Characterization of carbon-containing organic functional groups in sludge and construction of its model compounds

Carbon contained in the organic structure of sludge is an active element with strong chemical activity. Its thermochemical reaction occurs easily during energy conversion, which has a significant impact on the chemical characteristics and formation of the resulting products from sludge energy conversion. Firstly, the distribution of carbon-containing functional groups on the surface of sludge were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The main carbon containing functional groups in sludge include Enyl (C-C), benzene ring (pi-pi*), ether (C-O-C), carboxyl (-COOH). Based on the obtained results regarding organic carbon and the composition of common organic compounds in sludge, a few typical carbon functional group model compounds of sludge were then constructed: M-xylene (pi-pi*), tetrahydrofuran (C-O-C), acetic acid (-COOH) and cyclopentene (C=C). Finally, pyrolysis apparatus and gas chromatography /mass spectrometry (Py-GC/MS) was combined to compare the pyrolysis characteristics of sludge and carbon-containing model compounds at different temperatures. It was proved that the constructed carbon-containing model compounds were basically reasonable and reliable. © 2019, Editorial Board of China Environmental Science. All right reserved.