Efficient Removal of Methylene Blue by Micro-/Mesoporous Heteroatom-doped Biochar Derived from Waste Bovine Horn

Abstract

Abstract Efficient removal of dyes from wastewater has become an urgent issue due to the rapid industrial development and increasing health concern. Here, micro-/mesoporous heteroatom-doped biochars (BHBs) were prepared from waste bovine horn by controlled pyrolysis. The BHB that had undergone a pre-oxidation reaction before pyrolysis has honeycomb-like porous structure with high specific surface area of 2447.41 m2 g− 1 and the pore size of lower than 5 nm. The tunable porous structure of the biochar could shorten the travel distance of dye molecules from external surface of biochar to inner surface of pores. And the heteroatoms could enhance the interactions, including electrostatic interaction and hydrogen bonding interaction between carbon surface and methylene blue molecules. For adsorption of methylene blue, the BHB exhibited high adsorption capacity of 1720.92 mg g− 1 at 30 ℃ and could reach a removal efficiency of near 100% in 0.5 h. The excellent adsorption performance of BHB for dye makes it a potential adsorbent for wastewater purification.