Synthesis of Porous Boron-Doped Carbon Nitride: Adsorption Capacity and Photo-Regeneration Properties

Carbon nitride (CN) with improved adsorption–degradation capacity was synthesized using B(2)O(3) and CN via calcination. The pollutant removal capacity of this B(2)O(3)/CN (B-CN) was studied by a powder suspension experiment and added into concrete to evaluate the adsorption and degradation of methylene blue (MB). The characterizations of all samples indicate that B(2)O(3) significantly affects CN, e.g., by increasing the CN specific surface area to 3.6 times the original value, extending visible light adsorption, and narrowing the band gap from 2.56 eV to 2.42 eV. Furthermore, the results show that B-CN composite materials have a higher MB-removal efficiency, with the adsorption capacity reaching 43.11 mg/g, which is about 3.3 times that of pristine CN. The MB adsorption process on B2-CN is mainly via electrostatic attraction and π–π interactions. In addition, B-CN added into concrete also has good performance. After five adsorption–degradation cycles, B-CN and photocatalytic concrete still exhibit a good regenerate ability and excellent stability, which are very important for practical applications.