Green synthesis of silica gel adsorbents: microwave boosts silanol groups for improved moisture uptake

Abstract

This research investigates the influence of microwave irradiation on the silanol content and moisture adsorption capacity of silica gel prepared from clear glass waste. Employing a green and efficient microwave-assisted synthesis method, we demonstrate rapid formation of silica gel with enhanced properties. Fourier-transform infrared (FTIR) analysis confirms the presence of silanol (Si-OH) groups on the synthesized gel, with a focus on the characteristic peak at 956.44 cm⁻¹ indicating their abundance. Notably, the peak area of this peak significantly increases with increasing irradiation time (5 to 15 minutes). This translates to a parallel increase in moisture adsorption capacity, rising from 56% to 82%. The enhanced silanol content suggests the potential of microwave-derived silica gel as a high-performance desiccant, as these groups directly contribute to moisture binding. Our findings highlight the promising potential of waste glass valorization via microwave synthesis for developing sustainable and effective moisture adsorbents.