Removal of Hexamethyldisiloxane via a Novel Hydrophobic (3-Aminopropyl)Trimethoxysilane-Modified Activated Porous Carbon.

Abstract

Volatile methyl siloxanes (VMS) must be removed because the formation of silica in the combustion process seriously affects the resource utilization of biogas. Herein, a series of APTMS ((3-aminopropyl)trimethoxysilane)-modified activated porous carbon (APC) adsorbents (named APTMS@APC) were prepared for VMS efficient removal. The as-prepared adsorbents were characterized using SEM, FTIR, Raman, X-ray diffraction analyses, and N2 adsorption/desorption. The results showed that the surface modification with APTMS enhanced the hydrophobicity of APC with the water contact angle increasing from 74.3° (hydrophilic) to 127.1° (hydrophobic), and meanwhile improved its texture properties with the SBET increasing from 981 to 1274 m2 g-1. The maximum breakthrough adsorption capacity of APTMS@APC for hexamethyldisiloxane (L2, model pollutant) was 360.1 mg g-1. Effects of an inlet L2 concentration (31.04-83.82 mg L-1) and a bed temperature (0-50 °C) on the removal of L2 were investigated. Meanwhile, after five adsorption-desorption cycles, the APTMS@APC demonstrated a superior cycling performance. This indicated that the hydrophobic APTMS@APC has a great significance to remove VMS.