The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level c...The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.展开更多
In a large eutrophic lake,the littoral zone is normally an area with high-density elevated aquatic plant life,including algal blooms,where the presence of reed wetlands allows the accumulation of algae.In this study,t...In a large eutrophic lake,the littoral zone is normally an area with high-density elevated aquatic plant life,including algal blooms,where the presence of reed wetlands allows the accumulation of algae.In this study,the impact of accumulated algal blooms in reed wetlands in the littoral zone s of Chaohu Lake was investigated seasonally from 2018 to 2019.The concentrations of chlorophyll a(Chl a),total nitrogen(TN),and total phosphorus(TP)were much higher in the reed-covered littoral zones(RCLZ)than in the unvegetated littoral zones(ULZ),indicating that more algal biomass was trapped and accumulated in the RCLZ.Algal biomass could be horizontally transported to downwind littoral zones under low wind speeds,favoring the establishment of blooms.Algal accumulation levels were highest in summer due to high water temperatures and algal biomasses.Likewise,the northern littoral zones were conducive to the development of large algal blooms because of the wind pattern.The values of TN,TP,Chl a,and loss on ignition in surface sediments were higher in the RCLZ than in the ULZ.Moreover,the diffusive fluxes of ammonium and soluble reactive pho sphorus were also higher in the RCLZ than in the ULZ.Considering the capability of reed wetlands to trap algae,mechanical salvage and other physical methods should be adopted to eliminate algal biomass when massive blooms accumulate in the RCLZ.展开更多
基金supported by the National Natural Science Foundation of China(No.42307090)the Open Subject from State Environmental Protection Key Laboratory of Aquatic Ecosystem Health in theMiddle and Lower Reaches of Yangtze River(No.AEHKF2023008).
文摘The copper complexing of dissolved organic matter released from hydrochar(HDOM)affects the former’s environmental behavior.In this study,how hydrothermal temperatures(180,220 and 260℃)influence the molecular-level constitutions and Cu(II)binding features of HDOM were elucidated via fourier transform ion cyclotron resonance mass spectrometry and multi-spectroscopic analysis.The findings demonstrated that the almost HDOM molecules had the traits of lower polarity and higher hydrophobicity.As the hydrothermal temperature increased,the molecules with particularly high relative strength gradually disappeared,average molecular weight,percentages of CHON and aliphatic compounds of HDOM reduced while the percentages of CHO and aromatic compounds increased.In general,the fluorescence quenching of Cu(II)weakened as hydrothermal temperature rose and the Cu(II)binding stability constants of fluorophores in HDOM were 4.50–5.31.In addition,the Cu(II) binding order of fluorophores in HDOM showed temperature heterogeneities, andpolysaccharides or aromatic rings of non-fluorescent substances had the fastest responsesto Cu(II) binding. Generally, fluorescent components tend to bind Cu(II) at relatively traceconcentrations (0–40 μmol/L), whereas non-fluorescent substances tend to the bind Cu(II)at relatively higher concentrations (50–100 μmol/L). This study contributed to the predictionof the potential environmental behaviors and risks of Cu(II) at the molecular level afterhydrochar application.
基金Supported by the National Natural Science Foundation of China(Nos.41877544,32071573,42177227)。
文摘In a large eutrophic lake,the littoral zone is normally an area with high-density elevated aquatic plant life,including algal blooms,where the presence of reed wetlands allows the accumulation of algae.In this study,the impact of accumulated algal blooms in reed wetlands in the littoral zone s of Chaohu Lake was investigated seasonally from 2018 to 2019.The concentrations of chlorophyll a(Chl a),total nitrogen(TN),and total phosphorus(TP)were much higher in the reed-covered littoral zones(RCLZ)than in the unvegetated littoral zones(ULZ),indicating that more algal biomass was trapped and accumulated in the RCLZ.Algal biomass could be horizontally transported to downwind littoral zones under low wind speeds,favoring the establishment of blooms.Algal accumulation levels were highest in summer due to high water temperatures and algal biomasses.Likewise,the northern littoral zones were conducive to the development of large algal blooms because of the wind pattern.The values of TN,TP,Chl a,and loss on ignition in surface sediments were higher in the RCLZ than in the ULZ.Moreover,the diffusive fluxes of ammonium and soluble reactive pho sphorus were also higher in the RCLZ than in the ULZ.Considering the capability of reed wetlands to trap algae,mechanical salvage and other physical methods should be adopted to eliminate algal biomass when massive blooms accumulate in the RCLZ.
