Key element course-tracked copyrolysis of sewage sludge and biomass for resource recovery and pollution control through kinetic and thermodynamic insights

•A real-time TG-FTIR-GC/MS pyrolysis system was adopted for tracking copyrolysis.•The production of profitable hydrocarbons is promoted with biomass addition.•Increasing biomass addition can depress pollutant formation and toxic metal bioavailability.•Low biomass addition prefers to maintain a congruent mechanism during copyrolysis.•The Cp converging to 1430 J/K at 700 °C substantiates pivotal functions of sludge ash matrix.