Fabricating functionalized carbon nitride using leachate evaporation residue and its adsorptive application

Abstract

Herein, we report a leachate evaporation residue (LER) functionalized carbon nitride (g-C3N4) material (RCNs) through a facile one-step calcination strategy, which simultaneously realizes the resource utilization of LER and its application in environmental remediation. The alkali metals (K, Na) and alkaline earth metals (Ca, Mg) in the LER were confirmed to be successfully anchored within the tri-s-triazine ring units or interlayer. LER inorganic salts cause the C-N = C bonds in RCNs to break and form cyanide groups, while organic compounds introduce aromatic rings and C = O/C-O functional groups into RCNs. These structural deformations in RCNs provides more adsorption sites for methylene blue (MB). Maximum RCNs adsorption capacity for MB increased to 1166.7 mg/g, which exceeded most of the carbon-based adsorbent materials. Meanwhile, RCNs were comprehensively evaluated as excellent selective adsorption, recycling, and practical utilization feasibility for MB. The adsorption mechanism has been systematically confirmed and attributed to fortified electrostatic interaction, hydrogen bonding, cation-π, and π-π interactions. This work provides a feasible strategy for modifying carbon nitride with high-value organic–inorganic composite waste.