Amino Silica Nanohybrid Membranes for Enhanced Removal of Cu(II) Ion in Aqueous Solutions

With the growing industrialization, heavy metal pollution of water has become an urgent concern. In the present study, we investigated a method of Cu(II) decontamination of water using amino-functionalized silica nanoparticles. In situ functionalized di (S-NN) and tri (S-NNN) amino-modified silica nanoparticles (SNPs) were synthesized using facile microwave-assisted sol-gel-based method and were characterized using FT-IR, Raman spectroscopy, DLS, SEM, TEM, and XPS. During the adsorption experiments, the S-NN and S-NNN achieved maximum adsorption capacities of 87.48 mg g-1 and 97.29 mg g-1 respectively for 110-ppm initial Cu(II) at a pH of 5, implying higher nitrogen content increases the removal capacity. In addition, a comparison of Cu(II) removal efficiency by S-NN and S-NN incorporated electrospun cellulose acetate (CA) nanofiber membranes was also performed and almost similar removal efficiencies of 41.7 +/- 2.3% and 45.2 +/- 6.2% achieved respectively at 20-ppm initial Cu(II) concentration. The study demonstrated that the incorporation of S-NN nanoparticles into electrospun membranes can create a portable filter material without compromising the removal efficiency of pristine S-NN. The adsorption of Cu(II) followed pseudo-second-order kinetics implying chemisorption of the metal ions onto nanoparticles and the isothermal data fitted well with the Freundlich model emphasizing multilayer adsorption. Overall, the possibility of adopting a low-cost, environmentally friendly adsorbent for Cu(II) removal is highlighted in this work, which will lead to innovative purification techniques in future.