In order to achieve the dual goals of complete deamination of magnesium ammonium phosphate（MAP） and ensure the pyrolysate＇s good removal properties towards ammonia-nitrogen, a temperature-programmed method for the ...In order to achieve the dual goals of complete deamination of magnesium ammonium phosphate（MAP） and ensure the pyrolysate＇s good removal properties towards ammonia-nitrogen, a temperature-programmed method for the pyrolysis of MAP was studied, as well as the thermodynamic and kinetic processes involved in the removal reaction system between MAP pyrolysate and aqueous ammonium. It was found that the pyrolysis method and pyrolysis final temperature had significant effects on the MAP pyrolysate＇s removal properties towards aqueous ammonium, and the following conditions were deemed to be more appropriate： pyrolysis final temperature and heating rate at 180 ℃ and 5 ℃/min, respectively, and a pH level of 9.5 for the removal reaction system. The resultant ammonium removal capacity by the MAP pyrolysate was 95.62 mg/g. After 120 min, the removal rate with an initial concentration of 1000 mg/L was 82%. The kinetic and thermodynamic results indicated that the removal of aqueous ammonium by MAP pyrolysate was the exchange process between H^＋ and NH4^＋ via MAP precipitation. The kinetics complied with the Lagergren quasi second-order model with an equilibrium time of 120 min, while the isothermal curves complied with the Freundlich model.展开更多
Analyses of the original and pyrolytic products of coccolithophore at various temperatures suggest that the contribution of coccolithophore to the formation of large immature oil reservoirs should attract keen interes...Analyses of the original and pyrolytic products of coccolithophore at various temperatures suggest that the contribution of coccolithophore to the formation of large immature oil reservoirs should attract keen interest. Through biochemical processes algae can change inorganic sulphur into organic sulphur, which could be one of the most important precursors of organic sulphur compounds in oil and source rocks. When Methylphenanthrene Index (MPI) and Methylphenanthrene Ratio (MPR) indices were used to evaluate the evolution degree of source rocks and oil maturity, other maturity indices must be used together for correction. In low maturity, the relative abundances of diben-zothiophene (DBT), fluorine (F) and dibenzofuran (DBF) can be used to identify the oxidation-reduction environments.展开更多
The asphaltene fractions of the bitumens of Eastern Dahomey Basin in Nigeria,were analyzed by flash pyrolysis-gas chromatography(Py-GC)method in order to unravel its geochemical history and properties.The distribution...The asphaltene fractions of the bitumens of Eastern Dahomey Basin in Nigeria,were analyzed by flash pyrolysis-gas chromatography(Py-GC)method in order to unravel its geochemical history and properties.The distributions of the initial biomarkers of the original oils from the pyrolysates are related to the assessment of organic matter source,paleo-redox conditions and source environment during deposition.Also,it effectively establishes the genetic relationship of the bitumens.The n-alkane distributions in the pyrolysates reveal nC_(9)-nC_(32)n-alkanes,maximizing at nC_(14),isoprenoids-pristane(Pr)and phytane(Ph),and some n-alkene peaks.High peaks of low to medium-weight nC_(9)-nC20 n-alkanes and low peaks of nC_(21)+n-alkanes characterize the distributions.These reveal that abundant algal organic matter with some terrigenous inputs contributed to the source rock of the bitumens.The high concentration of marine organic matter inputs to the source rock is further confirmed by the nC_(17)/nC27 ratios which range from 5.39 to 19.82 and shows the predominance of nC_(17)alkanes.The general unimodal n-alkane distributions in the bitumens indicate derivation from similar organic matter types showing that they are genetically related.The anoxic to suboxic environmental conditions that prevailed during the deposition of the sediments is revealed by the isoprenoids,Pr/Ph ratios(0.72-1.28).Pristane/nC_(17)and Phytane/nC_(18)range from 0.16 to 0.33 and 0.22 to 0.56,revealing that the bitumens were from predominantly marine organic matter(type II kerogen)preserved in a reducing environment with no evidence of biodegradation.However,the Ph/nC_(18)ratio and the cross plot of Pr+Ph/nC_(17)+nC_(18)allow the classification of the bitumens into two subfamilies/groups(A and B).The bitumen samples have low wax content as indicated by the degree of waxiness ranging from 0.21 to 0.38 which confirms low terrigenous input.Based on the carbon preference index(CPI:0.92 to 1.55)and odd-even predominance(OEP:0.70 to 1.36),it is concluded that the bitumens are immature to marginally mature.展开更多
The large amount of microplanktonic algae in nature are not all thermally degraded directly into organic matter from their original green autotrophic state. When the algae are old or dead and deposited at the bottom o...The large amount of microplanktonic algae in nature are not all thermally degraded directly into organic matter from their original green autotrophic state. When the algae are old or dead and deposited at the bottom of lake or ocean, some changes may take place in the cells, including the disappearance of the chlorophyll, the展开更多
Enukuania huxleyi is marine nanoplanktonic alga with calcify scale called coccolith om its cell surface.This ubiquitous species with the Lafgest biomass in marice forms gigantic blooms covering thousands
基金Project(ZDSY20120619093952884)supported by Shenzhen Strategic New Industry Development,China
文摘In order to achieve the dual goals of complete deamination of magnesium ammonium phosphate（MAP） and ensure the pyrolysate＇s good removal properties towards ammonia-nitrogen, a temperature-programmed method for the pyrolysis of MAP was studied, as well as the thermodynamic and kinetic processes involved in the removal reaction system between MAP pyrolysate and aqueous ammonium. It was found that the pyrolysis method and pyrolysis final temperature had significant effects on the MAP pyrolysate＇s removal properties towards aqueous ammonium, and the following conditions were deemed to be more appropriate： pyrolysis final temperature and heating rate at 180 ℃ and 5 ℃/min, respectively, and a pH level of 9.5 for the removal reaction system. The resultant ammonium removal capacity by the MAP pyrolysate was 95.62 mg/g. After 120 min, the removal rate with an initial concentration of 1000 mg/L was 82%. The kinetic and thermodynamic results indicated that the removal of aqueous ammonium by MAP pyrolysate was the exchange process between H^＋ and NH4^＋ via MAP precipitation. The kinetics complied with the Lagergren quasi second-order model with an equilibrium time of 120 min, while the isothermal curves complied with the Freundlich model.
基金This study was supported by the National Natural Science Foundation of China (Grant No. 39870064) and the State Key Basic Research Development Program (Grant No. G19990433).
文摘Analyses of the original and pyrolytic products of coccolithophore at various temperatures suggest that the contribution of coccolithophore to the formation of large immature oil reservoirs should attract keen interest. Through biochemical processes algae can change inorganic sulphur into organic sulphur, which could be one of the most important precursors of organic sulphur compounds in oil and source rocks. When Methylphenanthrene Index (MPI) and Methylphenanthrene Ratio (MPR) indices were used to evaluate the evolution degree of source rocks and oil maturity, other maturity indices must be used together for correction. In low maturity, the relative abundances of diben-zothiophene (DBT), fluorine (F) and dibenzofuran (DBF) can be used to identify the oxidation-reduction environments.
基金The authors acknowledge the Nigerian Geological Survey Agency(NGSA)which made available core samples(from shallow exploration wells in the bitumen belt of Eastern Dahomey Basin)used for this study.Flash pyrolysis-gas chromatography(Py-GC)analyses were performed at the Geochemistry Laboratory of Newcastle University,United Kingdom.
文摘The asphaltene fractions of the bitumens of Eastern Dahomey Basin in Nigeria,were analyzed by flash pyrolysis-gas chromatography(Py-GC)method in order to unravel its geochemical history and properties.The distributions of the initial biomarkers of the original oils from the pyrolysates are related to the assessment of organic matter source,paleo-redox conditions and source environment during deposition.Also,it effectively establishes the genetic relationship of the bitumens.The n-alkane distributions in the pyrolysates reveal nC_(9)-nC_(32)n-alkanes,maximizing at nC_(14),isoprenoids-pristane(Pr)and phytane(Ph),and some n-alkene peaks.High peaks of low to medium-weight nC_(9)-nC20 n-alkanes and low peaks of nC_(21)+n-alkanes characterize the distributions.These reveal that abundant algal organic matter with some terrigenous inputs contributed to the source rock of the bitumens.The high concentration of marine organic matter inputs to the source rock is further confirmed by the nC_(17)/nC27 ratios which range from 5.39 to 19.82 and shows the predominance of nC_(17)alkanes.The general unimodal n-alkane distributions in the bitumens indicate derivation from similar organic matter types showing that they are genetically related.The anoxic to suboxic environmental conditions that prevailed during the deposition of the sediments is revealed by the isoprenoids,Pr/Ph ratios(0.72-1.28).Pristane/nC_(17)and Phytane/nC_(18)range from 0.16 to 0.33 and 0.22 to 0.56,revealing that the bitumens were from predominantly marine organic matter(type II kerogen)preserved in a reducing environment with no evidence of biodegradation.However,the Ph/nC_(18)ratio and the cross plot of Pr+Ph/nC_(17)+nC_(18)allow the classification of the bitumens into two subfamilies/groups(A and B).The bitumen samples have low wax content as indicated by the degree of waxiness ranging from 0.21 to 0.38 which confirms low terrigenous input.Based on the carbon preference index(CPI:0.92 to 1.55)and odd-even predominance(OEP:0.70 to 1.36),it is concluded that the bitumens are immature to marginally mature.
基金Project supported by the National Natural Science Foundation of Chinathe State Key Laboratory of Organic Geochemistry.
文摘The large amount of microplanktonic algae in nature are not all thermally degraded directly into organic matter from their original green autotrophic state. When the algae are old or dead and deposited at the bottom of lake or ocean, some changes may take place in the cells, including the disappearance of the chlorophyll, the
文摘Enukuania huxleyi is marine nanoplanktonic alga with calcify scale called coccolith om its cell surface.This ubiquitous species with the Lafgest biomass in marice forms gigantic blooms covering thousands
