Sodium borohydride-modified graphitic carbon nitride for enhanced tetracycline removal from aqueous solution

Graphite carbon nitride (g-C₃N₄) is a promising inorganic nonmetallic material. However, due to its small specific surface area and insufficient active centers, the adsorption capacity is very low. In order to improve the adsorption performance of g-C₃N₄, we employed a soft-template method to modify g-C₃N₄ with NaBH₄, resulting in the synthesis of the RCN-1-550 adsorbent, which exhibited a larger specific surface area and enhanced active sites. Compared to unmodified g-C₃N₄, RCN-1-550 exhibited a significantly increased specific surface area and introduced nitrogen vacancies and electron-deficient −C≡N groups, which greatly enhanced its adsorption capacity. RCN-1-550 had enhanced adsorption capacity for tetracycline (TC), which was 4.96 times that of the original g-C₃N₄, and the removal rate could reach 98.56 %. Additionally, RCN-1-550 achieved adsorption equilibrium within 10 min and could be reused at least five times. These results highlight the potential of RCN-1-550 as an effective and sustainable adsorbent for the removal of antibiotics from wastewater, offering a promising solution for environmental pollution control and water purification applications.