Visible Light Active Magnesium Silicate–Graphitic Carbon Nitride Nanocomposites for Methylene Blue Degradation and Pb²⁺ Adsorption

Abstract

Magnesium silicate nanosheets (MgSiNS) and graphitic carbon nitride (g-C3N4) nanocomposites were produced by varying different weight percentages of g-C3N4. The obtained nanocomposites were characterized by various techniques such as X-Ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), diffuse reflectance UV–vis spectroscopy (DR UV–vis), N2-physisorption, transmission electron microscopy (TEM), and X-ray photon spectroscopy (XPS). The photocatalytic activities of the nanocomposites were measured using visible light irradiation to degrade methylene blue (MB) and Pb2+ adsorption in aqueous solution. The ideal physicochemical properties such as porosity, band gap energy, and functional groups in the MgSiNS-GN20 composite (80% MgSiNS and 20 wt % of g-C3N4) offered high Pb2+ adsorption (0.005 mol/g) and excellent MB degradation efficiency (approximately 93%) at pH 7 within 200 min compared to other composites. In addition, the influences of different reaction parameters such as the effect of pH, the load catalyst, and the concentration of MB and Pb+2 ions were examined. The obtained results indicate that inexpensive and eco-friendly MgSiNS and g-C3N4 composites could be recycled several times, hence representing a promising material to purify water from both organic and inorganic contaminants.

Keywords

• magnesium silicate
• g-C₃N₄
• nanosheets
• photodegradation
• methylene blue
• visible light