1. Water purification of activated carbon

Activated carbon can remove smell and taste, chroma, residual chlorine, colloid, organic matter (synthetic detergent, pesticide, herbicide, insecticide, synthetic dye, trihalomethane, haloacetic acid, endocrine disruptors such as phthalate esters PAEs), heavy metals (such as mercury, silver, cadmium, chromium, lead, nickel, etc.), radioactive substances, etc. it is the earliest and most widely used water purifier Material Science. Activated carbon is used not only in general activated carbon water purifiers, but also in household reverse osmosis water purifiers, as well as in most ultrafiltration, ceramic, KDF, UV and other water purifiers.

Both activated carbon and KDF can remove the residual chlorine in water, but the reaction of KDF and chlorine can produce zinc ion (Zn2), which may lead to excessive zinc in water. However, there is no such worry about using activated carbon to remove chlorine.

During the activation of activated carbon, a large number of micropores with various shapes are formed, forming a huge surface area with adsorption. The specific surface area is 500-1200 m2 / g. the larger the specific surface area is, the better the adsorption effect is.

2. Negative effects of activated carbon

(1) Activated carbon adsorbs a large amount of organic matter, which will become the nutrition of bacteria and other microorganisms. Bacteria will multiply and proliferate in the micropores of activated carbon, and may cause the total number of colonies in the effluent to exceed the standard.

(2) The activated carbon in the water purifier transforms ammonia nitrogen into nitrite nitrogen in the water under the catalysis of microorganism. The nitrite in the effluent of the water purifier is often many times higher than that in the influent. Nitrite itself is not a carcinogen, but the nitrosamine formed by the reaction of nitrite with amines in water is a strong carcinogen.

(3) Adding brominated resin (brominated polystyrene hydantoin) to the effluent of activated carbon adsorption filtration or UV sterilization is a good method to solve the problem of excessive microorganisms in water.

2、 How to improve the water purification effect of activated carbon water purifier

Water purifier manufacturers should purchase high-quality activated carbon, and spot check and test each batch of purchased activated carbon to prevent purchasing inferior products.

1. Now many activated carbons in the market are mixed with recycled materials, some even all recycled materials. Activated carbon manufacturers buy the activated carbon that has been used and discarded by users, and then return it to the furnace for treatment. Some even put it in the open yard to dry in the sun and then sell it as new products or mix it with new activated carbon to reduce the cost and price. Shanghai CDC has detected that the CODMn removal rate of activated carbon filter is zero.

In addition, there is water washing, which should use pure water, but the cost is high. Many activated carbon plants do not have pure water devices, so they use river water, well water and even water from stinky ditch to wash carbon. Such activated carbon is polluted.

2. Whether physical adsorption or chemical adsorption, it takes a certain time for activated carbon to play the role of water purification. Therefore, the water purifier manufacturers should improve the design of activated carbon filter or activated carbon filter element, increase the contact time of water and activated carbon as far as possible, contact time = carbon column length / water flow rate in the carbon column, increase the carbon column length and activated carbon consumption, reduce the water flow rate, can prolong the contact time of water and activated carbon, improve the water purification effect and effluent quality of activated carbon.

3. In the operation manual of activated carbon water purifier, the user should be warned that after opening the water purifier, part of the water should be discharged, the accumulated water in the filter cartridge and pipe of the water purifier should be discharged, and then fresh filtered water should be used. Otherwise, after soaking for a long time, a large number of bacteria in the activated carbon will multiply and exceed the standard, and nitrite may also increase. Therefore, the residual water in the water purifier must be discharged first.

4. The user's Manual of activated carbon water purifier should warn the user that the activated carbon should be replaced frequently, and generally it should be replaced in half a year. Especially in the southern tap water with surface water as the water source, there are many colloidal substances and high content of organic matter in the water, so it is necessary to replace the activated carbon filter element in the water purifier in time. When the organic matter adsorbed by activated carbon is saturated, it can no longer play the role of adsorption and water purification. On the contrary, it will release harmful substances, making the water purifier a "sewage purifier".