Preparation of Nanoporous Silica Aerogel from Wheat Husk Ash by Ambient Pressure Drying Process for the Adsorptive Removal of Lead from Aqueous Solution

Abstract

Hydrophilic nonporous silica aerogels were synthesized from a low-cost wheat husk silica precursor via ambient pressure drying method for the first time. The prepared aerogels were characterized by using Fourier transform infrared spectra (FTIR), nitrogen adsorption/desorption measurement and scanning electron microscopy- energy dispersive X-ray (SEM -EDX) techniques. The aerogels were used in adsorption of lead (II) ions from aqueous solutions under various conditions such as pH, the adsorbent dosage, the initial lead (II) concentration and the contact time. The optimum adsorption efficiency (99%) was obtained in a pH of 5.5, adsorbent dosage of 4 g L-1, initial lead concentration of 50 mg mL-1 and contact time of 30 minutes. The adsorption data was well described by Langmuir isotherm and pseudo-second-order kinetic model. These results show that low-cost silica aerogel prepared from an agricultural waste can be used as an effective sorbent for lead (II) ions removal.