Recovery of Fumaric Acid from Industrial Wastewater by Chemical Extraction and Stripping

Abstract

The study on chemical extraction and stripping for the recovery of fumaric acid from low concentration organic acid wastewater has been carried out. The parameters influencing the extraction efficiency were investigated, including extractant concentration, the initial pH, the volume ratio of water to oil (W/O), the extraction temperature, and the concentration of n‐octanol. The heat effect of the extraction process, the formation of acid‐amine complexes, and the corresponding equilibrium constant were determined. In the optimum condition that kerosene/N₇₃₀₁/n‐octanol was 2:2:1, pH was 0.5, W/O was 1:1, and the temperature was 303K, through chemical extraction and stripping, the COD_cr value of fumaric acid wastewater decreased from 71040 mg/l to 8411 mg/l, and the overall COD_cr removal rate reached 88.16%, and the extraction efficiency of fumaric acid was 70.67%. The extractant was regenerated by a stripping process with 2% NaOH, and the stripping rate almost arrived at 100%. The regenerated extractant was cycled seven times without decreasing extraction efficiency and the stripping rate. And fumaric acid was obtained by adjusting the pH of the salt from stripping. After extraction, the fumaric acid wastewater can be further treated by oxidation or biodegradation to environmentally acceptable levels.

Keywords:

• Chemical extraction
• fumaric acid
• organic wastewater
• COD removal rate
• N₇₃₀₁

Acknowledgements

The authors thank X.F. Huang, R. Yao, and T.T. Zhi for their sincere help in this experiment.