Removal of silica from rice straw by using alkaline hydrogen peroxide solution in a fixed bed column

Abstract

This paper investigates the efficiency of alkaline hydrogen peroxide (AHP) solution to remove silica from rice straw in a fixed-bed column. Characterization of rice straw was performed by using Fourier transforms infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques. The experiments were operated with different bed heights (12 and 7 cm), influent H2O2 concentrations (2, 4, 6, 8 and 10 %) using constant flow rates (2 mL/min) in order to obtain experimental breakthrough curves. The maximum silica removal was observed 3.0575 mg/g at 8% of AHP influent concentration at 12 cm bed depth. To evaluate the column performance, Adams-Bohart model and Thomas model were used. To analyzed the Adams- Bohart and Thomas model parameter the value of rate constant decreases with increase of influent concentration, but increases with increasing the bed depth.