Amide-functionalized g-C3N4 nanosheet for the adsorption of arsenite (As3+): Process optimization, experimental, and density functional theory insight

Long-term exposure to arsenite (As3+) from water resources poses a global health concern. In the current study, g-C3N4 (C3N4) nanosheets were functionalized with amide groups to increase their adsorption capacity to remove As3+ from aqueous environments. Experimental assessments and density functional theory (DFT) calculations have been utilized to explore the adsorption characteristics of As3+ on C3N4 and amide-functionalized C3N4 (AC3N4) nanosheets. The central composite design (CCD) method unveiled the optimal operating conditions, including a pH level of 6.5, an adsorbent mass of 0.12 g, and an As3+ initial concentration of 250 mg/L. The AC3N4 nanosheet showed a higher adsorption capacity (205.8 mg/g) than the pristine C3N4 nanosheet (27.7 mg/g). The experimental data demonstrated conformity with the Freundlich isotherm in the adsorption study. DFT calculations revealed that the As3+/AC3N4 complex exhibited a higher adsorption energy (-40.98 eV) and stronger covalent bonds than the As3+/C3N4 complex (28.34 eV). The outstanding adsorptive properties of AC3N4 present it as an effective adsorbent for eliminating heavy metal ions from water, highlighting its capability for environmental remediation. [Display omitted]