Reactive Separation of Gallic Acid Using Phosphoric and Aminic Extractants in Non-Toxic Natural Diluents

Abstract

Bio production of gallic acid and its recovery from bioconversion media have captured considerable interest of researchers. Extractive separation with solvents can be utilized for the recovery of gallic acid; however, the issue of toxicity of solvents towards microbes needs to be addressed. Physical extraction with natural solvents is observed to be insufficient as highest distribution coefficient (KD) were observed to be 0.136 for sesame oil, 0.111 for rice bran oil and around 0.041 for sunflower oil. Higher separation efficiencies are desirable for a successful extraction system and in this regard employing a reactive component (extractants) could be intensified solution. Three different extractants (tri-n-butyl phosphate (TBP), tri-octyl amine (TOA) and Aliquat 336) were investigated for their capabilities to improve extraction when present in three non-toxic diluents (sunflower oil, rice bran oil and sesame oil) comprising 9 possible combinations employed over acid concentrations (0.01-0.05 kmol.m-3). TBP-sunflower oil (KD = 0.81-15.66, KE = 1.922 - 7.894), Aliquat 336-rice bran oil (KD = 3-10.71, KE = 6.378-10.67), and TOA-sesame oil (KD =0.1-3.54, KE = 2.081-3.409) combinations were observed to result in most suited systems resulting in higher distribution of acid. Thus, they were found to be ideal for efficient and low toxic extractant systems for acid recovery.