Offshore oil pollution has caused serious impacts on plants and aquatic organisms in the marine ecosystem.Bioremediation of oil pollution by immobilized bacteria has aroused wide attention due to the high degradation ...Offshore oil pollution has caused serious impacts on plants and aquatic organisms in the marine ecosystem.Bioremediation of oil pollution by immobilized bacteria has aroused wide attention due to the high degradation rate compared with free bacteria.The properties of the carrier for immobilization play an important role in the oil degradation efficiency.In our study,a marine oil degrading bacteria Sp8(Shewanella algae)was selected from sea water,and enteromorpha was used as carrier material for the immobilization of Sp8.In order to increase the hydrophobicity,sodium dodecylbenzene sulfonate(SDBS)was used as modifier to modify the surface of enteromorpha by the dipping method.Sodium alginate was used as the embedding carrier,and anhydrous calcium chloride was used as the cross-linking agent to prepare the SDBS-E immobilized microbial agent by the embedding method.Compared with the degradation rate achieved by free bacteria(78.87±8.29%),the diesel removal rate accomplished by SDBS-E immobilized microbial agent increased to 90.39±1.24%.The analysis of diesel removal mechanism showed that the diesel removal pathway mainly included surface adsorption,internal uptake,and biodegradation.The diesel removal efficiency relied on surface adsorption in the early stage,and then depended on biodegradation in the later stage.The removal of diesel by SDBS-E immobilized microbial agent conformed to the quasi-first-order degradation kinetic model.The results of software-MOE suggested that enteromorpha-immobilized microbial agent adsorbed diesel mainly through hydrogen bonds formed with diesel components.This study can provide a research basis and idea for the practical application of immobilization technology to remove petroleum from seawater in the future.展开更多
As one of the methods of urban environmental assessment,sensitivity assessment of urban climatic environment can accurately reflect the problem areas of current urban climate and built environment through visual means...As one of the methods of urban environmental assessment,sensitivity assessment of urban climatic environment can accurately reflect the problem areas of current urban climate and built environment through visual means,and help cities to carry out sustainable transformation and renewal in the stock era to optimize the living environment.Taking the central urban area of Beijing as the research object,the sensitivity of climatic environment was evaluated by meteorological data and built environment element data.The results showed that the distribution of sensitive units showed a centrifugal radiation pattern of"high in the center and low in the periphery".Block units with high climate sensitivity were mostly concentrated in Xicheng District and Dongcheng District,accounting for 93%of the total number of units.Further research showed that complex built environment and lack of elements to regulate climatic environment were the main reasons for the poor local climatic environment in the region with high climate sensitivity.Finally,a comprehensive evaluation of the remolding capacity,renewal potential and future development intensity of different grades of climate sensitive units was given.The results will provide scientific reference for urban renewal and reconstruction under climatic and environmental changes,so as to promote urban sustainable development and improvement of living environment.展开更多
基金This study was funded by the scientific research fund project of National Natural Science Foundation of China(Grant No.52070123)the Natural Science Foundation of Shandong Province(grant numbers ZR2020ME224,ZR2019PB031)the Project of Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team[Wastewater treatment and resource innovation team].
文摘Offshore oil pollution has caused serious impacts on plants and aquatic organisms in the marine ecosystem.Bioremediation of oil pollution by immobilized bacteria has aroused wide attention due to the high degradation rate compared with free bacteria.The properties of the carrier for immobilization play an important role in the oil degradation efficiency.In our study,a marine oil degrading bacteria Sp8(Shewanella algae)was selected from sea water,and enteromorpha was used as carrier material for the immobilization of Sp8.In order to increase the hydrophobicity,sodium dodecylbenzene sulfonate(SDBS)was used as modifier to modify the surface of enteromorpha by the dipping method.Sodium alginate was used as the embedding carrier,and anhydrous calcium chloride was used as the cross-linking agent to prepare the SDBS-E immobilized microbial agent by the embedding method.Compared with the degradation rate achieved by free bacteria(78.87±8.29%),the diesel removal rate accomplished by SDBS-E immobilized microbial agent increased to 90.39±1.24%.The analysis of diesel removal mechanism showed that the diesel removal pathway mainly included surface adsorption,internal uptake,and biodegradation.The diesel removal efficiency relied on surface adsorption in the early stage,and then depended on biodegradation in the later stage.The removal of diesel by SDBS-E immobilized microbial agent conformed to the quasi-first-order degradation kinetic model.The results of software-MOE suggested that enteromorpha-immobilized microbial agent adsorbed diesel mainly through hydrogen bonds formed with diesel components.This study can provide a research basis and idea for the practical application of immobilization technology to remove petroleum from seawater in the future.
基金Sponsored by General Project of Natural Science Foundation of Beijing City(8202017)Youth Talent Support Program of 2018 Beijing Municipal University Academic Human Resources Development(PXM2018_014212_000043)。
文摘As one of the methods of urban environmental assessment,sensitivity assessment of urban climatic environment can accurately reflect the problem areas of current urban climate and built environment through visual means,and help cities to carry out sustainable transformation and renewal in the stock era to optimize the living environment.Taking the central urban area of Beijing as the research object,the sensitivity of climatic environment was evaluated by meteorological data and built environment element data.The results showed that the distribution of sensitive units showed a centrifugal radiation pattern of"high in the center and low in the periphery".Block units with high climate sensitivity were mostly concentrated in Xicheng District and Dongcheng District,accounting for 93%of the total number of units.Further research showed that complex built environment and lack of elements to regulate climatic environment were the main reasons for the poor local climatic environment in the region with high climate sensitivity.Finally,a comprehensive evaluation of the remolding capacity,renewal potential and future development intensity of different grades of climate sensitive units was given.The results will provide scientific reference for urban renewal and reconstruction under climatic and environmental changes,so as to promote urban sustainable development and improvement of living environment.
