Super activated carbons (SACs) can be widely used in adsorption and separation, but it remains challenging to find a facile method to prepare such SACs. In this research, we proposed to synthesize SACs via suddenly heating H3PO4-loaded coconut shell in CO2 flow, without using a traditional slow heating step. The utilization of sudden heating instead of slow heating was favorable for saving preparation time and controlling heating process. Moreover, the SAC prepared by sudden heating at impregnation ratio of 1 in CO2 flow showed a high specific surface area of 2648 m(2)/g. The SAC made at impregnation ratio of 2 showed a large pore volume of 1.762 cm(3)/g, superior benzene adsorption capacity (1419 mg/g), and excellent recyclability (no benzene adsorption capacity loss over 7 adsorption/desorption cycles). Both H3PO4 and CO2 contributed to the development of SACs, but the latter contributed more. This research provides a new route to prepare SACs with high application potentials in benzene adsorption. (C) 2020 Elsevier Ltd. All rights reserved.