The invention discloses a method for treating a last
monosodium glutamate mother liquor, which comprises the steps: removing
sulfate radicals in the last
monosodium glutamate mother liquor containing
sodium pyroglutamate impurities through
barium salt first, then using ionic membrane caustic soda to hydrolyze to ensure that
sodium pyroglutamate is unlinked and transformed into
sodium glutamate, precipitating a large amount of flocculent
colloid at the same time, then removing precipitated
colloid protein, salt precipitations and the like through two plate-and-frame filtrations, sending filtrate into an inorganic membrane for
microfiltration separation to further remove impurities such as
solid protein to obtain clear permeate liquid, sending the permeate liquid into a nanofilration membrane
separation system to remove impurities such as soluble
colloid,
protein, residual
sugar and
pigment to obtain high-quality feed liquid, and re-sending the feed liquid into a
monosodium glutamate production cycle chain to produce monosodium glutamate. The method removes impurities such as
sulfate, metallic ions (such as
calcium,
magnesium, iron and the like), colloid, protein, residual
sugar and
pigment in the last monosodium glutamate
mother liquor, improves the quality of the
hydrolysis of the last monosodium glutamate mother liquor, replaces
acid hydrolysis, reduces the consumption of a decoloring agent and the
discharge amount of
wastewater, and ensures that the production cost is greatly reduced.