Separation of succinic acid from its salts on a high-silica zeolite bed

Abstract

Succinic acid production from renewable resources might replace production of several petroleum derived chemicals. This study focuses on development of a sorption process for efficient separation of succinic acid from its salts in a low pH fermentation medium. Therefore, solutions of succinic acid in water and Saccharomyces cerevisiae at pH 2.8–4.7 were eluted over high-silica ZSM-5 zeolite particles, which were packed in laboratory columns. Succinic acid adsorbed well, whereas succinate salts eluted from the column with an early breakthrough. A mathematical model, involving succinic acid dissociation, described the breakthrough behavior correctly. The presence of acetic acid slightly reduced the observed succinic acid capacity, but most acetic acid eluted during succinic acid loading, which is favorable. The adsorbed succinic acid was completely desorbed already when the temperature was increased to 80 °C. Experiments with fermentation medium decreased the column's capacity, but this was restored by calcining at 600 °C. So succinic acid was separated from its salts without use of additional chemicals such as acids or bases. Issues that require further study are modeling nonlinear mass transfer, and the prolonged use of sorbent, especially when using fermentation medium.