Oil pollution in marine environment is becoming increasingly serious. Oil bioremediation by immobilization technology has been widely studied. However, the effect of bacteria immobilization was limited because of lack...Oil pollution in marine environment is becoming increasingly serious. Oil bioremediation by immobilization technology has been widely studied. However, the effect of bacteria immobilization was limited because of lack of nutrients. In this paper, the organic materials(corn straw, corn cob and corn leaf) were used as carriers. The diesel removal rate achieved by the immobilized bacteria was studied, and the effects of nutrients(e.g. nitrogen and phosphorus) released from organic carriers to the immobilized bacteria were analyzed. Test results indicated that a certain amount of nutrients was released from organic carriers. Additionally, the diesel removal rates achieved by different immobilized bacteria were all higher than those achieved by free bacteria. And, the diesel removal rates achieved by bacteria decreased in the following order: bacteria immobilized on corn straw(79%), bacteria immobilized on corn leaf(70%) and bacteria immobilized on corn cob(43%). These findings indicated two aspects, viz.: the carriers porous structure and the nutrients, which were favorable to biodegradation. Finally, the changes in nitrogen and phosphorus contents that were released from different carriers during biodegradation were studied. The results showed that the rate of diesel biodegradation was fast in the initial phase because of the sufficient nutrients released from carriers. Meanwhile, in the final phase, the rate of diesel biodegradation was relatively slow because of few nutrients released from carriers.展开更多
On the basis of the analysis of the process of treating low concentrations of sulfur dioxide （SO2） gas in a fixed bed reactor, a kinetic model is proposed for this process after taking into consideration the effects...On the basis of the analysis of the process of treating low concentrations of sulfur dioxide （SO2） gas in a fixed bed reactor, a kinetic model is proposed for this process after taking into consideration the effects of internal diffusion, cell concentration, and production yield of microorganisms but ignoring the effect of external diffusion. The results obtained from the model simulation show that this model can indicate the influence of the process factors, Cin, η μmax, Cx, A, h, Kin, and Q, on the removal of SO2 and that the prediction of the results by this model is also satisfactory. This kinetic model can also provide some very important indications regarding the preparation of immobilized microorganisms, selection and domestication of proper species of microorganisms, as well as the design of bioreactors.展开更多
Pd-containing ionic liquid （IL） 1-hexyl-3-methylimidazolium tetrafluoroborate （C6MIMBF4） immobilized on γ-Al2O3 （Pd-IL/γ-Al2O3） was prepared and characterized by Fourier transform infrared spectroscopy （FTIR...Pd-containing ionic liquid （IL） 1-hexyl-3-methylimidazolium tetrafluoroborate （C6MIMBF4） immobilized on γ-Al2O3 （Pd-IL/γ-Al2O3） was prepared and characterized by Fourier transform infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） and Brunauer-Emmett- Teller （BET） analysis. The influences of C6MIMBF4 loading and Pd on methane conversion to C2 hydrocarbons under cold plasma were investigated. FTIR and SEM analyses indicated that C6MIMBF4 had been successfully immobilized on γ-Al2O3 and the C6MIMBF4 showed excellent stability under cold plasma. The results of BET and methane conversion showed that with the increase in immobilization amount of C6MIMBF4 onto γ-Al2O3, the specific surface area and pore volume of IL/γ-Al2O3 decreased, while the selectivity and yield of C2 hydrocarbons increased. The selectivity of C2 hydrocarbons was 94.6% when the loading of C6MIMBF4 was 40%, and the percentage of C2H4 in C2 hydrocarbons was as high as 64% when using Pd-IL/γ-Al2O3 as a catalyst with no conventional thermal reduction treatment. Optical emission spectra （OES） from the cold plasma reactor during methane conversion were also studied. The results indicated that the intensity of the C2, CH, H, and C active species from methane and hydrogen decomposition increased when IL/γ-Al2O3 or Pd-IL/γ-Al2O3 was introduced into the plasma system. Based on the analyses of the gas product and OES spectra, it can be concluded that the surface catalyzed reactions between plasma and ionic liquid were very important for the reduction of Pd2＋ and the formation of C2H4.展开更多
Photocatalyst was prepared by immobilizing TiO2 on glass beads using the traditional sol-gel method. Ultraviolet light （UV） produced by pulsed streamer discharge was then used to induce photocatalytic activity of Ti...Photocatalyst was prepared by immobilizing TiO2 on glass beads using the traditional sol-gel method. Ultraviolet light （UV） produced by pulsed streamer discharge was then used to induce photocatalytic activity of TiO2 photocatalyst. Decolouration efficiency of the representative azo dye （acid orange 7, AOT） was investigated using the synergistic system of pulsed streamer discharge plasma and TiO2 photocatalysis. The obtained results showed that the decolouration rate of AO7 could be increased by 16.7% under the condition of adding supported TiO2 in the pulsed streamer discharge system, compared to that in the sole pulsed streamer discharge plasma system, due to the synergistic effect of pulsed streamer discharge and TiO2 photocatalysis induced by pulsed streamer discharge. The synergistic system of pulsed streamer discharge and TiO2 photocatalyst was found to have more reactive radicals for degradation of organic compounds in water.展开更多
Immobilized Rhizopus oryzae culturing may be a solution to the inhibited production of L（＋）-lactic acid in submerged fermentation, which is caused by aggregated mycelia floc. In the present study, a R. oryzae muta...Immobilized Rhizopus oryzae culturing may be a solution to the inhibited production of L（＋）-lactic acid in submerged fermentation, which is caused by aggregated mycelia floc. In the present study, a R. oryzae mutant （RL6041） with a 90% conversion rate of glucose into L-lactic acid was obtained by N＋ implantation under the optimized conditions of a beam energy of 15 keV and a dose of 2.6 ×10^15 ions/cm^2. Using polyurethane foam as the immobilization matrix, the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam, 150 r/min, 50 g/L ～ 80 g/L of initial glucose, 38℃ and pH 6.0. 15-cycle repeated productions of L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditions and over 80% of the glucose was converted into L-lactic acid in 30 hours on average. The results show that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.展开更多
Production of chemicals and fuels from microcrystalline cellulose has inspired scholars’ attention. Deactivation of metallic catalysts including acid leaching and hydrothermal aggregation is still one of the core iss...Production of chemicals and fuels from microcrystalline cellulose has inspired scholars’ attention. Deactivation of metallic catalysts including acid leaching and hydrothermal aggregation is still one of the core issues in these systems. To address these problems, we designed and fabricated a series of Ni-W/SiO2 catalysts, which were decorated by CxNy species using C-and N- sources and applied in cellulose conversion to C2,3 oxygenated compounds. The Ni-W/SiO2@CxNy catalysts, underwent complexing and selfassembling process, exhibited special heterojunctions, accompanying strong interactions mainly among Ni phase and CxNy layers. Catalytic results showed that the heterojunctions and outer CxNy layers extensively enhanced productions of hydroxyacetone(HDA) and ethylene glycol(EG) and promoted the hydrothermal stability through prospering in concentration of Lewis pairs from Ni–N—N structure and immobilizing the metallic nanoclusters. 48.25% of EG was yielded under 5.0 MPa H2 pressurized 240 ℃ water for 2.0 h. The Lewis pair further improved the formation of HDA with 20.92% yield. High hydrothermal stability of NiW/SiO2@CxNy catalyst was proved according to the recycling results and trace leaching concentration of Ni and W. This construction of metallic catalysts exploited a new strategy to manufacture extraordinary durability of metallic nanoclusters for cellulose conversion under harsh reaction conditions.展开更多
In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including r...In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including reaction pH, DA concentration and enzyme concentration, a central composite response surface method was applied. The optimal condition was determined as p H value of 5.92, laccase concentration of 0.25 mg mL^(-1) and DA concentration of 12.74 mg mL^(-1), under which a high enzyme activity recovery of 88.17% was obtained.By comparing with free laccase, the stabilities of immobilized laccase towards p H, thermostability, storage were enhanced significantly.Approximately 60% of relative activity for immobilized laccase was remained after being incubated for 6 h at 50℃, but the free laccase only remained 25%. After 40 days of storage at 4℃, the laccase immobilized by DA kept about 89% of its original activity, but the free laccase only retained 48%. After recycled 10 times, the relative activity of immobilized laccase still retained 70%. The immobilized laccase was then applied to catalyze the degradation of 4-chlorophenol(4-CP), 86% percentage of 4-CP was removed within 2 h. After degraded 10 times, the relative activity of immobilized laccase still remained 64% of its initial activity, which exhibits an excellent reusability and operational stability.展开更多
Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co...Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co TPP and the porphyrin structure are the major factors that have significant effects on the catalytic performance of the electrode.As confirmed by spectrophotometric titration,pyridine has a stronger coordination bond to Co TPP than DMF and THF thus leading to the highest efficiency among the dropcasting solvents tested in the study.Based on the spectrophotometric analysis,possible coordination mechanism between drop-casting solvents and Co TPP is put forward.On the other hand,introduction of-COOMe substituents in phenyl rings of Co TPP weakens the coordination bond between pyridine and Co TPP as clearly evidenced by deuterium NMR spectra,resulting in a detrimental effect on CO_(2) ERR.Therefore,the manipulation of the coordination environment around the metal center of immobilized catalyst is crucial in designing an efficient electrocatalytic system.展开更多
Experimental studies were carried out on the purification of eutrophicTaihu Lake water by dynamic experiment using immobilized nitrogen cycle bacteria(INCB). The results showed that the eutrophic water of Taihu Lake c...Experimental studies were carried out on the purification of eutrophicTaihu Lake water by dynamic experiment using immobilized nitrogen cycle bacteria(INCB). The results showed that the eutrophic water of Taihu Lake can be purifiedeffectively as it passes through the experimental reactor into which some immobilizednitrogen cycle bacteria were put. The removal efficiencies for Total N (TN), NH4+-Nwith immobilized nitrogen cycle bacteria were 72.4% and 85.6%, respectively. It wasfound that the immobilized nitrogen cycle bacteria also have purificatory effect oneutrophic water of Taihu Lake at winter temperature (7°C), and that the removalmefficiencies for Total N (TN), NH4+-N were 55.6%, and 58.9%, respectively. Theremoval efficiencies for TN and NH4+-N depend on the time the water stays in theexperimental reactor.展开更多
In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized b...In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized by radiation technique at low temperature (-78℃) and several kinds of copolymer carriers were obtained. Yeast cells were immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The etharol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg /( ml·h), which was 4 times as high as that of free cells. In this study, the effect of adding of crosslinking reagent (4G) in copolymer on activity of yeast cells immobilized with the carriers were also studied. It was found that the effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work.展开更多
Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter...Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.展开更多
The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters wer...The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters were optimized by using the respond surface methodology(RSM). The corrosion inhibition performance of co-immobilized lipase and lysozyme was evaluated by weight loss measurements and electrochemical measurements. The results revealed that the optimal co-immobilization method should be the sequential immobilization of lysozyme and then lipase. The inhibition efficiency was 86.10% under the optimal co-immobilized conditions. Electrochemical data showed that co-immobilized lysozyme and lipase was a mixed-type inhibitor and the corrosion inhibition efficiency was 81%.展开更多
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
In order to improve the stability and corrosion inhibition performance of bioenzyme, lipase and lsozyme were co-immobilized on the mesoporous molecular sieve MCM-41 by the adsorption method. Then the immobilized enzym...In order to improve the stability and corrosion inhibition performance of bioenzyme, lipase and lsozyme were co-immobilized on the mesoporous molecular sieve MCM-41 by the adsorption method. Then the immobilized enzymes were combined with amino trimethylene phosphonic acid and polyaspartic acid to prevent corrosion caused by circulating cooling water. The weight-loss method and electrochemical techniques were used to evaluate the performance of composite inhibitors. The co-immobilized lysozyme and lipase achieved good inhibition effects. After they were combined with amino trimethylene phosphonic acid and polyaspartic acid, the corrosion inhibition properties were further improved. The inhibition efficiency was promoted to 94.4%. During the corrosion inhibition process, the immobilized enzymes played an important role. The addition of corrosion inhibitor could inhibit the anodic dissolution and cathodic hydrogen evolution process of carbon steel at the same time. The adsorption of co-immobilized lysozyme and lipase composite inhibitor on the steel surface was a joint action involving physical adsorption and chemical adsorption.展开更多
Compared to the algal oxidation pond, treatment of wastewater using the immobilized algal cell technology has excellent effect, which not only can effectively avoid the disadvantage of oxidation pond, but can also rem...Compared to the algal oxidation pond, treatment of wastewater using the immobilized algal cell technology has excellent effect, which not only can effectively avoid the disadvantage of oxidation pond, but can also remarkably improve the efficiency of treating system and the effluent quality. When the treating system operates umder an optimal control conditions, such as a 55% loading rate, an illumination intensity of 2500-3500 lux and a hydraulic residence time of 4 hours, the COD and ammonia nitrogen removal can reach 90%. Water after deep treatment can comply with the requirement of the refinery for the quality of recycled water.展开更多
Metal-organic frameworks(MOFs)have attracted considerable research attention as a new type of porous material for catalytic applications.Herein,2,5-dihydroxyterephthalic acid was proposed to replace conventional terep...Metal-organic frameworks(MOFs)have attracted considerable research attention as a new type of porous material for catalytic applications.Herein,2,5-dihydroxyterephthalic acid was proposed to replace conventional terephthalic acid and reacted with chromic nitrate nonahydrate to synthesize a functional metal–organic framework(FMIL-101).This was then used to immobilize various compound ionic liquids to prepare three ionic liquids immobilized on FMIL-101 catalysts,namely,FMIL-101-[HeMIM]Cl/(ZnBr_(2))_(2),FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),and FMIL-101-[AeMIM]Br/(ZnBr_(2))_(2).After characterization by Fourier-transform infrared spectroscopy,X-ray diffraction,ultraviolet spectroscopy,thermogravimetry,specific surface area analysis,and scanning electron microscopy,the catalysts were used to mediate cycloaddition reactions between carbon dioxide(CO_(2))and propylene oxide.The effects of reaction temperature,reaction pressure,reaction time,and catalyst dosage on the catalytic performance were investigated.The results revealed that the FMIL-101-supported CIL catalysts afforded the target product propylene carbonate with good catalytic performance and thermal stability.The optimal catalyst,FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),displayed a propylene oxide conversion of 98.64%and a propylene carbonate selectivity of 96.63%at a reaction temperature of 110℃,a reaction pressure of 2.0 MPa,a catalyst dosage of 2.0%relative to propylene oxide,and a reaction time of 2.5 h.In addition,the conversion and selectivity of the catalyst decreased slightly after four cycles.Additionally,the catalyst decreased slightly in catalytic performance after being recycled four times.展开更多
This paper theoretically studies the continuous immobilized cell (IMC) fer mentation system. A kinetic model of IMC is established, and the relational expressions between production rate, substrate concentration, biom...This paper theoretically studies the continuous immobilized cell (IMC) fer mentation system. A kinetic model of IMC is established, and the relational expressions between production rate, substrate concentration, biomass concentration and dilution rate in the IMC continuous stirred tank reactor (CSTR) are derived. These equations and some numerical calculations show that as compared with the free cell system the IMC system has many advantages: high production rate, steady operation, and being independent of the dilution rote. They also indicate that the diffusion of substrate is a constraint to the production of metablite.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 51408347, 51474140)the Scientific Research Fund Project of Introduced Talents (2014RCJJ015)+1 种基金Young Teachers Taleuts Training Plan (BJRC20170502) of Shandong University of Science and Technologythe Science and Technology Projects of Qingdao (Grant No. 15-9-1-58-jch and 15-9-1-32-jch)
文摘Oil pollution in marine environment is becoming increasingly serious. Oil bioremediation by immobilization technology has been widely studied. However, the effect of bacteria immobilization was limited because of lack of nutrients. In this paper, the organic materials(corn straw, corn cob and corn leaf) were used as carriers. The diesel removal rate achieved by the immobilized bacteria was studied, and the effects of nutrients(e.g. nitrogen and phosphorus) released from organic carriers to the immobilized bacteria were analyzed. Test results indicated that a certain amount of nutrients was released from organic carriers. Additionally, the diesel removal rates achieved by different immobilized bacteria were all higher than those achieved by free bacteria. And, the diesel removal rates achieved by bacteria decreased in the following order: bacteria immobilized on corn straw(79%), bacteria immobilized on corn leaf(70%) and bacteria immobilized on corn cob(43%). These findings indicated two aspects, viz.: the carriers porous structure and the nutrients, which were favorable to biodegradation. Finally, the changes in nitrogen and phosphorus contents that were released from different carriers during biodegradation were studied. The results showed that the rate of diesel biodegradation was fast in the initial phase because of the sufficient nutrients released from carriers. Meanwhile, in the final phase, the rate of diesel biodegradation was relatively slow because of few nutrients released from carriers.
基金This project was supported by the National Natural Science Foundation of China (2003E0027M)
文摘On the basis of the analysis of the process of treating low concentrations of sulfur dioxide （SO2） gas in a fixed bed reactor, a kinetic model is proposed for this process after taking into consideration the effects of internal diffusion, cell concentration, and production yield of microorganisms but ignoring the effect of external diffusion. The results obtained from the model simulation show that this model can indicate the influence of the process factors, Cin, η μmax, Cx, A, h, Kin, and Q, on the removal of SO2 and that the prediction of the results by this model is also satisfactory. This kinetic model can also provide some very important indications regarding the preparation of immobilized microorganisms, selection and domestication of proper species of microorganisms, as well as the design of bioreactors.
基金supported by the National Science Foundation of China(No.20973028)
文摘Pd-containing ionic liquid （IL） 1-hexyl-3-methylimidazolium tetrafluoroborate （C6MIMBF4） immobilized on γ-Al2O3 （Pd-IL/γ-Al2O3） was prepared and characterized by Fourier transform infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） and Brunauer-Emmett- Teller （BET） analysis. The influences of C6MIMBF4 loading and Pd on methane conversion to C2 hydrocarbons under cold plasma were investigated. FTIR and SEM analyses indicated that C6MIMBF4 had been successfully immobilized on γ-Al2O3 and the C6MIMBF4 showed excellent stability under cold plasma. The results of BET and methane conversion showed that with the increase in immobilization amount of C6MIMBF4 onto γ-Al2O3, the specific surface area and pore volume of IL/γ-Al2O3 decreased, while the selectivity and yield of C2 hydrocarbons increased. The selectivity of C2 hydrocarbons was 94.6% when the loading of C6MIMBF4 was 40%, and the percentage of C2H4 in C2 hydrocarbons was as high as 64% when using Pd-IL/γ-Al2O3 as a catalyst with no conventional thermal reduction treatment. Optical emission spectra （OES） from the cold plasma reactor during methane conversion were also studied. The results indicated that the intensity of the C2, CH, H, and C active species from methane and hydrogen decomposition increased when IL/γ-Al2O3 or Pd-IL/γ-Al2O3 was introduced into the plasma system. Based on the analyses of the gas product and OES spectra, it can be concluded that the surface catalyzed reactions between plasma and ionic liquid were very important for the reduction of Pd2＋ and the formation of C2H4.
基金supported by the National Natural Science Foundation Committee of China(No.20377006)Foundation of Education Ministry of China(No.2005141002)
文摘Photocatalyst was prepared by immobilizing TiO2 on glass beads using the traditional sol-gel method. Ultraviolet light （UV） produced by pulsed streamer discharge was then used to induce photocatalytic activity of TiO2 photocatalyst. Decolouration efficiency of the representative azo dye （acid orange 7, AOT） was investigated using the synergistic system of pulsed streamer discharge plasma and TiO2 photocatalysis. The obtained results showed that the decolouration rate of AO7 could be increased by 16.7% under the condition of adding supported TiO2 in the pulsed streamer discharge system, compared to that in the sole pulsed streamer discharge plasma system, due to the synergistic effect of pulsed streamer discharge and TiO2 photocatalysis induced by pulsed streamer discharge. The synergistic system of pulsed streamer discharge and TiO2 photocatalyst was found to have more reactive radicals for degradation of organic compounds in water.
基金Key 863 fund of China(No.2006AA020102)the Key Technologies Research and Development Programme of Anhui Province(07010202076)
文摘Immobilized Rhizopus oryzae culturing may be a solution to the inhibited production of L（＋）-lactic acid in submerged fermentation, which is caused by aggregated mycelia floc. In the present study, a R. oryzae mutant （RL6041） with a 90% conversion rate of glucose into L-lactic acid was obtained by N＋ implantation under the optimized conditions of a beam energy of 15 keV and a dose of 2.6 ×10^15 ions/cm^2. Using polyurethane foam as the immobilization matrix, the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam, 150 r/min, 50 g/L ～ 80 g/L of initial glucose, 38℃ and pH 6.0. 15-cycle repeated productions of L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditions and over 80% of the glucose was converted into L-lactic acid in 30 hours on average. The results show that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.
基金financially supported by the Natural Science Foundation of Zhejiang Province of China(No.LY19B060002)the Enterprise Research Programme by Huzhou City of Zhejiang Province(China)founded by Huzhou Municipal Government(20190040)。
文摘Production of chemicals and fuels from microcrystalline cellulose has inspired scholars’ attention. Deactivation of metallic catalysts including acid leaching and hydrothermal aggregation is still one of the core issues in these systems. To address these problems, we designed and fabricated a series of Ni-W/SiO2 catalysts, which were decorated by CxNy species using C-and N- sources and applied in cellulose conversion to C2,3 oxygenated compounds. The Ni-W/SiO2@CxNy catalysts, underwent complexing and selfassembling process, exhibited special heterojunctions, accompanying strong interactions mainly among Ni phase and CxNy layers. Catalytic results showed that the heterojunctions and outer CxNy layers extensively enhanced productions of hydroxyacetone(HDA) and ethylene glycol(EG) and promoted the hydrothermal stability through prospering in concentration of Lewis pairs from Ni–N—N structure and immobilizing the metallic nanoclusters. 48.25% of EG was yielded under 5.0 MPa H2 pressurized 240 ℃ water for 2.0 h. The Lewis pair further improved the formation of HDA with 20.92% yield. High hydrothermal stability of NiW/SiO2@CxNy catalyst was proved according to the recycling results and trace leaching concentration of Ni and W. This construction of metallic catalysts exploited a new strategy to manufacture extraordinary durability of metallic nanoclusters for cellulose conversion under harsh reaction conditions.
基金support from the National Natural Science Foundation of China(Grant Nos.51378487,51425405,21376249,21336010)Youth Innovation Promotion Association,CAS(2014037)973 Program(2013CB733604)
文摘In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including reaction pH, DA concentration and enzyme concentration, a central composite response surface method was applied. The optimal condition was determined as p H value of 5.92, laccase concentration of 0.25 mg mL^(-1) and DA concentration of 12.74 mg mL^(-1), under which a high enzyme activity recovery of 88.17% was obtained.By comparing with free laccase, the stabilities of immobilized laccase towards p H, thermostability, storage were enhanced significantly.Approximately 60% of relative activity for immobilized laccase was remained after being incubated for 6 h at 50℃, but the free laccase only remained 25%. After 40 days of storage at 4℃, the laccase immobilized by DA kept about 89% of its original activity, but the free laccase only retained 48%. After recycled 10 times, the relative activity of immobilized laccase still retained 70%. The immobilized laccase was then applied to catalyze the degradation of 4-chlorophenol(4-CP), 86% percentage of 4-CP was removed within 2 h. After degraded 10 times, the relative activity of immobilized laccase still remained 64% of its initial activity, which exhibits an excellent reusability and operational stability.
基金Financial support from the ARC Discovery Project(DP1901013720)。
文摘Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co TPP and the porphyrin structure are the major factors that have significant effects on the catalytic performance of the electrode.As confirmed by spectrophotometric titration,pyridine has a stronger coordination bond to Co TPP than DMF and THF thus leading to the highest efficiency among the dropcasting solvents tested in the study.Based on the spectrophotometric analysis,possible coordination mechanism between drop-casting solvents and Co TPP is put forward.On the other hand,introduction of-COOMe substituents in phenyl rings of Co TPP weakens the coordination bond between pyridine and Co TPP as clearly evidenced by deuterium NMR spectra,resulting in a detrimental effect on CO_(2) ERR.Therefore,the manipulation of the coordination environment around the metal center of immobilized catalyst is crucial in designing an efficient electrocatalytic system.
基金Supported by European Union[Contract No.CI1*-CT93-0094(DG 12 HSMU)],also by the social development project of Jiangsu Province,China(No.BS99021)
文摘Experimental studies were carried out on the purification of eutrophicTaihu Lake water by dynamic experiment using immobilized nitrogen cycle bacteria(INCB). The results showed that the eutrophic water of Taihu Lake can be purifiedeffectively as it passes through the experimental reactor into which some immobilizednitrogen cycle bacteria were put. The removal efficiencies for Total N (TN), NH4+-Nwith immobilized nitrogen cycle bacteria were 72.4% and 85.6%, respectively. It wasfound that the immobilized nitrogen cycle bacteria also have purificatory effect oneutrophic water of Taihu Lake at winter temperature (7°C), and that the removalmefficiencies for Total N (TN), NH4+-N were 55.6%, and 58.9%, respectively. Theremoval efficiencies for TN and NH4+-N depend on the time the water stays in theexperimental reactor.
基金This research projcct was financed by applied base research fund of jiangsu provicial Scicntific and Tcchniquuc Committee from 1989-1991
文摘In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized by radiation technique at low temperature (-78℃) and several kinds of copolymer carriers were obtained. Yeast cells were immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The etharol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg /( ml·h), which was 4 times as high as that of free cells. In this study, the effect of adding of crosslinking reagent (4G) in copolymer on activity of yeast cells immobilized with the carriers were also studied. It was found that the effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work.
基金supported by the Foundation for Top Talents Program of China University of Petroleum
文摘Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.
基金financially supported by the National Natural Science Foundation of China (project 21077133)the Natural Foundation of Shandong Province and the Top Talent Project of China University of Petroleum (16RC17040003)
文摘The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters were optimized by using the respond surface methodology(RSM). The corrosion inhibition performance of co-immobilized lipase and lysozyme was evaluated by weight loss measurements and electrochemical measurements. The results revealed that the optimal co-immobilization method should be the sequential immobilization of lysozyme and then lipase. The inhibition efficiency was 86.10% under the optimal co-immobilized conditions. Electrochemical data showed that co-immobilized lysozyme and lipase was a mixed-type inhibitor and the corrosion inhibition efficiency was 81%.
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financially supported by Shandong Natural Science Foundation (ZR201702140013)
文摘In order to improve the stability and corrosion inhibition performance of bioenzyme, lipase and lsozyme were co-immobilized on the mesoporous molecular sieve MCM-41 by the adsorption method. Then the immobilized enzymes were combined with amino trimethylene phosphonic acid and polyaspartic acid to prevent corrosion caused by circulating cooling water. The weight-loss method and electrochemical techniques were used to evaluate the performance of composite inhibitors. The co-immobilized lysozyme and lipase achieved good inhibition effects. After they were combined with amino trimethylene phosphonic acid and polyaspartic acid, the corrosion inhibition properties were further improved. The inhibition efficiency was promoted to 94.4%. During the corrosion inhibition process, the immobilized enzymes played an important role. The addition of corrosion inhibitor could inhibit the anodic dissolution and cathodic hydrogen evolution process of carbon steel at the same time. The adsorption of co-immobilized lysozyme and lipase composite inhibitor on the steel surface was a joint action involving physical adsorption and chemical adsorption.
文摘Compared to the algal oxidation pond, treatment of wastewater using the immobilized algal cell technology has excellent effect, which not only can effectively avoid the disadvantage of oxidation pond, but can also remarkably improve the efficiency of treating system and the effluent quality. When the treating system operates umder an optimal control conditions, such as a 55% loading rate, an illumination intensity of 2500-3500 lux and a hydraulic residence time of 4 hours, the COD and ammonia nitrogen removal can reach 90%. Water after deep treatment can comply with the requirement of the refinery for the quality of recycled water.
基金supported by the National Natural Science Foundation of China (Grant No.22278271)the Key Project of Education Department of Liaoning Province(Grant No.LZGD2020005)
文摘Metal-organic frameworks(MOFs)have attracted considerable research attention as a new type of porous material for catalytic applications.Herein,2,5-dihydroxyterephthalic acid was proposed to replace conventional terephthalic acid and reacted with chromic nitrate nonahydrate to synthesize a functional metal–organic framework(FMIL-101).This was then used to immobilize various compound ionic liquids to prepare three ionic liquids immobilized on FMIL-101 catalysts,namely,FMIL-101-[HeMIM]Cl/(ZnBr_(2))_(2),FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),and FMIL-101-[AeMIM]Br/(ZnBr_(2))_(2).After characterization by Fourier-transform infrared spectroscopy,X-ray diffraction,ultraviolet spectroscopy,thermogravimetry,specific surface area analysis,and scanning electron microscopy,the catalysts were used to mediate cycloaddition reactions between carbon dioxide(CO_(2))and propylene oxide.The effects of reaction temperature,reaction pressure,reaction time,and catalyst dosage on the catalytic performance were investigated.The results revealed that the FMIL-101-supported CIL catalysts afforded the target product propylene carbonate with good catalytic performance and thermal stability.The optimal catalyst,FMIL-101-[CeMIM]Cl/(ZnBr_(2))_(2),displayed a propylene oxide conversion of 98.64%and a propylene carbonate selectivity of 96.63%at a reaction temperature of 110℃,a reaction pressure of 2.0 MPa,a catalyst dosage of 2.0%relative to propylene oxide,and a reaction time of 2.5 h.In addition,the conversion and selectivity of the catalyst decreased slightly after four cycles.Additionally,the catalyst decreased slightly in catalytic performance after being recycled four times.
文摘This paper theoretically studies the continuous immobilized cell (IMC) fer mentation system. A kinetic model of IMC is established, and the relational expressions between production rate, substrate concentration, biomass concentration and dilution rate in the IMC continuous stirred tank reactor (CSTR) are derived. These equations and some numerical calculations show that as compared with the free cell system the IMC system has many advantages: high production rate, steady operation, and being independent of the dilution rote. They also indicate that the diffusion of substrate is a constraint to the production of metablite.
