Oxygen Carrier Derived from Ferric Sludge for Chemical Looping Combustion of Msw Syngas: Waste Derived Material Performance and Carbon Footprint Assessment

•Ferric sludge is an effective dual functioning waste-derived oxygen carrier (OC)•Ferric sludge achieves > 88 % combustion efficiency and > 71 % HCl removal efficiency.•Stability of ferric sludge OC improved with the application of Al2O3 as support.•Ferric sludge is superior to iron ore for chemical looping combustion.•Carbon footprint of ferric sludge is lower than iron ore by 108.0 kgCO2/t.