Synthesis of Silicate Nanoporous and Its Grafting with Amine and Metal Ligands for the Removal of Cr(VI) in Industry and Environment

The carcinogenicity and high toxicity of chromium (VI) show that the removal of this pollutant in industry, water resources, and the environment is necessary. Nanoporous materials have a high ability to remove pollutants. The aim of this study was to synthesize SBA-16 nanostructure using P123 and F127 surfactants and TEOS precursor and grafting its surface in two steps with -NH2 (NH2-SBA-16) and then with copper (Cu-NH2-SBA -16). Cu-NH2-SBA-16 was identified as a new adsorbent by XRD, SEM, EDX, and FT-IR analysis. The synthesis of nanoporous functionalized with amino group -NH2 was done by reflux and then grafting of prepared nanoporous with copper (II) solution was performed. The maximum adsorption capacity of NH2-SBA-16 and Cu-NH2-SBA-16 was 6.66 and 34.48 mg/g, respectively. In addition, the kinetics of chromium adsorption followed the pseudo-second-order kinetic model. The maximum efficiency of chromium removal by Cu-NH2-SBA-16 for contact time, initial concentration, amount of adsorbent, pH and temperature were 15 min, 10 mg/l, 1 g/l, 2, and 25 °C, respectively; adsorption capacity of Cu-NH2-SBA-16 increased after the modification process. The synthesized nanoadsorbent with an efficiency of 90% had a spontaneous and endothermic adsorption process, and its adsorption capacity did not decrease significantly after 3 regenerations.