Selective removal of Cu(II) ions by magnetic mesoporous silica with surface ion-imprinted quaternized Schiff base coating.

The highly selective capture and efficient utilization of recovered Cu(II) ions using a multifunctional material holds substantial practical significance. In this study, a novel type of magnetic adsorbent, MSBA-IIA, was successfully synthesized by grafting a Cu(II) ion-imprinted quaternized salicylaldehyde Schiff base coating onto the surface of magnetic mesoporous silica, aiming to enhance the recognition and separation selectivity for target ions during the adsorption process. Batch Cu(II) ion adsorption experiments demonstrated a dependence of adsorption efficiency on the solution pH level. The Cu(II) adsorption behavior onto MSBA-IIA followed the pseudo-second-order adsorption kinetic model and Langmuir isothermal model. MSBA-IIA exhibited a maximum adsorption capacity of 32.7 mg/g, surpassing that of the non-ion-imprinted counterpart MSBA-NIIA. Thermodynamic study unveiled the spontaneous and exothermic nature of the adsorption process. The relative separation factors α' of MSBA-IIA for Cu(II) were determined to be much more than 1, suggesting that the imprinted adsorbent exhibited superior selectivity for Cu(II) ions in the presence of other co-existing metal ions when compared to the MSBA-NIIA. Due to its magnetic collection and regenerable nature, the proposed approach holds promise for the selective removal of Cu(II) ions from water. Highlight: MSBA-IIA with surface Cu(II) ion-imprinted coating was prepared. MSBA-IIA is capable of selectively adsorbing and recovering Cu(II) ions. The maximum adsorption capacity is 32.7 mg/g for Cu(II) ions. The adsorbent shows excellent reusability. [ABSTRACT FROM AUTHOR]