Use of ionic liquids as a means of recovering value from key organic waste streams in Nigeria

• Main Author: Thompson, Feyisetan Oluremi
• Other Authors: Grimes, Sue
• Published: Imperial College London 2013
• Subjects: 628
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.693915

Two novel processes based on ionic liquid methodology, including steps to recover the ionic liquids for reuse and recycle, are developed for the recovery of key value components from food wastes: namely glycosaminoglycans (GAGs) from seafood waste (scallop gut) and chitin-glucan complexes from cider yeast wastes. Both these components are high-added value materials in nutraceuticals and the chitin- glucan complexes are of particular interest because they are recovered from a vegetarian source. GAG recovery from scallop gut involves treatment of the wet waste with the ionic liquid, HBetNTf2, in a low temperature (30oC) process to separate the insoluble GAG mixture from other components of the waste, which are soluble. The important aspects of this process from the point of view of economic viability are: (i) it is a low-temperature process, (ii) the extraction of the unwanted components occurs quickly, (iii) the product GAGs are obtained in good yield, and (iv) all solvents used can be recovered. The recovery of chitin-glucan involves enzymatic pre-treatment of the cider yeast waste to give a digested pellet from which the complex can be recovered by treatment with the IL, BMIMCl. Two low temperature ionic liquid processes (TESA/TESAC and P6,6,6,14 Cl) for re-refining waste lubricant oils to recover base oils, of sufficient quality to be reused in lubricant applications, are also developed. The TESA/TESAC process is based on a reversible reaction from a solvent, TESA, in which the base oil is soluble to an ionic liquid, TESAC in which the base oil is insoluble. The conversion occurs when carbon dioxide is passed through the solvent and reversed by heating above 50oC. In the P6,6,6,14 Cl process the base oils are recovered from a direct solution of the hydrocarbon content of the waste in the ionic liquid. In both processes all solvents used can be recovered for reuse.