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About 35-40 kton used mattresses available yearly for the recycling only in the Netherlands. Mattresses that are offered at recycling companies, municipal yards and retailers often find their way to incinerators. However, several fraction components of used mattresses can be reused/resale in a useful manner. One of the mattress fractions is textile cover with residue of Polyurethane (PU) foam. Effective removal of PU foam would enable further reuse of textile materials. Use of harsh chemicals/ thermo-, photo-, oxidative, processes including hydrolysis, aminolysis, phosphorolysis, glycolysis etc [1,2] for PU foam degradation is not a good solution, since it will cause non-specific damage to textiles and other parts, making recycle/ reuse difficult. Therefore, Mattress Recycling Europe BV (MRE) is looking for an eco-friendly mild process for selective degradation of PU foam component. PU is a mixed polymer; therefore, it is important to establish the physio-chemical nature of PU before identifying suitable and sustainable degradation route.
The proposed solution is selective degradation of PU polymer using biotechnology. Enzymatic bio-catalysis enables a targeted, specific reaction at mild process conditions (pH, temperature) without harming other components in the process. Primarily hydrolase class of enzymes is assumed to be among the most effective options for the proposed degradation of PU foam residue [3,4]. From previous research, adding mechanical shear provides a synergistic effect for enzyme catalysed reaction [5-7]. Therefore, within the scope of this exploratory practice-oriented project, technical feasibility of bio-catalyst and shear (including well established PU degradation techniques) towards the selective degradation of PU foam residue attached to textile part from used mattresses will be explored together with cost estimation of the overall process and re-usability of enzymes using suitable immobilisation technique, addressing an urgent industrial need in the field of green chemistry.