Design and fabrication of highly ordered ion imprinted SBA-15 and MCM-41 mesoporous organosilicas for efficient removal of Ni2+ from different properties of wastewaters

We developed two types of novel highly ordered Ni2+ imprinted mesoporous organosilica materials (SBA-15 (NiIMS1) and MCM-41 (NiIMS2)) through co-condensation for selective adsorption of Ni2+ from electroplating Ni2+ effluents. FTIR and solid-state 13C NMR spectra demonstrated the successful embedment of functionalized iminodiacetic acid and ethanediamine chelating groups in NiIMS1 and NiIMS2, respectively. X-ray photoelectron spectroscopy analysis confirmed that Ni2+ was coordinated by N atom and carboxyl O atom of the functional groups. Furthermore, NiIMS1 and NiIMS2 displayed highly ordered periodic hexagonal P6mm meso-structure, large surface area, and highly specific recognition ability toward Ni2+. The adsorption experimental results proved that NiIMS1 was suitable for acidic wastewater treatment, whereas NiIMS2 was fit for alkaline wastewater. The saturated adsorption capacity of NiIMS2 was 20.8 mg/g at pH 6.0, and that of NiIMS1 reached up to 22.9 mg/g at pH 3.0. The values of selectivity coefficients of NiIMS1 and NiIMS2 for five competing metal ions ranged from 46.4 to 12.4 and 36.9 to 18.8, respectively. The adsorption efficiency of NiIMS1 was above 92.5% even after seven extraction-stripping cycles, while that for NiIMS2 was 90.9%. The real sample adsorption experiments demonstrated that these mesoporous organosilica materials have high potential for water treatment applications.