A Novel Approach for Modification of Biosorbent by Silane Functionalization and its Industrial Application for Single and Multi-Component Solute System

The potential of an economically cheap raw material (rice husk) was evaluated in the present study to remove dyes including reactive yellow 15 (RY15) and reactive red 241 (RR241) in single and multi-component systems. The adsorbent was modified and functionalized chemically using glycidoxypropyltrimethoxysilane, sulfur and silane to enhance the removal efficiency of pollutants. The modified rice husk was evaluated by scanning electron microscope (SEM) and Fourier transform Infrared Spectroscopy (FTIR). Batch adsorption study showed that the modified rice husk with silane graft (RHSi) had highest removal efficiency of both dyes with 20% more removal compared to raw rice husk. The sorption correlated well with Langmuir, Freundlich, SIPS and Redlich-Peterson models for adsorption. Highest sorption was obtained at 10 mg L-1 of dye, 50 degrees C, 200 mg g(-1) of adsorbent dose and pH 4. The mixture of two dyes poorly fit to the original Langmuir but fit best to the Langmuir-like model. This indicates that competitive Langmuir-like model considers that the capacities of adsorbents are equal. Results showed that the components compete for the available binding sites on adsorbent surface. It was also indicated that silane grafting can offer comparatively more binding sites compared to the raw rice husk and single-solute isotherm parameters cannot used for multi-component solute system.