As a special biofilm structure,microbial attachment is believed to play an important role in the granulation of aerobic granular activated sludge（AGAS）.This experiment was to investigate the biological effect of Ca^...As a special biofilm structure,microbial attachment is believed to play an important role in the granulation of aerobic granular activated sludge（AGAS）.This experiment was to investigate the biological effect of Ca^2＋,Mg^2＋,Cu^2＋,Fe^2＋,Zn^2＋,and K＋which are the most common ions present in biological wastewater treatment systems,on the microbial attachment of AGAS and flocculent activated sludge（FAS）,from which AGAS is always derived,in order to provide a new strategy for the rapid cultivation and stability control of AGAS.The result showed that attachment biomass of AGAS was about 300%higher than that of FAS without the addition of metal ions.Different metal ions had different effects on the process of microbial attachment.FAS and AGAS reacted differently to the metal ions as well,and in fact,AGAS was more sensitive to the metal ions.Specifically,Ca^2＋,Mg^2＋,and K＋could increase the microbial attachment ability of both AGAS and FAS under appropriate concentrations,Cu^2＋,Fe^2＋,and Zn^2＋were also beneficial to the microbial attachment of FAS at low concentrations,but Cu^2＋,Fe^2＋,and Zn^2＋greatly inhibited the attachment process of AGAS even at extremely low concentrations.In addition,the acylated homoserine lactone（AHL）-based quorum sensing system,the content of extracellular polymeric substances and the relative hydrophobicity of the sludges were greatly influenced by metal ions.As all these parameters had close relationships with the microbial attachment process,the microbial attachment may be affected by changes of these parameters.展开更多
Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanopartic...Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution.展开更多
Quantum dots(QDs)based heterojunction is a candidate for the photocatalytic CO_(2)reduction,owing to the large extinction coefficient and easy modification of band structures.However,the van der Waals interaction caus...Quantum dots(QDs)based heterojunction is a candidate for the photocatalytic CO_(2)reduction,owing to the large extinction coefficient and easy modification of band structures.However,the van der Waals interaction causes the large charge resistance and strong recombination centers between QDs and host materials,which makes the poor photocatalytic performance.Herein,a covalent bonded CdSeTeQDs and NH_(2)-UiO-66 heterojunction(NUC-x)is constructed through an acylamino(-CONH-).The results indicate that the acylamino between NH_(2)-UiO-66 and Cd Se Te QDs can serve as the transfer channels for the photogenerated charges and stabilize the QDs.The optimized NUC-1200 achieved a CO generation rate of 228.68μmol/g,which is 13 and 4 times higher than that of NH_(2)-UiO-66 and Cd Se Te QDs,respectively.This work provides a new avenue for efficient and stable photocatalysis of QDs.展开更多
To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution ...To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community;however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria,Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38%in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.展开更多
Flexible thermoelectric power generation isincreasingly recognized as a viable solution for poweringwearable electronic devices. However, the performance limitationsof n-type flexible thin films have restricted their ...Flexible thermoelectric power generation isincreasingly recognized as a viable solution for poweringwearable electronic devices. However, the performance limitationsof n-type flexible thin films have restricted their widerapplication. Here, we successfully fabricated n-type Ag_(2)Se thinfilms with a high power factor of 2.14 mW m^(−1) K^(−2) at 300 Kthrough texture engineering. Utilizing a straightforwardthermal evaporation technique, we produced (201)-textured ntypeAg_(2)Se thin films by employing Se precursor strategies.Both experimental and theoretical analyses reveal that Ag_(2)Sethin films with this specific orientation exhibit superior carriermobility and a high Seebeck coefficient. Moreover, theinherent low thermal conductivity of Ag_(2)Se is further reducedby the presence of nanopores and random in-plane orientation,which effectively scatter phonons across various wavelengths.As a result, the Ag_(2)Se films achieved an optimal ZTvalue of 0.73 at 363 K, suggesting substantial potential forfurther improvements. This research not only demonstrates astrategic method to manipulate the crystallographic orientationof Ag_(2)Se thin films but also opens up new possibilities fordeveloping high-performance thermoelectric materials.展开更多
基金supported by the National Natural Science Foundation of China (No. 51578069)
文摘As a special biofilm structure,microbial attachment is believed to play an important role in the granulation of aerobic granular activated sludge（AGAS）.This experiment was to investigate the biological effect of Ca^2＋,Mg^2＋,Cu^2＋,Fe^2＋,Zn^2＋,and K＋which are the most common ions present in biological wastewater treatment systems,on the microbial attachment of AGAS and flocculent activated sludge（FAS）,from which AGAS is always derived,in order to provide a new strategy for the rapid cultivation and stability control of AGAS.The result showed that attachment biomass of AGAS was about 300%higher than that of FAS without the addition of metal ions.Different metal ions had different effects on the process of microbial attachment.FAS and AGAS reacted differently to the metal ions as well,and in fact,AGAS was more sensitive to the metal ions.Specifically,Ca^2＋,Mg^2＋,and K＋could increase the microbial attachment ability of both AGAS and FAS under appropriate concentrations,Cu^2＋,Fe^2＋,and Zn^2＋were also beneficial to the microbial attachment of FAS at low concentrations,but Cu^2＋,Fe^2＋,and Zn^2＋greatly inhibited the attachment process of AGAS even at extremely low concentrations.In addition,the acylated homoserine lactone（AHL）-based quorum sensing system,the content of extracellular polymeric substances and the relative hydrophobicity of the sludges were greatly influenced by metal ions.As all these parameters had close relationships with the microbial attachment process,the microbial attachment may be affected by changes of these parameters.
基金the National Natural Science Foundation of China(Nos.51868050,51938007,51878325,51868052,52100186,52170082,and 52063024)the Natural Science Foundation of Jiangxi Province(Nos.20202BAB213011 and 20181BBG78034)the Scientific Research Foundation of Nanchang Hangkong University(No.EA201902377)。
文摘Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution.
基金the financial support of the National Natural Science Foundation of China(Nos.52100186 and 52170082)the Natural Science Foundation of Jiangxi Province(No.20212ACB203008)。
文摘Quantum dots(QDs)based heterojunction is a candidate for the photocatalytic CO_(2)reduction,owing to the large extinction coefficient and easy modification of band structures.However,the van der Waals interaction causes the large charge resistance and strong recombination centers between QDs and host materials,which makes the poor photocatalytic performance.Herein,a covalent bonded CdSeTeQDs and NH_(2)-UiO-66 heterojunction(NUC-x)is constructed through an acylamino(-CONH-).The results indicate that the acylamino between NH_(2)-UiO-66 and Cd Se Te QDs can serve as the transfer channels for the photogenerated charges and stabilize the QDs.The optimized NUC-1200 achieved a CO generation rate of 228.68μmol/g,which is 13 and 4 times higher than that of NH_(2)-UiO-66 and Cd Se Te QDs,respectively.This work provides a new avenue for efficient and stable photocatalysis of QDs.
基金This work was supported by the Special Fund for Forest Scientific Research in the Public Welfare of China(No.201104068).
文摘To date, research on the adverse effects of continuous cropping has focused on field crops;forest plantations, despite their very significant economic and ecological value, have received less attention. The evolution of microbial community in the rhizosphere of forest plantations, in particular, has rarely been examined. In this study, changes in the size, composition, and structure of bacterial and fungal communities in the rhizosphere of different generations of poplar (Populus deltoides) plantations were studied using real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis and compared with the composition of the microbial community in a bare land (control) adjacent to the plantation sites through sequencing analysis and by constructing phylogenetic trees. The numbers of bacteria and fungi increased significantly with successive poplar generations, although the increases in the two groups were not parallel. When compared with the control, the bacterial community increased greatly in the second generation, and the most significant increase occurred in the third generation. In contrast, the most significant increase in the fungal community occurred in the first generation, and the increase in the third generation was insignificant. In terms of community composition, the first generation showed little change in either community;however, the second generation showed remarkable changes in the bacterial community, and the third in the fungal community. The numbers of Gammaproteobacteria,Alphaproteobacteria, and Actinobacteria increased by 10.92%, 7.38%, and 5.46%, respectively, whereas those of Acidobacteria decreased by 18.38%in the second generation. These changes in the number and composition of microbial communities in the rhizosphere could be one of the reasons for the decline in yield and quality associated with long-term monoculture.
基金supported by the National Key Research and Development Program of China (2023YFB3809400)the National Natural Science Foundation of China (52130203 and 92463310)。
文摘Flexible thermoelectric power generation isincreasingly recognized as a viable solution for poweringwearable electronic devices. However, the performance limitationsof n-type flexible thin films have restricted their widerapplication. Here, we successfully fabricated n-type Ag_(2)Se thinfilms with a high power factor of 2.14 mW m^(−1) K^(−2) at 300 Kthrough texture engineering. Utilizing a straightforwardthermal evaporation technique, we produced (201)-textured ntypeAg_(2)Se thin films by employing Se precursor strategies.Both experimental and theoretical analyses reveal that Ag_(2)Sethin films with this specific orientation exhibit superior carriermobility and a high Seebeck coefficient. Moreover, theinherent low thermal conductivity of Ag_(2)Se is further reducedby the presence of nanopores and random in-plane orientation,which effectively scatter phonons across various wavelengths.As a result, the Ag_(2)Se films achieved an optimal ZTvalue of 0.73 at 363 K, suggesting substantial potential forfurther improvements. This research not only demonstrates astrategic method to manipulate the crystallographic orientationof Ag_(2)Se thin films but also opens up new possibilities fordeveloping high-performance thermoelectric materials.
