A incorporation of metal into worm-like mesoporous silica materials for selective adsorption of MB in dyestuff

Abstract

Worm-like mesoporous silica was synthesized using hydroxyethyl cellulose (HEC) as the template agent and sodium metasilicate as the silicon source (hereinafter referred to as HECMS). Different types of metal-doped adsorbents (namely Zr-HECMS-P, Fe-HECMS-P, and Al-HECMS-P) were prepared using the post-grafting method. The three adsorbents were used for the selective adsorption of methylene blue (MB) from an MB/methylene orange (MO) solution. Results showed that under acidic conditions, Fe-HECMS-P exhibited simultaneous adsorption of MB and MO, whereas Zr-HECMS-P and Al-HECMS-P preferably adsorbed MB. Zr-HECMS was determined to be the best adsorbent based on the evaluation results of the selective-adsorption effect of MB in different adsorption environments. Furthermore, different zirconium-silicon molar ratio samples were synthesized (The name is designated as Zr(0.01)-HECMS-P, Zr(0.02)-HECMS-P and Zr(0.04)-HECMS-P.). Results revealed that at pH = 3 and an initial MB concentration of 25 mg/L, Zr(0.01)-HECMS-P exhibited the best selective-adsorption performance for MB, reaching adsorption equilibrium in 2 h with a maximum removal rate of 97.8 %. The adsorption process followed a pseudo-second-order model, and the adsorption mechanism involved coordination and electrostatic action. In a simple binary system (MB + MO), the Zr(0.01)-HECMS-P adsorbent exhibited good selectivity for the MB dye. Finally, after five cycles of regeneration, the adsorption performance of Zr(0.01)-HECMS-P remains stable.