ABSTRACT
In this work, a combined mechanical activation and FeCl3 (MA + FeCl3) method was applied to pretreat chitin to enhance the degree of hydrothermal carbonization. MA + FeCl3 pretreatment significantly disrupt the crystalline region of chitin and Fe3+ entered into the molecular chain, resulting in the destruction of the stable structure of chitin. The chemical and structural properties of hydrochars were characterized by EA, SEM, FTIR, XRD, XPS, 13C solid state NMR, and N2 adsorption-desorption analyses. The results showed that the H/C and O/C atomic ratios of HC-MAFCT/230 (the hydrochar derived from MA + FeCl3 pretreated chitin with hydrothermal reaction temperature of 230 °C) were 0.96 and 0.34, respectively. Van Krevelen diagram indicated that the hydrothermal carbonization of chitin underwent a series of reactions such as dehydration, decarboxylation, and aromatization. HC-MAFCT/230 had abundant oxygen- and nitrogen-containing functional groups. HC-MAFCT/230 exhibited a porous structure, with the specific surface area of 128 m2 g-1, which was a promising carbon material.
Subject(s)
Carbon/chemistry , Chitin/chemistry , Chlorides/chemistry , Ferric Compounds/chemistry , Mechanical Phenomena , Temperature , Water/chemistry , Adsorption , Carbohydrate Conformation , Carbon-13 Magnetic Resonance Spectroscopy , Charcoal/chemistry , Nitrogen , Photoelectron Spectroscopy , Porosity , Spectroscopy, Fourier Transform Infrared , X-Ray DiffractionABSTRACT
The study aims to qualitatively and quantitatively analyze phenolic acids and flavonoids in Artemisiae Argyi Folium cultivated in Qichun(Qiai) for the quality control of this genuine regional herbs. UPLC-LTQ-Orbitrap-MS was used for rapid separation and structural identification of the constituents. Samples were separated on an UPLC column(2. 1 mm×100 mm,1. 8 µm) by gradient elution using 0. 1% formic acid and acetonitrile as mobile phases at a flow rate of 0. 4 m L·min-1. By UPLC-LTQ-Orbitrap-MS,16 compounds including phenolic acids and flavonoids were identified by comparison with reference standards or literature data. For quantitative analysis,12 identified compounds were simultaneously determined by UPLC-DAD at wavelengths of 330 nm. The method was validated with respect to linearity,precision,repeatability,stability and recovery. The contents of these compounds were found to differ significantly between the samples from Qichun and other areas. This strategy was novel,effective and straightforward,which provided a potential approach for holistic quality control of Qiai.
