Adjusting Porosity of Zhundong Coal-based Activated Carbons Based on Catalytically Physical Activation Process With Trace Calcium Source

At present, high raw material cost and complex preparation process are the main keys to limit the large-scale application of high performance porous carbon. Physical activation method has been well commercialized due to low production cost, which is regarded as the simplest and most economical craft. In this work, we select the recently discovered Zhundong coal, a typical low-rank coal as feedstocks and use the catalytic gasification of intrinsic or adding minerals, to study the changing regularity of pore structure for coal-based activated carbons. As a result, the typical microporous carbon was obtained by mineral-free coal sample, while hierarchically porous carbon could be obtained by raw coal samples or Ca-loaded coal samples. The catalytic gasification of the intrinsic or external Ca source was beneficial to the formation of the mesoporous pore through the analysis of the phase before and after the coal activation and the TGA of activation reaction process. At the same time, ball mill assisted processing has synergistic effect on pore development. To verify the application potentials of resulting activated carbons with various pore structure, Rhodamine B (RhB) removal tests were conducted. As-obtained hierarchically porous carbons are applicative for RhB removal. Hierarchically porous ZD(B)-AC has the best performance for RhB adsorption with capacity up to 400 mg•g^-1 after 1 min. This work not only offers a new route for adjusting the porosity of activated carbons during physical activation process, but also provides a simple and scalable method for preparing coal-based activated carbons for rapidly liquid adsorption application.