Reactive extraction of tartaric acid from aqueous solutions using environmentally-friendly solvents and trioctylamine

Tartaric acid (TA) is a dicarboxylic acid naturally exists in especially grapes, oranges, raspberries and bananas. Tartaric acid and its salts are white in color and have crystalline structures. They are extensively employed in food and pharmaceutical industries. Several methods have been developed and tested for the recovery of tartaric acid from aqueous solutions such as fermentation media and industrial wastewaters. Reactive extraction has been preferred to these methods due to its various advantages. In the process, target material can be transferred into the organic phase via chemical extraction besides physical extraction. However, toxic effects of the process members need to be eliminated. In this MS thesis, separation of tartaric acid by reactive extraction using vegetable oils and trioctylamine (TOA) was investigated. The performances of eight vegetable oils (canola, sunflower, safflower, almond, hazelnut, soybean, sesame, corn oil) were probed and the results were compared with those obtained with octanol. The process reached the equilibrium by 60 minutes. The recovery efficiencies were negatively influenced by the increase in the pH of the aqueous phase and temperature. The highest extraction efficiency was obtained with canola oil among the natural diluents studied. Separation efficiencies decreased with TA concentration and increased with TOA concentration. The trend was observed for both solvents. The maximum recovery efficiencies were 89,55% (KD=8,57) and 97,23% (KD=35,09) with canola oil and octanol, respectively. The values obtained with the two organic phase diluents were very close to each other. The tartaric acid extracted into the organic phase was successfully transferred into the second aqueous phase by back extraction process. The maximum extraction efficiency was obtained with NaNO3. This MS thesis exhibited that the vegetable oils can be used as the organic phase solvents during the recovery of tartaric acid by reactive extraction.