Record-high benzene adsorption capacity of colloid-imprinted mesoporous carbons synthesized from biomass by ball milling

Abstract

A facile mechanochemical synthesis was used for the preparation of mesoporous carbons with large uniform mesopores. The one-pot synthesis relied on the fast ball milling of only two reagents, tannins, and silica colloids, within 10 min, followed by direct thermal treatment at 750 °C leading to carbons with uniform mesopores of about 25 nm, high specific surface areas up to ∼1000 m²/g, and total pore volumes up to 2.80 cm³/g. This seems to be the first attempt to employ mechanochemistry for the synthesis of colloid-imprinted carbons. Moreover, the procedure can be easily extended for the synthesis of carbons with bimodal mesoporosity by adding a Pluronic-type soft template to the milling system. The latter synthesis afforded carbons with bimodal mesoporosity, having predominantly pore sizes of 13.8 and 24.8 nm, a high specific surface area of 1218 m²/g, and an exceptionally high pore volume of 4.75 cm³/g, without using an activating agent. To the best of our knowledge, this sample adsorbed a record amount of benzene at 20 °C, namely 48.0 mmol/g (375 wt%). It is shown that the total pore volume is a determining factor for benzene adsorption on diverse porous solids. High mesoporosity in carbons might be essential in adsorption and catalysis-related applications.