Poly(ethyleneimine)-exfoliated g-C₃N₄ nanosheets implanted in alginate beads and their application towards adsorptive desulfurization

Advances in material science dictate the search for sustainable options that target diverse applications that impact climate change. In this context, we report the exfoliation and expansion of g-C₃N₄ using PEI polymer, followed by gelation as beads using calcium alginate for adsorptive desulfurization of thiophene compounds. Adsorbent characteristics were exemplified through FT-IR, FE-SEM-EDX, TGA, XRD, BET-N₂ isotherm, contact angle meter, XPS, HR-TEM, ZPC, and UTM. The PEI–g-C₃N₄ NSs@Ca-Alg bead composite with a mesoporous structure gave a specific surface area of 142.062 m² g⁻¹ yielding a high adsorption capacity of 183.03 mg S g⁻¹. The material exhibited an ultimate tensile strength of 3500 kPa and a compressive stress of 527 kPa, accompanied by a compressive strain of 79%. The isotherm, kinetics, and thermodynamic investigations confirmed that the system exhibits pseudo-first-order kinetics and exothermic characteristics with spontaneity. The composite material had good potential for re-use for up to 5 adsorptive–desorption cycles with the potential to decrease the sulfur content to 58% in commercial diesel fuel.