Chemical laboratories often produce certain toxic gases. Liquids or waste residues need to be treated, especially some highly toxic substances. If they are directly discharged, they may pollute the surrounding air and water sources, causing environmental pollution and harming human health. Therefore, the waste liquid, waste gas and waste residue must be treated before being disposed of. It is forbidden to pour concentrated acid, concentrated alkali waste liquid and insoluble solid matter into the pool to prevent blockage and corrosion of water pipes. The “three wastes†emissions from chemical laboratories should do the following: 3 Mercury : If metal mercury is accidentally scattered in the laboratory, all the mercury droplets must be immediately picked up by a thin copper piece soaked with a straw, a brush or a solution of mercury nitrate, collected in a suitable bottle and covered with water. The ground where the mercury is scattered should be sprinkled with sulfur powder, cover the spill area for a period of time to generate mercury sulfide, and then try to sweep it. It can also spray 20% ferric chloride solution, let it dry and then clean. Ophthalmology Drape,Surgery Ophthalmology Drape,Disposable Ophthalmology Drape,Ophthalmology Surgery Eye Drape Xinxiang Huaxi Sanitary Materials Co., Ltd. , https://www.huaximedical.com
1. Exhaust gas : The laboratory that produces a small amount of toxic gas should be carried out in a fume hood, and a small amount of toxic gas is discharged to the outside through the exhaust device. Laboratories that produce large amounts of toxic gas must have absorption or treatment equipment. For example, NO2, SO2, H2S, HF, etc. can be passed into the alkaline solution to allow most of it to be absorbed and discharged, and CO can be ignited to generate CO2.
2. Waste residue : A small amount of toxic waste residue should be arranged at a designated location and buried deep underground.
3. Waste liquid : The treatment of waste liquid is related to its nature, and different waste liquid treatment methods are different. For example, the waste sulfuric acid solution can be neutralized with the spent caustic and the alkali solution to prepare pH 6-8, and then discharged from the water channel. Waste liquids containing phenol, cyanide, mercury, chromium and arsenic can be discharged by the following treatments, as follows:
1 Phenol : A high concentration of phenol can be extracted with butyl hexanoate and recovered by double distillation. Low concentrations of phenol waste can be added to sodium hypochlorite or bleach to oxidize the phenol to carbon dioxide and water.
2Cyanide : The waste liquid containing cyanide should not be directly poured into the laboratory pool. Sodium hydroxide should be added to make it sputum and then poured into ferrous sulfate solution (by mass: 1 part of ferrous sulfate to 1 part) Sodium hydroxide), which produces non-toxic sodium ferrous hydride and is discharged into the sewer line.
The waste liquid containing mercury salt can be adjusted to pH 8-10 first, adding excess sodium sulfide to form mercury sulfide precipitate, and then adding ferrous sulfate as a precipitant, which can be discharged in the night, and the residue can be recovered by roasting method, or Re-formed into mercury salts.
4 Chromium : If the chromic acid washing liquid turns green, it can be concentrated and cooled, then added with potassium permanganate powder for oxidation, and then filtered with manganese core funnel to remove manganese dioxide. The spent waste washing liquid can be used to reduce the residual six-price of waste iron scraps, and then neutralized with waste alkali liquor or lime to form a low-toxic chromium hydroxide precipitate.
5 Cadmium : Adjust the waste liquid to pH 8-10 with lime, precipitate lead and cadmium in the waste liquid, and add ferrous sulfate as a coprecipitant.
Treatment of 6 combined wastewater : The mixed waste liquid in the laboratory can be treated by iron powder method. This method is simple in operation, does not interfere with each other, and has good effect. The treatment method is to adjust the wastewater to pH 3-4 with acid, add iron powder, and stir for 0.5 h. The mixture was adjusted to pH 9 with alkali, stirring was continued for 10 min, and then a polymer coagulant was added to precipitate after coagulation, and the supernatant was discharged, and the precipitate was treated with waste residue. 