MCM-48 encapsulated with reduced graphene oxide/graphene oxide and as-synthesised MCM-48 application in remediation of pharmaceuticals from aqueous system

Abstract As-synthesised MCM-48 (ASM48), graphene oxide encapsulated MCM-48 (M48GO) and reduced graphene oxide encapsulated MCM-48 (M48G) was synthesised and applied in remediation of caffeine (CAF) and phenacetin (PHE) from aqueous solution. Effects of surfactant template (cetyltrimethylammonium bromide) on MCM-48 on the removal of CAF and PHE from wastewater samples was also investigated. Adsorbents were characterized with the following techniques; FTIR, TGA, XRD, SEM, TEM, BET, EA. Elemental analysis revealed ASM48 had improved hydrophobic properties and the successful synthesis of M48GO and M48G. All adsorbents were applied in batch sorption studies of CAF and PHE to determine the effects of adsorbent dose, pH and initial concentration. Adsorption mechanism was through π-π interaction, EDA interaction and hydrophobic effects. Sorption kinetics showed that the data fitted pseudo-second order and intraparticle diffusion models. Equilibrium data obtained fitted the Freundlich and Langmuir adsorption isotherm. M48G had the best adsorption capacity of 153.8 and 212.7 mg/g for CAF and PHE, respectively and ASM48 showed significant adsorption which was attributed to increased hydrophobicity created by the surfactant template in ASM48. Thermodynamic studies revealed adsorption process as spontaneous and exothermic. Desorption studies revealed that adsorbents could be regenerated and reused for adsorption.