Method for determining biochemical oxygen demand of activated carbon in shell Biochemical oxygen demand refers to the amount of oxygen required for the decomposition of organic matter in water into a stable state under the action of aerobic bacteria, in mg/L. Biochemical oxygen demand is not only an indicator of the degree of organic pollution in water, but also an important parameter for determining the volume and operation management of water treatment equipment. The larger the value, the more serious the pollution. Since the biological oxidation process of organic matter in water is related to the temperature of water and the time of oxidation, the determination of biochemical oxygen demand is carried out according to the specified water temperature and time. Generally, the collected water sample is diluted to an appropriate ratio and sealed at a water temperature of 20 °C. After culturing for 5 days, the amount of dissolved oxygen consumed for 5 days was determined, and the biochemical oxygen demand (BOD5) was determined by the following formula. Where D1 is the mass concentration of dissolved oxygen before the increase or decrease of the diluted water sample, mg/L; D2——the mass concentration of dissolved oxygen in the diluted water sample after 5 days of culture, mg/L; B1——the mass concentration of dissolved oxygen before dilution in culture, mg/L; B2——the mass concentration of dissolved oxygen after 5 days of dilution water, mg/L; F1——the proportion of dilution water in the culture solution, %; F2——the proportion of water sample in the culture solution, %; In the determination of biochemical oxygen demand in the shell activated carbon, the following matters should be noted: 1. Since the biochemical reaction is utilized for the measurement, the dilution water in the culture must have a certain biological phase. When there is no organism or bacteria in the wastewater, it must be inoculated with river water or sewage; 2. There must be no harmful substances that hinder the reproduction of the organism. 3. Must contain micronutrients for biological reproduction 4. The dissolved oxygen must be brought close to the helium state, because the dissolved oxygen is too small, the biochemical reaction cannot be fully performed, and the supersaturation is liable to cause measurement errors. 5. Grasp the appropriate dilution rate of water sample, otherwise it will affect the accuracy of the measured value. Generally, the same water sample is diluted into several different dilution factors. What kind of water purification can be treated by shell activated carbon? In wastewater treatment, activated carbon is mainly used to remove trace contaminants from wastewater to achieve deep purification. 1. Activated carbon treatment of chromium-containing wastewater. Chromium is a kind of metal raw material which is used in a large amount in electroplating. In the waste water, hexavalent chromium exists in different forms depending on the pH value. Activated carbon has a well-developed microporous structure and high specific surface area, and has strong physical adsorption capacity, which can effectively adsorb Cr(VI) in wastewater. The surface of activated carbon has a large number of oxygen-containing groups such as hydroxyl groups (-OH). ), carboxyl groups (-COOH), etc., all of which have electrostatic adsorption functions and produce chemisorption of Cr(VI). It can be used to treat Cr(VI) in electroplating wastewater, and the adsorbed wastewater can meet national emission standards. The test shows that the adsorption concentration of Cr(VI) and the removal rate of Cr(VI) are the best when the concentration of Cr(VI) in the solution is 50mg/L, pH=3, and the adsorption time is 1.5h. Therefore, the process of treating chromium-containing wastewater by using activated carbon is the result of the combined action of activated carbon on physical adsorption, chemical adsorption and chemical reduction of Cr(VI) in solution. The activated carbon treatment of chromium-containing wastewater has stable adsorption performance, high treatment efficiency, low operating cost, and certain social and economic benefits. 2. Charcoal treatment of cyanide-containing wastewater. In industrial production, gold and silver wet extraction, chemical fiber production, coking, ammonia synthesis, electroplating, gas production and other industries use cyanide or by-product cyanide, so in the production process must emit a certain amount of cyanide Waste water. Activated carbon has been used for purifying wastewater for a long time. There are more and more reports on the treatment of cyanide-containing wastewater. However, due to the small adsorption capacity of CN_ and HCN on activated carbon, it is generally 3mgCN/gAC～8mgCN/gAC. Variety varies and is not cost effective in terms of processing costs. 3. Activated carbon treatment of mercury-containing wastewater. Activated carbon has the property of adsorbing mercury and mercury-containing compounds, but has limited adsorption capacity and 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. After treatment, it contains about 1 mg/L of mercury, and when it is high, it can reach 2-3 mg/L, and then it is further treated with activated carbon. 4. Activated carbon treatment of phenol-containing wastewater. Phenol-containing wastewater is widely used in petrochemical plants, resin plants, coking plants and refinery plants. It has been proved by experiments that the adsorption performance of activated carbon on phenol is good, the temperature increase is not conducive to adsorption, and the adsorption capacity is reduced; but the time to increase the adsorption equilibrium is shortened. The optimum amount of activated carbon and adsorption time existed. Under acidic and neutral conditions, the removal rate did not change much. Under strong alkaline conditions, the removal rate of phenol decreased sharply. The stronger the basicity, the worse the adsorption effect. 5. Activated carbon treatment of wastewater containing methanol. Activated carbon can adsorb methanol, but its adsorption capacity is not strong, and it is only suitable for treating wastewater with low methanol content. The engineering operation results show that the COD of the mixture can be reduced from 40mg/L to less than 12mg/L, and the removal rate of methanol can reach 93.16%~100%. 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