. The stronger the alkalinity, the worse the adsorption effect.

(5) Activated carbon treatment of methanol-containing wastewater

Activated carbon can adsorb methanol, but its adsorption capacity is not strong, and it is only used to treat wastewater with low methanol content. The project operation results show that the COD of the mixed liquid can be reduced from 40mg/L to below 12mg/L, the removal rate of methanol can reach 93.16%~100%, and the water quality of the effluent can meet the water quality of the boiler desalination system. Require.

(6) Advanced Treatment in Refinery

The oil refinery contains wastewater, which, after oil separation, air flotation and biological treatment, is further treated by sand filtration and activated carbon filtration. The phenol content of wastewater was reduced from 0.1mg/L (after biological treatment) to 0.005mg/L, cyanide was reduced from 0.19mg/L to 0.048mg/L, and COD was reduced from 85mg/L to 18mg/L.