Graphitic Carbon Nitride Nanosheet as an Excellent Compound for the Adsorption of Calcium and Magnesium Ions: Theoretical and Experimental Studies

In this work, the removal of calcium (Ca۲+) and magnesium (Mg۲+) ions was studied using graphitic carbon nitride (g-C۳N۴) nanosheet as an adsorbent from aqueous solutions. In experimental studies, the effects of various adsorption parameters were investigated by batch method culture including pH, initial Ca۲+ and Mg۲+ concentrations, temperature, time, and adsorbent mass. The best results were obtained at pH=۸.۵۰, ۰.۰۵ g of g-C۳N۴, ۹۰ min, ۱۰ ppm of ion concentration, ۲۳.۸۰ mg/g of maximum adsorption capacity for Ca۲+, and pH=۹, ۰.۰۵ g of g-C۳N۴, ۶۰ min, ۱۵ ppm of ion concentration, ۴۰.۰۰ mg/g maximum adsorption capacity for Mg۲+ ion. The adsorption of calcium and magnesium ions obeyed the Langmuir model on the adsorbent. In a theoretical study, g-C۳N۴ nanosheet as an interesting material was studied by first-principle calculation using the Quantum Espresso package. The Ca۲+ and Mg۲+ ions were located at different positions on g-C۳N۴ nanosheet to obtain a stable configuration. The Eads, HOMO, LUMO, Eg, band structure, DOS, and PDOS plots were investigated at a stable configuration of g-C۳N۴ nanosheet. The adsorption energy (Eads) was calculated -۱۵.۵۵ and -۲۶.۲۴ eV for Ca۲+ and Mg۲+ ions, respectively. Further, the results indicated that Mg۲+can be located at the center of the porous g-C۳N۴ nanosheet, and the adsorption of Mg۲+ on the surface of g-C۳N۴ nanosheet was stronger than that of Ca۲+ ion. Theoretical and experimental data confirmed each other’s findings. The adsorption of Ca۲+ and Mg۲+ ions was shown to be simple, high-yield, eco-friendly, and economical performance from aqueous solutions using g-C۳N۴ nanosheet.

کلیدواژه ها:

Graphitic carbon nitride nanosheet ، Adsorption ، Calcium ، Magnesium ، DFT