This study aims to compare iso-rank vitrinite-rich and inertinite-rich coal samples to understand the impact of coal-forming processes on pyrolysis chemistry.A medium rank C bituminous coal was density-fractionated to...This study aims to compare iso-rank vitrinite-rich and inertinite-rich coal samples to understand the impact of coal-forming processes on pyrolysis chemistry.A medium rank C bituminous coal was density-fractionated to create a vitrinite-rich and an inertinite-rich sub-sample.The vitrinite-rich sample has 83 vol% total vitrinite (mineral-matter-free basis),whereas the inertinite-rich counterpart has 66 vol% total inertinite.The vitrinite-rich sample is dominated by collotelinite and collodetrinite.Fusinite,semifusinite,and inertodetrinite are the main macerals of the inertinite-rich sample.Molecular chemistry was assessed using a pyrolysis gas chromatograph (py-GC) equipped with a thermal desorption unit coupled to a time of flight mass spectrometer (MS) (py-GC/MS) and solid-state nuclear magnetic resonance (13C CP-MAS SS NMR).The pyrolysis products of the coal samples are generally similar,comprised of low and high molecular weight alkanes,alkylbenzenes,alkylphenols,and alkyl-subtituted polycyclic aromatic hydrocarbons,although the vitrinite-rich sample is chemically more diverse.The lack of diversity exhibited by the inertinite-rich sample upon pyrolysis may be interpreted to suggest that major components were heated in their geologic history.Based on the 13C CP-MAS SS NMR analysis,the inertinite-rich sample has a greater fraction of phenolics,reflected in the py-GC/MS results as substituted and unsubstituted derivatives.The greater abundance of phenolics for the inertinite-rich sample may suggest a fire-related origin for the dominant macerals of this sample.The C2-alkylbenzene isomers (p-xylene and o-xylene) were detected in the pyrolysis products for the vitrinite-rich and inertinite-rich samples,though more abundant in the former.The presence of these in both samples likely reflects common source vegetation for the dominant vitrinite and inertinite rnacerals.展开更多
^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.R...^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.展开更多
Soil nitrogen is the most important element affecting the growth and yield of crops and is also a key component of soil organic matter. Despite great efforts that have been made, the nature of about 50% of nitrogen in...Soil nitrogen is the most important element affecting the growth and yield of crops and is also a key component of soil organic matter. Despite great efforts that have been made, the nature of about 50% of nitrogen in soils and humic acids still remains obscure. Usually called unknown nitrogen, such nitrogen might be divided into two categories, the hydrolyzable nitrogen (HUN) and the nonhydrolyzable nitrogen.展开更多
基金The lead author acknowledges the Research,Education and Investment(REI)Fund of the Geological Society of South Africa(GSSA),National Research Foundation of South Africa(NRF),and the University of Johannesburg’s(UJ)Centre of Excellence for Integrated Mineral and Energy Resource Analysis(CIMERA)for funding.
文摘This study aims to compare iso-rank vitrinite-rich and inertinite-rich coal samples to understand the impact of coal-forming processes on pyrolysis chemistry.A medium rank C bituminous coal was density-fractionated to create a vitrinite-rich and an inertinite-rich sub-sample.The vitrinite-rich sample has 83 vol% total vitrinite (mineral-matter-free basis),whereas the inertinite-rich counterpart has 66 vol% total inertinite.The vitrinite-rich sample is dominated by collotelinite and collodetrinite.Fusinite,semifusinite,and inertodetrinite are the main macerals of the inertinite-rich sample.Molecular chemistry was assessed using a pyrolysis gas chromatograph (py-GC) equipped with a thermal desorption unit coupled to a time of flight mass spectrometer (MS) (py-GC/MS) and solid-state nuclear magnetic resonance (13C CP-MAS SS NMR).The pyrolysis products of the coal samples are generally similar,comprised of low and high molecular weight alkanes,alkylbenzenes,alkylphenols,and alkyl-subtituted polycyclic aromatic hydrocarbons,although the vitrinite-rich sample is chemically more diverse.The lack of diversity exhibited by the inertinite-rich sample upon pyrolysis may be interpreted to suggest that major components were heated in their geologic history.Based on the 13C CP-MAS SS NMR analysis,the inertinite-rich sample has a greater fraction of phenolics,reflected in the py-GC/MS results as substituted and unsubstituted derivatives.The greater abundance of phenolics for the inertinite-rich sample may suggest a fire-related origin for the dominant macerals of this sample.The C2-alkylbenzene isomers (p-xylene and o-xylene) were detected in the pyrolysis products for the vitrinite-rich and inertinite-rich samples,though more abundant in the former.The presence of these in both samples likely reflects common source vegetation for the dominant vitrinite and inertinite rnacerals.
基金Project supported by the National Natural Science Foundation of China.
文摘^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.
基金Project supported by the National Natural Science Foundation of China
文摘Soil nitrogen is the most important element affecting the growth and yield of crops and is also a key component of soil organic matter. Despite great efforts that have been made, the nature of about 50% of nitrogen in soils and humic acids still remains obscure. Usually called unknown nitrogen, such nitrogen might be divided into two categories, the hydrolyzable nitrogen (HUN) and the nonhydrolyzable nitrogen.
