The invention discloses a method for separating and purifying nicotinic acid from 3-cyanopyridine
wastewater, which comprises the steps of (1) soaking resin in
methanol for 4-12h, treating with a 4% NaOH solution, and cleaning with water; (2) adding
activated carbon accounting for 3-5% of the
mass of the
wastewater to decolorize and filter; (3) adsorbing the
wastewater in the step (2) on a column;(4) after the adsorption is finished, desorbing by using hot water with the temperature of 7080 DEG C to obtain a nicotinic acid analytic solution ; (5) introducing a
methanol solution of which the volume is 3 times that of the column, introducing a NaOH solution of which the volume is 3 times that of the column, and washing with pure water until the pH value is 7.0+ / -0.5; (6) concentrating the nicotinic acid analytic solution obtained in the step (4) by 10-20 times, adding
activated carbon accounting for 3--5% of the
mass of the concentrated solution for decoloration, and performing acidification
crystallization to obtain a crude product, recovering
crystallization mother liquor, and performing
column chromatography crystallization according to the step (3) to obtain a crude product; and(7) adding the nicotinic acid crude product obtained in the step (6) into absolute ethyl
alcohol, heating for dissolving, adding
activated carbon accounting for 3-5% of the
mass of the nicotinic acidethanol solution for decoloration, cooling the filtrate to the temperature of 15-25 DEG C, controlling the temperature for crystallization, and
drying to obtain a nicotinic acid finished product.