Method for purifying and recovering acetonitrile waste liquid

The invention relates to the technical field of organic solvent recovery, in particular to an acetonitrile waste liquid purification and recovery method which comprises the following steps: S1, passing acetonitrile waste liquid through an azeotropic tower or a rectifying tower to obtain an acetonitrile crude product; s2, enabling the acetonitrile crude product to pass through a liquid phase membrane to obtain a high-purity acetonitrile solution; wherein the acetonitrile concentration in the acetonitrile waste liquid is 3-80 wt%; the liquid-phase membrane is selected from one of a zeolite molecular sieve membrane, a silicon dioxide membrane and an organic polymer membrane. According to the purification and recovery method of the acetonitrile waste liquid, provided by the invention, the recovery energy consumption and cost can be effectively reduced, and meanwhile, a large amount of vaporization potential is saved. 本发明涉及有机溶剂回收技术领域，特别涉及一种乙腈废液的纯化回收方法，包括如下步骤：S1、将乙腈废液过共沸塔或精馏塔，获得乙腈粗品；S2、将所述乙腈粗品过液相膜，获得高纯度的乙腈溶液；其中，所述乙