Treatment of cyanide - containing sewage
In the industrial production, the wet extraction of gold and silver, the production of chemical fiber, coking, synthetic ammonia, electroplating, gas production and other industries to use cyanide or by-product cyanide, the production process is bound to discharge a certain amount of cyanide wastewater. Activated carbon has been used to purify sewage for a long time, and there are more and more reports on its application in cyanide wastewater treatment.
Ii. Treatment of methanol-containing sewage
Activated carbon can adsorb methanol, but the adsorption capacity is not strong, only suitable for the treatment of sewage with low methanol content. The project operation results show that activated carbon can be used to treat the sewage with low methanol content, the COD of the mixed liquid can be reduced from 40 mg/L to 12 mg/L, the removal rate of methanol can be up to 93.16% ~100%, the treatment can meet the water quality requirements of the desalting water system of the reuse boiler.
Treatment of phenolic sewage
Phenolic wastewater is widely sourced from petrochemical plants, resin plants, coking plants and refinery plants. The experimental results show that the adsorption performance of activated carbon on phenol is good, but the increase of temperature is not conducive to adsorption, which will reduce the adsorption capacity, but the increase of temperature can shorten the time to reach the adsorption equilibrium. When activated carbon is used to treat wastewater containing phenol, its dosage and adsorption time have the best value. Under acidic and neutral conditions, the removal rate does not change much, but under strong alkaline conditions, the removal rate of phenol drops sharply. The stronger the alkalinity, the worse the adsorption effect.
Iv. Treatment of mercury-containing sewage
Activated carbon has the ability to adsorb mercury and mercury-containing compounds, but its adsorption capacity is limited, and it is only suitable for the treatment of sewage with low mercury content. If it is to treat sewage with high mercury content, chemical precipitation method can be used first (mercury content is about 1 mg/L after treatment, up to 2~3mg/L at high temperature), and then activated carbon can be used for further treatment.
V. treatment of chromium-containing sewage
Chromium is a kind of metal raw material with large amount in electroplating. Hexavalent chromium exists in different forms with different pH in sewage. Therefore, the use of activated carbon treatment of chromium containing wastewater process is activated carbon for Cr (Ⅵ) in the solution of physical adsorption and chemical adsorption, a result of the combined action of chemical reduction, etc. Activated carbon treatment of chromium-containing sewage, stable adsorption performance, high treatment efficiency, low operating costs, economic benefits obviously.
With the progress of science and technology and the special requirements of sewage treatment, the research on activated carbon has developed from its own structure and specific surface area to the research on the influence of surface functional groups on the adsorption performance of activated carbon. It has been found that activated carbon not only has adsorption characteristics, but also shows catalytic characteristics, thus the development of catalytic oxidation method is now also increasingly valued, its research is also deepening.
