Valorization of floral foam waste via pyrolysis optimization for enhanced phenols recovery

Utilization of phenol formaldehyde foams is becoming increasingly widespread, especially in floral bouquets, generating toxic microplastics in the environment. The present study evaluated phenols recovery from floral foam waste (FFW) of floral bouquets through optimization of pyrolysis conditions. Compared to the biomass portion in the floral bouquet, FFW showed 55.1% higher carbon content, 56.9% lower nitrogen content, and 44.6% lower oxygen content, with the highest recorded calorific value of 27.43 MJ kg^-1. Thermogravimetric analysis showed the relative thermal stability of FFW with gradual weight loss and numerous small peaks at 70 °C (representing short chain volatiles such as formaldehyde and phenol), 450 and 570 °C (due to phenolic and aromatic products release), indicating the richness of FFW with phenolic compounds. Optimization of pyrolysis conditions showed the highest significant biocrude yield of 36.0% at 700 °C for 20 min using FFW load of 2.5 g. However, optimization of phenolic production suggested 520 °C, 30 min, and 3.49 g FFW load as optimum conditions for high biocrude yield with enhanced phenolic proportion. Experimental results using the aforementioned conditions showed phenolics potential of 0.22 g phenolics/g FFW, with 78.8% phenolic compounds composed mainly of phenol and its methyl derivatives.