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In order to study the effects of different atmospheres ( nitrogen and air) and temperature ranges (300 ~ 500 °C, 300 ~ 700 °C and 300 ~ 900 °C ) on the composition and amount of pyrolysis products in paper-making reconstituted tobacco substrates, solid phase microextraction, adsorption-desorption and gas chromatography-mass spectrometry methods were used for analysis. The results showed that under the nitrogen and air atmospheres, the pyrolysis products of substrates at the range of 300 ~ 700 °C and 300 ~ 900 °C obviously increased when compared with those at the range of 300 ~500 °C . A large number of polycyclic aromatic hydrocarbons and olefins were produced in these two temperature ranges. Nicotine was only found in the pyrolysis products of substrates at the range of 300 ~ 500 °C. The contents of furfural and phytadiene were higher at these three temperature ranges. In the same temperature range,under the air atmosphere,the release amount of important cleavage products such as crotonaldehyde, 2-methyl-furan and furfural with relatively low molecular weight was higher than that under nitrogen atmosphere. The relative release of alcohols increased, and the presence of oxygen in air promoted the full combustion of substrates, thereby resulting in the reduction of total pyrolysis products. [ABSTRACT FROM AUTHOR]

A novel synergic evolution of dynamic assembly, from vesicles to nanotubes, between the metallophosphates and organic amines, is disclosed, by which the multicomponent metallophosphate (Cu2(OH)PO4) nanotubes are synthesized for the first time. [ABSTRACT FROM AUTHOR]

The presence of persistent free radicals (PFR) in biochars may greatly broaden the application of biochars in pollution control, but may also cause negative impacts to the environment. Understanding the structural basis and the formation mechanisms of PFR is essential for a targeted biochar production and application. This study used rice straw (RS), a ubiquitous agricultural waste, to investigate the generation processes of PFR in relation to RS pyrolysis kinetics. Based on a detailed thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis, the activation energy was calculated by Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. This work combined pyrolysis kinetics analysis and solid particle characterization. Our results showed that lignin started to pyrolyze at a lower temperature than cellulose and hemicellulose. Lignin was the main factor for PFR generation. Chemical bond breaking contributed only slightly to PFR formation. The reconfiguration of the carbonaceous structures may be a more important contributor to PFR formation, while the cross-linking between different compositions and the interactions between the chemical compositions and inorganic minerals may play a significant role for PFR generation and stabilization in RS. This study provides useful theoretical basis to understand the thermal pyrolysis process of RS and the manipulation of biochar properties. Unlabelled Image • Similar activation energies are obtained by KAS and FWO methods. • Lignin pyrolyzes at a lower temperature than cellulose and hemicellulose • Lignin is a main contributor to PFR generation in rice straw biochar. • Carbonization of the structures is the major process for PFR generation. [ABSTRACT FROM AUTHOR]