Two-dimensional activated carbon nanosheets for rapid removal of tetracycline via strong π-π electron donor receptor interactions

Natural flake structure of corn stalk piths is utilized to prepare two-dimensional nanosheets via a simple activation method. The nanosheets with ultra-high specific area exhibit a fast and high-efficient adsorption capacity of tetracycline, which is better than those of other biochar derived from agricultural waste because the formation of abundant π-π electron donor receptor interactions. Mechanism studies indicates that the π-π electron donor receptor interactions, pore filling and hydrogen bonding were responsible for TC adsorption. [Display omitted] •Transform agricultural waste corn straw piths into nanosheets by a simple method.•The nanosheets exhibit fast and high-efficient TC adsorption capacity.•The importance of π-π EDA interactions in rapid adsorption is revealed.•The mechanism of adsorption was systematically studied. Two-dimensional carbonaceous materials have sparked extensive attention in organic pollutants adsorption due to their unique structure to facilitate the formation of the physical or chemical bonding. Herein, natural two-dimensional porous activated carbon nanosheets with ultra-high specific surface area (2276.44 m2 g−1) are prepared by alkaline immersion-assisted circulating calcination techniques from corn straw piths. The prepared nanosheets exhibit rapid tetracycline adsorption capacity (633 mg g−1 within 5 min) and high equilibrium adsorption capacity of 804.5 mg g−1. Significantly, the nanosheets can adapt to a wide range of pH (at least between pH = 3–10) and are almost unaffected by coexisting ions. Mechanism studies and theoretical calculations demonstrate that the rapid and high-efficient adsorption of tetracycline mainly depends on the π-π electron donor receptor interactions. In addition, hydrogen bonding and pore filling was also responsible for tetracycline adsorption. This work provides important guidance for the development of the biobased high-performance adsorbents from agricultural waste.