A novel method based on the selective pressure of particle size （particle-size cultivation method, PSCM） was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and c...A novel method based on the selective pressure of particle size （particle-size cultivation method, PSCM） was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity （settling-velocity cultivation method, SVCM）. Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14 days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids （MLSS） in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrifieation and phosphorus removal, but lower settling velocity. Under long term operation of more than 30 days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand （COD）, NH4^＋-N, total nitrogen （TN） and total phosphorus （TP） removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors.展开更多
The floc morphology was investigated in a continuous-flow reactor, in order to understand the evolution of flocs in practical flocculation and sedimentation processes in water utilities. Kaolin-humic acid suspension w...The floc morphology was investigated in a continuous-flow reactor, in order to understand the evolution of flocs in practical flocculation and sedimentation processes in water utilities. Kaolin-humic acid suspension was used as the test water, and polyaluminum chloride was chosen as the coagulant. An in-situ recognition system was applied to analyze the floc size, boundary fractal dimension, and eccentricity ratios. Particle numbers and turbidity were also determined in the sedimentation stage. At a coagulant dose of 1 mg/L as Al, the average floc size increased from 62 to 78 μm and the boundary fractal dimension was around 1.14, suggesting that flocs were compact and continuously grew during the entire flocculation process. However, with the dose increased to 5 mg/L, the average floc size decreased and stabilized at around 65 μm, with the fractal dimension of 1.20. It can be concluded that the excess coagulant doses resulted in the formation of chain-shaped, lower density, and more branched structure flocs, thereby restricting flocs’ further growth in the subsequent flocculation. Floc morphology analysis suggested that charge neutralization dominated in the initial flocculation stage, then the bridge and sweep mechanisms were dominant in the subsequent flocculation. In addition, compared with the traditional inclined plate settler, a novel V-shaped plate settler introduced in this study had an advantage in small size floc（less than 5 μm） removal. The V-shaped region could promote aggregate restructuring and re-flocculation; therefore, the V-shaped plate settler provides an alternative method for sedimentation.展开更多
The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe （Fe/AC） in acetonitrile using H2O2 as the oxidant was studied in a continuous flow reactor. Results showed that the continuous...The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe （Fe/AC） in acetonitrile using H2O2 as the oxidant was studied in a continuous flow reactor. Results showed that the continuous operation could obtain high phenol yield of 28.1%, coupled with the turnover frequency of 3 h^-1, and high selectivity of 98% under mild condition. The catalyst was characterized by N2 adsorption/desorption, Boehm titration, X-ray photoelectron spectra, and Fourier transform infrared spectroscopy. It was observed that iron may interact with the carboxyl group forming iron-carboxylate like species, which act as the active phase. The apparent activation energy obtained by fitting an Arrhenius model to the experimental data was 13.4 kJ/mol. The reaction order was calculated to be about i, 0.2 for benzene and 0.7 for H202.展开更多
Erlotinib is an orally administered, highly effective, specific epidermal growth factor receptor tyrosine kinase inhibitor, used to treat non-small cell lung cancer and pancreatic cancer. The traditional synthetic met...Erlotinib is an orally administered, highly effective, specific epidermal growth factor receptor tyrosine kinase inhibitor, used to treat non-small cell lung cancer and pancreatic cancer. The traditional synthetic methods for Erlotinib exhibit long reaction time and safety concern. Herein, we describe a novel five-step route for the synthesis of Erlotinib in flow. These five steps comprise etherification, nitration, reduction,addition and cyclization reactions. All steps were optimized and converted to continuous flow process,which drastically reduces the reaction time and considerably improves the process safety as well as the total yield. Enabled by five continuous flow units, Erlotinib is efficiently afforded with an E-factor of 38,an overall yield of 83%, and a total residence time of 25.1 min. Majority steps in this process have been optimized for quantitative conversion, which offers the possibility of telescoping the entire process.展开更多
Reductive amination by amine dehydrogenases is a green and sustainable process that produces only water as the by-product.In this study,a continuous flow process was designed utilizing a packed bed reactor filled with...Reductive amination by amine dehydrogenases is a green and sustainable process that produces only water as the by-product.In this study,a continuous flow process was designed utilizing a packed bed reactor filled with co-immobilized amine dehydrogenase wh84 and glucose dehydrogenase for the highly efficient biocatalytic synthesis of chiral amino alcohols.The immobilized amine dehydrogenase wh84 exhibited better thermo-,pH and solvent stability with high activity recovery.(S)-2-aminobutan-1-ol was produced in up to 99%conversion and 99%ee in the continuous flow processes,and the space-time yields were up to 124.5 g L-1 d-1.The continuous reactions were also extended to 48 h affording up to 91.8%average conversions.This study showcased the important potential to sustainable production of chiral amino alcohols in continuous flow processes.展开更多
This paper reports a comparative evaluation between 2 kinetic models for predicting nitrification and biodegradable organics(BOD5)removal rates in 5 vertical flow(VF)wetland systems,that received strong wastewaters(i....This paper reports a comparative evaluation between 2 kinetic models for predicting nitrification and biodegradable organics(BOD5)removal rates in 5 vertical flow(VF)wetland systems,that received strong wastewaters(i.e.tannery,textile and municipal effluents).The models were formulated by combining first order and Monod kinetics,with continuous-stirred tank reactor(CSTR)flow approach.The performance of the 2 models had been evaluated with3 statistical parameters:coefficient of determination(R2),relative root mean square error(RRMSE),and model efficiency(ME).The statistical parameters indicated better performance of the Monod CSTR model(over first order CSTR approach),for correlating ammoniacal nitrogen(NH4+—N)and BOD5removal profiles across VF systems.Higher Monod coefficient values(from Monod CSTR model)coincided with greater input NH4+—N and BOD5loading,and experimentally measured removal rate(g/(m2·d))values.Such trends indicate that NH4+—N and BOD5removals in the VF systems were mainly achieved via biological routes.On the other hand,the rate constants(from the first order CSTR model)did not exhibit such correlations(of Monod coefficients),elucidating their inefficiencies in capturing overall removal mechanisms.The interference of organics removal on nitrification process(in VF wetlands)was identified through Monod coefficients.The deviation between NH4+—N and BOD5Monod coefficients imply incorporation of both coefficients,for calculating the area of a single VF bed.Overall,closer performance of the Monod CSTR model for predicting NH4+—N and BOD5removals indicate its potential application,as a design tool for VF systems.展开更多
基金supported by the National Natural Science Foundation of China (No. 51208231)
文摘A novel method based on the selective pressure of particle size （particle-size cultivation method, PSCM） was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity （settling-velocity cultivation method, SVCM）. Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14 days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids （MLSS） in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrifieation and phosphorus removal, but lower settling velocity. Under long term operation of more than 30 days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand （COD）, NH4^＋-N, total nitrogen （TN） and total phosphorus （TP） removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors.
基金supported by the National Science and Technology Major Project of Twelfth Five Years(Nos.2014ZX07201-012-2,2013ZX07201007-002)the National Innovation Team supported by the National Science Foundation of China(No.50821002)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2012DX07)
文摘The floc morphology was investigated in a continuous-flow reactor, in order to understand the evolution of flocs in practical flocculation and sedimentation processes in water utilities. Kaolin-humic acid suspension was used as the test water, and polyaluminum chloride was chosen as the coagulant. An in-situ recognition system was applied to analyze the floc size, boundary fractal dimension, and eccentricity ratios. Particle numbers and turbidity were also determined in the sedimentation stage. At a coagulant dose of 1 mg/L as Al, the average floc size increased from 62 to 78 μm and the boundary fractal dimension was around 1.14, suggesting that flocs were compact and continuously grew during the entire flocculation process. However, with the dose increased to 5 mg/L, the average floc size decreased and stabilized at around 65 μm, with the fractal dimension of 1.20. It can be concluded that the excess coagulant doses resulted in the formation of chain-shaped, lower density, and more branched structure flocs, thereby restricting flocs’ further growth in the subsequent flocculation. Floc morphology analysis suggested that charge neutralization dominated in the initial flocculation stage, then the bridge and sweep mechanisms were dominant in the subsequent flocculation. In addition, compared with the traditional inclined plate settler, a novel V-shaped plate settler introduced in this study had an advantage in small size floc（less than 5 μm） removal. The V-shaped region could promote aggregate restructuring and re-flocculation; therefore, the V-shaped plate settler provides an alternative method for sedimentation.
文摘The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe （Fe/AC） in acetonitrile using H2O2 as the oxidant was studied in a continuous flow reactor. Results showed that the continuous operation could obtain high phenol yield of 28.1%, coupled with the turnover frequency of 3 h^-1, and high selectivity of 98% under mild condition. The catalyst was characterized by N2 adsorption/desorption, Boehm titration, X-ray photoelectron spectra, and Fourier transform infrared spectroscopy. It was observed that iron may interact with the carboxyl group forming iron-carboxylate like species, which act as the active phase. The apparent activation energy obtained by fitting an Arrhenius model to the experimental data was 13.4 kJ/mol. The reaction order was calculated to be about i, 0.2 for benzene and 0.7 for H202.
基金the National Natural Science Foundation of China(Nos.21878088, 21476077)Key Projects of Shanghai Science and Technology Commission (No.18DZ1112703) for financial support。
文摘Erlotinib is an orally administered, highly effective, specific epidermal growth factor receptor tyrosine kinase inhibitor, used to treat non-small cell lung cancer and pancreatic cancer. The traditional synthetic methods for Erlotinib exhibit long reaction time and safety concern. Herein, we describe a novel five-step route for the synthesis of Erlotinib in flow. These five steps comprise etherification, nitration, reduction,addition and cyclization reactions. All steps were optimized and converted to continuous flow process,which drastically reduces the reaction time and considerably improves the process safety as well as the total yield. Enabled by five continuous flow units, Erlotinib is efficiently afforded with an E-factor of 38,an overall yield of 83%, and a total residence time of 25.1 min. Majority steps in this process have been optimized for quantitative conversion, which offers the possibility of telescoping the entire process.
基金supported by the National Key Research and Development Program of China(No.2021YFA0910400 and 2019YFA0905100)the National Natural Science Foundation of China(No.32171462)+1 种基金Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(No.TSBICIP-CXRC-040)the Natural Science Foundation of Tianjin(No.21JCJQJC00110).
文摘Reductive amination by amine dehydrogenases is a green and sustainable process that produces only water as the by-product.In this study,a continuous flow process was designed utilizing a packed bed reactor filled with co-immobilized amine dehydrogenase wh84 and glucose dehydrogenase for the highly efficient biocatalytic synthesis of chiral amino alcohols.The immobilized amine dehydrogenase wh84 exhibited better thermo-,pH and solvent stability with high activity recovery.(S)-2-aminobutan-1-ol was produced in up to 99%conversion and 99%ee in the continuous flow processes,and the space-time yields were up to 124.5 g L-1 d-1.The continuous reactions were also extended to 48 h affording up to 91.8%average conversions.This study showcased the important potential to sustainable production of chiral amino alcohols in continuous flow processes.
文摘This paper reports a comparative evaluation between 2 kinetic models for predicting nitrification and biodegradable organics(BOD5)removal rates in 5 vertical flow(VF)wetland systems,that received strong wastewaters(i.e.tannery,textile and municipal effluents).The models were formulated by combining first order and Monod kinetics,with continuous-stirred tank reactor(CSTR)flow approach.The performance of the 2 models had been evaluated with3 statistical parameters:coefficient of determination(R2),relative root mean square error(RRMSE),and model efficiency(ME).The statistical parameters indicated better performance of the Monod CSTR model(over first order CSTR approach),for correlating ammoniacal nitrogen(NH4+—N)and BOD5removal profiles across VF systems.Higher Monod coefficient values(from Monod CSTR model)coincided with greater input NH4+—N and BOD5loading,and experimentally measured removal rate(g/(m2·d))values.Such trends indicate that NH4+—N and BOD5removals in the VF systems were mainly achieved via biological routes.On the other hand,the rate constants(from the first order CSTR model)did not exhibit such correlations(of Monod coefficients),elucidating their inefficiencies in capturing overall removal mechanisms.The interference of organics removal on nitrification process(in VF wetlands)was identified through Monod coefficients.The deviation between NH4+—N and BOD5Monod coefficients imply incorporation of both coefficients,for calculating the area of a single VF bed.Overall,closer performance of the Monod CSTR model for predicting NH4+—N and BOD5removals indicate its potential application,as a design tool for VF systems.
