Summary The usage of plastic materials in daily life has continuously increased over the last 30 years. The amount of plastic consumed per inhabitant in the industrialized countries has increased by a factor of 60 over this period, while the generation of plastic wastes has grown at a similar rate. Recycling of plastic materials is now an important field in the plastics industry, not just an activity born under environmental pressure. The recycling processes include industrial operations in which secondary materials are reprocessed and/or monomers recovered for further polymerization; such processes are termed secondary and tertiary recycling. At present, there are three main alternatives for the management of plastic wastes in addition to land filling: (i) mechanical recycling by melting and regranulation of the used plastics, (ii) feedstock recycling and (iii) energy recovery. Consequently, feedstock recycling appears as a potentially interesting approach, based on the conversion of plastic wastes into valuable chemicals useful as fuels or as raw materials for the chemical industry. The cleavage and degradation of the polymer chains may be promoted by temperature, chemical agents, catalysts, etc. The purpose of this work is to describe and review the different alternatives developed for the feedstock recycling of plastic wastes, with emphasis on both the scientific and technical aspects.

Reactive extraction of gluconic acid (GA) from aqueous solutions was investigated using trioctylamine (TOA) as extractant in the presence of benzyl alcohol (BA) and 1-decanol (DE) as diluents. Physical extraction of GA with pure diluents in the absence of TOA was found to be poor. Reactive extraction with an aminediluent mixture enhanced the separation process. Higher extraction efficiencies and distribution coefficients were achieved in the presence of BA as compared to DE. Further optimization studies were carried out to determine the synergistic effect of amine/diluent ratio. Loading ratios higher than 0.5 suggested 3:1 complex formation of GA with the amine. A reactive extraction mechanism of GA in TOA was proposed, and the equilibrium complexation constant was determined.

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