Method for preparing nicotine sulfate

The invention relates to a method for preparing nicotine sulfate, and belongs to the technical field of tobacco chemistry. According to the method, an aquaporin membrane and a polyamide membrane are used as forward osmosis concentration membranes, an inorganic salt is used as an absorbing agent, and a low-concentration nicotine distillate is subjected to forward osmosis concentration until the trapped fluid nicotine concentration is 5%-20%; 5%-40% sulfuric acid which is slightly excessive in chemical calculation is added into a trapped fluid to obtain a nicotine sulfate solution with relatively high concentration, and then evaporating and concentrating are carried out to obtain a 40%-60% nicotine sulfate product. According to the method, the concentration of the reactant nicotine during nicotine sulfate generation is greatly improved by adopting forward osmosis concentration, so that the concentration of the reaction product nicotine sulfate is improved, the evaporation capacity of water during preparation of