Thermal and structural analysis of the reaction mechanisms during the preparation of activated carbon from sugarcane bagasse by urea phosphate activation
Haifeng Zuo, Zhigao Liu
Abstract
In this study, sugarcane bagasse was used to prepare urea phosphate activated carbons (UPACs) using a novel activator urea phosphate (UP) at three different temperatures (300 ℃, 550 ℃, and 800 ℃) to analyze the reaction mechanism during the pyrolysis process by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), elemental analysis, and thermogravimetric Fourier transform infrared spectroscopy-mass spectrometry (TG-FTIR-MS), to deduce the reaction mechanism of UP activation. Below 300 °C, the functional groups on the surface of sugarcane bagasse fibers undergo hydroxyl dehydration and oxidation reactions, and molecular chains were broken to produce H2O, CH4, CO2, H2, HCHO, and NH3 small molecule gas products. At 300–800 °C was the main temperature range for activation reactions, and the molecular structure gradually formed an ordered carbon network structure. Nitrogen-containing compounds were gradually transformed into graphite N and oxidized N as temperature increased and functional groups containing phosphorus underwent decomposition. Above 800 °C, the pyrolysis was basically complete. Phosphorus compounds were completely decomposed, with fewer macromolecular products and gaseous products being mainly H2O, CO2, CO, and HCHO.