Adsorption of cationic dyes from aqueous solution using hydrophilic silica aerogel via ambient pressure drying

Abstract

In order to remove the organic dyes of textile waste water, the silica aerogel was successfully prepared by using E-40 as a novel precursor and then dried in ambient pressure. The synthesized sample was verified by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). After calcining, the hydrophilic silica aerogel (HSA) was used as adsorbent to remove Methylene Blue (MB), Malachite Green (MG), and Gentian Violet (GV) from aqueous solution. The effects of initial concentration of dyes and adsorbent dosage on the adsorption process were examined. It was found that HSA showed excellent adsorption capacities, the maximum percentage of removal dyes could reach 98%. Herein, the Langmuir, Freundlich and de Boer-Zwikker isotherm modes were employed to discuss the adsorption behavior. The results indicated that the de Boer–Zwikker model can effectively describe the adsorption behavior. Besides, the HSA could be utilized as the recyclable adsorbent in degradation experiment, after five cycles, no obvious loss of adsorption capacity was found. As an efficient, low-cost, environmental friendly and recyclable adsorbent, silica aerogel is expected to be used for dyes removal. • Hydrophobic silica aerogel was successfully synthesized by using E-40 as a novel precursor • Hydrophilic silica aerogel showed excellent adsorption capacity for cationic dyes • Hydrophilic silica aerogel showed a higher adsorption capacity toward methylene blue than the other cationic dyes • The prepared sample could be easily regenerated and showed good reusability • Hydrophilic silica aerogel could be a potent candidate for water purification