2.8 Recovery of chloroform
The chloroform waste liquid is washed once with water, concentrated sulfuric acid (one-tenth of the amount of chloroform), pure water, and hydroxylamine hydrochloride solution (0.5% AR). Wash twice with double distilled water, dehydrate the washed chloroform with sewage calcium chloride, leave it for a few days, filter and distill. The distillation rate is 1 to 2 drops per second, and the distillate with a boiling range of 60 to 62 degrees Celsius is collected (under the marked box) and stored in a brown reagent bottle (rubber stopper is not available).
Precautions
1). Try to recover the solvent as much as possible, and use it repeatedly as long as it does not interfere with the experiment
2). In order to facilitate processing, its collection and classification are often divided into: a) flammable substances b) non-flammable substances c) aqueous waste liquid d) solid substances and so on.
3). A substance that is soluble in water is easily lost as an aqueous solution. Therefore, pay attention when recycling. However, solvents such as methanol, ethanol and acetic acid can be easily decomposed by bacteria. Therefore, the dilute solution of this kind of solvent can be discharged after being diluted with a large amount of water.
4). The waste liquid containing heavy metals is treated as an inorganic waste liquid after the organic matter is decomposed.
Approach
1). Incineration
①Put the waste liquid of combustible material in the combustion furnace and burn it. If the quantity is small, you can put it in an iron or porcelain container and burn it in a safe outdoor place. When igniting, take a long stick, tie a rag with oil on one end, or use wood chips and other things, stand upwind to ignite and burn. And, it must be monitored until the burn is finished.
②For substances that are difficult to burn, it can be mixed and burned with combustible substances, or sprayed into an incinerator equipped with a combustor for combustion. For hard-to-burn substances such as polychlorinated biphenyls, some of the unburnt substances are often discharged, so be careful. For high-concentration organic waste liquid containing water, this method can also be incinerated.
③The waste liquid that produces harmful gases such as NO2 SO2 or HCl due to combustion must be burned in an incinerator equipped with a scrubber. At this time, the combustion exhaust gas must be washed with lye to remove harmful gases.
④For solid substances, it can also be dissolved in a flammable solvent and then burned.
2). Solvent extraction
① Extract the low-concentration waste liquid of water with a solvent such as water that does not mix with water. After the solvent layer is separated, it is burned. Then use the method of blowing in air to blow out the solvent in the water layer.
②Waste liquids that form emulsions cannot be treated by this method, but must be treated by incineration.
3). Permeation method
Use charcoal diatomaceous earth soil layer to form pseudo-flaky formic acid, granular straw and saws and other materials that can be adsorbed well, which can be fully heated and burned with the adsorbent.
4) Delete division (refer to the treatment of waste liquid containing method)
In the low-concentration organic waste liquid containing water, the easily decomposable waste liquid is removed, and the mixed liquid of H2O2 KMnO4NaOCl H2SO4+HNO3 HNO3+HClO4H2SO4+HClO4 and the waste solution is used to oxidize and decompose it. Treatment method of similar experimental waste liquid.
5).
For organic acids or inorganic acids, as well as an organic phosphorus compound and other easily occurring substances, sodium hydroxide or calcium hydroxide can be added, and the process can be carried out at high temperature or under heating. After nothing, if the waste liquid is poisoned. At the time, neutralize it, then drain it out. If there are harmful substances, use appropriate time and other methods to dispose of them.
6). Biochemical treatment
For example, dilute solutions containing alcohol, protection, animal and vegetable fats, bacteria, starch, etc. can generally be processed in this way. Solvent refers to substances composed of C, H, O elements, such as type, nature type, organic acid and organic matter. The low-concentration waste liquid of flammable substances is treated by solvent extraction, removal and classification. That is, a substance that is easily decomposed by the action of a substance, and its dilute solution will be produced after hydrolyzing plants. Liquid containing petroleum dynamic grease.
Hazardous waste liquids include: waste liquids of benzene, viscous, petroleum, kerosene, light oil, heavy oil, lubricating oil, chemical grease, machine oil, vegetable oil, fluids and resins. For waste liquids such as contained substances, and waste liquids such as contained substances, when residues are contained, it is difficult to keep the residues.