Fabrication and characterization of a novel nanoporous nanoaerogel based on gelatin as a biosorbent for removing heavy metal ions

In this research, we proposed a synthesis of nano-silica aerogel (NSA, S₁–S₃) and nano-silica aerogel gelatin (NSA-G, S₄–S₆), which were hybrid aerogel by sol–gel method via ambient pressure drying. The aerogels’ backbone was modified by montmorillonite (MMT) in NSA and for NSA-G gelatin (G) and MMT were used to stabilize their building block. Also, free hydroxyl groups on their surface were changed to TMS-O and became more hydrophobic aerogels. The porosity results showed that the density of the optimum aerogels (S₂ and S₅) ranged from 0.084 to 0.047 g/cm³. It was also found that the hydrophobicity of the NSA-G aerogel decreased with increasing the content of gelatin into the silica aerogels. However, these aerogels were fully characterized by FTIR, FESEM, EDS, XRD, BET, and TGA/DTA analysis and they used as the adsorbent of Cu²⁺ and Ni²⁺ ions in aqueous media. The prepared aerogels effectively could remove these heavy metals from the aqueous media and NSA-G absorbent also illustrated a favorable result for adsorption. Also, the recyclability test for four adsorption–desorption of aerogels cycles was examined and they had a good effect even after the fourth cycle.