Carboxymethyl-imidazolium O-vanillin Schiff base grafted into NH2-tagged MIL-101 (Cr) for effective removal of cupric ions from aqueous effluents.

Abstract

A novel adsorbent (MIL-CMIVSB) was fabricated by modification of H2N-MIL-101(Cr) with carboxymethyl-imidazolium O-vanillin Schiff base. The MIL-CMIVSB's physicochemical characteristics were examined using the pertinent characterization methods. NH2-MIL-101(Cr) has a BET surface area of 1492.4 m2g-1, while MIL-CMIVSB adsorbent had 1278.7 m2g-1. Batch adsorption experiments examined the MIL-CMIVSB's cupric ion adsorption capacity from aqueous solutions at different adsorbent doses (0.1-3mg), pH (2.0-10.0), contact times (0-240min), metal ion initial concentrations (10-300mg/L), and temperatures (298-308K). The optimum conditions were 1mg/mL of MIL-CMIVSB adsorbent, 46min adsorption time, pH 7, 100ppm initial cupric ion concentration, and 303K temperature. MIL-CMIVSB effectively and selectively removes cupric ions with an adsorption capability of 359.05 ± 12.06mg/g. The nonlinear Liu isotherm governed Cu(II) sorption performance on MIL-CMIVSB (KL = 0.257 ± 0.01mg/g, R2 = 0.99892) and pseudo-2nd-order kinetically (k2 = 0.00116 × 10-4g/mg min, R2 = 0.99721).