The use of functionalized aerogels as a low level chromium scavenger

• High sorption capacity and fast removal of sorbed ions.
• Single step synthesis and easy handling.
• No swelling in solvent and high thermodynamic stability.
• Can be used in radioactive and chemical environment.
• Regeneration and complete recovery of the sorbed ions.

This paper communicates synthesis of aminopropyl functionalized aerogel by grafting 3-aminopropyltrimethoxy silane (APTMS) onto the surface of nano sol–gel silica by post synthetic grafting procedure. The physico-chemical behavior of the grafted silica is investigated by SEM, XRD, FTIR and TGA techniques. The BET surface area analysis technique is used for the determination of the surface area, total pore volume and pore diameter. The effectiveness of chromium removal was systematically monitored as a function of the pH of the medium, agitation time, Cr(III) ions concentration and functionalized silica dosage. The chromium uptake followed Freundlich, Langmuir and D–R isotherm models and sorption capacity computed from the Langmuir model is 1.67 mmol g−1. The effect of temperature on sorption is also checked and various thermodynamic parameters like ΔH, ΔS, and ΔG are calculated and discussed. Regeneration studies show that the sorbent is reusable. The effect of interfering cations and anions is also investigated.

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