Ultralow loaded waste polystyrene derived hyper-cross-linked polymer for incineration flue gas demercuration: Synergistic effect of transition metal and halogen species

Gaseous mercury pollution control is pressing to both human health and environment protection. Achieving high demercuration performance with the lowest possible amount of active species is critical for developing demercuration adsorbent. Herein, motivated by waste plastic recycling and flue gas demercuration, we report a cost-effective and mild method to reclaim waste polystyrene into highly porous hyper-cross-linked polymers for flue gas demercuration. The waste derived hyper-cross-linked polymer exhibits superior porosity and strong hydrophobic property. Further chemical modification at ultralow concentration (similar to 0.001 mmol/g) over pristine HCPs could promote the chemically Hg-0 bonding ability thus obtaining remarkable demercuration ability (>90% in 15 mins for FeBr3-HCPs) under complicated flue gas conditions along with the interference of 1200 ppm SO2 and 10% H2O. Such HCP-based demercuration adsorbents could greatly surpass state-of-the-art adsorbents. Comprehensive characterizations and density functional theory calculations are performed to illustrate the interaction between HCPs substrate and different active species as well as the Hg-0 removal process over metal and halogen sites. The activity of Fe sites can be optimized by surrounding Cl and Br sites thus promoting the Hg-0 bonding and oxidation. This work could broaden the reutilization methods for waste polystyrene and contribute to the development of gaseous Hg-0 control technology.

Automated summary

Transforming waste polystyrene into highly porous hyper-cross-linked polymers is a cost-effective method for developing efficient adsorbents for flue gas demercuration, which is crucial for human health and environmental protection.