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
This paper presents the carbon isotopic values of individual n alkanes in pyrolysates of algae, which are widely spread in marine and lacustrine environments. The carbon isotopic values of n alkanes originated from di...This paper presents the carbon isotopic values of individual n alkanes in pyrolysates of algae, which are widely spread in marine and lacustrine environments. The carbon isotopic values of n alkanes originated from different algal precursors vary greatly, and those of n alkanes originated from C. protothecoides, S. sp PCC 6803 and I. Galbana are even heavier than from higher plants. n alkanes with different carbon numbers derived from the same organism may stem from different biomacromolecules. The dominant product nC 31 diene yielded at 300℃ or lower temperature also is different from n alkanes yielded at the same thermal evolution phase with respect to their origin. The catalysis of mineral components in limestone may lead to a lighter carbon isotope composition of n alkanes.展开更多
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.
文摘This paper presents the carbon isotopic values of individual n alkanes in pyrolysates of algae, which are widely spread in marine and lacustrine environments. The carbon isotopic values of n alkanes originated from different algal precursors vary greatly, and those of n alkanes originated from C. protothecoides, S. sp PCC 6803 and I. Galbana are even heavier than from higher plants. n alkanes with different carbon numbers derived from the same organism may stem from different biomacromolecules. The dominant product nC 31 diene yielded at 300℃ or lower temperature also is different from n alkanes yielded at the same thermal evolution phase with respect to their origin. The catalysis of mineral components in limestone may lead to a lighter carbon isotope composition of n alkanes.
