CO2 sequestration study on the surface of mechanically activated coal at ambient temperature and pressure

Abstract

This article aims to assess the potential use of high-ash coal and evaluate the feasibility of capturing CO2 through adsorption onto the surface of mechanically activated coal at 25 degrees C and 1 atmospheric pressure in fixed-bed columns. The novelty within the study lies in its chosen methodology for comprehensively activating the coal in its natural form for CO2 sequestration for the first time, without removing the carbon, hydrocarbons, volatile, and mineral matter present in it via Mechanical Activation, employing a high-energy planetary ball mill, as opposed to the synthesis of activated porous carbon via conventional physical or chemical activation methods followed by carbonization. The results indicate that smaller ball sizes and longer milling durations lead to effective surface activation, as evidenced by particle size analysis. Furthermore, a correlation among particle size, specific surface area, and the CO2 adsorption capacity has been established. A remarkable improvement in the adsorption capacity is observed, & and the maximum adsorption (41.104 mg/g) is found in the sample activated with a 6 mm ball size for 18 hours representing a 28-fold increase compared to the feed coal (1.468 mg/g). A comparison has been made between CO2 sequestration capacity and the carbon footprint involved in the process. This substantial surge in CO2 sequestration is an environmentally benign approach to address the issue of greenhouse emissions and climate change, achieved through mechanical activation, and demonstrates superiority over chemical activation primarily due to reduced corrosive impact, diminished environmental pollution, and high-temperature prerequisite for carbonization.