Self-capturing carbon dioxide (CO2) from the polluted atmosphere and consuming it into the coal reactor for cheap coal desulphurization is an ideal solution to smog and global warming. Herein, a novel engineered microbial ecosystem was developed over zero-valent iron (nZVI) decorated functional polyurethane (FPUF) biocarrier for coal bio-desulphurization coupled with rapid utilization of CO2. FPUF was structured with nZVI for quenching sulphur, iron, and nitrogen species from coal, and present them to TAC/ASP microbes for rapid degradation. Self-assembled and rapid CO2 utilizing microbial ecosystem (FPUF@nZVI@TAC@ASP) was shortly emerged as rapid coal treatment device as it removed CO2 (54 kg/m(3)/day), sulphur (43.3 kg/m3/day), iron (20 kg/m(3)/day), NH4+ (0.08 kg/m(3)/day), NO3- (0.05 kg/m3/day), and PO43-(0.01 kg/m(3)/day). Super-high CO2 fixation along with high sulphur removal rate (43.3 kg/m(3)/day) also yielded 400 mol/h/g protein. That further provided ample supply of HCO3-, S2O32- and SO42- species to microbes, which ultimately resulted in highly dense microbial ecosystem (14 g/L/h). Highest coal treatment efficiency (90%) was recorded, at sulphur/CO2 ratio of 20 and 14-h residence time, which was 30 times better performance than previously reported studies. Practical and commercialized application of developed process (tested in 5-liter coal-reactor), was found very impressive, as treatment of 1 kg coal produced 180 g of sulphur and mitigated 4500 ppm of CO2. The developed process has potential direct industrial application for coal, crude oil, petroleum, flue gas and natural gas desulphurization. This study opens a new gateway for the investigation and design of more innovative desulphurization and CO2 mitigation researches.