Effective sequestration of tetracycline from aqueous streams using metal-free chemically functionalized porous g-C₃N₄

The facile preparation of visible-light-driven low-cost photocatalysts with extraordinary catalytic activity is highly beneficial in treating emerging pharmaceutical contaminants. Herein, oxalic acid-induced chemically functionalized graphitic carbon nitride (OCN) was prepared using a one-pot calcination method for the degradation of tetracycline. The estimated structural, morphological, and optical properties proved the formation of highly porous oxalic acid functionalized g-C₃N₄ (OCN) with enhanced surface area and abundant amino groups. The photocatalytic degradation studies reported a maximum tetracycline removal of 92% within 90 min of visible light illumination and followed pseudo-first-order kinetics (k = 0.03068min^-1). The phenomenal photocatalytic efficacy of the functionalized OCN is ascribed to the increased presence of amino groups, strengthening visible light absorption. The enriched surface area also generated many active sites for the reclamation of tetracycline. The radicals trapping studies show that holes and superoxides are mainly responsible for the redemption of tetracycline. The degradation pathways of the tetracycline using OCN were predicted using HRMS. This study provides more insights into the reclamation of tetracycline using a highly efficient metal-free photocatalyst.