A method for removing cyanide from coking wastewater

Abstract

The invention discloses a method for removing cyanide in coking wastewater, mainly through the oxidation of Fenton, to effectively remove various forms of cyanide in the wastewater; at the same time, combined with the adsorption of activated carbon and the existence conditions of hydrogen peroxide The catalytic oxidation that occurs under the environment makes the effluent concentration lower; and it has a good cost advantage; it can make the effluent meet the national first-level discharge standard (<0.5mg / L).

Description

【Technical Field】 [0001] The invention relates to the field of water treatment, in particular to using Fenton reagent to oxidize part of the cyanide in the coking wastewater, and then use activated carbon to remove most of the cyanide in the coking wastewater. 【Background technique】 [0002] Cyanide refers to a substance containing a cyano group (CN-) in the compound molecule. Cyanide in water can be divided into free cyanide and complex cyanide. The total amount of the two cyanides is called total cyanide. The total cyanide in coking wastewater is basically complex cyanide. According to whether the element or group connected to the cyano group is organic or inorganic, cyanide is divided into two categories, namely, organic cyanide and inorganic cyanide. Cyanide is a highly toxic substance, and its toxicity to the human body is mainly combined with ferricytochrome enzyme to generate cyanide ferricytochrome oxidase and lose the role of oxygen transfer, causing tissue asphyxiation...

AI Technical Summary

Problems solved by technology

[0012] The method of using the strong oxidation of chlorine to oxidize cyanide to decompose it into low-toxic or non-toxic substances is called chlorine oxidation; during the reaction, in order to prevent cyanogen chloride and chlorine from escaping into the air, the reaction is often carried out under alkaline conditions. It is often called the alkaline chlorination method; the chlorine oxidation method has been applied to industrial production in 1942, and it has been more than 60 years, so this method is relatively mature; the disadvantage of this method is that if the equipment is used in the process of treating wastewater The sealing is not good, CNCl escapes into the air, polluting the operating environment; the cyanide in the ferrocyanide complex and the ferricyanide complex cannot be destroyed, nor can it be removed by forming a precipitate, so the total cyanide is sometimes high; the drain chlorine The high concentration of ions will lead to salinization of surface water and soil, and corrosion of water conservancy facilities;

[0014] Coagulation method, metal ions and CN in water can be made by adding coagulation agent - Coagulate together and sink to the bottom of the water to achieve the effect of removing heavy metals and cyanide. The precipitation effect is restricted by the pH value and the composition of wastewater. When the pH value is low, the effect is good, the operation is simple, and the treatment cost is low. There is a lot of slag, and the effluent cannot meet the standard; ozone oxidation, using air to generate ozone through corona discharge at high voltage and high frequency, oxidizes cyanide, cyanate and thiocyanate. The source of raw materials is wide and the operation is simple, but the investment is too high and the consumption is too high. High electricity, can not destroy ferrous and ferricyanide; ozone and ultraviolet photocatalytic oxidation, liquid phase ozone will decompose under ultraviolet radiation to produce hydroxyl radical OH (it is a strong oxidant), and then react with cyanide to make which is eventually completely oxidized to CO 2 and H 2 O, the disadvantage is that the oxidation ability is strong, the selectivity is small, the reaction speed is fast, the oxidation is thorough, and the treatment efficiency is high, but the pH value has a certain influence on the treatment effect, and it consumes more power.