Optimization and surface functionalization of biologically synthesized mesoporous silica nanoparticles to remove ASA drug from water: Sorption and regeneration study

Abstract

Several studies have reported the rapid development of adsorbents with high efficacy, high stability and ample porosity for environmental remediation, where it still represents the significant challenges due to their expensive and less ecofriendly production. In present study, a newly optimized and functionalized green biosurfactant-mediated silica nanoparticle utilized to improve the surface properties and effectively remove the toxic drug acetylsalicylic acid (ASA) from water. The successful synthesis and physicochemical properties of BMSN (Biologically synthesized mesoporous silica nanoparticles), A-BMSN-NH2 and A-BMSN-CS was carried out through characterization techniques such as FESEM, HRTEM, EDXS, XRD, FTIR, BET, and XPS. However, FESEM and HRTEM analysis reveal the perfectly spherical particles with minimal aggregation (60–82nm). The XRD confirms amorphous characteristics and FTIR indicates the presence of Si-O and –NH groups. Furthermore, BET demonstrates a high surface area of 0.015 (40.1907m2/g), and XPS identifies Si-O-Si linkages with strong binding energy. Furthermore, the study also examined the influence of various experimental parameters during the optimization process of adsorption study, including adsorbent dosage, pH, initial concentration, contact time, and temperature. The adsorption study demonstrated the highest removal efficiency at pH∼6 with effective adsorbent (A-BMSN-CS) dosage of 3.25mg/40mL, and optimum initial concentration 100ppm over 180min at room temperature. Moreover, Freundlich isotherm model (R2=0.88014) exhibited well-fitted with higher adsorption capacity as compared to other isotherm models in case of A-BMSN-CS adsorbent. The adsorption kinetics described well-fitted by Pseudo second order model comprising R2=0.99999. In addition, thermodynamic parameters exhibited that the adsorption of ASA on adsorbents surface is spontaneous and exothermic process due to negative values of ΔH°, ΔS°, and ΔG°. Therefore, the promising formed adsorbents could be highly recommended to use in potential significant applications including use as drug carrier in pharmaceutics, heavy metals removal, energy storage, as biomarkers, etc.